The reaction of porphyrins with organolithium reagents

FULL PAPER

The Reaction of Porphyrins with Organolithium Reagents

Mathias O. Senge,* Werner W. Kalisch, and Ines Bischoff^[a]

Abstract: Porphyrins react readily with

organolithium reagents, preferentially in

the meso positions. The overall reaction

is a nucleophilic substitution and pro-

ceeds via initial reaction of the organic

nucleophile with a meso carbon yielding

an anionic species which is hydrolyzed

to a porphodimethene (5,15-dihydropor-

phyrin), formally constituting an addi-

tion reaction to two C_mpositions. Sub-

sequent oxidation with 2,3-dichloro-5,6-

dicyano-1,4-benzoquinone (DDQ) yields

meso-substituted porphyrins. The reac-

tion is highly versatile as it is accom-

plished in high, often quantitative yields

with various alkyl or aryl lithium re-

agents. In addition, LiR can be used for

reaction with a variety of metal com-

plexes (best with Ni^II, but also with Zn^II,

Cu^II, and Co^II) and most useful with free

base porphyrins. Similarly beneficial this

reaction can be used in sequence for the

introduction of 1, 2, 3, or 4 (different)

meso substituents giving for the first

time an entry into any desired meso-

substituted porphyrin. If meso-substitut-

ed porphyrins are used, reaction with

LiR can be used for either the prepara-

tion of phlorins (already known reac-

tion), porphodimethenes (5,15-dihydro-

porphyrins, including those with exocy-

clic double bonds, for example, 5¹,5²-

didehydroporphyrins) or chlorins (2,3-

dihydroporphyrins) depending on the

substituent type in the reactant porphyr-

ins. Thus, this reaction presents a gen-

erally applicable method for the facile

and versatile functionalization of por-

phyrins.

À

Keywords: alkylations ´ C Ccou-

pling ´ lithium ´ nucleophilic aro-

matic substitutions ´ porphyrinoids

modification of preformed porphyrins. As symmetric por-

phyrins like 5,10,15,20-tetraphenylporphyrin {H₂(TPP) 1a}^[9a]

or 2,3,7,8,12,13,17,18-octaethylporphyrin {H₂(OEP) 2a}^[9b]are

easily prepared in large amounts, a subsequent modification

of these compounds to more complex, asymmetrically func-

tionalized porphyrins would be highly beneficial. A total

synthesis of an OEP derivative with one additional meso

substituent or a TPP derivative with an additional b sub-

stituent, although possible, is often impractical, especially

when the desired target compound contains more than two

different types of meso- and b substituents. Existing methods

for such synthetic strategies, which are in high demand due to

the above-described developments, require highly involved

pyrrole and dipyrrin chemistry, followed by appropriate

[22]- or [31]-condensation reactions or cyclizations.^[10]

Ideally, syntheses of complex porphyrins should involve easily

available reagents, proceed with both high regiospecifity and

yield and preferably involve reactions that, once established

in a laboratory, can easily be applied to various educts and

used for the introduction of highly divergent residues.

Introduction

Porphyrins have been the focus of intense chemical studies for

almost a century beginning with the comprehensive studies of

Willstätter^[1]and Fischer.^[2]Since then a considerable body of

chemical knowledge has been accumulated.^{[3, 4]}This is not

only a result of their biological functions, which can be

investigated with modern instruments in greater detail, but

also of their relevance for understanding basic physicochem-

ical processes like electron and exciton transfer. In addition,

tetrapyrroles in general have potential technical use in the

area of solar energy conversion,^[5]catalysis,^[6]nonlinear

optics,^[7]and an increasing number of medicinal applications,^[8]

including their use as photosensibilisators, fluorescence

markers, and antitumor (PDT), or antiviral (PVT) agents,

are being reported.

Despite their importance, the development of novel

synthetic methods for tetrapyrroles has not been in step with

the demand for more complex porphyrin systems coming

from the applied and biological area. Indeed, several white

specks remain on the porphyrin synthesis and modification

map. One such case involves the lack of methods for the facile

Unfortunately, porphyrins have proven to be very resilient

towards many reactions that on paper should proceed quite

easily, for example, Friedel ± Crafts or Grignard reactions.^[11]

Several electrophilic substitution reactions^[12]have been

described over the years,^[11]including meso methylation of

Pd^II(OEP),^[13a]reaction of porphyrins with carbenes,^[13b]re-

arrangements of N-substituted porphyrins,^[14a]reductive pro-

[a] Priv.-Doz. Dr. M. O. Senge, Dr. W. W. Kalisch, I. Bischoff

Institut für Chemie, Organische Chemie

Freie Universität Berlin, Takustrasse 3, 14195 Berlin (Germany)

Fax : (49)30-838-4248

E-mail: mosenge@chemie.fu-berlin.de

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Results and Discussion

Reaction of LiR with 2,3,7,8,12,13,17,18-octaalkylporphyrins:

Initially, we attempted the preparation of Grignard com-

pounds starting with the 5-halogeno-2,3,7,8,12,13,17,18-octae-

thylporphyrins,^[29]but never observed any change in the

starting material. As organolithium compounds are more

reactive we then attempted an halogeno-metal exchange.

Reaction of (5-bromo-2,3,7,8,12,13,17,18-octaethylporphyri-

nato)nickel(ii)^[30]with n-butyl lithium (BuLi) in dry THF

resulted in the formation of several very apolar, lightly

colored products. Addition of benzaldehyde, to trap a

putative organolithium porphyrin, did not change the reaction

products. UV/Vis spectroscopy of the reaction mixture

indicated the presence of a porphodimethene (l_maxin

CH₂Cl₂ 446 and 554 nm). For work up the reaction mixture

was hydrolyzed with water and filtered through neutral

alumina, which retained several polar, blue fractions. The

filtrate consisted mainly of an intensively red colored fraction,

with absorption maxima indicative of a porphyrin (l_maxin

CH₂Cl₂ 414 and 580 nm). Thin-layer chromatography

showed this fraction to consist of two individual compounds,

which could not be separated by chromatography.^[31]

For more detailed studies we then performed similar

reactions with Ni^II(OEP) 2b treating it with various amounts

of BuLi. Utilization of about four equivalents of BuLi with

respect to the porphyrin resulted in formation of a lightly

yellow colored solution which, upon contact with atmospheric

oxygen, immediately turned brightly red (l_maxin CH₂Cl₂ 410

and 572 nm). Spectroscopic analysis revealed the product to

be the monobutylated porphyrin (5-butyl-2,3,7,8,12,13,17,18-

octaethylporphyrinato)nickel(ii) (3a). Hydrolysis of the reac-

tion mixture at low temperatures followed by subsequent

addition of an excess of DDQ resulted in complete oxidation

of the intermediate to the porphyrin giving 3a in quantitative

yield (Scheme 1). Use of a larger excess of BuLi resulted in

increased yields of several polar, blue products, presumably

ring-opened tetrapyrroles.

tonation,^[14b]and Buchlerꢁs reductive methylation.^[15]Of the

older reactions, the most widely used reaction is the Vilsmeier

formylation which continues to be a convenient entry reaction

into many other porphyrin derivatives.^[16]Similarly, nitrati-

on,^[17a±c]nitrene,^[17d]and thiocyanation^[17e]reactions have been

described.^[18]Of greater importance is the use of halogenation

reactions,^[18]notably chlorination and bromination in both the

meso- and b positions.^[6]Halogenated porphyrins are of consid-

erable importance in catalytic applications^[6]and have been

À

used in recent years as entry points for modern C Ccoupling

reactions,^[19]for example, Heck-^[19a]and Suzuki^[19b]reactions.

Similarly, only few examples for nucleophilic addition or

substitution reactions have been described for porphyrins.^[13]

While porphyrins are easily reduced by electrons to the phlorins

or chlorins,^[20]their reactivity towards nucleophiles has only been

studied rather randomly. For example, Zn^II(OEP) p-cation

radicals and p dications,^[21a]or Fe^III(TPP) p-cation radicals^[21b]

have been shown to react with nucleophiles, and several

examples for use of activated porphyrins in S_Nreactions have

been given. Activation can be achieved either via electron-

withdrawing substituents (e.g., NO₂,^{[17b, 22]}formyl,^[23]) appro-

priate central metals (Rh or Au),^[24]or steric effects.^{[25, 26]}In

practical terms, with the exception of the alkyne-substituted

porphyrins,^[19d]synthetically useful is only the reaction of

meso-brominated metalloporphyrins with organotin or orga-

nozinc reagents. For example, 5,15-dibromo-10,20-diarylpor-

phyrins could be converted in almost quantitative yield to the

5,15-disubstituted porphyrins.^[27]The reactions mentioned,

either require modification of the porphyrin, are limited with

regard to the type and number of substituents that can be

introduced or proceed under irreversible formation of non-

aromatic systems or often give only low yields.

As to date no general method exists for the direct meso

substitution of unactivated porphyrins with alkyl or aryl

residues or for the introduction of more than two meso

substituents we have undertaken a comprehensive investiga-

tion of the reactivity of the porphyrin system towards

organometallic reagents. As will be shown below, organo-

lithium reagents present a class of reagents that fulfill all the

criteria listed above and can be used to introduce, often

quantitatively, almost any desired residue into the porphyr-

in.^[28]

Scheme 1. meso Monofunctionalization of (metallo)octaethylporphyrins.

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Porphyrins

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On the basis of these observations we surmised the

following mechanism. First, reaction of 2b with BuLi pro-

ceeds via addition of BuLi at two meso positions, giving a

Meisenheimer-type complex 4 (a phlorin in porphyrin termi-

nology) that is hydrolyzed by water to the porphodimethene 5

which in turn is oxidized to the porphyrin 3a (Scheme 2).

Thus, formally, BuLi reacts under nucleophilic substitution

with Ni^II(OEP), presumably via an addition ± oxidation mech-

anism (Scheme 2) akin to the Ziegler reaction.^[32]

In a similar manner, introduction of protected alcohol

functionalities is possible. For example, the ether 3g was

prepared in 60% yield using 4-phenoxybutyl lithium. The

lithium reagents were prepared from the corresponding

halogeno derivatives with di-tert-butylbiphenyllithium^[35]and

used immediately for reaction with Ni^II(OEP) (5 ± 10 equiv).

Similar to the versatility of alkyl lithium reagents for the

modification of porphyrins aryl lithium reagents could be used

with ease. Treatment of 2b with phenyl lithium gave the meso-

phenylated porphyrin 3h in 65% yield. Aryl lithium reagents

gave meso-functionalized porphyrins amenable for further

transformations. For example, the p-bromophenyl substituted

porphyrin 3j, suitable for a variety of further organometallic

coupling reactions, was obtained in 40% yield using p-

bromophenyllithium.^[36]Use of 2,5-dimethoxyphenyllithi-

um^[37]gave the porphyrin 3k, formally a protected p-quinone,

suitable starting materials for entry into donor± acceptor

complexes.

As shown, one meso substituent can be introduced into the

porphyrin macrocycle in high yield, a reaction applicable to a

wide variety of substrates. Thus, the question arose whether

such a reaction can be repeated with the same starting

porphyrin, that is, if introduction of 2-, 3-, or 4-meso

substituents is possible. Potentially, such a sequence would

allow a novel entry into dodecasubstituted nonplanar por-

phyrins. Thus, the monobutylated porphyrin 3a was again

treated with BuLi, the intermediate hydrolyzed with water,

and oxidized with DDQ. Two different reaction products were

observed, which were identified as the two regioisomers 6 and

7, that is the Ni^IIporphyrins with either 5,15-or 5,10-

disubstitution pattern. Intriguingly, the ªcisº (5,10)-dibuty-

lated product 7 was obtained in 70% yield compared with

15% for the ªtransº (5,15)-disubstituted porphyrin 6. This

preference for attack in the neighboring meso position (over

the statistical ratio of 2:1) appears to be a general phenom-

enon and has been observed by us for a variety of lithium

reagents.

Tri- and tetrabutylated porphyrins are accessible by this

method, as well. Reaction of either 6 or 7, or the regioisomeric

mixture gave the 5,10,15-tributyl porphyrin 8, again in

quantitative yields. Use of 8 for another substitution reaction

with BuLi yields the tetra-meso substituted porphyrin 9 in

50% yield (see Scheme 3). The remainder of the starting

material was converted to the porphodimethene 10 (see

below). The porphyrin 9 is a highly symmetric compound.

This is evidenced in the ¹³C-NMR spectrum that shows six

aliphatic signals between d 10 and 40; the C_mcarbon atoms

show a signal at d 116.59, while the remaining 16 carbon

atoms of the aromatic ring systems give two signals at d

135.85 and 146.48, respectively. Technically, the reaction of

meso-butylated porphyrins is easier than that of for example

2b as the solubility increases with the introduction of more

and more alkyl chains. As expected, the polarity decreases

drastically with the number of butyl chains; compound 9 is

almost apolar, soluble only in hexane and purification

requires neutral alumina and elution with neat hexane.

This sequence for four subsequent addition ± oxidation

cycles allows, for the first time, a synthesis of sterically

hindered dodecaalkylporphyrins. Sterically strained porphyr-

Scheme 2. Putative mechanism for the reaction of Ni^II(OEP) with BuLi.

In order to test the general applicability we first inves-

tigated the use of different metal complexes of OEP. The Zn^II,

II

Cu^II, C o, and Fe^IIICl complexes of OEP (2c ± f) were

prepared and treated with BuLi under the conditions

described for Ni^II(OEP). Zn^II(OEP) 2c gave the monobuty-

lated product 3b in 40% yield, however, the reaction with

Zn^IIcomplex always proceeded under almost complete

II

demetallation to the corresponding free base 3c. C u(OEP)

2d gave 3d in 75% yield, while Co^II(OEP) 2e was converted

into 3e in 40% yield. Use of Fe^III(OEP)Cl 2 f resulted only in

the observation of various degradation products, no butyla-

tion of the porphyrin was observed. Generally, most metal

complexes are suitable reactants for this reaction although

yields were lower compared to Ni^II(OEP). Use of metal

complexes like Zn^II(OEP) offers the advantage of higher

solubility compared to 2b, while reaction with Cu^II(OEP),

despite the satisfactory yield, suffers from the low solubility of

the starting material. Thus, Ni^IIcomplexes were used for most

other transformations.^[33]

The ease of the reaction with BuLi suggested that a wide

variety of alkyl lithium reagents might be applicable to the

functionalization of porphyrins. Indeed, any alkyl or aryl

lithium compound tested gave at least satisfactory if not

excellent yields of meso substitution. For example, 2b was

treated with 2-(1,2-dioxane-2-yl)ethyl lithium to the protected

aldehyde 3 f in 70% yield. After deprotection, this compound

can be used for a variety of further modification reactions.^[34]

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FULL PAPER

tion attempts to the desired

porphyrin. This problem has

now been overcome with the

present methodology.

In addition, the present study

gives some indication on the

problem involved with the oxi-

dation resistance of sterically

hindered porphodimethenes.

As mentioned above, reaction

of the highly nonplanar por-

phyrin 8 with BuLi gave the

porphyrin 9 in only 50% yield,

while all other reactions involv-

ing BuLi proceeded almost

quantitatively to the desired

porphyrins. Most of the remain-

ing starting material was con-

verted into the porphodime-

thene 10 that showed syn-axial

orientation of the two meso-

hydrogen atoms. This tetrapyr-

role was stable against oxidants

such as air, DDQ, Br₂, or p-

Scheme 3. Successive meso butylation of Ni^II(OEP). a) 1) BuLi, THF, À808C , 2) HO, 3) DDQ; b) 1) BuLi,

2

THF, À1008C , 2) HO, 3) DDQ. Numbers underneath formulas give main absorption maxima in CH₂Cl₂.

2

ins have become of prime interest in the last decade, as

macrocycle conformational effects have been shown to be

involved in the control of cofactor properties in intact

pigment ± protein complexes.^{[18, 38]}Indeed, the majority of

tetrapyrrole cofactors in vivo exhibits more or less distorted

macrocycle conformations.^{[18, 38b,c]}So-called highly substituted

porphyrins^[38]have found wide applications in the study of the

conformational control of physicochemical properties and

wide-ranging studies have been presented on nonplanar

porphyrins.^[38a]While several different distortion modes are

possible for porphyrins, the two most widely found types of

nonplanar porphyrins are macrocycles with either saddle-type

or ruffled distortion modes.^[38e]In the case of model com-

pounds, the former is easily accessible by preparation of for

example 5,10,15,20-tetraaryl-2,3,7,8,12,13,17,18-octaalkyl/ar-

ylporphyrins.^[39]Ruffled macrocycles have been observed as

the result of metal effects,^[38e]and for porphyrins with bulky

meso-alkyl substituents.^{[26, 40]}

chloranil, even using elevated reaction temperatures. The

configuration at the sp³-hybridized meso carbon atoms was

unambiguously determined by single crystal X-ray crystallog-

raphy (see below). As porphodimethenes of the general

constitution 10 are oxidizable to the porphyrin 9Ðotherwise

no formation of the porphyrin would have been possibleÐwe

surmise that the specific syn-axial orientation of the meso-

hydrogen atoms constitutes a configuration in which removal

of the hydrogen atoms is rather difficult.^[44]

In this context, the synthesis of dodecasubstituted porphyr-

ins with meso-alkyl substituents is of high interest, as such

compounds should exhibit nonplanar macrocycles with an

extreme degree of ruffling. Earlier attempts to prepare such

porphyrins by standard condensation methods, that is, mixing

of 3,4-disubstituted pyrroles with an alkyl aldehyde under acid

catalysis, failed for sterically hindered systems.^[39a]The only

porphyrins accessible through this route were porphyrins

involving b-cyclopentenyl rings, where the b-CH₂groups were

effectively removed from steric interactions with the meso-

alkyl substituents due to the ring constraints.^[41]A typical

example involved the synthesis of (tetracyclopenta[b,g,l,q]-

5,10,15,20-tetrapentylporphyrinato)nickel(ii).^[39a]In contrast,

the attempted synthesis of tetracyclohexa[b,g,l,q]-5,10,15,20-

tetraethylporphyrin yielded, after oxidation with DDQ, only

the porphodimethene tetracyclohexa[b,g,l,q]-5,10,5,20-tet-

raethyl-5,15-dihydroporphyrin,^[43]which resisted any oxida-

Further evidence for this was obtained from the observa-

tion that brown side products (such as 10) were frequently

observed during the synthesis of porphyrins 6 ± 9 when the

reaction temperature was allowed to rise above À808C . For

example, the conversion of 8 to the green porphyrin 9 is

quantitative only at temperatures below À80/ À 1008C . At

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higher reaction temperatures the formation of a brown

product, the porphodimethene 11, was observed. At temper-

atures above À308C, formation of this product became

quantitative and no porphyrin formation was observed.

Again, this porphodimethene was resistant to any of the

usual oxidants employed in porphyrin chemistry. A crystal

structure analysis (see Figure 6) showed the same syn-axial

configuration of the meso-hydrogen atoms as in any of the

other nonoxidizable porphodimethenes. Presumably, thermo-

dynamic control of the initial substitution reaction locks the

porphodimethene into a configuration that is more difficult to

oxidize than the one (probably anti-configurated) that is the

normal intermediate of the porphyrin formation described

here. In addition, the observation of the formation of

porphodimethenes gives some indication for the validity of

the mechanism for this reaction suggested above inasmuch

that a porphodimethene is the product of the initial reaction

(formally an addition step) in the sequence leading to

substituted porphyrins described here.

The formation of different configuration isomers for

5,5',15,15'-substituted decaalkylporphyrins has already been

described by Buchler in his elegant studies on the reductive

alkylation of Zn^II(OEP).^[15]Notably, crystal structures of his

stable porphodimethenes showed the same syn-axial orienta-

tion of the meso-alkyl groups as described here for 10.^[15b±d]

As the use of novel porphyrins in applications such as

catalysis or modeling of natural electron transfer processes

requires the preparation of metal complexes other than those

normally employed in synthetic projects, an entry into the

corresponding free bases of the porphyrins with novel

substituent pattern needed to be found. Initially, we attempt-

ed demetalation using standard methodologies, for example

with sulfuric acid. This method works well for unsubstituted

porphyrins. For example, 3a was demetallated in 80% yield to

3c, 3h in 90% yield to 3i and 3k to 3l in 90% yield. Upon

going to decasubstituted porphyrins the situation becomes

more problematic. The symmetric porphyrin 6 was demetal-

lated to 12 in 80% yield. In contrast, while demetallation of 7

and 8 gave the desired free bases, these were very unstable

and during work up degraded to brown-blue products. Thus,

the more sterically hindered (and nonplanar) the meso

alkylporphyrins are, the more difficult the formation of the

free bases becomes. The reason for this can be found in the

very high reactivity of strongly ruffled alkylporphyrins

towards nucleophiles, which readily react with solvate mole-

cules at the substituted meso positions under disruption of the

aromatic system and formation of porphodimethenes similar

to those described above.^[26]

As indicated by the possibility of introducing up to four

meso substituents through this reaction, porphyrins with

mixed meso-substituent pattern can easily be prepared. For

example, 3a and 7 could be converted in 50% yield to the

deca- and undecasubstituted porphyrins 13 and 14, respec-

tively. Thus, the methodology reported here, is applicable for

the synthesis of basically any desired meso-substituted

porphyrin. Detailed studies on porphyrins with mixed sub-

stituent pattern and suitable synthetic strategies will be

reported elsewhere.^[46]

Reaction of LiR with 5,10,15,20-tetraarylporphyrins: In order

to investigate the mechanism of nucleophilic additions in

meso position in more detail the reaction of LiR with various

5,10,15,20-tetrasubstituted porphyrins was investigated. In

contrast to OEP, these porphyrins have free b- and occupied

meso positions and thus some directing effect towards the b

positions was expected. Callot had shown that H₂(TPP) 1a

reacts with BuLi in 18% yield to the 23-hydro-5-butyl-

5,10,15,20-tetraphenylporphyrin, a phlorin, namely under

attack at the meso position.^[25b,c]In addition, he observed

formation of the chlorin 15 (in 7% yield, see Scheme 4), that

À

is, the product of a BuLi addition to a C_bC_bdouble bond.

Use of Zn^II(TPP) 1c for reaction with BuLi gave a similar

result. However, two chlorins, the mono- and dibutylated

products 15 and 16 were obtained in 6.5 and 18% yield,

respectively (see Scheme 4). Similar products were described

by Krattinger and Callot for the reaction of H₂(TPP) with

tBuLi.^[25c]The constitution of the unusual double addition

product 16 was unambiguously proven by single crystal X-ray

structural analysis of both the free base 16 and its corre-

sponding zinc(ii) complex 17 (see below). Thus, for meso-aryl

porphyrins both meso- and b attack of LiR are possible.

With these results in mind we attempted the direct reaction

of free base porphyrins with LiR. Surprisingly, the free base

2a readily treated with BuLi in 50% yield under formation of

the meso-butylated porphyrin 3c. In a similar manner,

reaction of 2a with PhLi gave 3i in quantitative yield, and

reaction with 2,5-dimethoxyphenyllithium gave 3l in 27%

yield. Presumably, reaction with the free bases proceeds by

initial formation of lithiated porphyrins [e.g. Li₂(OEP] as

described by Arnold.^[45]Thus, the LiR reagents are equally

versatile for the direct substitution of free base porphyrins

and metalloporphyrins.^[46]

Scheme 4. Reaction of Zn^II(TPP) with BuLi. a) 1) BuLi, THF, À408C;

2) H₂O, 15% HCl. b) ZnBr₂, THF.

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Reaction of LiR with 5,10,15,20-tetraalkylporphyrins: The

conformation of 5,10,15,20-tetraalkylporphyrins can vary

from planar to highly ruffled, depending on the steric demand

of the meso-alkyl group.^{[26, 40]}Thus, the nickel(ii) porphyrins 18

and 21 were treated with BuLi to investigate the influence of

meso-alkyl groups on the reactivity with organolithium

reagents. Treatment of the tetrabutylporphyrin 18 with BuLi

resulted in the almost quantitative formation of an orange

compound with broad absorption maxima at 432 and 524 nm

in CH₂Cl₂. Such spectra are typical for a porphodimethene,

that is here reaction had occurred exclusively at the meso

position. The porphodimethene 19 was slowly converted by

atmospheric oxygen into an orange-red compound that was

different from 19 by 2 amu. Spectroscopic studies revealed

this compound to be the novel porphodimethene 20

(Scheme 5) with an exocyclic double bond that is formed via

investigation of the step by step effect of introduction of

successively more meso-butyl groups. Selected conforma-

tional and structural parameters are compiled in Table 1.

Compound 3a with one meso-butyl chain exhibits a ruffled

conformation typical for Ni^IIporphyrins (see Figures 1 and

10). This is evidenced by significant displacements of the C_m

positions (DC_m 0.69 ). These displacements are larger than

those observed for the ruffled modification of Ni^II(OEP)

(DC_m 0.51 )^[48a]and a localized steric influence of the butyl

chain on the conformation is indicated by the significantly

larger displacement value for C5 (DC₅ 0.87 ). These

results are in line with those described for other

2,3,5,7,8,12,13,17,18-nonaalkylporphyrins.^{[18, 48b]}The packing

in these and related compounds is uneventful and needs not

be discussed in detail. However, a recurring theme of

nonplanar porphyrinsÐthe incorporation of solvate mole-

cules in the crystal latticeÐis already evidenced in the

structure of 3a. This compound forms layers of molecules

with the butyl ªarmsº pointing towards each other. Together

with the ruffled macrocycle the latter form a convenient

binding cavity that contains a methylene chloride of solvation

(Figure 1).

The corresponding free base 3c exhibits a planar macro-

cycle (with some wave contribution, not shown). However,

steric strain is present in the molecule as indicated by the

significant core elongation. As described before, a rectangular

elongation of the N4 core is the result of in-plane distortion of

the porphyrin, which is the preferred way of steric relief for

nona- and decasubstituted free base porphyrins.^[49]This is

accompanied by significant widening of the unsubstituted C_a-

C_m-C_aangles compared with the meso R quadrant in

decasubstituted porphyrins. The present structure shows that

even with in-plane distortion some redistribution of the steric

strain occurs. Both the substituted C_mposition C5 and the

opposing meso position C15 exhibit C_a-C_m-C_aangles of 123 ±

1248, while the average C_a-C_m-C_aangle for C10 and C20 is

131.3(5)8.

Scheme 5. Reaktion of tetra-meso alkylporphyrins with BuLi. a) 1) BuLi,

THF, À408C ; 2) HO; b) DDQ.

2

dehydrogenation at the C5 and C5¹position. Formation of the

exocyclic double bond results in a shift of the absorption

maxima to 434 and 524 nm. Synthetically, 20 is easily prepared

in 80% yield by oxidation of 19 with DDQ.

Similar results were obtained with porphyrins bearing

isobutyl (21a) or neopentyl (21b) residues. For example,

reaction of 21a with BuLi, followed by addition of DDQ

without isolation of the intermediary porphodimethene gave

the 15¹,15²-didehydroporphodimethene 22 in 60% yield.

Reaction of the tert-butyl porphyrin 21c with BuLi resulted

in the formation of the oxidation stable porphodimethene 23,

whose exact configuration at C5 or C15 (23a or 23b) could not

be determined yet. Thus, meso alkylporphyrins react with

organolithium reagents exclusively at the meso positions a

further indication for the higher reactivity of the C_mpositions

towards nucleophilic attack.^[47]

Crystallographic studies: As several of the novel porphyrins

discussed here have potentially nonplanar macrocycle con-

formations, extensive crystallographic studies were performed

on the compounds described above. Of prime interest was an

Like many other planar or moderately distorted porphyrin

compounds, 3 f forms p-stacked layers in the crystal (Fig-

ure 2). The dimeric aggregates are characterized by an

À

interplanar separation of 3.78 , a ct ct distance of 5.464 ,

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Chem. Eur. J. 2000, 6, No. 15

Porphyrins

2721±2738

Table 1. Selected bond lengths and structural parameters for some of the porphyrins studied [in ].

6 ^[a]

X^[b]

D24^[c]

DC_m

dC_m

subst.^[e]

dC_m

unsubst.^[f]

[d]

À

M N

M N22

À

M N23

À

M N24

M N21

3a

1.911(5)

1.892(5)

1.916(5)

1.905(5)

1.906

0.037

0.338

0.69

0.87

0.63

av. 1.906

3c

3 f

±

2.086

1.915

0.385

0.051

0.032

0.308

0.03

0.64

0.07

0.82

0.01

0.58

1.913(2)

1.911(2)

1.917(2)

1.921(2)

av. 1.916

3h

1.920(4)

1.922(4)

1.932(4)

1.922(4)

1.924

0.074

0.263

0.52

0.51

0.52

av. 1.924

±

3i Mol. 1^[g]

3i Mol. 2^[g]

3k

±

2.077

2.078

1.936

0.313

0.29

0.07

0.039

0.042

0.262

0.07

0.06

0.52

0.1

0.03

0.52

0.06

0.04

0.53

1.927(3)

1.934(3)

1.941(3)

1.939(3)

av. 1.935

3l

±

2.073

1.904

0.308

0.089

0.083

0.390

0.10

0.81

0.14

0.83

0.07

0.78

6 Mol. 1 ^[g]

1.908(4)

1.902(3)

1.908(4)

1.899(3)

av. 1.904(4)

6 Mol. 2^[g]

1.890(4)

1.902(4)

1.910(4)

1.906(4)

1.899(3)

1.873(3)

1.891(4)

1.916(4)

1.902(4)

1.895(3)

1.883(3)

1.905(4)

1.923(4)

1.909(4)

1.907(3)

1.880(3)

1.897

1.913

1.904

1.900

1.879

0.1

0

0.408

0.365

0.382

0.401

0.446

0.84

0.75

0.79

0.76

0.93

0.86

0.85

0.90

0.86

0.97

0.81

0.65

0.68

0.66

0.81

av. 1.897(4)

1.901(4)

7 monocl. Mol. 1^[g]

7 monocl. Mol. 2^[g]

7 triclinic

av. 1.913(4)

1.899(4)

0.01

À 0.05

av. 1.904(4)

1.899(3)

av. 1.900(3)

8

1.882(3)

av. 1.880(3)

av. 1.873(3)

1.885(4)

9^[51]

10 Mol. 1 ^[g]

1.872

1.881

n.d.

0.079

0.462

0.531

1.044

1.16

1.044

1.16

±

1.889(4)

1.871(4)

1.890(3)

±

1.881(4)

1.890(4)

1.891(3)

±

1.874(5)

1.895(4)

1.896(3)

±

av. 1.882(4)

10 Mol. 2 ^[g]

1.880(4)

1.884

1.892

2.097

0.095

0.032

0.615

0.544

0.497

0.014

1.18

±

av. 1.884(4)

1.895(3)

11

12

1.087

0.045

1.124

0.041

0.976

0.051

av. 1.893(3)

±

[a] Core size, average vector length from the geometric center of the four nitrogen atoms to the nitrogen atoms. [b] Core elongation parameter defined as the

difference between the vector lengths (jN21 À N22 j j N23 À N24 j ) À (jN22 À N23 j j N21 À N24 j ). [c] Average deviation of the 24 macrocycle atoms

from their least-squares plane. [d] Average deviation of the C_mcarbon atoms from the 4N-plane. [e] Average deviation of the substituted C_mcarbon atoms

from the 4N-plane. [f] Average deviation of the unsubstituted C_mcarbon atoms from the 4N-plane. [g] Two crystallographically independent molecules.

Figure 2. View of the dimeric aggregates formed by 3 f in the crystal.

Hydrogen atoms have been omitted for clarity.

Figure 1. View of the molecular structure of 3a in the crystal with a solvate

methylene chloride loosely bound in the cavity. Thermal ellipsoids are

drawn for 50% occupancy, hydrogen atoms have been omitted for clarity.

positions is observed for the phenyl derivative 3h (not

shown). The degree of ruffling present in this compound

(Table 1) does not exceed that found in the sterically un-

a slip angle of 46.28, and a lateral shift of the metal centers of

3.94 .^[38e]The conformation is again characterized by overall

ruffling with a localized contribution from the C5 phenyl

substituent. The magnitude of the difference in displacement

values for the substituted and unsubstituted C_mpositions is

about the same in both alkyl substituted derivatives 3a and 3 f.

In contrast, almost no difference between individual C_m

strained Ni^II(OEP). This compound does not exhibit any in-

plane rotation of the meso-phenyl group (tilt angle of meso

aryl with 4N plane 89.48). As aryl tilt normally correlates with

the degree of nonplanarity present in meso-aryl porphyr-

ins,^[38e]this is another indication that no significant steric strain

occurs in compounds of this type. The crystal packing is

similar to 3 f, although the interplanar separation is larger.

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Similar results were obtained for the related 2,5-dimethoxy-

phenyl derivative 3k (tilt angle of meso aryl with 4N plane

88.58, not shown).

The free base 3i (Figure 3) gave a similar result to that

described for 3c, that is preferential use of in-plane distortion

over out-of-plane distortion for relief of steric strain (X

0.29 ± 0.31 ) and almost no phenyl tilt (tilt angles are 94.7

ments for the substituted C_mpositions (see Figure 10). The

differences between the individual C_mpositions are small, an

indication for the significant redistribution of steric strain in

symmetrically substituted porphyrins. Compound 6 crystal-

lized with two crystallographically independent molecules;

both exhibit very similar conformations and structural pa-

rameters. The molecular packing in the crystal is character-

ized by an arrangement in which the macrocycle rings enclose

each other with the alkyl chains always pointing towards each

other. In effect the areas of nonpolar butyl chains are shielded

by the ruffled macrocycles and vice versa.

The regioisomer 7 was crystallized in two different mod-

ifications. In line with the 5,10-disubstitution pattern both

show more asymmetric distortions.^[49b]Compared with 6 the

differences in displacements between the substituted and

unsubstituted C_mpositions are now significant (0.85 ± 0.9 vs.

0.65 ± 0.68 , respectively). In addition, both the monoclinic

(not shown) and triclinic (Figure 5) modification are not

Figure 3. View of the molecular structure of one of the two independent

molecules of 3i in the crystal. Thermal ellipsoids are drawn for 50%

occupancy, hydrogen atoms have been omitted for clarity.

and 83.68 for the two crystallographically independent

molecules). However, a slight tendency towards saddle

distortion is observed. The largest C_bdisplacements observed

were 0.18 and might be due to packing effects as the

molecules form p ± p aggregates in the crystal. The closely

related free base 3l with a 2,5-dimethoxyphenyl substituent

(not shown) exhibits a mixture of in-plane distortion (X

0.31 ), slight ruffling (DC_m 0.14 ) and saddle distortion

(C_bdisplacements of 0.24 for C17 and C18).

Figure 5. View of the molecular structure of one of the two independent

molecules of 7 (triclinic modification) in the crystal. Thermal ellipsoids are

drawn for 40% occupancy, hydrogen atoms and disordered positions have

been omitted for clarity.

Figure 4 shows a view of the molecular structure of the 5,15-

dibutyl derivative 6 in the crystal. Its conformation is that of a

symmetrically ruffled macrocycle with slightly larger displace-

purely ruffled but show out-of-plane tilting for some pyrrole

rings (see Figure 10). As other nickel^IIporphyrins, 7 shows no

evidence for rectangular core elongation as described above

for some free base porphyrins. Nevertheless, the core

conformation is asymmetric as the vector lengths connecting

À

neighboring N N pairs are shorter by 0.02 ± 0.03 for the

substituted (N21/N22 and N22/N23) quadrants compared to

the unsubstituted ones (N23/N24 and N24/N21).

The conformation of the tributylated derivative 8 is again

highly ruffled with C_mdisplacements significantly exceeding

those of the porphyrins discussed before.^[50]As listed in

Table 1, increasing macrocycle distortion in these porphyrins

À

is accompanied by a shortening of the Ni N bond lengths.

Additionally, these structures show the expected effects of

macrocycle distortion on trends for increasingly nonplanar

porphyrins.^[18]Among other effects, increasing ruffling dis-

tortion here leads to smaller M-N-C_a[127.1(4)8 in 3a to

126.6(3)8 in 8], larger C_m-C_a-C_b[124.6(5)8 in 3a to 127.1(3)8 in

8], smaller C_a-C_m-C_aangles [121.7(5)8 in 3a to 120.5(3)8 in 8],

Figure 4. View of the molecular structure of one of the two independent

molecules of 6 in the crystal. Thermal ellipsoids are drawn for 50%

occupancy, hydrogen atoms and disordered positions have been omitted for

clarity.

À

and longer C_aC_mbonds [1.389(10) in 3 a to 1.404(6) in

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Chem. Eur. J. 2000, 6, No. 15

Porphyrins

2721±2738

8]. These trends are further confirmed when the crystal

structure of the tetrabutylated derivative 9 (see Figure 10) is

taken into account.^[51]Often the relative changes are more

pronounced within a given molecule than upon comparison of

different molecules. For example, compound 3a, where one

meso-butyl group leads to a significantly localized distortion,

derivative 10 shows absorption maxima (451, 551 nm) slightly

more bathochromic than the tributyl derivative 11 (445,

549 nm). Thus, taking the porphodimethene character into

account, similar conformational substituent effects are ob-

served in porphyrins and in 5,15-dihydroporphyrins.

The free base 12 (Figure 7) exhibits an almost planar

macrocycle with considerable differences in the C_a-C_m-C_a

angles for the substituted [124.7(7)8] and unsubstituted meso

À

exhibits average C_aC_mbond lengths of 1.415(10) for the

substituted position C5. Compared with an average of

1.381(10) for the three unsubstituted C_mpositions, this

yields a difference of 0.034 . In comparison, the overall

À

average of all eight C_a

C_mbonds of 1.389(10) in 3a differs

only by 0.02 from that of compound 9 [1.409(4) ]. The

various compounds exhibit UV/Vis spectra with absorption

maxima that are progressively shifted towards the red with

increasing macrocycle distortion. For example, in the series

2b, 3a, 6, 7, 8, and 9^[52]the Soret absorption bands are 391, 410,

423, 427, 442, and 459 nm in CH₂Cl₂, respectively. This effect

has been noted before^[38a]and indicates that similar conforma-

tional trends are retained in solution. Structurally, this

confirms that varying numbers of meso-alkyl substituents

can be used in a similar manner as b substituents to yield

porphyrins with graded degree of conformational distor-

tion.^[54]

Crystal structure analyses of the two porphodimethenes 10

(not shown)^[50]and 11 (Figure 6) both establish the syn-axial

orientation of the meso-hydrogen atoms. The presence of the

Figure 7. View of the molecular structure of 12 in the crystal. Thermal

ellipsoids are drawn for 50% occupancy, hydrogen atoms have been

omitted for clarity.

quadrants [132.7(7)8]. This is indicative for in-plane distor-

tion. With a X of 0.615 the core elongation is severe and

exceeds that observed in other 5,15-disubstituted porphyr-

ins.^[49b]

The two crystal structures obtained for the free base chlorin

16 give evidence for the conformational flexibility in chlor-

ins^[55]and confirm the structural assignments made before for

the double b addition reaction products of free base TPP with

alkyl lithium reagents.^{[25b,c, 28]}The unsolvated (Figure 8) and

Figure 6. Side view of the molecular structure of 11 in the crystal. Except

for meso positions hydrogen atoms and have been omitted for clarity.

two sp³-hybridized meso carbon atoms leads to a folding of the

À

macrocycle along the C5 C15 axis. Overall this results in a

roof-type structure, namely a mixture of doming and ruffling

(see Figure 10) as described before.^[15b±d]Only the structure of

Ni^II(5,15-syn-dihydro-5,15-dimethyl-OEP) is directly compa-

rable with the present ones.^[53]A comparison of the relevant

porphodimethene structures shows that the butyl groups exert

additional steric strain in a similar manner as observed in

porphyrins. This is evidenced best by the structure of 10 where

the C_a-C_m-C_aangles of the two sp²-hybridized meso carbons

differ. The one carrying a butyl group has an C_a-C_m-C_aangle

of 122.8(4)8 while the unsubstituted one has an angle of

124.4(4)8. In addition, the dC_mvalues are larger for the

substituted position (1.12 vs. 0.98 ) and the tetrabutyl

Figure 8. View of the molecular structure of 16 (triclinic unsolvated form)

in the crystal. Thermal ellipsoids are drawn for 50% occupancy; except for

the C2 and C3 positions, hydrogen atoms have been omitted for clarity.

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M. O. Senge et al.

FULL PAPER

solvated triclinic modification (not shown) show quite differ-

ent degrees of conformational distortion (D24 0.08 and

0.15 ) with average C_bdisplacements for individual pyrrole

rings ranging from 0.07 to 0.4 . The corresponding zinc(ii)

complex 17 (Figure 9) shows a similar conformation (D24

0.1 ) with the largest C_bdisplacements found for the

pyrrolenine ring (0.27 ) and the pyrrole ring containing

N24 (0.31 ). The core conformational parameters are typical

for a five-coordinated zinc(ii)chlorins.^{[55, 56]}The axial methanol

is hydrogen bonded to another methanol of solvation.

and simple synthetic approach to highly substituted porphyr-

ins including those with meso alkyl groups and to dodecasub-

stituted porphyrins with mixed substituent pattern has

become possible.

Figure 9. View of the molecular stacks formed by 17(MeOH) in the

crystal. Dashed lines indicate hydrogen bonding; hydrogen atoms have

À

been omitted for clarity. Selected bond lengths and angles: Zn N(21)

Figure 10. Skeletal deviation plots for selected nonplanar porphyrins. The

x axis is not to scale and the sequence of pyrrole rings follows the IUPAC

À

2.112(4) , Zn N(22) 2.056(4) , Zn N(23) 2.099(4) , Zn N(24)

À

&

2.043(4) , Zn O(1A) 2.116(3) , C(2) C(3) 1.515(6) , C(1)-C(2)-C(3)

101.2(4)8, C(3)-C(2)-C(21) 112.1(4)8, C(1)-C(2)-C(21) 110.5(4)8, C(2)-

C(3)-C(4) 102.2(4)8.

nomenclature from left to right (N21, N22, N23, N24). ( indicates a

substituted meso-carbon atom for a porphyrin or the sp³-hybridized meso-

carbon atoms for porphodimethenes. For compounds 6, 7, 10, and 12 only

one of the two crystallographically independent molecules is shown.

The structural studies of several nonplanar porphyrins gave

results in line with earlier studies and/or predictions. Notably,

mono-5- or di-5,15-substituted free base porphyrins rather

exhibited in-plane distortion instead of out-of-plane distor-

tions. The metalloporphyrins showed a dependency of the

degree and type of distortion on the number and localization

of the meso substituents. This indicates that nona- to

dodecasubstituted alkylporphyrins follow the same conforma-

tional trends and exhibit a behavior similar to other highly

substituted porphyrins. The distortion mode contributing

most significantly to the macrocycle conformation in meso

alkylporphyrins was ruffling. The degree of overall distortion

correlated with observed bathochromic shifts of the absorp-

tion maxima, indicative of highly nonplanar conformations

both in solution and in the solid state. Similar results were

obtained for the highly substituted porphodimethenes 10 and

Conclusion

The present results clearly show, that porphyrins react readily

and often quantitatively with organolithium reagents, pref-

erably at the meso position. The use of a variety of different

alkyl and aryl lithium reagents for the meso modification of

porphyrins, and our results from other projects using similar

chemistry, indicates that, in principle, any organolithium

reagent can be used for the facile meso substitution of

porphyrins, including residues amenable for further trans-

formations to more complex systems. Mechanistically, the

reaction follows an addition ± oxidation sequence as indicated

by the observation that the initial reaction of the porphyrin

with LiR can yield oxidation resistant porphodimethenes. The

method described here can be used to prepare mono-, di-, tri-,

and tetra-meso-functionalized porphyrins. Thus, a rational

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Chem. Eur. J. 2000, 6, No. 15

Porphyrins

2721±2738

s, 2 H; NH), 0.91 (t, ³J(H,H) 7.5 Hz, 3H; butyl-CH₃), 1.52 (m, 4H; butyl-

CH₂), 1.83, 1.87, 1.88, 1.89 (each t, ³J(H,H) 7.5 Hz, 24H; ethyl-CH₃),

3.97 ± 4.14 (m, 16H; ethyl-CH₂), 5.06 (q, 2H; butyl-CH₂), 9.79 (s, 1H; 15-

H), 10.02 (s, 2H; 10-, 20-H); ¹³C NMR (126 MHz CDCl₃): d 14.08, 17.82,

18.41, 18.46, 19.65, 19.76, 19.96, 22.73, 23.70, 31.37, 40.42, 94.91, 96.33,

118.79, 120.30, 140.37, 140.64, 140.87, 141.98, 142.35, 143.98, 144.56, 145.55;

UV/Vis (CH₂Cl₂1% NEt₃): l_max(lg e) 407 (5.26), 507 (4.20), 540 (3.92),

575 (3.90), 620 nm (3.49); UV/Vis (CH₂Cl₂1% TFA): l_max(lg e) 415

(5.47), 560 (4.20), 600 nm (3.86); MS (80 eV, 1508C): m/z (%): 590 (100)

11, both of which showed a syn-axial orientation of the meso-

hydrogen atoms. In addition, crystal structures for the double

b-addition products of the reaction of LiR with Zn^II(TPP)

established an anti orientation of the two added butyl residues

with respect to the molecular plane.

[M] , 547 (16) [M À C₃H₇] , 295 (12) [M]²; HR-MS [C₄₀H₅₄N₄] calcd

646.3546, found 646.3578; C₄₀H₅₄N₄(590.90): calcd C81.31, H 9.21, N 9.48;

found C81.01, H 8.75, N 9.56.

Experimental Section

General: All chemicals used were of analytical grade and purified before

use by distillation. Methylene chloride was dried before use by filtration

through basic alumina (grade I); methanol was dried by refluxing over

magnesium turnings followed by distillation. All manipulations involving

LiR reagents were performed under a purified argon atmosphere by using

modified Schlenk techniques with dried and degassed solvents. Melting

points are uncorrected and were measured with a Reichert Thermovar

apparatus. Silica gel 60 (Merck) or basic alumina (Alfa) (usually

Brockmann Grade III, i.e., deactivated with 7.5% water) were used for

column chromatography. Analytical thin-layer chromatography (TLC) was

carried out using silica gel 60 aluminum plates or alumina 60 (neutral,

II

(5-Butyl-2,3,7,8,12,13,17,18-octaethylporphyrinato)copper(ii) (3d): C u(OEP)

2d (100 mg, 0.17 mmol) was dissolved in THF (70 mL) and treated with

BuLi at À208Cas described for 3a to give red crystals (83 mg, 0.13 mmol,

75%). M.p.: 2528C; UV/Vis (CH ₂Cl₂): l_max(lg e) 409 (5.44), 537 (3.85),

571 nm (3.71); MS (80 eV, 2008C): m/z (%): 651 (100) [M] , 608 (16) [M À

C₃H₇] , 326 (8) [M]²; C₄₀H₅₂N₄Cu ´ 0.5CH₃OH (668.45): calcd C72.77, H

8.14, N 8.38; found C72.75, H 7.76, N 8.08. A small aliquot was

demetallated to the free base and gave a NMR spectrum identical to that

of 3c.

II

(5-Butyl-2,3,7,8,12,13,17,18-octaethylporphyrinato)cobalt(ii) (3e): C o(OEP)

fluorescence indicator F₂₅₄

) plates (precoated sheets, 0.2 mm thick).

2e (100 mg, 0.17 mmol) was dissolved in THF (50 mL) and treated with

BuLi at À708Cas described for 3a to give red crystals (36 mg, 5.6 mmol,

40%). M.p.: 2478C; UV/Vis (CH ₂Cl₂): l_max(lg e) 406 (5.29), 525 (3.79),

563 nm (3.55); C₄₀H₅₂N₄Co ´ 0.5CH₃OH (663.84): calcd C73.28, H 8.20, N

8.44; found C73.51, H 7.83, N 8.81. A small aliquot was demetallated to the

free base and gave a NMR spectrum identical to that of 3c.

Reactions were monitored by TLCand spectrophotometry and were

carried out in dimmed light. Proton NMR spectra were recorded at a

frequency of 250 MHz (AC250) or 500 MHz (Bruker, AMX 500). All

chemical shifts are given in ppm and have been converted to the d scale and

are referenced against the TMS signal as internal standard. Electronic

absorption spectra were recorded with

a Specord S10 (Carl Zeiss)

{5-[2-(1,3-Dioxane-2-yl)ethyl]-2,3,7,8,12,13,17,18-octaethylporphyrinato}-

nickel(ii) (3 f): For the preparation of di-tert-butylphenyllithium lithium

(0.067 g, 9.6 mmol) was combined with di-tert-butylbiphenyl (1g,

4.42 mmol) in THF (5 mL). Immediately after addition of the lithium

reagent the solution turned deep blue indicating the formation of the

radical anion. The mixture was stirred overnight and used for the

preparation of 2-(1,3-dioxane-2-yl)ethyllithium.^[35]2-(2-Bromoethyl)-1,3-

dioxolane (0.286 g, 1.47 mmol) was dissolved in dry THF (1 mL), cooled to

À608Cand the di- tert-butylphenyllithium solution was added dropwise

until the color of the mixture remained light blue. Subsequently, a solution

of Ni^II(OEP) 2b (100 mg) in THF (60 mL) was added and the solution

stirred for 10 min at À608C. The reaction mixture was hydrolyzed with a

solution of THF (5 mL) and water (1 mL), stirred for 5 min and treated

with a solution of DDQ in CH₂Cl₂(0.06m, 10 mL). After stirring for an

additional 15 min the mixture was filtered through neutral alumina and

purified by column chromatography on alumina (grade III, hexane/CH₂Cl₂

2:1, v/v). After recrystallization from CH₂Cl₂/CH₃OH the product 3 f was

spectrophotometer using CH₂Cl₂as solvent. Mass spectra were obtained

using a Varian MAT 711 mass spectrometer. Elemental analyses were

performed with a Perkin ± Elmer 240-analyzer.

II

Metallation reactions: C u , Ni^II, C o , and Zn^IIwere inserted into free base

porphyrins using standard acetate methodology in chlorinated hydro-

carbons.^[3]Alternatively, Ni^IIwas inserted using nickel acetate and DMF as

solvent, while metallation with zinc bromide was often superior to use of

zinc acetate.

(5-Butyl-2,3,7,8,12,13,17,18-octaethylporphyrinato)nickel(ii) (3a): Ni^II(OEP)

2b (100 mg, 0.17 mmol) was dissolved in 60 mL THF and the solution

cooled to À 708C . Ann-Butyl lithium solution (2m, 0.3 mL in cyclohexane;

0.6 mmol) was added dropwise within 10 min. After addition of BuLi the

cold bath was removed and a mixture of water (1 mL) and THF (5 mL)

added dropwise. Subsequently a 0.06m solution of DDQ in CH₂Cl₂(10 mL)

were added to the cold solution. The mixture was stirred for 20 min and

filtered through neutral alumina (grade I). Chromatographic purification

was achieved on alumina (grade III) eluting with hexane/CH₂Cl₂4:1 (v/v).

Recrystallization from CH₂Cl₂/methanol gave red crystals of 3a in

quantitative yield. M.p.: 2358C; ¹H NMR (500 MHz, CDCl₃): d À0.51

1

obtained as red crystals (85 mg, 0.12 mmol, 70%). M.p.: 2588C; H NMR

(500 MHz, CDCl₃): d 1.07 (d, ²J(H,H) 13 Hz, 1H; dioxane-5-H_eq), 1.25

(m, 2H; 5²-H), 1.71, 1.781, 1.785, 1.87 (each t, ³J(H,H) 7.5 Hz, 24H; CH₃),

1.88 (m, 1H; dioxane-5-H_ax), 3.28 (td, J 13 Hz, ³J(H,H) 2.5 Hz, 2H;

dioxane-4,6-H_ax), 3.71 ± 3.90 (m, 16H; CH₂), 4.63 (t, ³J(H,H) 7.5 Hz, 2H;

5¹-H), 9.387 (s, 2H; 10-, 20-H), 9.389 (s, 1H; 15-H); ¹³CNMR (126 MHz,

CDCl₃): d 17.90, 18.08, 19.49, 22.44, 25.59, 26.21, 66.40, 95.55, 96.35,

100.79, 113.76, 137.55, 139.16, 139.61, 140.06, 142.64, 142.85, 144.09, 145.45;

UV/Vis (CH₂Cl₂): l_max(lg e) 410 (5.31), 533 (4.08), 572 nm (4.19); MS

3

(t, J(H,H) 7.5 Hz, 3H; butyl-CH₃), 0.85 (m, 4H; butyl-CH₂), 1.68, 1.74,

1.75, 1.85 (each t, ³J(H,H) 7.5 Hz, 24H; ethyl-CH₃), 3.79 (brs, 16H; ethyl-

CH₂), 4.42 (t, J 7.5 Hz, 2H; 5-CH₂CH₂CH₂CH₃), 9.32 (s, 1H; 15-H), 9.33

(s, 2H; 10,20-H); UV/Vis (CH₂Cl₂): l_max(lg e) 410 (5.23), 535 (4.02),

572 nm (4.10); MS (80 eV, 3508C): m/z (%): 646 (100) [M] , 323 (18) [M]²

;

HR-MS [C₄₀H₅₂N₄Ni] calcd 646.3546, found 646.3578; C₄₀H₅₂N₄Ni (647.67):

calcd C74.19, H 8.09, N 8.65; found C73.98, H 7.90, N 8.50.

(80 eV, 2808C): m/z (%): 704 (100) [M] , 352 (2) [M]²; C₄₂H₅₄N₄O₂Ni

(705.61): calcd C71.49, H 7.71, N 7.94; found C71.43, H 7.51, N 8.22.

5-Butyl-2,3,7,8,12,13,17,18-octaethylporphyrin (3c): Free base OEP 2a

(100 mg, 0.19 mmol) was dissolved in THF (50 mL) and cooled to

À708C. BuLi stock solution (2m, 0.5 mL; 1 mmol) was added dropwise

and stirred for 15 min. A mixture of water (1 mL) and THF (5 mL) was

added and stirring continued for 5 min. This was followed by addition of

DDQ solution (0.06m, 10 mL) in CH₂Cl₂to the cold reaction mixture. After

stirring for 20 min the reaction mixture was filtered through alumina (grade

I) and purified by chromatography on neutral alumina (grade III) eluting

with hexane/CH₂Cl₂1:1 (v/v). Yield: 55 mg, 50%. Alternatively, 3c is

accessible via demetallation of 3a. For this, 3a (30 mg, 46 mmol) was

dissolved in concentrated sulfuric acid (5 mL) at room temperature and

stirred for 25 min. The reaction mixture was diluted with a saturated

solution of sodium acetate (25 mL), extracted with CH₂Cl₂, and washed

with water. After drying via filtration through alumina (grade I) column

chromatographic purification as described above yielded purple crystals

(80%). M.p.: 2118C; ¹H NMR (500 MHz, CDCl₃): d À2.83, À2.77 (each

{5-(4-Phenoxybut-1-yl)-2,3,7,8,12,13,17,18-octaethylporphyrinato}nickel(ii)

(3g): Similar to the procedure given for 3h 4-phenoxybutyl bromide

(230 mg, 1 mmol) was treated with di-tert-butylphenyl lithium followed by

reaction with Ni^II(OEP) 2b(100 mg, 0.17 mmol). Compound 3g was

obtained as red crystals (75 mg, 60%), while 30% of the starting material

1

Ni^II(OEP) could be recovered. M.p.: 2408C; H NMR (500 MHz, CDCl₃):

d 1.12, 1.20 (each m, 4H; butyl-5²-, 5³-H), 1.71, 1.782, 1.786, 1.88 (each t,

³J(H,H) 7.5 Hz, 24H; ethyl-CH₃), 3.36 (t, ³J(H,H) 6.5 Hz, 2H; butyl-5⁴-

H), 3.84 (brs, 16H; ethyl-CH₂), 4.55 (t, ³J(H,H) 6.5 Hz, 2H; butyl-5¹-H),

6.48 (dd, ³J(H,H) 9 Hz, ⁴J 1 Hz, 2H; H_o-phenyl), 6.77 (tt, ³J(H,H) 9 Hz,

⁴J 1 Hz, 1H, H_p-phenyl), 7.03 (dd, ³J(H,H) 9 Hz, 2H; H_m-phenyl), 9.37 (s,

2H; 10-, 20-H), 9.38 (s, 1H; 15-H); ¹³CNMR (126 MHz, CDCl ₃): d 18.08,

19.53, 22.46, 29.16, 31.35, 31.91, 67.01, 95.61, 96.47, 114.17, 120.20, 129.09,

137.44, 139.22, 139.43, 140.15, 142.74, 142.93, 143.88, 145.53; UV/Vis

(CH₂Cl₂): l_max(lg e) 410 (5.23), 535 (4.03), 573 nm (4.14); MS (80 eV,

Chem. Eur. J. 2000, 6, No. 15

ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000

0947-6539/00/0615-2731 $ 17.50+.50/0

2731

M. O. Senge et al.

FULL PAPER

2508C): m/z (%): 738 (100) [M] ; C₄₆H₅₆N₄ONi (739.67): calcd C74.70, H

graphed on alumina (grade III) eluting with hexane/CH₂Cl₂2:1 (v/v) and

yielded deep red crystals (85 mg, 0.095 mmol, 60%). M.p.: 2428C;

¹H NMR (500 MHz, CDCl₃): d 0.99, 1.74 (each t, ³J(H,H) 7.5 Hz,

12H; CH₃), 1.807, 1.811 (each t, ³J(H,H) 7.5 Hz, 12H; CH₃), 2.79, 2.90

(each m, 4H; 3¹-, 7¹-H), 3.62, 3.82 (each s, 3H; OCH₃), 3.68 ± 3.92 (m, 12H;

CH₂), 7.07 (each d, ³J(H,H) 9 Hz, 1H; 2-H_phenyl), 7.25 (dd, ³J(H,H) 9 Hz,

⁴J(H,H) 3 Hz, 1H; 3-H_phenyl), 7.31 (d, ⁴J(H,H) 3 Hz, 1H; 5-H_phenyl), 9.52

(s, 1H; 15-H), 9.57 (s, 2H; 10-, 20-H); ¹³C NMR (126 MHz, CDCl₃): d

16.80, 18.13, 19.59, 21.20, 55.36, 55.94, 95.48, 96.33, 110.81, 115.18, 121.08,

130.47, 139.21, 139.24, 139.57, 140.64, 142.85, 142.93, 144.81, 145.07, 152.67,

152.93; UV/Vis (CH₂Cl₂): l_max(lg e) 401 (5.29), 522 (4.12), 558 nm (4.36);

7.63, N 7.54; found C74.31, H 7.63, N 7.54.

(2,3,7,8,12,13,17,18-Octaethyl-5-phenylporphyrinato)nickel(ii) (3h): Ni^II(OEP)

2b (100 mg, 0.17 mmol) was dissolved in THF (60 mL). The solution was

cooled to À108Cand treated with a solution of phenyl lithium in

cyclohexane (1.8m, 1.5 mL; 2.7 mmol). The reaction mixture was heated

to 358Cand stirred for 30 min. The reaction product was hydrolyzed by

addition of water (1 mL) followed by addition of a solution of DDQ in

CH₂Cl₂(0.06m, 10 mL). Stirring was continued for 15 min and the mixture

filtered through alumina grade I, followed by chromatography on neutral

alumina (grade III) eluting with hexane/CH₂Cl₂3:1 (v/v). After recrystal-

lization from CH₂Cl₂/CH₃OH the product 3h was obtained (75 mg, 68%).

M.p.: 2268C; ¹H NMR (500 MHz, CDCl₃): d 0.89 (t, ³J(H,H) 7.5 Hz,

6H; CH₃), 1.68 (t, ³J(H,H) 7.5 Hz, 6H; CH₃), 1.76 (t, ³J(H,H) 7.5 Hz,

12H; CH₃), 2.59 (q, ³J(H,H) 7.5 Hz, 4H; CH₂), 3.75, 3.82, 3.84 (each q,

³J(H,H) 7.5 Hz, 12H; CH₂), 7.42 ± 7.70 (m, 3H; H_phenyl), 7.98 (m, 2H;

MS (80 eV, 3008C): m/z (%): 726 (100) [M] , 363 (9) [M]²; C₄₄H₅₂N₄NiO₂

(727.61): calcd C72.63, H 7.20, N 7.70; found C72.75, H 6.90, N 7.42.

2,3,7,8,12,13,17,18-Octaethyl-5-(1,4-dimethoxyphen-6-yl)porphyrin

(3l):

Using the procedure described for 3k free base OEP 2a (100 mg,

0.19 mmol) was treated with in situ generated 2,5-dimethoxyphenyl lithium

and yielded 3l (35 mg, 27%). Alternatively, this compound is accessible via

demetallation of 3k. Using the procedure given for 3c this gives 3l in 90%

yield. M.p.: 1688C; ¹H NMR (500 MHz, CDCl₃): d À3.15, À2.97 (each s,

2H; NH), 1.21, 1.87 (each t, ³J(H,H) 7.5 Hz, 12H; CH₃), 1.92 (t,

³J(H,H) 7.5 Hz, 12H; CH₃), 2.30, 2.90 (each m, 4H; 3¹-, 7¹-H), 3.55,

3.88 (each s, 3H; OCH₃), 4.02 (m, 12H; CH₂), 7.13 (d, ³J(H,H) 9.5 Hz,

1H; 2-H_phenyl), 7.31 (dd, ³J(H,H) 9.5 Hz, ⁴J(H,H) 3.5 Hz, 1H; 3-H_phenyl),

H

_phenyl), 9.49 (s, 1H; 15-H), 9.54 (s, 2H; 10-, 20-H); UV/Vis (CH₂Cl₂): l_max

(lg e) 401 (5.27), 523 (4.07), 558 nm (4.33); MS (80 eV, 2808C): m/z (%):

666 (100) [M] , 333 (8) [M]²; C₄₂H₄₈N₄Ni ´ 0.5CH₃OH (683.58): calcd C

74.68, H 7.37, N 8.20; found C74.50, H 7.09, N 8.55.

2,3,7,8,12,13,17,18-Octaethyl-5-phenylporphyrin (3i): Free base OEP 2a

(100 mg, 0.19 mmol) was dissolved in THF (40 mL). The solution was

cooled to 08Cand treated with a solution of phenyl lithium in cyclohexane

(1.8m, 1 mL, 1.8 mmol). The reaction mixture was heated to 408Cand

stirred for 15 min. After cooling to 08Cwater (1 mL) was added followed

by addition of a solution of DDQ in CH₂Cl₂(0.06m, 7 mL). Stirring was

continued for 5 min and the mixture filtered through alumina grade I,

followed by chromatography on neutral alumina (grade III) eluting with

hexane/CH₂Cl₂2:1 (v/v). After recrystallization from CH₂Cl₂/CH₃OH the

product 3i was obtained in quantitative yield. M.p.: 2618C; ¹H NMR

(500 MHz, CDCl₃): d À3.61, À3.02 (each s, 2H; NH), 1.15 (t, ³J(H,H)

7.5 Hz, 6H; CH₃), 1.85 (t, ³J(H,H) 7.5 Hz, 6H; CH₃), 1.91 (t, ³J(H,H)

7.5 Hz, 12H; CH₃), 2.74 (q, ³J(H,H) 7.5 Hz, 4H; CH₂), 3.97 ± 4.12 (m,

12H; CH₂), 7.60 ± 7.85 (m, 3H; H_phenyl), 8.20 (m, 2H; H_phenyl), 9.92 (s, 1H; 15-

H), 10.17 (s, 2H; 10-, 20-H); UV/Vis (CH₂Cl₂1% NEt₃): l_max(lg e) 404

(5.32), 503 (4.27), 536 (4.02), 572 (3.99), 622 nm (3.57); (CH₂Cl₂1% TFA):

l_max(lg e) 419 (5.56), 560 (4.29), 603sh nm (3.74); MS (80 eV, 2508C): m/z

4

7.56 (d, J(H,H) 3.5 Hz, 1H; 5-H_phenyl), 9.92 (s, 1H; 15-H), 10.16 (s, 2H;

10-, 20-H); ¹³C NMR (126 MHz, CDCl₃): d 17.05, 18.45, 18.60, 19.73,

19.82, 20.75, 55.40, 55.98, 95.30, 96.56, 110.96, 114.71, 115.18, 121.33, 131.40,

140.78, 141.71, 142.04, 142.36, 142.58, 143.73, 144.21, 145.47, 152.61; UV/Vis

(CH₂Cl₂1% NEt₃): l_max(lg e) 404 (5.26), 504 (4.11), 537 (3.89), 571

(3.90), 623 nm (3.44); UV/Vis (CH₂Cl₂1% TFA): l_max(lg e) 413 (5.41),

562 (4.18), 607sh nm (3.69); MS (80 eV, 3008C): m/z (%): 670 (100) [M] ,

335 (24) [M]²; C₄₄H₅₄N₄O₂´ 0.5CH₃OH (670.94): calcd C77.81, H 8.22, N

8.16; found C77.71, H 7.97, N 7.46.

Butylation of 3a: According to the protocol given for 2b compound 3a

(100 mg, 0.15 mmol) was combined in THF (30 mL). Column chromatog-

raphy on alumina (grade III) with hexane/CH₂Cl₂9:1 (v/v) yielded two

deep red regioisomeric fractions. The first fraction was

6 (87 mg,

0.12 mmol, 80%) followed by 7 (20 mg, 2.8 mmol, 19%); the compounds

were recrystallized from CH₂Cl₂/CH₃OH.

(%): 610 (100) [M] , 305 (18) [M]²; HR-MS [C₄₂H₅₀N₄] calcd 610.4036,

found 610.4059; C₄₂H₅₀N₄´ 0.2CH₂Cl₂(627.87): calcd C80.73, H 8.09, N

8.92; found C80.79, H 7.98, N 8.74. Alternatively, this compound is

available via demetallation of 3h (see demetallation procedure for 3c) in

90% yield.

(5,10-Dibutyl-2,3,7,8,12,13,17,18-octaethylporphyrinato)nickel(ii) (6): M.p.:

2328C; ¹H NMR (500 MHz, CDCl₃): d 0.60 (t, ³J(H,H) 7.5 Hz, 6H;

butyl-CH₃), 0.77 (brs, 4H; butyl-CH₂), 1.05 (m, 4H; butyl-CH₂), 1.69, 1.75,

1.85 (each t, ³J(H,H) 7.5 Hz, 24H; ethyl-CH₃), 3.73 (brs, 16H; ethyl-

CH₂), 4.27 (t, ³J(H,H) 7.5 Hz, 4H; 5,10-CH₂CH₂CH₂CH₃), 9.05 (s, 2H;

15,20-H); ¹³CNMR (126 MHz, CDCl ₃) d 13.69, 17.92, 22.13, 22.21, 23.32,

32.19, 36.92, 95.32, 116.09, 136.29, 137.48, 138.80, 139.28, 142.68, 144.11,

{2,3,7,8,12,13,17,18-Octaethyl-5-(4-bromophenyl)porphyrinato}nickel(ii) (3j):

Dibromobenzene (1 g, 4.24 mmol) was dissolved in THF (20 mL) and

cooled to À808Cand treated dropwise with a solution of butyl lithium in

cyclohexane (2m, 2.12 mL, 4.24 mmol) to yield p-bromophenyl lithium.^[36]

The solution was warmed to room temperature and added over the course

of 1 h to a solution of Ni^II(OEP) 2b (100 mg, 0.17 mmol) in THF (80 mL).

The temperature of the reaction mixture was raised to 508C. Subsequent

steps after hydrolysis were as described for 3h and yielded brown-red

needles (52 mg, 0.07 mmol, 40%). M.p.: 2568C; ¹H NMR (500 MHz,

145.49, 146.75; UV/Vis (CH₂Cl₂): l_max(lg e) 427 (5.19), 555 (4.09), 595 nm

(3.99); MS (80 eV, 210 8C): m/z (%): 703 (100) [M] , 351 (21) [M]²

C₄₄H₆₀N₄Ni (703.68): calcd C75.10, H 8.59, N 7.96; found C75.02, H 8.51, N

7.99.

;

(5,15-Dibutyl-2,3,7,8,12,13,17,18-octaethylporphyrinato)nickel(ii) (7): M.p.:

218 8C; ¹H NMR (500 MHz, CDCl₃): d 0.53 (t, ³J(H,H) 7.5 Hz, 6H;

butyl-CH₃), 0.85 (m, 6H; butyl-CH₂), 0.93 (m, 4H; butyl-CH₂), 1.65, 1.79

(each t,³J(H,H) 7.5 Hz, 24H; ethyl-CH₃), 3.69 (brs, 16H; ethyl-CH₂), 4.29

3

CDCl₃): d 0.92 (t, J(H,H) 7.5 Hz, 6H; CH₃), 1.70 (t, J(H,H) 7.5 Hz,

6H; CH₃), 1.77 (t, ³J(H,H) 7.5 Hz, 12H; CH₃), 2.65, 3.77 (each q,

³J(H,H) 7.5 Hz, 8 H ; CH₂), 3.84 (m, 8H; CH₂), 7.73, 7.89 (each d,

²J(H,H) 8 Hz, 4H; H_phenyl), 9.52 (s, 1H; 15-H), 9.57 (s, 2H; 10-, 20-H);

¹³C NMR (126 MHz, CDCl₃): d 17.69, 18.12, 19.57, 21.43, 95.71, 96.60,

122.55, 129.62, 134.70, 138.85, 139.48, 141.11, 143.12, 144.83, 144.97; UV/Vis

(CH₂Cl₂): l_max(lg e) 401 (5.29), 522 (4.08), 559 nm (4.34); MS (80 eV,

3

(t, J(H,H) 7.5 Hz, 4H; 10,20-CH₂CH₂CH₂CH₃), 9.05 (s, 2H; 10 ± 20-H);

¹³C NMR (126 MHz, CDCl₃) d 13.69, 17.86, 18.04, 19.31, 22.21, 23.16,

31.06, 37.06, 96.43, 114.26, 136.35, 139.40, 144.23, 144.93; UV/Vis (CH₂Cl₂):

l_max(lg e) 423 (5.20), 552 (4.00), 595 nm (3.82); MS (80 eV, 2108C): m/z

(%): 703 (100) [M] , 351 (13) [M]²; C₄₄H₆₀N₄Ni (703.68): calcd C75.10, H

2208C): m/z (%): 746 (100) [M] , 373 (9) [M]²; C₄₂H₄₇N₄BrNi (746.46):

8.59, N 7.96; found C74.77, H 8.55, N 7.58.

calcd C67.58, H 6.35, N 7.51; found C67.90, H 6.11, N 6.63.

{2,3,7,8,12,13,17,18-Octaethyl-5-(1,4-dimethoxyphen-6-yl)porphyrinato}-

nickel(ii) (3k): For the in situ preparation of 2,5-dimethoxyphenyllithium

1-bromo-2,4-dimethoxybenzene (1 g, 4.6 mmol) was dissolved in THF

(5 mL) and cooled to À808C.^[37]The solution was treated dropwise with a

solution of butyl lithium in cyclohexane (2m, 2.12 mL, 4.8 mmol). The

solution was heated to room temperature and, over the course of 1 h added

to a solution of Ni^II(OEP) 3b (100 mg, 0.17 mmol) in THF (60 mL) and the

temperature of the reaction mixture was raised to 508C. After cooling to

room temperature the reaction mixture was hydrolyzed with water and a

solution of DDQ in CH₂Cl₂(0.06m, 10 mL) was added. After stirring for

10 min the mixture was filtered through neutral alumina and chromato-

(5,10,15-Tributyl-2,3,7,8,12,13,17,18-octaethylporphyrinato)nickel(ii) (8):

Compound 6 (100 mg, 0.15 mmol) was dissolved THF (10 mL) and treated

rapidly with a solution of BuLi in cyclohexane (2m, 1 mL, 2 mmol) at

À1008C. At the same temperature a 10% solution of water in THF (1 mL)

was added and the mixture stirred for 2 min. The cold mixture was then

treated with a solution of DDQ in CH₂Cl₂(0.06m, 10 mL) and stirred for an

additional 20 min. After warming up the mixture was filtered through

neutral alumina (grade I) eluting with CH₂Cl₂. Column chromatography on

alumina (grade III) with hexane/CH₂Cl₂19:1 (v/v) gave green red crystals

of 8 in quantitative yield after recrystallization from CH₂Cl₂/CH₃OH.

M.p.: 2558C; ¹H NMR (500 MHz, CDCl₃): d 0.58 (t, ³J(H,H) 7.5 Hz,

2732

ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000

0947-6539/00/0615-2732 $ 17.50+.50/0

Chem. Eur. J. 2000, 6, No. 15

Porphyrins

2721±2738

6H; butyl-CH₃), 0.65 (brs, 2H; butyl-CH₂), 0.97 (brs, 4H; butyl-CH₂), 1.04

³J(H,H) 7.5 Hz, 4H; butyl-CH₂), 9.78 (s, 2H; 10-, 20-H); UV/Vis

(CH₂Cl₂1% NEt₃): l_max(lg e) 414 (5.42), 516 (4.43), 584 (4.10); MS

3

(brs, 6H; butyl-CH₂), 1.65, 1.75, 1.78, 1.79 (each t, J(H,H) 7.5 Hz, 24H;

ethyl-CH₃), 3.44 ± 3.52 (m, 16H; ethyl-CH₂), 4.03 ± 4.18 (m, 6H;

CH₂CH₂CH₂CH₃), 8.77 (s, 1H; 20-H); ¹³C NMR (126 MHz, CDCl₃) d

13.69, 17.71, 17.80, 17.88, 19.22, 21.96, 22.06, 23.28, 23.41, 31.55, 32.32, 36.88,

95.30, 115.47, 117.35, 135.60, 136.33, 136.66, 138.83, 144.13, 144.97, 146.37,

146.91; UV/Vis (CH₂Cl₂): l_max(lg e) 441 (5.08), 570 (3.91), 613sh nm

(80 eV, 2008C): m/z (%): 646 (100) [M] , 603 (25) [M À C₃H₇] , 323 (12)

[M]²; HR-MS (C₄₄H₆₂N₄): calcd 646.4975, found 646.4930; C₄₄H₆₂N₄´

0.33CH₂Cl₂(675.31): calcd C78.85, H 9.35, N 8.30; found C79.08, H

9.31, N 7.65.

{5-Butyl-2,3,7,8,12,13,17,18-octaethyl-10-(1,4-dimethoxyphen-6-yl)porphyr-

inato}nickel(ii) (13): Using the procedure described for 3k compound 3a

(100 mg, 0.15 mmol) was treated with in situ generated 2,5-dimethoxy-

phenyl lithium and yielded purple crystals of 13 (60 mg, 0.08 mmol, 50%).

30% of the starting material could be recovered. M.p.: 2358C; ¹H NMR

(3.20); MS (80 eV, 2208C): m/z (%): 758 (100) [M] , 715 (33) [M À C₃H₇] ,

701 (30) [M À C₄H₉] , 379 (10) [M]²; C₄₄H₆₈N₄Ni (759.78): calcd C75.88, H

9.02, N 7.37; found C75.75, H 8.68, N 7.22.

Butylation of 8: Porphyrin 8 (100 mg, 0.13 mmol) was dissolved in THF

(30 mL) and cooled to À1008C. A BuLi solution (2m, 0.8 mL, 1.6 mmol)

was added dropwise and the mixture stirred for 10 min. Subsequently a

10% solution of water in THF (10 mL) was added at À1008Cand the

mixture stirred for 5 min. Then a solution of DDQ in CH₂Cl₂(0.06m,

10 mL) was added to the cold solution and stirring continued for 20 min.

After warming up the mixture was filtered through alumina (grade I).

Column chromatography on alumina (grade III) with neat hexane yielded

first the tetrabutylated porphyrin 9 (50 mg, 0.06 mmol, 50%) followed by

the porphodimethene 10 (40 mg, 0.05 mmol, 40%). Both compounds were

recrystallized from CH₂Cl₂/CH₃OH.

3

(500 MHz, CDCl₃): d 0.58 (t, J(H,H) 7.5 Hz, 3H; butyl-CH₃), 0.60 (t,

³J(H,H) 7.5 Hz, 3H; ethyl-CH₃), 0.76, 1.02 (each m, 4H; butyl-CH₂), 1.07

(t, ³J(H,H) 7.5 Hz, 3H; ethyl-CH₃), 1.64, 1.69, 1.73, 1.74, 1.85 (each t,

³J(H,H) 7.5 Hz, 18H; ethyl-CH₃), 2.67, 2.79 (each m, 4H; ethyl-CH₂),

3.64 ± 3.79 (m, 18H; ethyl-CH₂, OCH₃), 4.20 (brs, 2H; butyl-CH₂), 7.03 (m,

1H; 2-H_phenyl), 7.19 (dd, ³J(H,H) 9.2 Hz, ⁴J(H,H) 3.1 Hz, 1H; 3-H_phenyl),

7.56 (d, ⁴J(H,H) 3.5 Hz, 1H; 5-H_phenyl), 9.10, 9.19 (each s, 2H; 15-, 20-H);

¹³C NMR (126 MHz, CDCl₃): d 13.61, 16.14, 16.64, 17.71, 17.90, 18.02,

18.19, 19.30, 19.42, 20.81, 21.10, 22.11, 23.32, 33.45, 36.67, 55.34, 55.92, 94.79,

95.55, 110.77, 113.72, 115.12, 137.96, 138.87, 139.46, 139.81, 140.23, 142.68,

143.10, 143.84, 144.58, 144.95, 145.36, 147.78, 152.67, 153.70; UV/Vis

(CH₂Cl₂): l_max(lg e) 419 (5.21), 543 (4.02), 585 nm (4.03); MS (80 eV,

(5,10,15,20-Tetrabutyl-2,3,7,8,12,13,17,18-octaethylporphyrinato)nickel(ii)

(9): M.p.: 2548C; ¹H NMR (500 MHz, CDCl₃): d 0.59 (t, ³J(H,H)

7.5 Hz, 12H; butyl-CH₃), 0.73 (brs, 6H; butyl-CH₂), 1.06 (m, 6H; butyl-

CH₂), 1.74 (t, ³J(H,H) 7.5 Hz, 24H; ethyl-CH₃), 3.48, 3.58 (each brs, 16H;

ethyl-CH₂), 4.03 (m, 6H; butyl-CH₂); ¹³CNMR (126 MHz, CDCl ₃) d

13.69, 1771, 21.82, 23.34, 31.66, 36.72, 116.59 (4C, 5-, 10-, 15-, 20-C), 135.85,

146.48; UV/Vis (CH₂Cl₂): l_max(lg e) 459 (4.93), 591 (3.92), 634 nm (3.56);

3008C): m/z (%): 784 (100) [M] , 391 (24) [M]²; C₄₈H₆₀N₄O₂Ni (784.73):

calcd C73.56, H 7.72, N 7.15; found C73.53, H 7.67, N 7.02.

{5,10-Dibutyl-2,3,7,8,12,13,17,18-octaethyl-10-(1,4-dimethoxyphen-6-yl)-

porphyrinato}nickel(ii) (14): Using the procedure described for 3k por-

phyrin 6 (100 mg, 0.14 mmol) was treated with in situ generated 2,5-

dimethoxyphenyl lithium and yielded purple crystals of 14 (60 mg,

0.08 mmol, 50%). 20% of the starting material could be recovered.

M.p.: 2248C; ¹H NMR (250 MHz, CDCl₃): d 0.58 (t, ³J(H,H) 7.5 Hz,

3H; butyl-CH₃), 0.60 (t, ³J(H,H) 7.5 Hz, 3H; butyl-CH₃), 0.69 (m, 5H;

ethyl-CH₃, butyl-CH₂), 0.78 (m, 2H; butyl-CH₂), 1.01 (t, ³J(H,H) 7.5 Hz,

3H; ethyl-CH₃), 1.08 (m, 4H; butyl-CH₂), 1.62, 1.67, 1.68, 1.80, 1.81, 1.84

(each t, ³J(H,H) 7.5 Hz, 21H; ethyl-CH₃), 2.60 ± 2.73 (m, 4H; ethyl-CH₂),

3.58 ± 3.67 (m, 18H; ethyl-CH₂, OCH₃), 4.18 (m, 4H; butyl-CH₂), 7.02 (m,

1H; 2-H_phenyl), 7.16 (dd, ³J(H,H) 8.8 Hz, ⁴J(H,H) 2.2 Hz, 1H; 3-H_phenyl),

7.56 (m, 1H; 5-H_phenyl), 8.90 (s, 1H; 20-H); UV/Vis (CH₂Cl₂): l_max(lg e)

436 (5.02), 564 (4.09), 585 nm (3.75); MS (80 eV, 3008C): m/z (%): 838 (100)

MS (80 eV, 2508C): m/z (%): 814 (100) [M] , 771 (18) [M À C₃H₇] , 751

(73) [M À C₄H₉] , 407 (19) [M]²; C₅₂H₇₆N₄Ni (815.89): calcd C76.55, H

9.36, N 6.87; found C76.64, H 9.17, N 7.10.

(5,10,15,20-Tetrabutyl-syn-5,15-dihydro-2,3,7,8,12,13,17,18-octaethylpor-

phyrinato)nickel(ii) (10): M.p.: 1808C; ¹H NMR (500 MHz, CDCl₃): d

0.95 (t, ³J(H,H) 7.5 Hz, 6H; 5⁴-, 15⁴-H), 0.98 (t, ³J(H,H) 7.5 Hz, 6H;

10⁴-, 20⁴-H), 1.03 (t, ³J(H,H) 7.5 Hz, 12H; 3²-, 7²-, 12²-, 17²-H), 1.13 (t,

³J(H,H) 7.5 Hz, 12H; 2²-, 8²-, 12²-, 18²-H), 1.41 ± 1.55 (m, 12H; 5²-, 5³-, 10³-

, 15²-, 15³-, 20³-H), 1.82 (m, 2H; 10²-, 20²-H), 2.30 (q, ³J(H,H) 7.5 Hz, 8H;

3¹-, 7¹-, 13¹-, 17¹-H), 2.58 (m, 8H; 2¹-, 8¹- 12¹-, 18¹-H), 3.12, (m, 2H; 5¹-, 15¹-

3

H), 3.78 (t, J(H,H) 7.5 Hz, 2H; 5-, 15-H); ¹³C NMR (126 MHz, CDCl₃)

[M] , 419 (14) [M]²; C₅₂H₆₈N₄O₂Ni (839.83): calcd C73.18, H 8.05, N 6.54;

d 14.04, 16.29, 16.52, 17.43, 21.17, 23.08, 23.71, 28.92, 31.33, 36.68, 37.55,

42.74, 129.85, 132.44, 140.90, 148.29, 155.65; UV/Vis (CH₂Cl₂): l_max(lg e)

326 (0.04), 451 (4.70), 551 nm (3.83); MS (80 eV, 2008C): m/z (%): 816 (40)

found C73.26, H 8.35, N 6.69.

Butylation of Zn^II(TPP): Zn^II(TPP) 1c (150 mg, 0.23 mmol) was dissolved

in THF (20 mL) and cooled to À408C. Butyl lithium (2m, 0.4 mL) solution

was added rapidly and the mixture warmed to rt. An additional butyl

lithium stock solution (0.3 mL) was added until the reaction of Zn^II(TPP)

was complete. The reaction mixture was treated with water and in order to

complete the demetallation HCl (15% in water) was added. The organic

phase was extracted with water and dried via filtration over alumina. This

step removes polar side products from the starting material which are

retained on the alumina. Final purification was achieved by chromatog-

raphy on alumina (grade III) using hexane/10% methanol in CH₂Cl₂as

eluant. The first fraction consisted 16 (30 mg, 27 mmol, 18%) and the

second fraction of 15 (10 mg, 15 mmol, 6.5%). Use of free base H₂TPP gives

the same products in lower yields 15: M.p.: 2188C; ¹H NMR (500 MHz,

[M] , 759 (100) [M À C₄H₉] , 702 [M À 2C₄H₉] , 408 (12) [M]²

C₅₂H₇₈N₄Ni (817.92): calcd C76.36, H 9.61, N 6.85; found C76.24, H 9.46,

N 6.88.

;

(5,10,15-Tributyl-syn-5,15-dihydro-2,3,7,8,12,13,17,18-octaethylporphyrina-

to)nickel(ii) (11): When the reaction of 6 with BuLi was performed at

temperatures above À1008Cformation of a brown side product was

observed, which was difficult to separate chromatographically from 8. At

temperatures above À308Cthe brown compound 11 was the sole product

formed and isolated in quantitative yield. M.p.: 1758C; ¹H NMR

(250 MHz, CDCl₃): d 0.93 (t, ³J(H,H) 7.5 Hz, 6H; 5⁴-, 15⁴-H), 0.96 (t,

3

³J(H,H) 7.5 Hz, 3 H ; 10⁴-H), 1.013, 1.022 (each t, J(H,H) 7.5 Hz, 12H;

2²-, 8²-, 12²-, 18²-H), 1.11 (t, ³J(H,H) 7.5 Hz, 12H; 3²-, 7²-, 13²-, 17²-H),

1.43 ± 1.50 (m, 10H; 5²-, 5³-, 10³-,15²-, 15³-H), 1.76 (m, 2H; 10²-H), 2.29 (q,

J 7.5 Hz, 8H; 3¹-, 7¹-, 13¹-, 171-H), 2.38 ± 2.50, 2.52 ± 2.62 (each m, 8H; 2¹-,

8¹-, 12¹-, 18¹-H), 2.96 (m, 6H; 5¹-, 10¹-, 15¹-H), 3.78 (t, ³J(H,H) 7.5 Hz, 2H;

5-, 15-H), 6.57 (s, 1H; 20-H); UV/Vis (CH₂Cl₂): l_max(lg e) 445 (4.75),

3

CDCl₃): d À1.41 (s, 2H; NH), 0.56 (t, J(H,H) 7.5 Hz, 3H; CH₃), 0.75,

0.83 (each m, 2H; CH₂), 0.98 (m, 2H CH₂), 1.37, 1.59 (each m, 2H; CH₂),

3.90 (dd, ³J(H,H) 1 Hz, ²J 17.5 Hz, 1H; 3-H_syn), 4.37 (dd, ³J(H,H)

9 Hz, ²J 17.5 Hz, 1H; 3-H_anti), 4.68 (m, 1H; 2-H), 7.60 ± 8.20 (m, 20H;

H_phenyl), 8.18, 8.20 (each d, J 5 Hz, H_pyrrole), 8.42 (s, 2H; 12-, 13-H), 8.56,

8.57 (each d, J 5 Hz, 7-, 8-, 17-, 18-H); UV/Vis (CH₂Cl₂1% NEt₃): l_max

(lg e) 406sh (5.17), 420 (5.27), 518 (4.21), 547 (4.07), 598 (3.87), 652 nm

549 nm (4.31); MS (80 eV, 2208C): m/z (%): 760 (48) [M] , 703 (100) [M À

C₄H₉] , 646 (29) [M À 2C₄H₉] , 380 (9) [M]²; C₄₈H₇₀N₄Ni (761.80): calcd C

75.68, H 9.26, N 7.35; found C75.66, H 8.87, N 7.30.

(4.53); MS (80 eV, 2508C): m/z (%): 672 (100) [M] , 615 (42) [M À C₄H₉] ,

336 (16) [M]²

; HR-MS [C₄₈H₄₀N₄] calcd 672.3253, found 672.3258;

5,15-Dibutyl-2,3,7,8,12,13,17,18-octaethylporphyrin (12): According to the

procedure given for the preparation of 3c, 12 was prepared in 80% yield via

demetallation of 7. M.p.: 2048C; ¹H NMR (250 MHz, CDCl₃): d À1.53

(brs, 2H; NH), 0.95 (brs, 6H; butyl-CH₃), 1.30 ± 2.13 (m, 32H; butyl-CH₂,

ethyl-CH₃), 3.93 ± 4.08 (m, 16H; ethyl-CH₂), 4.93 (t, ³J(H,H) 7.5 Hz, 4H;

C₄₈H₄₀N₄´ 0.25CH₃OH (680.9): calcd C85.11, H 6.07, N 8.23; found C

85.27, H 5.84, N 8.27.

1

trans-2,3-Dibutyl-5,10,15,20-tetraphenylchlorin (16): M.p.: 2468C; H NMR

3

(500 MHz, CDCl₃): d À1.42 (s, 2H; NH), 0.64 (t, J(H,H) 7.5 Hz, 6H;

1

butyl-CH₂), 9.98 (brs, 2H; 10-, 20-H); H NMR (250 MHz, CDCl₃0.5%

CH₃), 0.80 ± 1.21 (m, 8H; CH₂), 1.53, 1.64 (m, 4H; CH₂), 4.34 (dd,

³J(H,H) 10 Hz, ²J 3 Hz, 2H; 2-, 3-H), 7.60 ± 8.25 (m, 20H; H_phenyl), 8.16,

8.5 (each d, ³J(H,H) 5 Hz, 4H; 7-, 8-, 17-, 18-H), 8.41 (s, 2H; 12-, 13-H);

¹³C NMR (126 MHz, CDCl₃) d 13.83, 22.07, 28.81, 33.80, 51.81, 112.83,

3

TFA, TMS): d À1.72 (s, 2H; NH), 1.22 (t, J(H,H) 7.5 Hz, 6H; butyl-

CH₃), 1.25, 1.38 (each t, ³J(H,H) 7.5 Hz, 24H; ethyl-CH₃), 1.93, 2.46 (each

m, 8H; butyl-CH₂), 3.48, 3.64 (each q, J 7.5 Hz, 16H; ethyl-CH₂), 4.63 (t,

Chem. Eur. J. 2000, 6, No. 15

ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000

0947-6539/00/0615-2733 $ 17.50+.50/0

2733

M. O. Senge et al.

FULL PAPER

Table 2. Summary of crystal data, data collection and refinement for the crystal structure determinations.

3a

3c

3 f

3h

3i

3k

chemical formula

C₄₀H₅₂N₄Ni ´

CH₂Cl₂

C₄₀H₅₄N₄

C₄₂H₅₄N₄NiO₂

C₄₂H₄₈N₄Ni

C₄₂H₅₀N₄´

C₄₄H₅₂N₄NiO₂

2CH Cl₂

2

mol. wt.

732.49

590.78

705.60

667.55

695.79

727.61

crystallization

color, habit

CH₂Cl₂/CH₃OH

red parallele-

piped

CH₂Cl₂/CH₃OH

black irregular

block

CH₂Cl₂/CH₃OH

red cube

CH₂Cl₂/CH₃OH

red parallele-

piped

CH₂Cl₂/CH₃OH

red block

CDCl₃/CH₃OH

red cube

crystal size [mm]

lattice type

space group

a []

b []

c []

0.4 Â 0.1 Â 0.05

orthorhombic

Pbca

13.664(6)

14.916(7)

0.5 Â 0.25 Â 1

0.65 Â 0.65 Â 0.65

monoclinic

P2₁/c

12.273(3)

16.443(5)

18.712(6)

0.78 Â 0.42 Â 0.13

0.35 Â 0.30 Â 0.10

0.41 Â 0.36 Â 0.30

monoclinic

P2₁/n

14.787(4)

13.987(3)

triclinic

Å

P1

9.549(4)

12.767(6)

14.537(7)

91.63(4)

103.89(3)

96.51(3)

1706(1)

2

1.150

0.507

0.95, 0.79

126

10.808(6)

12.527(10)

14.743(6)

65.16(5)

71.95(4)

78.43(6)

1717(2)

2

1.291

1.079

0.87, 0.49

129

13.752(7)

15.043(7)

18.590(7)

78.88(4)

87.54(4)

89.32(4)

3770(3)

4

1.226

1.811

0.84, 0.57

129

36.765(16)

18.219(5)

a [8]

b [8]

g [8]

V [³]

Z

102.57(2)

92.04(2)

7493(6)

8

1.299

2.312

0.89, 0.46

129

3686(2)

4

1.272

1.071

0.5, 0.5

126

3766(2)

4

1.283

1.067

0.74, 0.67

129

d_calcd[Mg m^À3

]

m [mm^À1

]

T_max, T_min

T [K]

q_max[8]

57.13

5646

5044

57.04

4951

4614

3008

57.0

57.04

4929

4622

4115

57.04

55.05

5206

4726

collec. reflections

indep. reflections

reflections with

F > 4.0s(F)

5472

4974

4565

10699

10179

6658

3697

3740

R_int

0.0778

313

0.864

0.1083

397

0.382

0.1348

442

0.402

0.1859

424

1.052

0.1190

819

0.721

0.0728

460

0.389

no. of parameters

D/1_max[e

À3

]

R1 [F > 4.0s(F)]

wR2 [F > 4.0s(F)]

R1 (all data)

0.0842

0.2332

0.1202

0.2792

0.0940

0.2302

0.1380

0.2631

0.0426

0.1090

0.0470

0.1119

0.0833

0.2327

0.0929

0.2443

0.0948

0.2149

0.1438

0.2446

0.0525

0.1270

0.0703

0.1376

wR2 (all data)

3l

6

7 monoclinic

7 triclinic

8

10

chemical formula

C₄₄H₅₄N₄O₂

C₄₄H₆₀N₄Ni

C₄₄H₆₀N₄Ni ´

CDCl₃

C₄₄H₆₀N₄Ni

C₄₈H₆₈N₄Ni ´ CH₂Cl₂

C₅₂H₈₈N₄Ni

mol. wt.

670.91

703.67

823.04

703.67

844.70

827.97

crystallization

color, habit

CDCl₃/CH₃OH

red parallele-

piped

CH₂Cl₂/CH₃OH

red parallele-

piped

CDCl₃/n-hexane

red block

CH₂Cl₂/CH₃OH

red plate

CH₂Cl₂/CH₃OH

red block

CH₂Cl₂/C₂H₅OH

red parallelepiped

crystal size [mm]

lattice type

space group

a []

b []

c []

0.54 Â 0.28 Â 0.16

monoclinic

P2₁/n

11.044(2)

15.371(3)

0.80 Â 0.15 Â 0.10

1 Â 1 Â 1

monoclinic

P2₁/c

23.763(6)

14.319(4)

25.479(7)

1.1 Â 1 Â 0.15

0.6 Â 0.4 Â 0.35

monoclinic

P2₁/c

22.798(9)

14.839(5)

13.620(4)

0.62 Â 0.5 Â 0.24

triclinic

Pꢀ1

triclinic

Å

P1

13.416(6)

14.168(7)

23.748(13)

90.48(4)

99.50(4)

117.27(3)

3939(3)

4

1.187

0.959

0.91, 0.51

129

9.609(3)

15.218(6)

15.338(4)

61.24(3)

78.36(2)

89.22(3)

1916.6(11)

2

1.219

0.542

0.92, 0.59

129

12.680(4)

18.406(7)

22.296(9)

110.59(3)

95.37(3)

103.62(3)

4644(3)

4

1.184

0.877

0.81, 0.58

126

22.218(4)

a [8]

b [8]

g [8]

V [³]

Z

94.836(14)

101.93(2)

93.28(3)

3758(1)

4

1.186

0.563

0.75, 0.92

129

8482(4)

8

1.289

0.683

0.55, 0.55

129

4600(3)

4

1.220

1.946

0.55, 0.39

129

d_calcd[Mg m^À3

]

m [mm^À1

]

T_max, T_min

T [K]

q_max[8]

56.34

5501

4952

56.54

10979

10434

8514

30.0

11807

11186

7728

57.04

6828

6215

56.95

13155

12471

9253

collec. reflections

indep. reflections

reflections with

F > 4.0s(F)

22357

20945

12456

3660

4757

R_int

0.0686

452

0.759

0.0673

905

1.291

0.0455

1009

1.360

0.0353

454

1.423

0.1049

360

0.561

0.0714

1014

1.318

no. of parameters

D/1_max[e

À3

]

R1 [F > 4.0s(F)]

wR2 [F > 4.0s(F)]

R1 (all data)

0.0833

0.2058

0.1113

0.2282

0.0775

0.2081

0.0912

0.2235

0.0941

0.2027

0.1648

0.2412

0.0723

0.1682

0.1140

0.1950

0.0710

0.1584

0.0967

0.1720

0.0831

0.2081

0.1112

0.2285

wR2 (all data)

2734

ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000

0947-6539/00/0615-2734 $ 17.50+.50/0

Chem. Eur. J. 2000, 6, No. 15

Porphyrins

2721±2738

Table 2 continued.

11

12

16 triclinic A

16 triclinic B

17

chemical formula

mol. wt.

crystallization

color, habit

crystal size [mm]

lattice type

space group

a []

b []

c []

a [8]

b [8]

C₄₈H₇₀N₄Ni ´ CH₂Cl₂

846.72

CH₂Cl₂/CH₃OH

red block

0.6 Â 0.4 Â 0.3

monoclinic

P2₁/n

14.782(6)

13.570(5)

23.697(9)

C₄₄H₆₂N₄

646.98

C₅₂H₄₈N₄

728.94

C₅₂H₄₈N₄´ CH₂Cl₂

813.87

C₅₃H₅₀N₄O₃Zn ´ 2CH₃OH

888.42

CH₂Cl₂/CH₃OH

red plate

0.81 Â 0.2 Â 0.03

monoclinic

P2₁/n

13.897(7)

8.674(3)

38.654(16)

CH₂Cl₂/CH₃OH

red plate

0.3 Â 0.2 Â 0.05

monoclinic

P2₁/n

16.536(3)

13.494(3)

8.7639(18)

CH₂Cl₂/CH₃OH

irregular shape

0.42 Â 0.2 Â 0.2

triclinic

Pꢀ1

11.883(1)

13.155(2)

14.040(2)

85.66(1)

74.89(1)

72.03(1)

2015.6(5)

2

CH₂Cl₂/CH₃OH

rhombic plate

0.52 Â 0.5 Â 0.04

triclinic

Pꢀ1

11.922(11)

13.401(10)

14.634(11)

96.86(6)

103.51(6)

103.57(6)

2172(3)

2

92.20(3)

97.70(3)

92.78(4)

g [8]

V [³]

Z

4750(3)

4

1.184

1.885

0.57, 0.32

126

1938.0(7)

2

1.109

0.484

0.86, 0.59

129

4654(4)

4

1.268

1.107

0.97, 0.47

128

d_calcd[Mg m^À3

]

1.201

0.536

0.9, 0.8

129

1.244

1.655

0.94, 0.48

128

m [mm^À1

]

T_max, T_min

T [K]

q_max[8]

56.09

6835

6201

4919

0.0720

505

0.841

0.0676

0.1618

0.0851

0.1749

56.30

2795

2448

1409

0.1061

217

0.567

0.1204

0.2931

0.1861

0.3317

56.07

5566

5255

4381

0.0532

506

0.195

0.0440

57.55

6205

5866

3836

0.0469

413

0.605

0.1130

55.11

6661

5866

4099

0.0387

569

0.501

0.0579

0.1279

0.0956

0.1486

collec. reflections

indep. reflections

reflections with F > 4.0s(F)

R_int

no. of parameters

D/1_max[e

R1 [F > 4.0s(F)]

wR2 [F > 4.0s(F)]

R1 (all data)

À3

]

0.1190

0.0535

0.1272

0.2848

0.1624

0.3264

wR2 (all data)

122.36, 123.70, 126.65, 127.14, 127.39, 127.52, 127.69, 127.79, 131.94, 132.70,

133.87, 134.10, 135.15, 141.18, 142.11, 142.39, 152.40, 169.09; UV/Vis

(CH₂Cl₂1% NEt₃): l_max(lg e) 406sh (5.16), 420 (5.30), 519 (4.22), 547

(4.07), 598 (3.85), 652 nm (4.50); UV/Vis (CH₂Cl₂1% TFA): l_max(lg e)

(5,5,10,15,20-Pentabutyl-15,15¹-didehydroporphyrinato)nickel(ii) (20): This

compound is obtained from the reaction leading to 19 when an oxidation

step is included after hydrolysis with water. The oxidation was performed

by adding a solution of DDQ (0.06m, 10 mL) in CH₂Cl₂followed by

standard work up as described for 19. In this case the porphodimethene 20

was obtained as orange-red powder (85 mg, 0.13 mmol, 80%).

M.p.: 1738C; ¹H NMR (250 MHz, CDCl₃): d 0.83 ± 1.05 (m, 15H; 5⁴-,

5'⁴-, 10⁴-, 15⁴-, 20⁴-H), 1.22 (m, 2H; 5¹-, 5'¹-H), 1.30 ± 1.42 (m, 2H; 5²-, 5'²-H),

1.47 (m, 8H; 5³-, 5'³, 10³-, 20³-H), 1.58 (m, 2H, 15³-H), 1.75 (m, 4H; 10²-, 20²-

H), 2.02 (m, 2H, 5²-, 5'²-H), 2.58 (m, 2H; 15²-H), 2.80 (m, 4H; 10¹-, 20¹-H),

2.99 (m, 2H, 5¹-, 5'¹-H), 6.37 (dd, ³J(H,H) 6 Hz, ³J(H,H) 9 Hz, 1H; 15¹-

H), 6.22, 6.24, 6.43, 6.45, 7.03, 7.05, 7.07, 7.09 (each d, ³J(H,H) 4.5 Hz, 8H;

b-H); UV/Vis (CH₂Cl₂): l_max(lg e) 434 (4.59), 524 nm (4.06); MS (80 eV,

436 (5.28), 640 nm (4.49); MS (80 eV, 2508C): m/z (%): 728 (100) [M] , 671

(36) [M À C₄H₉] , 614 (7) [M À 2C₄H₉] , 364 (15) [M]²

; HR-MS

[C₅₂H₄₈N₄] calcd 728.3879, found 728.3892; C₅₂H₄₈N₄´ 0.5CH₃OH (745.0):

calcd C84.64, H 6.67, N 7.52; found C84.89, H 6.51, N 7.53.

(trans-2,3-Dibutyl-5,10,15,20-tetraphenylchlorinato)zinc(ii) (17): Zinc in-

sertion into 16 using zinc bromide in THF gave 19 (90%). M.p.: 3208C;

¹H NMR (500 MHz, CDCl₃): d 0.65 (t, ³J(H,H) 7.5 Hz, 6H; CH₃),

0.84 ± 1.30 (m, 8H; CH₂), 1.52 ± 1.72 (m, 4H; CH₂), 4.22 (dd, ³J(H,H)

2

10 Hz, J 3 Hz, 2H; 2-, 3-H), 7.56 ± 7.73 (m, 14H; H_phenyl), 7.93, 8.06, 8.16

2508C): m/z (%): 646 (23) [M] , 589 (100) [M À C₄H₉] , 323 (5) [M]²; HR-

MS (C₄₀H₅₂N₄Ni) calcd 646.3546, found 646.3574; C₄₀H₅₂N₄Ni (647.57):

calcd C74.19, H 8.09, N 8.65; found C73.96, H 7.84, N 8.84.

(each m, 6H; H_o-phenyl), 8.05,8.48 (each d, ³J(H,H) 5 Hz, 4H; 7-, 8-, 17-, 18-

H), 8.34 (s, 2H; 12-, 13-H); UV/Vis (CH₂Cl₂): l_max(lg e) 419 (5.24), 591sh

(3.76), 621 nm (4.39); MS (80 eV, 2508C): m/z (%): 790 (100) [M] , 733 (7)

[M À C₄H₉] , 676 (42) [M À 2C₄H₉] , 395 (16) [M]²

.

(5-Butyl-15,15¹-didehydro-5,10,15,20-tetrakis(1-methylpropyl)porphyrina-

to)nickel(ii) (22): Following the procedure given for 19 reaction of 21a

(100 mg, 0.17 mmol) with BuLi gave an orange-red powder of 22(70 mg,

0.11 mmol, 60%). M.p.: 1788C; ¹H NMR (500 MHz, CDCl₃): d 0.72, 0.78

(each d, ³J(H,H) 7 Hz, 6H; isobutyl-5³-H), 0.9 (m, 1H; butyl-5¹-H), 0.79

(t, ³J(H,H) 7 Hz, 2H; butyl-5⁴-H), 1.01 (m, 14H; butyl-5³-H, isobutyl-10³-

(5,5,10,15,20-Pentabutyl-15-hydroporphyrinato)nickel(ii) (19): NiTnBuP

18 (100 mg, 0.17 mmol) was dissolved in THF (20 mL), cooled to À408C

and treated with butyl lithium (2m, 0.3 mL in cyclohexane). The reaction

mixture was stirred for 20 min and then water (1 mL) was added. The

solution was filtered through neutral alumina (grade III) and chromato-

graphed on alumina (grade III, hexane/CH₂Cl₂9:1 v/v). The porphodime-

thene 19 was obtained as orange powder (90%, 95 mg, 0.15 mmol).

M.p.: 1698C; ¹H NMR (500 MHz, CDCl₃): d 0.89 ± 1.02 (m, 17H; 5⁴-, 4'⁴-,

10⁴-, 15³-, 15⁴-, 20⁴-H), 1.29 (m, 2H; 5¹-, 5'¹-H), 1.39 ± 1.50 (m, 12H; 5²-, 5'²-,

5³-, 10³-, 15²-, 20³-H), 1.75 (m, 4H; 10²-, 20²-H), 1.99 (m, 2H, 5²-, 5'²-H), 2.75

(m, 6H; 10¹-, 15¹-, 20¹-H), 3.32 (m, 2H, 5¹-, 5'¹-H), 3.77 (t, ³J(H,H) 7.5 Hz,

1H; 15-H), 6.10, 6.17, 6.93, 6.96 (each d, ³J(H,H) 4.5 Hz, 8H; b-H); UV/

Vis (CH₂Cl₂): l_max(lg e) 432 (4.69), 524 nm (4.32); MS (80 eV, 2508C):

3

, 20³-H), 1.02, 1.25 (each d, J(H,H) 7 Hz, 6H; isobutyl-15³-H), 1.49 (m,

2H; butyl-5²-H), 1.73 (m, 1H; isobutyl-5²-H), 2.09 (m, 5H, butyl-5¹-, 5²-H,

isobutyl-10²-, 20²-H), 2.66 (m, 4H; isobutyl-10¹-, 20¹-H), 3.04 ± 3.18 (m, 3H,

3

isobutyl-5¹-, 15²-H), 6.21 (d, J(H,H) 11 Hz, 1H; 15¹-H), 6.24, 6.44, 6.45,

7.02, 7.04, 7.05, 7.08 (each d, ³J(H,H) 4.5 Hz, 8H; b-H); UV/Vis (CH₂Cl₂):

l_max(lg e) 434 (4.59), 548 nm (4.33); MS (80 eV, 2508C): m/z (%): 646 (18)

[M] , 589 (100) [M À C₄H₉] , 323 (7) [M]²; HR-MS [C₄₀H₅₂N₄Ni] calcd

646.3546, found 646.3510; C₄₀H₅₂N₄Ni ´ 1.5 CH₂Cl₂(774.97): calcd C64.32,

H 7.15, N 7.23; found C64.70, H 7.02, N 7.09.

m/z (%): 648 (15) [M] , 591 (100) [M À C₄H₉] , 534 (15) [M À 2C₄H₉] , 491

(27) [M À 2C₄H₉À C₃H₇] , 324 (6) [M]²; HR-MS (C₄₀H₅₄N₄Ni): calcd

(5-Butyl-5,10,15,20-tetra(tert-butyl)-15-hydroporphyrinato)nickel(ii) (23):

Following the procedure given for 19 porphyrin 21c (100 mg, 0.17 mmol)

yielded (40 mg, 0.06 mmol, 40%). M.p.: 1578C, ¹H NMR (500 MHz,

648.3702, found 648.3722; C₄₀H₅₄N₄Ni ´ 0.25CH₂Cl₂(662.47): calcd C72.02,

H 8.19, N 8.35; found C71.96, H 7.55, N 7.92.

Chem. Eur. J. 2000, 6, No. 15

ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000

0947-6539/00/0615-2735 $ 17.50+.50/0

2735

M. O. Senge et al.

FULL PAPER

CDCl₃): d 0.80 (t, ³J(H,H) 7.5 Hz, 3H; butyl-5⁴-H), 0.75 ± 0.82 (m, 2H;

butyl-5³-H), 1.24 (m, 2H; butyl-5²-H), 1.27, 1.41 (each s, 18H; t-butyl-5²-,

15²-H), 1.70 (s, 18H; t-butyl-10²-, 20²-H), 2.21 (m, 2H; butyl-5¹-H), 3.88 (s,

1H; 15-H), 6.085 (d, ³J(H,H) 4.5 Hz, 2H; 13-, 17-H), 6.225 (d, ³J(H,H)

4.5 Hz, 2H; 3-, 7-H), 7.175 (d, ³J(H,H) 4.5 Hz, 2H; 2-, 8-H), 7.195 (d,

³J(H,H) 4.5 Hz, 2H; 12-, 18-H); UV/Vis (CH₂Cl₂): l_max(lg e) 452 (4.47),

atoms each were refined with a common isotropic thermal parameter. 9:

This compound was crystallized from CHCl₃/CH₃OH. However, the

crystals were twinned and the best refinement converged only at R1

ꢀ0.15. Crystal data: C₆₀H₇₆N₄Ni ´ 2CHCl₃, triclinic P1, a 13.509(8) ,

Å

b 14.213(10) , c 15.460(8) , a 91.72(5)8, b 90.43(4)8, g

113.72(4)8, Z 2. A different crystal form is described elsewhere.^[51]10:

One pyrrole ring and several n-butyl chains were disordered or showed

high thermal motion. Atoms C2, C2A, C2B, C3, C3A, C3B, C20C, C30C

and C30D were refined as disordered over two split positions with equal

occupancies. No hydrogen atoms were included in the refinement for the

disordered positions. Residual electron density was located in the

disordered region. 11: Atom C10D shows very strong librational move-

ment; refinement with split positions gave no improvement of the overall

refinement. 12: The crystal underwent considerable decay during the data

collection (19.8%) what probably accounts for the unsatisfactory R values.

We were unable to obtain better crystals. 16 (triclinic B): The crystal

showed only weak diffraction. The phenyl carbon atoms were refined with

isotropic thermal parameters. 17: No hydrogen atoms were included in the

refinement for the solvate methanol molecules and the oxygen atom of the

axial methanol.

534 nm (4.49); MS (80 eV, 2508C): m/z (%): 648 (8) [M] , 591 (100) [M À

C₄H₉] , 535 (100) [M À 2 C₄H₉] ; HR-MS (C₄₀H₅₄N₄Ni) calcd 648.3702,

found 648.3721.

Crystallography: The crystals were immersed in hydrocarbon oil (Paraton

N), suitable single crystals selected under the microscope, mounted on a

glass fiber and placed in the low-temperature N₂stream on the diffrac-

tometer.^[57]Intensity data for 7 (monoclinic and triclinic modification) were

collected with an Siemens R3m/V diffractometer using graphite mono-

chromated Mo_Karadiation (l 0.71073 ) with w scans. Intensity data for

3a, 3c, 3 f, 3h, 3i, 8, 10, 16 (triclinic B), were collected with an Syntex P2₁

instrument using graphite filtered Cu_Karadiation (l 1.54178 ) with 2q À

q scans, while data for 3k, 3l, 6, 11, 12, 16 (triclinic A), and 17 were

collected using an Siemens P4 diffractometer equipped with a rotating

anode (2q-q scans, Ni-filtered Cu_Karadiation, l 1.54178 ). The inten-

sities were corrected for Lorentz and polarization effects. Absorption

corrections were applied using the program XABS2,^[58]extinction effects

were disregarded. The structures of 3a, 3 f, 3h, 3k, 6, 7 (monoclinic and

triclinic modification), 8, and 10 were solved with via a Patterson synthesis

followed by structure expansion, while the structures of 3c, 3i, 3l, 11, 12, 16

(triclinic A and B), and 17 were solved using direct methods.^[59]Refine-

ments were carried out by full-matrix least squares on jF²j with the

program SHELXL-97 using all data.^[60]Unless otherwise stated, non-

hydrogen atoms were refined with anisotropic thermal parameters. Except

for disordered groups, hydrogen atoms were generally placed into geo-

metrically calculated positions and refined using a ridging model. Details

for the crystal data, data collection and refinement are given in Table 2.

Acknowledgement

This work was generously supported by the Deutsche Forschungsgemein-

schaft (Se543/2-4 and Heisenberg-Fellowship/3-1) and the Fonds der

Chemischen Industrie. We are indebted to the UC Davis crystallographic

facility (Dr. M. M. Olmstead, director) for their cooperation and use of

their facilities.

Crystallographic data (excluding structure factors) for the structures

reported in this paper have been deposited with the Cambridge Crystallo-

graphic Data Centre as supplementary publication no. CCDC-135222 to

CCDC-135236. Data for 8 and 10 were deposited earlier.^[28]Copies of the

data can be obtained free of charge on application to CCDC, 12 Union

Road, Cambridge CB21EZ, UK (fax: (44)1223-336-033; e-mail: deposit

@ccdc.cam.ac.uk).

[1] R. M. Willstätter, A. Stoll, Untersuchungen über das Chlorophyll,

Springer Verlag, Berlin, 1913.

[2] H. Fischer, H. Orth, Die Chemie des Pyrrols, Akademische Verlags-

gesellschaft, Leipzig, 1937.

[3] J. E. Falk, Porphyrins and Metalloporphyrins, Elsevier, Amsterdam,

1964; Porphyrins and Metalloporphyrins (Ed.: K. M. Smith), Elsevier,

Amsterdam, 1975; The Porphyrins (Ed.: D. Dolphin), Academic

Press, New York, 1978.

Refinement details: 3a: Only the nickel atom, side chain carbon atoms and

non-hydrogen solvate atoms were refined with anisotropic thermal

parameters. 3c: One ethyl group was found to be disordered and atom

C22 was refined with split positions using free refined occupancies of 0.55

and 0.45, respectively. Hydrogen atoms were treated accordingly. 3h:

Residual electron density was located near the Ni center. 3i: The phenyl

groups were refined as rigid hexagons with isotropic thermal parameters.

Hydrogen atoms were added in the riding model to all four pyrrole nitrogen

atoms and refined with occupancies of 0.5. The two methylene chloride

molecules of solvation both were disordered. One chlorine atom in each

solvate molecule was refined with two split positions: Cl1S (0.566), Cl1'

(0.434); Cl3S (0.66), Cl3' (0.34). No hydrogen atoms were included in the

refinement for the solvate molecules. 3i: One ethyl side chain was

disordered and refined with two split positions for C181 and C182, each.

Occupancies were determined by refinement to 0.61 and 0.39 and hydrogen

atoms were treated accordingly. 6: Two n-butyl chains showed large

thermal parameters for the carbon atoms. Accordingly, C5C, C5D and

C25D were refined as disordered over two split positions with equal

occupancies. Hydrogen atoms were treated accordingly. With the exception

of C25' all nonhydrogen atoms were refined with anisotropic thermal

parameters. 7 (monoclinic modification): Residual electron density is

located near the Ni center. One of the pyrrole rings in molecule 1

(containing C17 and C18) was disordered. C17, C18 and the associated

ethyl side chains were refined as two separate sets of positions with equal

occupancies. Hydrogen atoms were included in the riding model accord-

ingly. 7 (triclinic modification): Some of the side chain alkyl groups showed

high thermal motion. Atom C54 was refined as disordered over two split

positions with occupancies of 0.53 (C54) and 0.47 (C54'), respectively. The

residual electron density is located as a single peak near the ethyl group at

C2. Attempts to model this group as disordered did not improve the

refinement model. 8: Only the side chain and solvent nonhydrogen atoms

were refined with anisotropic thermal parameters. The N, C_a, C_b, and C_m

[4] Handbook of Porphyrins (Eds.: K. M. Kadish, K. M. Smith, R.

Guilard), Academic Press, New York, 2000.

[5] D. Gust, A. Moore, Top. Curr. Chem. 1991, 159, 103; M. Bixon, J. Fajer,

J. H. Freed, D. Gamliel, A. J. Hoff, H. Levanon, K. Möbius, R.

Nechushtai, J. R. Norris, A. Scherz, J. L. Sessler, D. Stehlik, Isr. J.

Chem. 1992, 32, 369; H. Kurreck, M. Huber, Angew. Chem. 1995, 107,

929; Angew. Chem. Int. Ed. Engl. 1995, 34, 849.

[6] a) Metalloporphyrins Catalyzed Reactions (Eds.: F. Montanari, L.

Casella), Kluwer, Dordrecht, 1994; Metalloporphyrins in Catalytic

Oxidations (Ed.: R. A. Sheldon), Marcel Dekker, New York, 1994;

b) P. E. Ellis, Jr., J. E. Lyons, Coord. Chem. Rev. 1990, 106, 181; D.

Ostovic, T. C. Bruice, Acc. Chem. Res. 1992, 25, 314; D. Mansuy,

Coord. Chem. Rev. 1993, 125, 129; D. Dolphin, D. T. Traylor, L. Y. Xie,

Acc. Chem. Res. 1997, 30, 251; c) Y. Furusho, T. Kimura, Y. Mizuno, T.

Aida, J. Am. Chem. Soc. 1997, 119, 5267.

[7] J. Kavandi, J. Callis, M. Gouterman, G. Khalil, D. Wright, E. Green, D.

Burns, B. Mclachlan, Rev. Sci. Instr. 1990, 61, 3340; W. W.-S. Lee, K.-Y.

Wong, X.-M. Li, Y.-B. Leung, C.-S. Chan, K. S. Chan, J. Mater. Chem.

1993, 3, 1031; M. Brunel, F. Chaput, S. A. Vinogradov, B. Campagne,

M. Canva, J. P. Boilot, A. Brun, Chem. Phys. 1997, 218, 301; W. Su,

T. M. Cooper, M. C. Brant, Chem. Mat. 1997, 10, 1212.

[8] K. R. Weishaupt, C. J. Gomer, T. J. Dougherty, Cancer Res. 1976, 1, 1;

T. J. Dougherty, S. C. Marcus, Eur. J. Cancer 1982, 28A, 1734; C. J.

Gomer, N. Rucker, A. Ferrario, S. Wang, Radiat. Res. 1989, 120, 1; R.

Bonnett, Chem. Rev. 1995, 24, 19; R. K. Pandey, D. F. Majchrzycki,

K. M. Smith, T. J. Dougherty, Proc. SPIE-Int. Soc. Opt. Eng. 1989,

1065, 164.

[9] a) A. D. Adler, F. R. Longo, J. D. Finarelli, J. Goldmacher, J. Assour,

L. Korsakoff, J. Org. Chem. 1967, 32, 476; J. S. Lindsey, I. C.

Schreiman, H. C. Hsu, P. C. Kearney, A. M. Maguerettaz, J. Org.

Chem. 1987, 52, 827; F. Li, K. Yang, J. S. Tyhonas, K. A. MacCrum, J. S.

2736

ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000

0947-6539/00/0615-2736 $ 17.50+.50/0

Chem. Eur. J. 2000, 6, No. 15

Porphyrins

2721±2738

Lindsey, Tetrahedron 1997, 53, 12339; b) J. L. Sessler, A. Mozaffari,

[21] a) G. H. Barnett, K. M. Smith, J. Chem. Soc. Chem. Commun. 1974,

772; K. M. Smith, G. H. Barnett, B. Evans, Z. Martynenko, J. Am.

Chem. Soc. 1979, 101, 5953 and references therein; b) A. L. Balch,

M. R. Johnson, Org. Synth. 1992, 70, 68; c) for reviews see: T. P.

Wijesekera, D. Dolphin in Metalloporphyrins in Catalytic Oxidations

(Ed.: R. A. Sheldon), Marcel Dekker, New York, 1994, pp. 193; J. S.

Lindsey in Metalloporphyrins Catalyzed Oxidations (Eds.: F. Mon-

tanari, L. Casella), Kluwer Academic Press, Dordrecht, 1994, pp. 49.

[10] H. Fischer, J. Klarer, Justus Liebigs Ann. Chem. 1926, 448, 178; G. P.

Arsenault, E. Bullock, S. F. McDonald, J. Am. Chem. Soc. 1960, 82,

4384; A. W. Johnson, I. T. Kay, J. Chem. Soc. 1961, 2418; J. B. Kim,

A. D. Adler, F. R. Longo in The Porphyrins, Vol. I (Ed.: D. Dolphin),

Academic Press, New York, 1978, pp. 85; J. B. Paine III in The

Porphyrins, Vol. I (Ed.: D. Dolphin), Academic Press, New York,

1978, pp. 101; A. W. Johnson in The Porphyrins, Vol. I (Ed. D.

Dolphin), Academic Press, New York, 1978, pp. 235; P. S. Clezy,

A. H. Jackson in The Porphyrins, Vol. I (Ed. D. Dolphin), Academic

Press, New York, 1978, pp. 265; P. S. Clezy, Aust. J. Chem. 1991, 44,

1163; D. M. Wallace, S. H. Leung, M. O. Senge, K. M. Smith, J. Org.

Chem. 1993, 58, 7245; T. L. Nguyen, M. O. Senge, K. M. Smith, J. Org.

Chem. 1996, 61, 998; T. D. Lash, Chem. Eur. J. 1996, 2, 1197.

[11] For a discussion of the theoretical and practical problems involved

see: J.-H. Fuhrhop in The Porphyrins, Vol. II (Ed.: D. Dolphin),

Academic Press, New York, 1978, pp. 131.

Â

R. L. Hart, L. Latos-GrzÇynski, T. G. Traylor, Inorg. Chem. 1991, 30,

Ç

Â

Ç

3222; A. Maøek, L. Latos-GrzÇynski, T. J. Bartczak, A. Zadøo, Inorg.

Ä

Chem. 1991, 30, 3222; K. Rachlewicz, L. Latos-GrzÇynski, Inorg. Chem.

1995, 34, 718.

[22] J. E. Baldwin, M. J. Crossley, J. DeBernardis, Tetrahedron 1982, 38,

685; M. J. Crossley, M. M. Harding, C. W. Tansey, J. Org. Chem. 1994,

59, 4433; M. M. Catalano, M. J. Crossley, L. G. King, J. Chem. Soc.

Chem. Commun. 1984, 1535; M. J. Crossley, L. G. King, J. Chem. Soc.

Perkin Trans. 1 1996, 1251.

[23] X. Jiang, D. J. Nurco, K. M. Smith, Chem. Commun. 1996, 1759.

[24] a) J.-i. Setsune, T. Yazawa, H. Ogoshi, Z.-i. Yoshida, J. Chem. Soc.

Perkin Trans. I 1980, 1641; b) H. Segawa, R. Azumi, T. Shimidzu, J.

Am. Chem. Soc. 1992, 114, 7564.

[25] a) B. Krattinger, H. J. Callot, Chem. Commun. 1996, 1341; b) B.

Krattinger, H. J. Callot, Tetrahedron Lett. 1996, 37, 7699; c) B.

Krattinger, H. J. Callot, Tetrahedron Lett. 1998, 39, 1165; B.

Krattinger, H. J. Callot, Eur. J. Org. Chem. 1999, 1857.

[26] T. Ema, M. O. Senge, N. Y. Nelson, H. Ogoshi, K. M. Smith, Angew.

Chem. 1994, 106, 1951; Angew. Chem. Int. Ed. Engl. 1994, 33, 1879;

M. O. Senge, I. Bischoff, N. Y. Nelson, K. M. Smith, J. Porphyrins

Phthalocyanines 1999, 3, 99.

[12] A. H. Corwin, A. B. Civvis, R. W. Poor, D. G. Whitten, E. W. Baker, J.

Am. Chem. Soc. 1968, 90, 6577.

[13] a) R. Grigg, A. Sweeney, A. W. Johnson, J. Chem. Soc. Chem.

Commun. 1970, 1237; b) A. W. Johnson, A. Sweeney, J. Chem. Soc.

Perkin Trans. I 1974, 1424; H. J. Callot, Tetrahedron Lett. 1972, 1011;

K. M. Shea, L. Jaquinod, R. G. Khoury, K. M. Smith, Chem. Commun.

1998, 759.

[27] S. G. DiMagno, V. S.-Y. Lin, M. J. Therien, J. Am. Chem. Soc. 1993,

115, 2513; S. G. DiMagno, V. S.-Y. Lin, M. J. Therien, J. Org. Chem.

1993, 58, 5983.

[28] W. W. Kalisch, M. O. Senge, Angew. Chem. 1998, 110, 1156; Angew.

Chem. Int. Ed. 1998, 37, 1107.

[14] a) H. J. Callot, T. Schamber, Tetrahedron Lett. 1974, 3155; H. J. Callot,

T. Schamber, Tetrahedron Lett. 1974, 3159; b) G. L. Closs, L. E. Closs,

J. Am. Chem. Soc. 1963, 85, 819.

[15] a) J. W. Buchler, L. W. Puppe, Liebigs Ann. Chem. 1970, 740, 142;

b) A. Botulinski, J. W. Buchler, K.-L. Lay, H. Stoppa, Liebigs Ann.

Chem. 1984, 1259; c) A. Botulinski, J. W. Buchler, N. E. Abbes, W. R.

Scheidt, Liebigs Ann. Chem. 1987, 305; d) P. N. Dwyer, L. Puppe, J. W.

Buchler, W. R. Scheidt, Inorg. Chem. 1975, 14, 1782.

[29] R. Bonnett, I. A. D. Gale, G. F. Stephenson, J. Chem. Soc. C 1966,

1600; H. J. Callot, Bull. Soc. Chim. Fr. 1974, 1492.

[30] H. Ali, J. E. van Lier, Tetrahedron Lett. 1991, 32, 5015.

[31] Presumably these fractions are the two regioisomers (5-bromo-10-

butyl-2,3,7,8,12,13,17,18-octaethylporphyrinato)nickel(ii) and (5-bro-

mo-15-butyl-2,3,7,8,12,13,17,18-octaethylporphyrinato)nickel(ii), re-

spectively.

[32] J. March, Advanced Organic Chemistry, 3rd edition, Wiley, New York,

1985.

[16] a) meso Formylation: H. H. Inhoffen, J.-H. Fuhrhop, H. Voigt, H.

Brockmann, Jr., Justus Liebigs Ann. Chem. 1966, 695, 133; D.

Oldfield, A. W. Johnson, J. Chem. Soc. C 1966, 794; D. P. Arnold,

A. W. Johnson, M. Mahendran, J. Chem. Soc. Perkin Trans. 1 1978,

366; b formylation: J. W. Buchler, C. Dreher, G. Herget, Liebigs Ann.

Chem. 1988, 43; J. W. Ischkov, Z. I. Zhilin, Zh. Org. Khim. 1995, 31,

136; M. O. Senge, V. Gerstung, K. Ruhlandt-Senge, S. Runge, I.

Lehmann, J. Chem. Soc. Dalton Trans. 1998, 4187; b) S. Runge, M. O.

Senge, Tetrahedron 1999, 55, 10375.

[17] a) J. E. Drach, F. R. Longo, J. Org. Chem. 1974, 39, 3282; R. Bonnett,

G. F. Stephenson, J. Org. Chem. 1965, 30, 2791; E. Watanabe, S.

Nishimura, H. Ogoshi, Z. Yoshida Tetrahedron 1975, 31, 1385; G.-Z.

Wu, H.-K. Leung, W.-X. Gan, Tetrahedron 1990, 46, 3233; L.-C. Gong,

D. Dolphin, Can. J. Chem. 1985, 63, 401, b) L.-C. Gong, D. Dolphin,

Can. J. Chem. 1985, 63, 406; c) M. O. Senge, J. Chem. Soc. Dalton

Trans. 1993, 3539; M. O. Senge, J. Porphyrins Phthalocyanines 1998, 2,

107; J. F. Bartoli, P. Battioni, W. R. De Foor, D. Mansuy, J. Chem. Soc.

Chem. Commun. 1994, 23; d) S. Besecke, B. Evans, G. H. Barnett,

K. M. Smith, J. H. Fuhrhop, Angew. Chem. 1976, 88, 616; Angew.

Chem. Int. Ed. Engl. 1976, 15, 551; e) P. S. Clezy, C. J. R. Fookes, J.

Chem. Soc. Chem. Commun. 1971, 1268.

[18] M. O. Senge in Handbook of Porphyrins (Eds.: K. M. Kadish, K. M.

Smith, R. Guilard), Academic Press, New York, 2000, Chapter 6.

[19] a) H. Ali, J. E. van Lier, Tetrahedron 1994, 50, 11933; R. W. Wagner,

T. E. Johnson, J. S. Lindsey, J. Am. Chem. Soc. 1996, 118, 11166; B.

König, H. Zieg, Synthesis 1998, 171; b) X. Zhou, Z.-y. Zhou, T. C. W.

Mak, K. S. Chan, J. Chem. Soc. Perkin Trans. 1 1994, 2519; X. Zhou,

M. K. Tse, T. S. M. Wan, K. S. Chan, J. Org. Chem. 1996, 61, 3590; K. S.

Chan, X. Zhou, M. T. Au, C. Y. Tam, Tetrahedron 1995, 51, 3129; A. G.

Hyslop, M. A. Kellett, P. M. Iovine, M. J. Therien, J. Am. Chem. Soc.

1998, 120, 12676; c) D. A. Shultz, K. P. Gwaltney, H. Lee, J. Org.

Chem. 1998, 63, 769; d) D. P. Arnold, M. Mahendran, A. W. Johnson,

J. Chem. Soc. Perkin Trans. 1 1978, 366; D. P. Arnold, D. A. James, J.

Org. Chem. 1997, 62, 3460 and references therein.

[33] The disadvantage of using nickel porphyrins associated with the harsh

conditions necessary for demetallation and the resulting loss of

material has been overcome. Demetallation of Ni^IIporphyrins can be

achieved more easily and in higher yields by using BBr₃; see ref. [16b].

[34] T. W. Greene, Protective Groups in Organic Synthesis, Wiley, New

York, 1981.

[35] P. K. Freeman, L. L. Hutchinson, J. Org. Chem. 1980, 45, 1924; T.

Cohen, I.-H. Jeong, B. Mudryk, M. Bhupathy, M. M. A. Awad, J. Org.

Chem. 1990, 55, 1528; S. Brandäge, O. Dahlman, B. Lindqvist, A.

Mahlen, L. Mörch, Acta Chem. Scand. 1984, B38, 837.

[36] H. Gilman, H. W. Melvin, Jr., J. Am. Chem. Soc. 1950, 72, 995.

Â

[37] J.-C. Florent, A. Genot, C. Monneret, Tetrahedron Lett. 1985, 5295.

[38] a) K. M. Barkigia, L. Chantranupong, K. M. Smith, J. Fajer, J. Am.

Chem. Soc. 1988, 110, 7566; J. Fajer, Chem. Ind. (London) 1991, 869;

M. O. Senge, J. Photochem. Photobiol. B: Biol. 1992, 16, 3; M.

Ravikanth, T. K. Chandrashekar, Struct. Bonding (Berlin) 1995, 82,

105; b) J. A. Shelnutt, X.-Z. Song, J.-G. Ma, S.-L. Jia, W. Jentzen, C. J.

Medforth, Chem. Soc. Rev. 1998, 27, 31; c) S. M. Prince, M. Z. Papiz,

A. A. Freer, G. McDermott, A. M. Hawthornthwaite-Lawless, R. J.

Cogdell, N. W. Isaacs, J. Mol. Biol. 1997, 268, 412; S. M. Prince, Y.-F.

Li, W. Zhou, R. E. Blankenship, J. P. Allen, J. Mol. Biol. 1997, 271, 456;

V. Ermler, G. Fritch, S. K. Buchanan, H. Michel, Structure, 1994, 2,

925; J. Deisenhofer, O. Epp, I. Sinning, H. Michel, J. Mol. Biol. 1995,

246, 429; M. Sundaramoorthy, K. Kishi, M. H. Gold, T. L. Poulos, J.

Biol. Chem. 1994, 269, 32759; K. G. Ravichandran, S. S. Boddupalli,

C. A. Hasemann, J. A. Peterson, J. Deisenhofer, Science 1993, 261,

731; B. R. Crane, L. M. Siegel, E. D. Getzoff, Science 1995, 270, 59;

Â

M. J. Mate, M. Zamocky, L. M. Nykyri, C. Herzog, P. M. Alzari, C.

Betzel, F. Koller, I. Fita, J. Mol. Biol. 1999, 268, 135; d) D. Dolphin, J.

Heterocycl. Chem. 1970, 7, 275; M. B. Hursthouse, S. Neidle, J. Chem.

Soc. Chem. Commun. 1972, 449; J.-H. Fuhrhop, L. Witte, W. S.

Sheldrick, Liebigs Ann. Chem. 1976, 1537; B. Evans, K. M. Smith, J.-H.

Fuhrhop, Tetrahedron Lett. 1977, 5, 443; e) W. R. Scheidt, Y. J. Lee,

Struct. Bonding 1987, 64, 1.

[20] H. W. Whitlock, M. Y. Oester, J. Am. Chem. Soc. 1973, 95, 5738.

Chem. Eur. J. 2000, 6, No. 15

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M. O. Senge et al.

FULL PAPER

[39] a) C. J. Medforth, M. O. Senge, K. M. Smith, L. D. Sparks, J. A.

Shelnutt, J. Am. Chem. Soc. 1992, 114, 9859; b) K. M. Barkigia, M. W.

Renner, L. Furenlid, C. J. Medforth, K. M. Smith, J. Fajer, J. Am.

Chem. Soc. 1993, 115, 3627; c) K. M. Barkigia, M. D. Berber, J. Fajer,

C. J. Medforth, M. W. Renner, K. M. Smith, J. Am. Chem. Soc. 1990,

112, 8851; J. A. Shelnutt, C. J. Medforth, M. D. Berber, K. M.

Barkigia, K. M.; Smith, J. Am. Chem. Soc. 1991, 113, 4077; M. O.

Senge, C. J. Medforth, L. D. Sparks, J. A. Shelnutt, K. M. Smith, Inorg.

Chem. 1993, 32, 1716; L. D. Sparks, C. J. Medforth, M.-S. Park, J.-R.

Chamberlain, M. R. Ondrias, M. O. Senge, K. M. Smith, J. A. Shel-

nutt, J. Am. Chem. Soc. 1993, 115, 581; M. W. Renner, K. M. Barkigia,

Y. Zhang, C. J. Medforth, K. M. Smith, J. Fajer, J. Am. Chem. Soc.

1994, 116, 8582; M. O. Senge, T. P. Forsyth, L. T. Nguyen, K. M. Smith,

Angew. Chem. 1994, 106, 2554; Angew. Chem. Int. Ed. Engl. 1994, 33,

2485; L. D. Sparks, K. K. Anderson, C. J. Medforth, K. M. Smith, J. A.

Shelnutt, Inorg. Chem. 1994, 33, 2297; C. J. Medforth, C. M. Muzzi,

K. M. Smith, R. J. Abraham, J. D. Hobbs, J. A. Shelnutt, J. Chem. Soc.

Chem. Commun. 1994, 1843; M. W. Renner, K. M. Barkigia, D.

Melamed, K. M. Smith, J. Fajer, Inorg. Chem. 1996, 35, 5120; R.-J.

Cheng, P.-Y. Chen, P.-R. Gau, S.-M. Peng, J. Am. Chem. Soc. 1997, 119,

2563; C. J. Medforth, C. M. Muzzi, K. M. Shea, K. M. Smith, R. J.

Abraham, S. Jia, J. A. Shelnutt, J. Chem. Soc. Perkin Trans. 2 1997, 833;

C. J. Medforth, C. M. Muzzi, K. M. Shea, K. M. Smith, R. J. Abraham,

S. Jia, J. A. Shelnutt, J. Chem. Soc. Perkin Trans. 2 1997, 839; d) Other

examples for sterically overloaded porphyrins include dodecaphenyl-

porphyrins, octaethyltetranitroporphyrin and octahalotetraarylpor-

phyrins.^[6b]Typical examples are described in: D. J. Nurco, C. J.

Medforth, T. P. Forsyth, M. M. Olmstead, K. M. Smith, J. Am. Chem.

Soc. 1996, 118, 10918; M. O. Senge, J. Porphyrins Phthalocyanines

1998, 2, 1; E. R. Birnbaum, J. A. Hodge, M. W. Grinstaff, W. P.

Schaefer, L. Henling, J. A. Labinger, J. E. Bercaw, H. B. Gray, Inorg.

Chem. 1995, 34, 3625; P. Ochsenbein, K. Ayougou, D. Mandon, J.

Fischer, R. Weiss, R. N. Austin, K. Jayaraj, A. Gold, J. Terner, J. Fajer,

Angew. Chem. 1994, 106, 355; Angew. Chem. Int. Ed. Engl. 1994, 33,

348. For more complete listings of the relevant literature see these

references or ref. [18].

has C_b-C_b-CH₂angles of about 1258^[42]close to those described for

(2,3,7,8,12,13,17,18-octaethyl-5,10,15,20-tetraphenylporphyrinato)-

nickel(ii)^[39b]or 9^[51][123.8(4)8].

[42] D. L. Cullen, E. F. Meyer, Jr., J. Am. Chem. Soc. 1974, 96, 2095.

[43] The exact configuration of this porphodimethene has not been

determined.

[44] We also observed oxidation resistant porphomethenes during the

attempted synthesis of 5-(2,5-dimethoxyphenyl-10,15,20-tris(tert-bu-

tyl)porphyrin via a cross condensation of pyrrole and the respective

aldehydes. Again, a syn-axial orientation of the three meso-hydrogen

atoms was observed: S. Runge, M. O. Senge, Z. Naturforsch. 1998, 53b,

1021.

[45] J. Arnold, Chem. Commun. 1990, 976; D. Y. Dawson, H. Brand, J.

Arnold, J. Am. Chem. Soc. 1994, 116, 9797; D. Y. Dawson, J. Arnold, J.

Porphyrins Phthalocyanines 1997, 1, 121.

[46] M. O. Senge, I. Bischoff, unpublished results.

[47] This conclusion is further substantiated by the observation that 5,15-

disubstituted porphyrins, i.e., tetrapyrroles with both free C_band C_m

positions, react with LiR preferentially at the meso positions: M. O.

Senge, X. Feng, Tetrahedron Lett. 1999, 40, 4165.

[48] a) E. F. Meyer, Jr., Acta Crystallogr. 1972, B28, 2162; b) M. O. Senge,

T. P. Forsyth, K. M. Smith, Z. Kristallogr. 1996, 211, 176.

[49] a) C. J. Medforth, M. O. Senge, T. P. Forsyth, J. D. Hobbs, J. A.

Shelnutt, K. M. Smith, Inorg. Chem. 1993, 33, 3865; b) M. O. Senge,

C. J. Medforth, T. P. Forsyth, D. A. Lee, M. M. Olmstead, W. Jentzen,

R. K. Pandey, J. A. Shelnutt, K. M. Smith, Inorg. Chem. 1997, 36, 1149.

[50] For a thermal ellipsoid plot see the figures in ref. [28].

[51] M. O. Senge, M. W. Renner, W. W. Kalisch, J. Fajer, unpublished

results.

[52] This compound has been used to show that the observed bath-

ochromic shifts of the absorption maxima of nonplanar porphyrins

compared to their planar counterparts is unambiguously due to the

macrocycle distortion and not due to any electronic or orbital overlap

substituent effects.^[51]

[53] P. N. Dwyer, J. W. Buchler, W. R. Scheidt, J. Am. Chem. Soc. 1974, 96,

2769.

[40] a) M. O. Senge, T. Ema, K. M. Smith, Chem. Commun. 1995, 733;

b) W. Jentzen, M. C. Simpson, J. D. Hobbs, X. Song, T. Ema, N. Y.

Nelson, C. J. Medforth, K. M. Smith, M. Veyrat, M. Mazzanti, R.

Ramasseul, J.-C. Marchon, T. Takeuchi, W. A. Goddard, J. A.

Shelnutt, J. Am. Chem. Soc. 1995, 117, 11085; M. Veyrat, R.

Ramasseul, J. C. Marchon, I. Turowska-Tyrk, W. R. Scheidt, New J.

Chem. 1995, 19, 1199; M. Mazzanti, J.-C. Marchon, M. Shang, W. R.

Scheidt, S. Jia, J. A. Shelnutt, J. Am. Chem. Soc. 1997, 119, 12400; S.

Runge, M. O. Senge, K. Ruhlandt-Senge, Z. Naturforsch. 1999, 54b,

662.

[54] W. W. Kalisch, M. O. Senge, Tetrahedron Lett. 1996, 37, 1183; M. O.

Senge, W. W. Kalisch, Inorg. Chem. 1997, 36, 6103.

[55] M. O. Senge, W. W. Kalisch, S. Runge, Tetrahedron 1998, 54, 3781.

[56] L. D. Spaulding, L. C. Andrews, G. J. B. Williams, J. Am. Chem. Soc.

1977, 99, 6918.

[57] H. Hope, Progr. Inorg. Chem. 1994, 41, 1.

[58] S. R. Parkin, B. Moezzi, H. Hope, J. Appl. Crystallogr. 1995, 28, 53.

[59] G. M. Sheldrick, SHELXS-97, Program for Crystal Structure Solution,

Universität Göttingen, Germany, 1997.

[60] G. M. Sheldrick, SHELXL-97, Program for Crystal Structure Refine-

ment, Universität Göttingen, Germany, 1997.

[41] The C_b-C_b-CH₂angles in this porphyrin are 112.4(9)8. This value is

typical for porphyrins where the b substituents are removed from

steric interactions with meso substituents. For comparison, Ni^II(OEP)

Received: October 4, 1999 [F2066]

2738

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