Pyrrole-appended derivatives of O-confused oxaporphyrins and their complexes with nickel(II), palladium(II), and silver(III)

Article abstract of DOI:10.1002/chem.200304899

Condensation of 2,4-bis(phenylhydroxymethyl)furan with pyrrole and p-toluylaldehyde formed, instead of the expected 5,20-diphenyl-10,15-di(p-tolyl)-2-oxa-21-carbaporphyrin, a pyrrole addition product [(H,pyr)OCPH]H₂; this product can formally b

Full text of DOI:10.1002/chem.200304899

FULL PAPER
Pyrrole-Appended Derivatives of O-Confused Oxaporphyrins and Their
Complexes with Nickel(ii),Palladium( ii),and Silver( iii)
Mi¯osz Pawlicki and Lechos¯aw Latos-Grazyn¬ski*[a]
«
Abstract: Condensation of 2,4-bis(phe-
nylhydroxymethyl)furan with pyrrole
and p-toluylaldehyde formed, instead
of the expected 5,20-diphenyl-10,15-
yields a stable AgIII complex [(C2H5O,-
with the NHgroup pointing out toward
the adjacent phenyl ring on the C5
position. Tetrahedral geometry around
pyr)OCP]AgIII] substituted at the C3
position by the ethoxy and pyrrole
moieties. The macrocyclic frame of
[(H,pyr)OCPH]H2 is conserved. Addi-
tion of trifluoroacetic acid to [(C2H5O,-
pyr)OCP]AgIII] yielded a new aromatic
the C3 atom was detected for [(C2H5O,-
III
À
À
di(p-tolyl)-2-oxa-21-carbaporphyrin,
a
pyr)OCP]Ag ]. The Ni C and Ag C
bond lengths are similar to other nick-
el(ii) or silver(iii) carbaporphyrinoids
where the trigonal carbon atom coordi-
nates the metal ion. The trend detected
in the 13C chemical shifts for the ap-
pended-pyrrole resonances has been
rationalized by the extent of effective
conjugation between the macrocycle
and the appended pyrrole moiety con-
trolled by the hybridization of the C3
atom and the metal ion oxidation state.
The dianionic or trianionic macrocyclic
core of the pyrrole-appended deriva-
tives is favored to match the oxidation
state of nickel(ii), palladium(ii), or sil-
ver(iii), respectively.
pyrrole addition product [(H,pyr)-
OCPH]H2; this product can formally
be considered as an effect of hydro-
genation of 3-(2'-pyrrolyl)-5,20-diphen-
yl-10,15-di(p-tolyl)-2-oxa-21-carbapor-
phyrin ([(pyr)OCPH]H). The new oxa-
carbaporphyrinoid presents the 1HNMR
spectroscopy features of an aromatic
molecule, including the upfield shift of
the inner H21 atom. Insertion of NiCl2
or PdCl2 into [(H,pyr)OCPH]H2 gave
two structurally related organometallic
complexes, [(pyr)OCP]NiII] and [(pyr)-
OCP]PdII], in which the metal ions are
bound by three pyrrolic nitrogens and
the trigonally hybridized C21 atom of
the inverted furan. The reaction of
[(H,pyr)OCPH]H2 with silver(i) acetate
‡
complex [(pyr)OCP]AgIII] . The struc-
tures of [(pyr)OCP]NiII] and [(C2H5O,-
pyr)OCP]AgIII] have been determined
by X-ray crystallography. In both mole-
cules the macrocycles are only slightly
distorted from planarity and the nickel-
(ii) and silver(iii) are located in the
NNNC plane. The dihedral angle be-
tween the macrocyclic and appended-
pyrrole planes of [(pyr)OCP]NiII] re-
flects the biphenyl-like arrangement
Keywords: macrocyclic ligands
¥
nickel ¥ palladium ¥ porphyrinoids
¥ silver
coordination properties of derivatives of meta-benziporphyr-
in, the first synthesized carbaporphyrinoid containing a
carbocyclic ring, are of particular significance. Originally the
benzene ring was embedded in an octaalkylporphyrin-like
environment to give 8,19-dimethyl-9,13,14,18-tetraethyl-m-
benziporphyrin.[26] The related macrocycle 6,11,16,21-tetra-
phenylbenziporphyrin ((TPmBPH)H) can give organometal-
lic complexes with palladium(ii) and platinum(ii),
[(TPmBP)PdII] and [(TPmBP)PtII].[22] The metal ion is
bound in the macrocyclic cavity by three pyrrolic nitrogen
atoms and a trigonal carbon atom of the benzene ring. A
hydroxy derivative of 8,9,13,14,18,19-hexaalkylbenziporphyr-
in, that is, 8,19-dimethyl-9,13,14,18-tetraethyloxybenzipor-
phyrin ((OBPH)H2),[27] coordinates palladium(ii) to form the
four-coordinate anionic complex [(OBP)PdII]À with retention
of macrocyclic aromaticity and coordination through a carbon
s donor.[23] Subsequently the palladium(ii) complexes of core-
modified oxybenziporphyrin,[25] nickel(ii) and palladium(ii)
Introduction
The inverted porphyrin 5,10,15,20-tetraaryl-2-aza-21-carba-
porphyrin ((CTPPH)H2)[1, 2] and its derivatives have revealed
a remarkable tendency to stabilize peculiar organometallic
compounds containing diamagnetic nickel(ii),[1, 3 paramag-
6]
netic nickel(ii) with one or two Ni C bonds,
nickel(iii),[9]
[7, 8]
À
copper(ii),[10] palladium(ii),[11] antimony(v),[12] silver(iii),[13]
manganese(ii) and manganese(iii),[14, 15] zinc(ii),[10, 16] iron-
(ii),[17, 18] and rhodium(i).[19]
The ability of carbaporphyrinoids to coordinate metal ions
and form metal carbon bonds[20] extends beyond the family
25]
of inverted porphyrins.[21
In this respect, studies on the
¬
[a] Prof. Dr. L. Latos-Graz«ynski, M. Pawlicki
Department of Chemistry
University of Wroc¯aw
ul. F. Joliot-Curie 14, 50-383 Wroc¯aw (Poland)
E-mail: LLG@wchuwr.chem.uni.wroc.pl
4650
¹ 2003 Wiley-VCHVerlag GmbH& Co. KGaA, Weinheim
DOI: 10.1002/chem.200304899
Chem. Eur. J. 2003, 9, 4650 4660

4650 4660
azuliporphyrins,[28] and silver(iii) benzocarbaporphyrin have
Pursuing our interest in benziporphyrin coordination
chemistry, we have recently reported on 5,10,15,20-tetraphen-
yl-p-benziporphyrin ((TPpBPH)H)–isomeric to 6,11,16,21-
tetraphenyl-m-benziporphyrin–with the benzene ring linked
at the para positions.[24] Significantly this p-benziporphyrin
forms a complex with cadmium(ii) and reveals an unprece-
dented h2 CdII arene interaction.
been investigated.[29]
Abstract in Polish: W wyniku kondensacji 2,4-bis(fenylohyd-
roksymetylo)furanu z pirolem i aldehydem p-toluilowym
otrzymano produkt addycji pirolu do 5,20-difenylo-10,15-
di(p-toluilo)-2-oksa-21-karbaporfiryny [(H)OCPH]H z wy-
In the present work we describe the synthesis and reactivity
of a new carbaporphyrinoid. The molecule has been con-
structed by applying the heteroatom confusion concept
(Scheme 1). Thus, by interchanging a heteroatom with a b-
methine group of the same five-membered ring one
can transform 5,10,15,20-tetraphenyl-21-heteroporphyrin (1)
into 5,10,15,20-tetraphenyl-2-hetero-21-carbaporphyrin (2),
which, while porphyrin-like in character, is expected to have
fundamentally different electronic and coordination proper-
ties. Previously we probed such an approach to obtain
5,10,15,20-tetraphenyl-2-thia-21-carbaporphyrin.[30, 31] Here
the synthesis of O-confused 5,10,15,20-tetraphenyl-21-oxa-
porphyrin derivatives and their ability to coordinate nickel(ii),
palladium(ii), and silver(iii) are explored.
¬
dajnosciaÀ 10%. Uzyskany makrocykl jest formalnie efektem
uwodornienia 3-(2'-pirolilo)-5,20-difenylo-10,15-di-p-toluilo-
2-oksa-21-karbaporfiryny [(pyr)OCPH]H. Nowy ligand, na-
lez«aÀcy do klasy karbaporfirynoidow, wykazuje w¯asciwosci
typowe dla zwiaÀzkow aromatycznych, w tym gornopolowe
przesunieÀcie wewneÀtrznego atomu wodoru H21 w widmie
H NMR (-5.11 ppm). Insercja niklu baÀdz palladu do [(H,pyr)-
OCPH]H2 daje strukturalnie podobne zwiaÀzki metaloorga-
niczne: [(pyr)OCP]Ni ] i [(pyr)OCP]Pd ], w ktorych jon
metalu jest zwiaÀzany przez trzy pirolowe atomy azotu i
trygonalny atom weÀgla C21, pochodzaÀcy z odwroconego
furanu. Koordynacja wymaga odwodornienia po¯aÀczonego
ze zmianaÀ hybrydyzacji atomu C3 z tetraedrycznej na
trygonalnaÀ. Struktura tak otrzymanego liganda odpowiada
budowaÀ ™prawdziwej∫ oksakarbaporfirynie z zachowanym
¬
¬
¬
¬
¬
1
¬
II
II
¬
¬
¬
pierscieniem furanowym, podstawionym w pozycji C3 piro-
lem, [(pyr)OCPH]H. Reakcja [(H,pyr)OCPH]H2 z octanem
srebra daje stabilny kompleks srebra(iii) [(C2H5O,pyr)-
OCP]AgIII] podstawiony w pozycji C3 grupaÀ etoksylowaÀ i
¬
pirolem. W tym przypadku zachowany jest szkielet wyjscio-
wego makrocyklu, [(H,pyr)OCPH]H2. Dowodem na koordy-
¬
nacjeÀ srebra przez atomy azotu jest, widoczne na czeÀsci
¬
¬
sygna¯ow b-pirolowych rozszczepienie, swiadczaÀce o skalar-
nym sprzeÀz«eniu ze srebrem (107/109Ag). Dodanie TFA do
[(C2H5O,pyr)OCP]AgIII] daje nowy, aromatyczny kompleks,
Scheme 1. The heteroatom confusion concept.
[(pyr)OCP]AgIII] powsta¯y w wyniku eliminacji grupy eto-
‡
ksylowej. Reakcja ta jest odwracalna. W jej trakcie zachodzi
¬
zmiana geometrii woko¯ weÀgla C3 z tetraedrycznej na trygo-
nalnaÀ, a zmiany struktury elektronowej majaÀ wp¯yw na ca¯y
makrocykl. Dla [(pyr)OCP]NiII] i [(C2H5O,pyr)OCP]AgIII]
otrzymano struktury krystaliczne. W obu przypadkach planar-
Results and Discussion
Synthesis of the oxacarbaporphyrins: The key step in the
synthesis of 5,10,15,20-tetraaryl-2-oxa-21-carbaporphyrins is
the construction of the condensation precursor, that is, 2,4-
bis(phenylhydroxymethyl)furan (3; Scheme 2), which is a
¬¬
nosc makrocyklu jest tylko nieznacznie zaburzona, a nikiel(ii) i
¬
¬
srebro(iii) znajdujaÀ sieÀ w p¯aszczyznie NNNC. KaÀt dwuscienny
pomieÀdzy p¯aszczyznaÀ makrocyklu a do¯aÀczonym pirolem w
II
¬
[(pyr)OCP]Ni ] zbliz«ony jest do wartosci charakterystycznej
dla bifenyli i wynosi 26.48 z grupaÀ NH skierowanaÀ w stroneÀ
¬
pobliskiego pierscienia 5-fenylowego. Stwierdzono tetraed-
¬
rycznaÀ geometrieÀ woko¯ atomu C3 w [(C2H5O,pyr)OCP]-
AgIII]. Otrzymane d¯ugosci wiaÀzan, odpowiednio Ni C
À
¬
¬
À
(1.892(4) ä) i Ag C (2.020(7) ä) saÀ zgodne z innymi przy-
¬
k¯adami niklu(ii) baÀdz srebra(iii), zwiaÀzanego przez karba-
¬
porpfirynoid, ktory koordynuje przez trygonalny atom weÀgla.
Zmiany przesunieÀc chemicznych 13C NMR, zaobserwowane
dla linii rezonansowych do¯aÀczonego pirolu, wynikajaÀ
rozszerzenia delokalizacji makrocyklicznej na dodatkowy
¬
z
Scheme 2. Synthesis of the condensation precursor 2,4-bis(phenylhydrox-
ymethyl)furan (3).
¬
¬
pierscien heterocykliczny, a kontrolowanej zmianaÀ hybrydy-
¬
zacji atomu C3 i stopniem utlenienia jonu metalu. Dwu- baÀdz
¬
trojujemny charakter centrum koordynacji badanego liganda
suitable synthon for introducing the inverted furan ring into a
porphyrin-like skeleton. The lithiation of an a-amino alk-
oxide, derived from 3-furancarboxaldehyde a was predom-
inantly directed to a remote a site of the furan ring by using
¬
¬
odpowiada za preferencje w wiaÀzaniu jonow metali na roz«nych
stopniach utlenienia, odpowiednio niklu(ii), palladu(ii) i sre-
bra(iii).
Chem. Eur. J. 2003, 9, 4650 4660
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4651

¬
L. Latos-Graz«ynski and M. Pawlicki
FULL PAPER
™blocking∫ amine components–morpholine and sec-buthyl-
lithium.[32] The formed 2-furyllithium derivative b, when
treated with benzaldehyde, yielded 2-(phenylhydroxymeth-
yl)-4-furancarboxaldehyde c. The reaction with a phenyl
Grignard reagent was applied to convert this aldehyde into
the targeted compound 3.
The procedure applied to synthesize the 5,10,15,20-tetraar-
yl-2-oxa-21-carbaporphyrin followed the methodology previ-
ously utilized for the synthesis of heteroporphyrins[33] includ-
ing 5,10,15,20-tetraphenyl-2-thia-21-carbaporphyrin.[30] Thus,
Two different pathways may lead to formation of 5. The
first involves an addition of pyrrole to preformed O-confused
2-oxa-21-carbaporphyrin 4. Alternatively, attack of pyrrole
could take place on the furan either at the precursor or at the
porphyrinogen stage.
The isolated carbaporphyrinoid 5 is structurally related to
the hypothetical 3,3-dihydro-5,20-diphenyl-10,15-di(p-tolyl)-
2-oxa-21-carbaporphyrin (6; Scheme 4) as both contain an
identical macrocyclic frame. In the same line of consideration,
macrocycles 4 and 6 are mutually interconvertible by a
hydrogenation/dehydrogenation step if the addition of the
two hydrogen atoms is localized on the C3 position and one of
the internal nitrogen atoms.
condensation of
3 with pyrrole and p-toluylaldehyde
(1:3:2 molar ratio) in a one-pot, two-step synthesis at room
temperature was expected to yield 5,20-diphenyl-10,15-di-
(p-tolyl)-2-oxa-21-carbaporphyrin (4; Scheme 3). However,
contrary to expectations, the condensation did not stop at the
Scheme 4. Hypothetical
3,3-dihydro-5,20-diphenyl-10,15-di(p-tolyl)-2-
oxa-21-carbaporphyrin (6) which is structurally related to the isolated
carbaporphyrinoid 5.
Studies on the coordination chemistry of 5 (see below)
revealed that the coordination implies transformation into the
novel structural form 7 (Scheme 5). The macrocycle 7 has not
been detected directly, but the related structure has been
trapped after the insertion of the metal ions. It is important to
Scheme 3. Condensation of 3 with pyrrole and p-toluylaldehyde. The
condensation does not stop at the expected oxacarbaporphyrin 4 and the
pyrrole addition product 5 is formed. DDQ ˆ 2,3-dichloro-5,6-dicyano-1,4-
benzoquinone.
Scheme 5. Structurally related macrocycles 7 and 8.
putative 4 and the pyrrole addition product 5 was obtained in
a relatively high yield of approximately 10%. An attempt was
made to direct the process of formation of the 2-oxa-21-
carbaporphyrin, based on the presumption that a substoichio-
metric concentration of pyrrole would favor the formation of
4. However, several attempted condensations with various
pyrrole concentrations led to the isolation of 5 as the single
2-oxa-21-carbaporphyrin related product. It is worth men-
tioning that an aza analogue of 5, 2-aza-3-(2'-pyrrolyl)-
5,10,15,20-tetraphenyl-21-carbaporphyrin, which is consid-
ered as the isomer of tetraphenylsapphyrin, was reported as
a product in the Rothemund condensation.[34] The identity of 5
has been confirmed by a combination of NMR spectroscopy,
including NOESY, HMQC, and HMBC experiments, and
high-resolution mass spectrometry.
note that, formally, 7 can be created from the tetraarylpor-
phyrin by replacement of the pyrrolic fragment with 2-(2'-
furyl)pyrrole, that is, by a moiety, which may provide an
external conjugation route. The structures 5 and 7 are
mutually interconvertible by hydrogenation/dehydrogenation
in the same way as already described for the 4 and 6 couple.
From now on we will use the symbol OCP to denote the
hypothetical dianion obtained from the O-confused oxapor-
phyrin by abstraction of a pyrrolic NHproton and the proton
attached at C21. The atoms or groups attached to the C3 atom
will be indicated by a prefix enclosed in parentheses. The
group attached at C21 will appear as a suffix. A similar
description will be used for the hypothetical trianion 6,
formally a dihydrogenation product of 4. Consequently the
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O-Confused Oxaporphyrins
4650 4660
following acronyms correspond to the neutral structures
already discussed: 4: [(H)OCPH]H; 5: [(H,pyr)OCPH]H2;
6: [(H,H)OCPH]H2; 7: [(pyr)OCPH]H.
Spectroscopic characterization of 5: The electronic absorption
spectra of 5 demonstrate the Soret band (437 nm) accompa-
nied by a set of four Q bands (Figure 1). The spectroscopic
pattern is typical for aromatic carbaporphyrinoids. The
‡
Figure 1. The electronic absorption spectra of 5 (solid line) and (5-H) in
dichloromethane.
isosbestic points, corresponding to a single protonation step,
were detected in the course of titration of a dichloromethane
solution of 5 with trifluoroacetic acid (TFA) to produce the
Figure 2. 1HNMR spectra of: A) 5 (CD2Cl2, 298 K), B) 5 (CD2Cl2, 253 K),
and C) (5-H) (TFA/CD2Cl2 (1:5 v/v), 298 K). The insets (not to scale)
show the NHand H21 resonances. Peak labels follow systematic position
numbering of the macrocycle or denote proton groups. o, m, and p ˆ the
ortho, meta, and para positions of meso-phenyl (Ph) or meso-p-tolyl (Tol)
rings, respectively.
‡
‡
monocationic form (5-H) . A strong bathochromic shift of the
‡
Soret band to 463 nm was observed for (5-H) . Acid titration
is accompanied by a distinct color change from brown to
green.
The complete assignment of all resonances in the 1HNMR
spectrum for 5 (Figure 2) was obtained by means of 2D
1HNMR COSY and NOESY experiments, with the unique
NOE correlation between H3 and the ortho protons of the
phenyl group attached to C5 as a starting point. All pyrrole
atoms, as documented by the rise of three NHresonances at
À0.49, À0.82, and À3.69 ppm (inset of Figure 2C). The
protonation is accompanied by the upfield relocation of b-H
pyrrole resonances.
3
resonances (d ˆ 8.49 (H17), 8.44 (H18; AB, J ˆ 4.9 Hz), 8.47
3
(H12), 8.45 (H13; AB, J ˆ 4.6 Hz), 8.47 (H8), 8.29 (H7; AB,
3J ˆ 4.9 Hz) ppm) are shifted downfield due to the ring-
current effect. The peculiar position of the methine H3
resonance at 8.09 ppm was noted. The hydrogen atom is
bound to a tetrahedral carbon atom, but the strong downfield
shift of its signal is caused by a combination of two effects: the
substitution by the oxygen atom at the 2-position and the
deshielding contribution of the ring-current effect. At the
same time the 13C NMR chemical shift for C3 (d ˆ 85.3 ppm)
is consistent with tetrahedral hybridization. Essentially,
molecule 5 demonstrates the aromaticity due for the typical
18 p electron delocalization pathway (Scheme 3). The strong-
ly upfield positions of the H21 (d ˆ À5.11 ppm) and inner
proton (d ˆ À2.47, À2.79 ppm at 188 K) resonances and the
significant chemical shift difference (Dd ˆ 9.52 ppm) between
the inner NHand the appended-pyrrole NHare readily
accounted for by the ring-current effect.
The resonances of the appended pyrrole ring of 5 were
unambiguously assigned at 5.54 (H3'), 5.82 (H4'), 6.33 (H5'),
and 7.26 (NH) ppm (Figure 2A). Due to the tetrahedral
geometry around the C3 atom, the two sides of the macro-
cyclic plane are differentiated by the position of the appended
pyrrole moiety. Consequently two ortho and meta protons on
each meso-aryl ring are unequivalent and should present two
separate resonances in the 1HNMR spectra while the rotation
about the Cmeso Cipso bond is restricted. Even at 298 K the five
well-separated, although slightly broadened, resonances were
detected for the phenyl ring at the 5-position, which is
adjacent to the appended pyrrole (Figure 2A). The steric
hindrance increases the rotation barrier in comparison to the
other meso positions, where single ortho and single meta
multiplets were detected at 298 K. Once the temperature was
lowered the dynamic processes could be detected for the
other three meso-aryl groups. The sets of five resonances for
each phenyl moiety and four for each p-tolyl ring were
detected once the rotations were completely frozen (Fig-
ure 2B).
A 1HNMR spectroscopic titration with TFA carried out in
CD2Cl2 at 228 K demonstrated that addition of a proton
resulted in a separate set of resonances that could be assigned
‡
directly to (5-H) . Protonation takes place at the nitrogen
Chem. Eur. J. 2003, 9, 4650 4660
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¬
L. Latos-Graz«ynski and M. Pawlicki
FULL PAPER
Formation and characterization of [(pyr)OCP]NiII] and
[(pyr)OCP]PdII]: The reaction between nickel(ii) chloride
and 5 in acetonitrile in the presence of anhydrous K2CO3
resulted in formation of the green, diamagnetic, four-coor-
dinate complex [(pyr)OCP]NiII] (9a). A similar procedure
with palladium(ii) chloride as the source of the metal ion
produced the analogous green complex [(pyr)OCP]PdII] (9b;
Scheme 6). Thus, the metal-insertion process is accompanied
by a dehydrogenation step and the macrocyclic ring corre-
sponds to the ™true∫ oxaporphyrin 4, although embedded into
the substituted form 7.
Figure 4. 1HNMR spectra of 9a (CD2Cl2, 298 K). The inset shows the
resonances of the appended pyrrole.
and 9b is the coordination through the unprotonated C21
atom of the furan ring, as inferred from the disappearance of
the resonance assigned to H21. Significantly the H3 reso-
nance, identified for 5, is also absent in the spectra of 9a and
9b. Thus, the 1HNMR spectra of 9a and 9b present three AB
systems of b-Hpyrrole protons. All pyrrole protons and all
meso-aryl protons of 9a and 9b demonstrate chemical shifts
that contain some downfield contribution due to the aromatic
ring-current effect. The effect is significantly less pronounced
than that detected for the starting macrocycle 5. The chemical
shift pattern of the pyrrole resonances closely resembles that
found for nickel(ii) complexes of the inverted porphyrin
methylated on the outer nitrogen atom, a fact which suggests
that the identical role of C21-bearing rings originated from N-
methylated pyrrole and furan in the overall p delocalization
route.[3]
Scheme 6. Structures of metal complexes [(pyr)OCP]NiII] (9a), [(pyr)-
‡
OCP]PdII] (9b), and [(pyr)OCP]AgIII
]
(9c).
The electronic absorption spectra of 9a and 9b are shown in
Figure 3. The spectrum of 9a shows a set of bands of
comparable intensity at 370, 473, and 490 nm accompanied
by a set of less intense bands at 578, 664, 763, and 843 nm. The
Crystal structure of [(pyr)OCP]NiII]: The structure of [(pyr)-
OCP]NiII] has been determined by X-ray crystallography.
Perspective views of the molecule are shown in Figure 5.
Table 1 contains selected bond lengths and angles. The
macrocycle is only slightly distorted from planarity, as can
be seen in Figure 5. The dihedral angle between the macro-
cyclic and the appended-pyrrole plane reflects the biphenyl-
like arrangement and equals 26.48, with the NHgroup
pointing towards the adjacent phenyl ring on the 5-position.
This value is significantly smaller than the dihedral angles
between the meso-aryl rings and the oxacarbaporphyrin plane
(phenyl(5) 60.98, phenyl(20) 58.68, p-tolyl(10) 61.58, p-tol-
yl(15) 54.48). For comparison, a coplanar arrangement of
pyrrole and furan rings was reported for unsubstituted simple
2-(2'-furyl)pyrrole in solution.[35, 36]
Figure 3. The electronic absorption spectra of 9a (solid line) and 9b
(dashed line) in dichloromethane.
spectrum is completely different from that of the macrocyclic
substrate 5. Although one can detect several bands in the
region typically assigned to the Soret-like band of aromatic
carbaporphyrinoids, their low extinction coefficients (e ꢀ 8 Â
103 mÀ1 cmÀ1) imply a lowering of the aromatic character of the
ligand in 9a or 9b in comparison to that in 5. The spectro-
scopic pattern for 9b resembles that of 9a although all bands
are bathochromically shifted.
À
The Ni N distances in 9a (Table 1) are comparable to those
in the nearly planar diamagnetic nickel(ii) porphyrins or
7, 28, 37]
porphyrinoids.[1, 5
The Ni C bond length of 9a
À
II
À
(1.892(4) ä) is in the middle range of Ni C bond lengths
(1.81 2.02 ä).[38, 39] This bond length is similar to other
nickel(ii) carbaporphyrinoids where the trigonal carbon
atom coordinates, for example, the nickel(ii) carbaporphyrin
1
The HNMR spectra of 9a and 9b differ essentially from
À
the spectrum of 5 (Figure 4). The most notable feature in 9a
containing the benzoindolizine-like moiety (Ni C21
4654
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Chem. Eur. J. 2003, 9, 4650 4660

O-Confused Oxaporphyrins
4650 4660
Scheme 7. Structures of metal complexes [(H,pyr)OCP]AgIII] (10a) and
[(C2H5O,pyr)OCP]AgIII] (10b).
related to 10a, was exclusively obtained. The compound
sustained the chromatographic purification to give an overall
78% yield of insertion.
The electronic absorption spectrum of 10b (Figure 6) with
its intense Soret-like band (443 nm in CH2Cl2) and a set of
bands in the Q region is similar to the spectrum of the free
ligand, which implies that 10b conserves the basic chromo-
phore of 5 (Figure 1).
Figure 5. The X-ray crystal structure of 9a. Top: perspective view, bottom:
side view (phenyl groups omitted for clarity). The thermal ellipsoids
represent 50% probability.
1.904(2) ä),[5]
nickel(ii)
azuliporphyrin
(Ni1 C21
À
1.897(3) ä),[28] and [(2-BrCH2CH2-CTPP)Ni] (Ni C21
1.906(4) ä).[6] The single case where nickel(ii) carbaporphyr-
inoids contain a coordinating tetrahedral carbon atom, [(21-
À
II
À
CH3CTPP)Ni ], demonstrates a longer Ni C bond length of
2.005(6) ä.[7] Analysis of the structural data, although limited
to the five available examples of nickel(ii) (NNNC) carba-
porphyrinoids, shows that nickel(ii) carbon(sp2) bond lengths
are very similar, in spite of the different nature of the carbon-
donor-bearing ring (N-confused pyrrole, O-confused furan,
azulene, fused heterocycle related to benzoindolizine).
Examination of the crystallographic data demonstrated that
there is some appreciable effect of the macrocyclic conjuga-
tion on the furan moiety. The Cb Cb bond lengths are larger
than those for Ca Cb. However, the Ca Cb distances are
Figure 6. The electronic absorption spectra of 10b (solid line) and 9c
(dashed line) in dichloromethane. The figure presents the starting and final
points of titration of 10b with TFA.
The 1HNMR spectra of 10a and 10b bear a strong
resemblance to the spectrum of the free ligand 5; thereby
proving that the macrocyclic frame of 5 is conserved in 10a
and 10b. Due to the coordination, the H21 and two inner NH
resonances seen for 5 are absent. The H3 atom has been
replaced by an ethoxy substituent. Consequently, the diag-
nostic set of two complex multiplets at 3.84 and 3.19 ppm was
assigned to the ethoxy methylene group (inset A2 in Fig-
ure 7A). The strong difference of the chemical shifts detected
for the two methylene multiplets is due to the diastereotopic
effect as the chirality center is created on the tetrahedral
hybridized C3 atom. The structurally informative H3 reso-
nance for 10a was identified at 8.08 ppm.
longer and the Cb Cb distances are shorter than in unper-
43]
turbed furan.[40
These bond changes indicate that the p
delocalization through the furan ring is altered. Thus, this is an
intermediary situation between those where the furan ring has
been built into nonaromatic and aromatic macrocycles.
Formation and characterization of [(C2H5O,pyr)OCP]AgIII]:
The reaction between silver acetate and 5 in acetonitrile
resulted in the formation of [(H,pyr)OCP]AgIII] (10a;
Scheme 7). In the course of metal insertion, other species,
which presumably preserve the overall macrocyclic skeleton
of 10a but contain unidentified substituents on the C3
position, were detected in the 1HNMR spectra as well.
Attempts to separate 10a by column chromatography con-
tinually led to a variety of derivatives due to the intrinsic
reactivity at the C3 position. Once ethanol was introduced on
purpose, [(C2H5O,pyr)OCP]AgIII] (10b), which is structurally
Coordination through the nitrogen donors in 10b is
reflected by the presence of 107/109Ag scalar splitting, seen for
the H7, H8, H17, and H18 b-Hpyrrolic signals. In each case
4
the coupling constant JAgH equals 1.5 Hz (inset A1 in Fig-
ure 7A). Such a coupling was not detected for the H12 and
H13 resonances of the central pyrrole ring.
Chem. Eur. J. 2003, 9, 4650 4660
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4655

¬
L. Latos-Graz«ynski and M. Pawlicki
FULL PAPER
Figure 8. The crystal structure of 10b. Top: perspective view, bottom: side
view (phenyl groups omitted for clarity). The thermal ellipsoids represent
50% probability.
Figure 7. 1HNMR spectra of: A) 10b (CD2Cl2, 298 K) and B) 9c (CD2Cl2,
298 K). Insets A1 and B1 (not to scale) present the b-Hresonances showing
couplings to 107/109Ag. The diasterotopic splitting of the CH2 resonances of
the ethoxy group on the 3-position is shown in inset A2.
Table 1. Selected bond lengths and angles.
Compound
Bond lengths [ä]
Angles [8]
[(pyr)OCP]NiII]
(9a)
Ni1 N22 1.945(4)
C21 Ni1 N22 88.5(2)
À
À
À
À
À
À
Ni1 N23 1.952(4)
C21 Ni1 N23 178.1(2)
À
À
À
Ni1 N24 1.975(4)
N22 Ni1 N23 91.2(2)
The ethoxy substituent on the 3-position of 10b could be
replaced by a methoxy group by addition of TFA followed by
treatment with sodium methoxide to yield [(CH3O,pyr)-
OCP]AgIII]; this was reflected by an OCH3 resonance at
3.30 ppm. The unique, diasterotopically split ethoxy multip-
lets were replaced by the typical quartet of the methylene
group of free ethanol. A related exchange was previously
detected in the case of cobalt(ii) methoxybiliverdin com-
plexes.[44]
À
À
À
Ni1 C21 1.892(4)
C21 Ni1 N24 90.1(2)
À
À
N22 Ni1 N24 177.9(2)
À
À
N23 Ni1 N24 90.2(2)
[(C2H5O,pyr)OCP]AgIII
(10b)
]
Ag1 N22 2.031(5)
C21 Ag1 N22 89.4(2)
À
À
À
À
À
À
Ag1 N23 2.069(5)
C21 Ag1 N24 89.3(2)
À
À
À
Ag1 N24 2.042(5)
N22 Ag1 N24 178.5(2)
À
À
À
Ag1 C21 2.020(7)
C21 Ag1 N23 179.5(3)
À
À
N22 Ag1 N23 90.2(2)
À
À
N24 Ag1 N23 91.1(2)
À
À
O1' C3 O2 106.3(6)
À
À
O1' C3 C1' 104.9(7)
À
À
O2 C3 C1' 107.1(6)
À
À
O1' C3 C4 116.7(6)
Crystal structure of [(C2H5O,pyr)OCP]AgIII] (10b): The
structure of 10b has been determined by X-ray crystallog-
raphy. The perspective views of the molecule are shown in
Figure 8. The macrocycle is only slightly distorted from
planarity, as can be seen in Figure 8. The tetrahedral geometry
around the C3 atom is demonstrated by the respective bond
angle values. Table 1 contains selected bond lengths and
angles.
À
À
O2 C3 C4 105.0(5)
À
À
C1' C3 C4 116.1(6)
The comparison of the structural data, although limited to
the three available examples of silver(iii) (NNNC) carbapor-
phyrinoids, shows that silver(iii) carbon(sp2) bond lengths
are very similar in spite of the different nature of the carbon-
donor-bearing ring (related to N-confused pyrrole, substituted
O-confused furan, or indene).
À
À
The Ag N and Ag C distances (Table 1) are comparable to
those in other silver(iii) carbaporphyrinoids, for example,
À
À
silver(iii) inverted porphyrin (Ag N22 2.06(2), Ag N23
2.08(2), Ag N24 2.03(2), and Ag C21 2.04(2) ä),[13] silver(iii)
Formation and characterization of [(pyr)OCP]AgIII] (9c):
À
À
1
benzocarbaporphyrin (Ag N22 2.038(4), Ag N23 2.084(4),
Ag N24 2.046(4), and Ag1 C21 2.015(4) ä),[29] and silver(iii)
The HNMR titration of [(C H5O,pyr)OCP]AgIII 10b with
À
À
2
À
À
TFA in CD2Cl2 was carried out. Under these conditions 10b is
À
À
double N-confused porphyrin (Ag C21 2.011(7), Ag C22
readily transformed into the new aromatic complex[(pyr)-
[45]
‡
1.987(2), Ag N23 2.064(5), and Ag N24 2.047(7) ä).
OCP]AgIII] (9c; Scheme 6), through an exocyclic C3 O
À
À
À
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O-Confused Oxaporphyrins
4650 4660
Table 2. Appended-pyrrole H (13C) NMR chemical shift values [ppm].
1
bond cleavage followed by an elimination of the ethoxy group.
Formally, the complex 9c can be produced by the insertion of
a silver(iii) cation into hypothetical compound 8 (Scheme 5),
with the replacement of H21 and an inner NH proton.
Addition of sodium ethoxide in ethanol to the solution of 9c
reverses the course of the titration to recover starting material
10b.
The observed changes in the electronic absorption spectra
are consistent with an equilibrium between two species, as the
well-defined sets of isosbestic points have been detected. The
electronic absorption spectrum of 9c is completely different
from that of starting material 10b; it does, however, resemble
that of 9a or 9b (Figure 6). The spectrum shows the intense,
Soret-like band at 498 nm accompanied by the comparable
ones at 660, 684, and 747 nm; this indicates coupling between
two conjugated moieties. The chromophore undergoes fun-
damental structural changes, in relation to 10b, that approach
the structure seen for 9a.
Compound
Position
3'
4'
5'
NH
pyrrole[46]
6.22 (108.2) 6.22 (108.2) 6.68 (118.5)
[(H,pyr)OCPH]H2 (5)
5.54 (109.8) 5.82 (108.5) 6.33 (118.5) 7.26
5.91 (111.5) 5.69 (107.6) 5.99 (120.1) 7.69
‡
‡
[(H,pyr)OCPH]H3 (5-H )
[(C2H5O,pyr)OCP]AgIII] (10b) 5.66 (107.4) 5.98 (108.9) 6.53 (116.6) 8.20
[(pyr)OCP]NiII] (9a)
[(pyr)OCP]PdII] (9b)
[(pyr)OCP]AgIII] (9c)
dipyrromethene[47]
6.34 (119.2) 6.17 (111.9) 6.76 (126.4) 8.10
6.36 (120.4) 6.20 (112.1) 6.79 (127.2) 8.16
6.60 (125.9) 6.40 (115.4) 7.27 (133.9) 9.81
6.64 (128.8) 6.39 (117.2) 7.63 (143.1)
of the two silver(iii) complexes, due its different orientation
with respect to the macrocyclic plane.
The analysis of the 13C chemical shifts (Table 2) provides an
essential insight into the different role of the pyrrole fragment
and underscores the direct electronic effects. The ring-current
contributions to overall changes in 13C NMR chemical shifts
are negligible. For the sake of comparison, the respective
chemical shift values of free pyrrole[46] and the conjugated
pyrrole ring of 5-anisol-dipyrromethene[47] have been includ-
ed in Table 2. These values set the spectroscopic standards for
two extreme structures of the appended pyrrole. Actually,
representative 13C chemical shifts for a conjugated pyrrole
have also been reported for other molecules, that is, ruthe-
nium complexes containing butatrienylidene (C3' 125.2, C4'
112.8, and C5' 140.5 ppm)[48] and bis-dipyrromethenes (C5'
141.1 ppm).[49]
In contrast to the marked changes seen in the electronic
1
absorption spectra, relatively small changes of the HNMR
chemical shifts were observed in comparison to 10b, a fact
which is clearly consistent with the macrocyclic aromaticity of
the ligand in 9c. The fine structure of b-Hresonances seen for
parental 10b due to the coupling with 107/109Ag was conserved.
The NH1' resonance was identified at 9.81 ppm. The marked
unequivalence of the ortho and meta resonances, character-
istic for 10b, disappeared over the whole investigated temper-
ature range of 203 293 K. In the course of titration with TFA,
the diasteropically split, ethoxy methylene multiplet was
gradually replaced by the quartet signal of free ethanol.
Importantly, one equivalent of ethyl alcohol was released, as
confirmed by careful integration of the alcohol resonances
with respect to those of 9c.
The spectroscopic data can be accounted for by the
structure presented in the Scheme 6. The elimination of the
ethoxy group allows a similar arrangement of whole macro-
cycle and the appended pyrrole ring as is seen in 9a, with the
relatively small dihedral angle between the macrocyclic plane
and the appended pyrrole plane but with the NHgroup
oriented toward the O2 atom. The unequivalency of the two
2-oxa-21-carbaporphyrin sides, seen for 10b, has been re-
moved in 9c, thereby rendering the ortho and meta protons of
the meso-phenyl groups equivalents. The critical insight into
the molecular structure of 9c was given by COSY and
NOESY studies. Considering in detail the spatial proximity of
H3' and H4' to the ortho proton of the phenyl on C5 and the
larger distance between H5' and the ortho proton of the same
phenyl group, one would expect strong NOE cross-peaks to
occur exclusively between the first two couples, as was
detected.
The 13C NMR chemical shifts found for the appended-
pyrrole resonances of 5, 10a, and 10b are fairly typical of
unperturbed pyrrole. These values are similar to relevant
shifts seen for 2-aza-3-(2'-pyrrolyl)-5,10,15,20-tetraphenyl-21-
carbaporphyrin.[34] The 13C chemical shifts seen for 9 increase
systematically in the series 9a, 9b, 9c to approach the limits of
5-phenyl-dipyrromethene. The trend can be rationalized by an
effective conjugation between the macrocycle and the ap-
pended pyrrole moiety. In terms of 13C chemical shifts, it is
clear that the extent of the conjugation is dependent on the
charge of the coordinated metal ions, with the largest effect
being seen for 9c.
To account for the structural and spectroscopic character-
istics of 9a c, one can formally include a set of canonical
¬
structures 11a c (Scheme 8). The Kekule structure of 11a
defines the metallocarbaporphyrinoid molecule where, for
topological reasons, the macrocyclic aromaticity typical of
porphyrin can not be retained. On the other hand, for 11b and
11c the 18 electron p-delocalization pathway allows macro-
cyclic aromaticity. Direct p conjugation between the append-
Remarkable changes of the appended-pyrrole 1HNMR
pattern have been observed in 9a c (Table 2). The marked
downfield relocation of the resonances of 9a c with respect
to those of 10b is the most analytically important. The reasons
for the changes are complex. The simultaneous modification
of the macrocyclic ring current and/or electronic structure of
the appended fragment are of importance. Definitely a
different ring-current effect is sensed by the appended pyrrole
Scheme 8. The set of formal canonical structures 11a c.
Chem. Eur. J. 2003, 9, 4650 4660
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¬
L. Latos-Graz«ynski and M. Pawlicki
FULL PAPER
ed pyrrole fragment and the carbaporphyrinoid p system is
expected in 11b and 11c. The exocyclic double bond connects
the C3 and C2' atoms, with the presumption that the
appended pyrrole ring is in the plane of the 2-oxa-21-
carbaporphyrin. Consequently, the appended moiety can
participate in the overall p delocalization. In reality, the
evolution of the conjugative effect when going from planar to
perpendicular conformations is expected, with the largest
effect for the coplanar arrangement. It is worth noting that the
relatively small dihedral angle between the pyrrole and furan
plane in 9b suggests the contribution of conjugation in the
determination of the macrocyclic structure. In this consider-
ation, we have taken into account the extensive interannular
conjugation in the description of the electronic and molecular
structure of 2-(2'-furyl)pyrrole alone, which adopts a cis-
planar conformation in solution.[35, 36] The conjugation be-
tween the pyrrole group and the aromatic macrocycle can be
related to that described for 2-(2'-furyl)pyrrole by presuming
that the furan ring, built into the 2-oxa-21-carbaporphyrin
structure, acts as an efficient bridge between the macrocycle
and the appended pyrrole.
over the whole structure. This important feature of O-
confused porphyrin derivatives has enabled us to investigate
and eventually to control the subtle interplay between their
structural flexibility, perimeter substitution, coordination, and
aromaticity. Essentially the oxidation of the central metal ion
can be considered as a factor that determines the molecular
structure of the ligand. The dianionic or trianionic macro-
cyclic core of the pyrrole-appended derivatives is favored to
match the oxidation state of nickel(ii), palladium(ii), or
silver(iii), respectively.
In general the coordinating environment provided by
carbaporphyrinoids offers a unique opportunity to create
novel organometallic compounds and to control their reac-
tivity. Thus, an original route to tune carbaporphyrinoids to
the coordination requirements of metal ions through a 2-(2'-
furyl)pyrrole moiety has been introduced.
Experimental Section
Materials: 3-Furaldehyde, phenyl Grignard reagent, sBuLi, and nBuLi (all
from Aldrich) were used as received.
Consequently, the electronic structures of 9a c can be
described by a combination of aromatic and nonaromatic
canonical structures, which participate in the overall picture in
proportions imposed by the charge of the central metal ion.
Clearly, the definitely aromatic character of the 2-oxa-21-
carbaporphyrin macrocycle in 9c is consistent with a domi-
nating contribution of 11b and 11c. On the other hand, the
participation of 11a is strongly marked for 9a and 9b.
2-(Phenylhydroxymethyl)-4-furaldehyde: nBuLi (23.91 mL, 38.25 mmol,
1.6 m solution in hexanes) was added to morpholine (3.33 mL, 38.25 mmol)
in THF (150 mL) at À788C.[32] 3-Furaldehyde (3 mL, 36.4 mmol) was
added after 20 min, to be followed after a further 20 min by sBuLi
(29.4 mL, 38.25 mmol, 1m solution in hexanes). The resulting mixture was
stirred for 4 h at À788C. After that time benzaldehyde (4.08 mL,
40.05 mmol) was added and the reaction was left for 16 h while the cooling
bath reached room temperature. The mixture was poured into hydrochloric
acid/ice (1:10 v/v). The organic products were extracted with diethyl ether
(three times). All organic layers were collected, dried with MgSO4, and
filtered. The solvents were evaporatd under reduced pressure. The residue
was dissolved in benzene and purified by chromatography through a basic
alumina column. The first orange fraction to be eluted with benzene was
collected, and the solvent was removed with a vacuum rotary evaporator to
give 2-(phenylhydroxymethyl)-4-furaldehyde as an orange oil (3.6 g, 50%).
1HNMR (500.13 MHz, CDCl 3): d ˆ 9.81 (s, 1H), 7.97 (s, 1H), 7.41 7.31 (m,
5H), 6.49 (s, 1H), 5.78 (s, 1H), 2.82 (s, 1H) ppm; 13C NMR (125.77 MHz,
CDCl3): d ˆ 184.5, 158.8, 151.2, 139.8, 128.6, 128.5, 126.5, 104.4, 69.8 ppm;
Conclusion
In the present work we have described the synthesis and
reactivity of a new carbaporphyrinoid. The molecule has been
constructed by applying the heteroatom confusion concept.
An interchange of an oxygen atom with a b-methine group of
furan transforms 5,10,15,20-tetraaryl-21-oxaporphyrin into
5,10,15,20-tetraaryl-2-oxa-21-carbaporphyrin. Inherent reac-
tivity of the furan ring in the presence of pyrrole required
during the course of the synthesis prevented formation of the
™pure∫ O-confused oxaporphyrin. Instead, the procedure
resulted in a modified macrocycle, which was, however,
directly related to the O-confused oxaporphyrin.
‡
‡
MS: m/z: calcd for C12H9O2 [M À OH] : 185.06; found: 185.1.
2,4-Bis(phenylhydroxymethyl)furan (3): 2-(Phenylhydroxymethyl)-4-fural-
dehyde (500 mg, 2.5 mmol) was dissolved in freshly distilled THF
(100 mL). PhMgBr (1.5 mL, 3m solution in diethyl ether) was added
through a syringe. The resulting mixture was stirred for 30 min, and 1%
H2SO4 (40 mL) was added. The solution was neutralized by addition of
Na2CO3 until the liberation of CO2 ceased. The product was extracted with
diethyl ether (three times). All organic layers were collected, dried with
MgSO4, filtered, and evaporated with a vacuum rotary evaporator. Product
3
was obtained almost quantitatively as an orange oil. 1HNMR
The new molecule, applied as a ligand toward selected
metal ions, reveals the peculiar plasticity of its molecular and
electronic structure. The structural changes are easily trig-
gered by addition/elimination of a nucleophile at the C3
position (Scheme 9). The tetrahedral trigonal rearrange-
ments originate at the C3 atom but the consequences extend
(500.13 MHz, CDCl3): d ˆ 7.71 7.31 (m, 10H), 7.22 (d, 1H), 6.07 (d, 1H),
5.74 (s, 1H), 5.68 (s, 1H), 2.37 (s, 1H), 2.11 (s, 1H) ppm; 13C NMR
(125.77 MHz, CDCl3): d ˆ 156.8, 142.8, 140.5, 139.7, 128.7, 128.5, 128.4,
128.1, 127.9, 127.2, 127.1, 126.6, 126.3, 106.98, 70.1, 69.8 ppm; MS: m/z: calcd
‡
‡
for C18H15O2 [M À OH] : 263.1; found: 263.3.
[(H,pyr)OCPH]H2 (5): Compound 3 (280 mg, 1 mmol), pyrrole (208 mL,
3 mmol), and p-toluylaldehyde (236 mL, 2 mmol) were dissolved in freshly
distilled dichloromethane (100 mL). N2 gas was bubbled through the
solution for 20 min to remove oxygen before BF3 ¥ Et2O (37 mL) was added.
The solution was stirred for 1 h in the absence of light, DDQ (681 mg,
3 mmol) was added, and the solution was stirred for an additional 20 min.
The solvent was removed with a vacuum rotary evaporator. The dark
residue was separated by chromatography on a basic alumina (grade II)
column. The fast-moving fraction was collected and immediately separated
again by chromatography on a silica gel (mesh 35 70) column. The
product was eluted with dichloromethane as a slow-moving, brown band.
Scheme 9. Addition/elimination of
structural changes.
a nucleophile at C3 triggers the
4658
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Chem. Eur. J. 2003, 9, 4650 4660

O-Confused Oxaporphyrins
4650 4660
‡
Recrystallization from dichloromethane/methanol (50:50 v/v) gave
5
(3.58) nm; HRMS: m/z: calcd for C50H34N4O1Pd [M] : 812.1785; found:
(70 mg, 10%). 1HNMR (500.13 MHz, CD 2Cl2): d ˆ 8.49 (d, 1H, 3J ˆ
4.9 Hz), 8.47 (d, 1H, 3J ˆ 4.9 Hz), 8.47 (d, 1H, 3J ˆ 4.6 Hz), 8.45 (d, 1H,
3J ˆ 4.6 Hz), 8.44 (d, 1H, 3J ˆ 4.9 Hz), 8.29 (d, 1H, 3J ˆ 4.9 Hz), 8.10 (d, 2H,
3J ˆ 7.6 Hz), 8.08 (s, 1H), 8.04 (m, 3H), 7.96 (m, 3H), 7.69 (t, 2H), 7.53 (m,
6H), 7.38 (brs), 7.26 (s, 1H), 7.21 (brs), 6.33 (m, 1H), 5.82 (m, 1H), 5.54 (m,
1H), 2.67 (s, 3H), 2.66 (s, 3H), À5.11 (s, 1H) ppm; 13C NMR (125.77 MHz,
CDCl3): d ˆ 160.3, 152.9, 152.4, 143.3, 140.4, 139.9, 139.4, 139.3, 139.3, 139.2,
138.4, 137.3, 137.3, 137.2, 135.1, 134.5, 134.3, 134.3, 134.2, 134.1, 134.0, 133.8,
133.6, 132.1, 131.8, 130.8, 130.1, 127.9, 127.6, 127.5, 127.4, 127.3, 127.2, 126.4,
126.3, 123.1, 123.0, 121.2, 120.4, 120.1, 117.9, 112.5, 109.3, 108.2, 106.4, 105.2,
85.3, 21.5, 21.5 ppm; UV/Vis: lmax (log e) ˆ 437 (5.01), 533 (3.96), 567 (3.81),
812.1765.
[(pyr)OCP]AgIII
]
(9c): Compound 10b (20 mg) was dissolved in freshly
‡
distilled dichloromethane (15 mL). A solution of TFA in dichloromethane
(60%) was added through a syringe until the color changed from red to
green. The product was precipitated from the reaction mixture with hexane
1
(17.5 mg, 82%). HNMR (500.13 MHz, CD 2Cl2): d ˆ 9.54 (brs), 8.73 (dd,
1H, 3J ˆ 5.4, JAg ˆ 1.5 Hz), 8.59 (dd, 1H, 3J ˆ 4.9, JAg ˆ 1.5 Hz), 8.55 (d,
4
4
3
4
1H, J ˆ 4.9 Hz), 8.52 (d, 1H, 3J ˆ 4.9 Hz), 8.51 (dd, 1H, 3J ˆ 5.3, JAg
ˆ
1.5 Hz), 8.44 (d, 1H, 3J ˆ 4.9 Hz), 8.19 (m, 2H), 8.12 (m, 2H), 7.89 (m,
10H), 7.58 (m, 4H), 7.27 (s, 1H), 6.60 (d, 1H), 7.68 7.63 (m), 6.40 (m, 1H),
2.68 (s, 3H), 2.67 (s, 3H) ppm; 13C NMR (125.77 MHz, CD2Cl2, partial
data): d ˆ 131.9 (18-C), 133.5 (7-C), 130.8 (17-C), 134.4 (13-C), 132.4 (8-C),
132.2 (12-C), 134.6 (20-o-C), 133.5 (5-o-C), 133.9 (10,15-o-C), 130.6 (5,20-
m-C), 129.8 and 128.6 (5,20-p-C), 128.8 (10,15-m-C), 133.9 (5'-C), 125.9 (3'-
C), 115.3 (4'-C), 21.5 (10,15-p-CH3) ppm; UV/Vis: lmax (log e) ˆ 335 (4.29),
384 (4.23), 499 (4.92), 660 (4.55), 683 (4.43), 749 (4.00) nm; HRMS: m/z:
‡
622 (3.58), 679 (3.84) nm; HRMS: m/z: calcd for C50H39N4O1 [M‡H] :
711.3124; found: 711.3118; elemental analysis calcd (%) for C50H38N4O1 ¥
(with 0.33 CH2Cl2): C 81.95, H5.24, N 7.59; found: C 81.65, H5.36, N 7.65.
[(C2H5O,pyr)OCP]AgIII] (10b): Compound 5 (15 mg, 0.021 mmol) was
dissolved in chloroform (20 mL), and silver acetate (146 mg) in acetonitrile
(20 mL) was added. The mixture was heated to reflux for 30 min, then the
solvent was removed with a vacuum rotary evaporator. The solid residue
was immediately separated on a silica gel (mesh 35 70) column. The red
fraction was eluted with toluene. The solvent was removed in a stream of
nitrogen. Recrystallization from chloroform/methanol (50:50 v/v) gave 10b
(13.4 mg, 78%). 1HNMR (500.13 MHz, CD 2Cl2): d ˆ 8.72 (dd, 1H, 3J ˆ 4.9,
‡
calcd for C50H34N4O1Ag [M] : 813.1783; found: 813.1778; elemental
analysis calcd (%) for C52H34N4O3F3Ag1 ¥ (with 1.33 CH2Cl2): C 61.61, H
3.53, N 5.39; found: C 61.72, H3.32, N 5.49.
Instrumentation: NMR spectra were recorded on a Bruker Avance 500
spectrometer. Absorption spectra were recorded on a diode array Hewlett
Packard 8453 spectrometer. Mass spectra were recorded on an AD-604
spectrometer by using the electrospray and liquid-matrix secondary-ion
mass spectrometry techniques.
4
4JAg ˆ 1.1 Hz), 8.65 (d, 1H, 3J ˆ 4.6), 8.64 (dd, 1H, 3J ˆ 4.9, JAg ˆ 1.5 Hz),
8.62 (dd, 1H, 3J ˆ 4.9, 4JAg ˆ 1.1 Hz), 8.60 (d, 1H, 3J ˆ 4.6 Hz), 8.34 (dd, 1H,
4
3J ˆ 4.9, JAg ˆ 1.5 Hz), 8.20 (s, 1H), 8.05 (m, 3H), 7.97 (m, 3H), 7.84 (m,
X-ray data collection and refinement: Crystals of 9a and 10b were
prepared by diffusion of methanol into dichloromethane (9a) and toluene
(10b) solutions, respectively, contained in a thin tube. Data were collected
at 100 K on a Kuma KM-4 CCD diffractometer. The data were corrected
for Lorentz and polarization effects. No absorption correction was applied.
1H), 7.71 (t, 2H), 7.64 (m, 1H), 7.59 7.49 (m, 6H), 7.25 (td, 1H, J ˆ 7.6,
1.5 Hz), 6.89 (m, 1H), 6.53 (m, 1H), 5.98 (m, 1H), 5.66 (m, 1H), 3.84 (m,
1H), 3.19 (m, 1H), 2.68 (s, 3H), 2.67 (s, 3H), 1.20 (t, 3H) ppm; 13C NMR
(125.77 MHz, CD2Cl2): d ˆ 148.1, 142.1, 142.1, 140.3, 140.3, 139.4, 139.3,
139.0, 138.5, 138.1, 138.1, 137.0, 136.8, 135.6, 134.7, 133.9, 133.9, 133.9, 133.8,
133.6, 133.3, 132.4, 129.8, 129.3, 129.3, 128.9, 128.9, 128.5, 128.1, 128.1, 128.1,
128.0, 127.8, 127.3, 127.2, 126.4, 126.1, 125.5, 125.5, 121.9, 121.8, 118.4, 118.3,
116.6, 111.9, 109.7, 109.7, 108.0, 107.4, 59.2, 21.6, 21.6, 15.1 ppm; UV/Vis:
lmax (log e) ˆ 432 (5.19), 508 (4.02), 524 (3.97), 560 (3.77), 607 (4.21) nm;
Table 3. Crystal data for [(pyr)OCP]NiII] (9a) and [(C2H5O,pyr)OCP]-
AgIII] (10b).
‡
HRMS: m/z: calcd for C52H39N4O2Ag [M] : 858.2123; found: 858.2118.
Compound
[(pyr)OCP]NiII] (9a): Comound 5 (20 mg, 0.028 mmol), NiCl2 (36.6 mg,
0.28 mmol), and K2CO3 (excess) were added to acetonitrile (25 mL). The
mixture was heated to reflux for 1.5 h. The solvent was removed under
reduced pressure. The remaining solid was dissolved in freshly distilled
[(pyr)OCP]NiII]
[(C2H5O,pyr)OCP]AgIII] ¥
0.5C7H8
crystals grown by
MeOHinto CH Cl2
MeOHinto toluene
2
slow diffusion of
crystal habit
formula
Mw
a [ä]
b [ä]
c [ä]
a [8]
b [8]
dichloromethane and separated by chromatography on
a silica gel
deep green block
C50H34N4O1Ni
765.52
10.2928(7)
23.7004(17)
14.7332(10)
dark red plate
C52H39N4O2Ag
859.74
(Mesh 35 70) column. The fast-moving, green band was collected.
Recrystallization from CHCl3/MeOHgave 9 (8.6 mg, 40%). 1HNMR
3
(500.13 MHz, CD2Cl2): d ˆ 8.12 (d, 1H, J ˆ 4.9 Hz), 8.10 (s, 1H), 7.98 (m,
3
3
11.1748(13)
14.5887(18)
14.8542(17)
63.094(12)
79.353(10)
88.349(10)
2118.1(4)
2
2H), 7.93 (d, 1H, J ˆ 4.9 Hz), 7.90 (m, 2H), 7.89 (d, 1H, J ˆ 3.8 Hz), 7.86
(d, 1H, 3J ˆ 4.9 Hz), 7.85 (d, 1H, 3J ˆ 4.9 Hz), 7.72 (d, 1H, 3J ˆ 3.8 Hz), 7.71
(m, 2H), 7.68 7.63 (m), 7.41 (m, 4H), 6.76(m, 1H), 6.34 (m, 1H), 6,17 (m,
1H), 2.58 (s, 3H), 2.56 (s, 3H) ppm; 13C NMR (125.77 MHz, CD2Cl2): d ˆ
164.5, 154.3, 151.3, 150.9, 149.4, 149.1, 147.9, 146.1, 141.8, 138.5, 138.3, 137.6,
137.6, 137.6, 134.8, 134.3, 133.8, 133.7, 133.3, 131.6, 131.5, 130.9, 129.3, 129.2,
128.3, 128.1, 128.1, 127.8, 127.7, 127.5, 126.5, 124.4, 123.0, 122.9, 121.9, 119.7,
119.2, 117.3, 111.9, 21.6, 21.5 ppm; UV/Vis: lmax (log e) ˆ 370 (3.75), 473
(3.87), 490 (3.90), 578 (3.29), 664 (3.52), 763 (2.96), 843 (2.93) nm; HRMS:
97.953(6)
g [8]
V [ä3]
Z
3559.5(4)
4
1.348
monoclinic
P21/c
0.593
1calcd [gcmÀ3
]
1.428
‡
crystal system
space group
triclinic
m/z: calcd for C50H34N4O1Ni [M] : 764.2086; found: 764.2081.
≈
P1
[(pyr)OCP]PdII] (9b): Compound 5 (15.5 mg, 0.022 mmol), PdCl2 (5.5 mg,
0.032 mmol), and K2CO3 (excess) were added to acetonitrile (25 mL). The
mixture was heated to reflux for 1.5 h. The solvent was removed under
reduced pressure. The remaining solid was dissolved in freshly distilled
m [mmÀ1
]
0.522
not applied
absorption
correction
T [K]
q range
hkl range
not applied
100(2)
100(2)
dichloromethane and separated by chromatography on
a silica gel
3.31 ꢁ q ꢁ 28.55
À 8 ꢁ h ꢁ 13
À 31 ꢁ k ꢁ 31
À 19 ꢁ l ꢁ 19
3.27 ꢁ q ꢁ 28.52
À 14 ꢁ h ꢁ 14
À 18 ꢁ k ꢁ 18
À 17 ꢁ l ꢁ 19
(mesh 35 70) column. The fast-moving, green band was collected.
Recrystallization from CHCl3/MeOH(50:50 v/v) gave 9b (12 mg, 68%).
1HNMR (500.13 MHz, CD 2Cl2): d ˆ 8.16 (s, 1H), 8.12 (d, 1H, 3J ˆ 4.9 Hz),
8.05 (m, 2H), 7.96 (m, 2H), 7.92 (d, 1H, 3J ˆ 4.9 Hz), 7.90 (d, 1H, 3J ˆ
4.9 Hz), 7.87 (d, 1H, 3J ˆ 4.9 Hz), 7.82 (d, 1H, 3J ˆ 4.9 Hz), 7.80 (d, 1H, 3J ˆ
4.9 Hz), 7.77 (m, 2H), 7.75 7.67 (m), 7.43 (m, 4H), 6.79 (m, 1H), 6.36 (m,
1H), 6.20 (m, 1H), 2.60 (s, 3H), 2.58 (s, 3H) ppm; 13C NMR (125.77 MHz,
CD2Cl2): d ˆ 167.6, 153.5, 151.6, 150.1, 149.2, 148.5, 147.7, 145.3, 141.5, 139.7,
139.5, 136.8, 135.9, 135.8, 135.4, 135.4, 135.2, 134.6, 132.8, 132.7, 132.5, 132.4,
131.3, 131.2, 130.4, 130.1, 130.1, 129.9, 129.7, 129.6, 129.2, 126.6, 126.5, 123.1,
122.5, 122.4, 122.3, 120.6, 114.1, 23.4, 23.4 ppm; UV/Vis: lmax (log e) ˆ 365
(4.28), 454 (4.36), 483 (4.51), 605 (3.75), 648 (4.31), 751 (3.61), 827
reflections:
measured
unique, I > 2s(I)
parameters/restraints
S
R1[a]
wR2[b]
8320
4638
606/0
1.115
0.0909
0.1844
9296
4637
597/0
0.950
0.0814
0.1767
[a] R1 ˆ S j jFo À Fc j j/S j Fo j . [b] wR2 ˆ [S[w(Fo2 À Fc2†2]/S[w(Fo2†2]]1/2
.
Chem. Eur. J. 2003, 9, 4650 4660
www.chemeurj.org
¹ 2003 Wiley-VCHVerlag GmbH& Co. KGaA, Weinheim
4659

¬
L. Latos-Graz«ynski and M. Pawlicki
FULL PAPER
Crystal data are compiled in Table 3. The structures were solved by the
heavy atom method (9a) and direct methods (10b) with SHELXS-97 and
refined by the full-matrix least-squares method by using SHELXL-97 with
anisotropic thermal parameters for the non-hydrogen atoms. Scattering
factors were those incorporated in SHELXS-97.[50, 51] In the structure of 10b
the high-temperature factors of some appended pyrrole and ethoxy group
atoms suggest disorder, which could not be resolved.[50] Crystallographic
data (excluding structure factors) have been deposited with the Cambridge
Crystallographic Data Centre as supplementary publication nos. CCDC-
205271 and -205272. 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; email: deposit@ccdc.cam.ac.uk).
[25] S. Venkatraman, V. G. Anand, S. K. Pushpan, J. Sankar, T. K.
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Acknowledgement
Financial support from the State Committee for Scientific Research KBN
of Poland (Grant: 4T09A14722) is gratefully acknowledged.
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[40] R. Forume, Acta Crystallogr. Sect. B: Struct. Sci. 1972, 28, 2984.
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J.-P. Gisselbrecht, M. Gross, Angew. Chem. 1993, 105, 1670; Angew.
Chem. Int. Ed. Engl. 1993, 32, 1600.
¬
[1] P. J. Chmielewski, L. Latos-Graz«ynski, K. Rachlewicz, T. G¯owiak,
Angew. Chem. 1994, 106, 805; Angew. Chem. Int. Ed. Engl. 1994, 33,
779.
[2] H. Furuta, T. Asano, T. Ogawa, J. Am. Chem. Soc. 1994, 116, 767.
[3] P. J. Chmielewski, L. Latos-Graz«ynski, J. Chem. Soc. Perkin Trans. 2
¬
1995, 503.
[4] T. D. Lash, D. T. Richter, C. M. Shiner, J. Org. Chem. 1999, 64, 7973.
[5] Z. Xiao, B. O. Patrick, D. Dolphin, Chem. Commun. 2002, 1816.
[6] I. Schmidt, P. J. Chmielewski, Z. Ciunik, J. Org. Chem. 2002, 67, 8917.
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Angew. Chem. 1988, 100, 450; Angew. Chem. Int. Ed. Engl. 1988, 27,
411.
¬
[7] P. J. Chmielewski, L. Latos-Graz«ynski, T. G¯owiak, J. Am. Chem. Soc.
1996, 118, 5690.
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[8] P. J. Chmielewski, L. Latos-Graz«ynski, Inorg. Chem. 2000, 39, 5639.
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[43] M. Pawlicki, L. Latos-Graz«ynski, L. Szterenberg, J. Org. Chem. 2002,
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[9] P. J. Chmielewski, L. Latos-Graz«ynski, Inorg. Chem. 1997, 36, 840.
[10] P. J. Chmielewski, L. Latos-Graz«ynski, I. Schmidt, Inorg. Chem. 2000,
67, 5644.
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[44] L. Latos-Graz«ynski, J. J. Johnson, S. Attar, M. M. Olmstead, A. L.
39, 5475.
Balch, Inorg. Chem. 1998, 37, 4493.
[11] H. Furuta, N. Kubo, H. Maeda, T. Ishizuka, A. Osuka, H. Nanami, T.
Ogawa, Inorg. Chem. 2000, 39, 5424.
[12] T. Ogawa, H. Furuta, M. Takahashi, A. Morino, H. Uno, J. Organomet.
Chem. 2000, 611, 551 557.
[13] H. Furuta, T. Ogawa, Y. Uwatoko, K. Araki, Inorg. Chem. 1999, 38,
2676.
[14] J. D. Harvey, C. J. Ziegler, Chem. Commun. 2002, 1942.
[15] D. S. Bohle, W.-C. Chen, C.-H. Hung, Inorg. Chem. 2002, 41, 3334.
[16] H. Furuta, T. Ishizuka, A. Osuka, J. Am. Chem. Soc. 2002, 124, 5622.
[17] W.-C. Chen, C.-H. Hung, Inorg. Chem. 2001, 40, 5070.
[18] C.-H. Hung, W.-C. Chen, G.-H. Lee, S.-M. Peng, Chem. Commun.
2002, 1516.
[45] H. Furuta, H. Maeda, A. Osuka, J. Am. Chem. Soc. 2000, 122, 803.
[46] A. R. Karitzky, A. F. Pozharski, Handbook ofHeterocyclic Chemistry ,
Pergamon, Amsterdam, 2000.
[47] 5-Anisol-dipyrromethene has been isolated in the course of the
preparation of an oxacarbaporphyrin in less than 1% yield. Once
identified it could be readily detected in other syntheses leading to
heteroporphyrins. 1HNMR (CDCl 3): d ˆ 7.63 (s, 2H), 7.43 (d, 2H,
3J ˆ 8.4 Hz), 6.96 (d, 2H, 3J ˆ 8.4 Hz), 6.64 (d, 2H, 3J ˆ 3.8 Hz), 6.39
(dd, 2H, 3J ˆ 4.2, 4J ˆ 1.5 Hz), 3.87(s, 3H) ppm; 13C NMR (CDCl3):
d ˆ 160.4, 143.2 (5'), 142.2, 140.7 (2'), 132.4, 129.7, 128.7 (3'), 117.3 (4'),
‡
113.0, 55.2 ppm; HRMS: m/z: calcd for C16H15N2O1 [M‡H] :
250.1184; found: 251.1179.
[19] A. Srinivasan, H. Furuta, A. Osuka, Chem. Commun. 2001, 1666.
[20] H. Furuta, H. Maeda, A. Osuka, Chem. Commun. 2002, 1795.
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Chem. Soc. Dalton Trans. 1998, 467.
[49] A. Thompson, D. Dolphin, J. Org. Chem. 2000, 65, 7870.
[50] G. M. Sheldrick, SHELXL97, program for crystal structure refinement,
University of Gˆttingen, 1997.
¬
[21] L. Latos-Graz«ynski, in The Porphyrin Handbook, Vol. 2 (Eds.: K. M.
Kadish, K. M. Smith, R. Guilard), Academic Press, New York, 2000,
pp. 361 416.
¬
¬
[22] M. SteÀpien, L. Latos-Graz«ynski, Chem. Eur. J. 2001, 7, 5113.
[51] G. M. Sheldrick, SHELXS97, program for solution of crystal struc-
tures, University of Gˆttingen, 1997.
¬
¬
[23] M. SteÀpien, L. Latos-Graz«ynski, T. D. Lash, L. Szterenberg, Inorg.
Chem. 2001, 40, 6892.
¬
¬
[24] M. SteÀpien, L. Latos-Graz«ynski, J. Am. Chem. Soc. 2002, 124, 3838.
Received: March 4, 2003 [F4995]
4660
¹ 2003 Wiley-VCHVerlag GmbH& Co. KGaA, Weinheim
www.chemeurj.org
Chem. Eur. J. 2003, 9, 4650 4660