Porphyrins with a carbosilane dendrimer periphery as synthetic components for supramolecular self-assembly

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Porphyrins with a carbosilane dendrimer periphery

as synthetic components for supramolecular self-

assembly†

Cite this: Dalton Trans., 2014, 43,

7868

Zakariyya Ishtaiwi,^aTobias Rüﬀer,^aSami Klaib,^bRoy Buschbeck,^aBernhard Walfort^a

and Heinrich Lang*^a

The preparation of the shape-persistent carbosilane-functionalized porphyrins H₂TPP(4-SiRR’Me)₄, Zn(II)-

TPP(4-SiRR’Me)₄(R

= R’ = Me, CH₂CHvCH₂, CH₂CH₂CH₂OH; R = Me, R’ = CH₂CHvCH₂,

CH₂CH₂CH₂OH; TPP = tetraphenyl porphyrin), H₂TPP(4-Si(C₆H₄-1,4-SiRR’Me)₃)₄, and Zn(II)-TPP(4-Si-

(C₆H₄-1,4-SiRR’Me)₃)₄(R = R’ = Me, CH₂CHvCH₂; R = Me, R’ = CH₂CHvCH₂) using the Lindsey conden-

sation methodology is described. For a series of ﬁve samples their structures in the solid state were deter-

mined by single crystal X-ray structure analysis. The appropriate 0^thand 1^stgeneration porphyrin-based

1,4-phenylene carbosilanes form 2D and 3D supramolecular network structures, primarily controlled by

either π–π interactions (between pyrrole units and neighboring phenylene rings) or directional molecular

hydrogen recognition and zinc–oxygen bond formation in the appropriate hydroxyl-functionalized mole-

cules. UV-Vis spectroscopic studies were carried out in order to analyze the eﬀect of the dendritic

branches on the optical properties of the porphyrin ring.

Received 19th December 2013,

Accepted 7th March 2014

DOI: 10.1039/c3dt53535e

www.rsc.org/dalton

assembling processes.³In the past, also snowflake-shaped

dendrimers containing rigid backbones within the dendrimer

Introduction

Highly branched macromolecular architectures as well as self- side chains were prepared.⁴Such systems were used, for

assembly processes have become very popular and represent example, as mediators in electron-transfer and energy-transfer

fascinating research areas both in natural sciences and engin- processes,⁵as dendritic boxes⁶or as drug carrier systems.⁷

eering.¹In this respect, dendrimers and metallo-dendrimers,

Porphyrins can successfully be used as core molecules, as

repetitive branched molecules of structural perfection, have branching units, or, for example, in the stepwise synthesis of

attracted considerable attention as nanoscale molecular cross-shaped covalent assemblies.⁸The micro-environments

materials due to their novel properties.²Dendrimers possess a set-up by such molecules can be used among others to tune

three-dimensional and well-designed highly symmetric spheri- and control both optical and electrochemical properties of the

cal arrangement with flexible structures employing isotropic appropriate porphyrin building block.^8,9Out of this, porphyr-

ins are very useful molecules to probe and hence to character-

ize dendritic local environments. Recently, metallo-porphyrins

tailored at a dendrimer core have been developed as synthetic

models to mimic naturally occurring systems including light-

harvesting and electron transfer processes (i.e., chloro-

^aTechnische Universität Chemnitz, Faculty of Natural Sciences,

Institute of Chemistry, Inorganic Chemistry, D-09107 Chemnitz, Germany.

E-mail: heinrich.lang@chemie.tu-chemnitz.de; Fax: +49-(0)371-531-21219;

Tel: +49-(0)371-531-21210

^bTafila Technical University, Faculty of Science, Department of Chemistry and

phyll),^8b,10molecular oxygen storage and transport phenomena

(i.e., hemoglobin) as well as oxidation enzymes (i.e., cyto-

chrome c).^11,12In such systems, the porphyrin building blocks

have site isolation eﬀects imposed by the dendritic shell. This

makes it possible to utilize such species in diverse applications

including homogeneous catalysis,¹³drug delivery¹⁴and singlet

oxygen generation.^11a,14b,15In addition, these compounds can

be applied as non-linear optical,¹⁶and light-emitting¹⁷

materials, as molecular sensors¹⁸or photo-active systems

which can be considered as artificial antennae devoted to

solar energy conversion.¹⁹

Chemical Technology, Tafila, Jordan

†Electronic supplementary information (ESI) available: X-ray crystal structure

data. Fig. S1/S2 and Fig. S3 display the crystal structure of 3c and 6a, respectively,

with respect to the orientation of the unit cell. Table S1 gives crystal and inten-

sity collection data of 3b·1/4CH₂Cl₂, 3c, 4a, 6a·2thf and 9b·3.5EtOH. Fig. S4–S6

illustrate T-shaped π–π interactions in the crystal structure of 9b·3.5EtOH.

Table S2 gives selected geometric features of intermolecular hydrogen bonds of

6a. Table S3 gives structural parameters of the porphyrin cores of 3b, 3c, 4a, 6a

and 9b. Fig. S7 illustrates geometrical features of saddling distorted porphyrins.

Fig. S8 shows the atom labelling for the NMR data. CCDC 976300–976304. For

ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/

c3dt53535e

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Recently, we got interested in the synthesis of by Lindsey was used.²⁰In this respect, the carbosilane alde-

SiCH₂CHvCH₂- and Si(CH₂)₃OH-functionalized tetraphenyl hydes H(O)C-1-C₆H₄-4-SiRR′Me (2a, R = R′ = Me; 2b, R = Me,

porphyrins and to use them as supramolecular tectons in the R′ = CH₂CHvCH₂; 2c, R = R′ = CH₂CHvCH₂), accessible by

formation of ordered network arrays, since this family of com- the consecutive treatment of 1-Br–C₆H₄-4-SiRR′Me (1a, R = R′ =

pounds provides a relatively unexplored class of molecules due Me; 1b, R = Me, R′ = CH₂CHvCH₂; 1c, R = R′ = CH₂CHvCH₂)

t

to their large size, ease of preparation and, for example, excellent with BuLi and dimethylformamide, were reacted with pyrrole

coordination ability. Out of these reasons, we here report the in the presence of catalytic amounts of [BF₃·OEt₂] followed by

Lindsey condensation methodology for the preparation of novel addition of 2,3-dichloro-5,6-dicyanobenzoquinone (= DDQ) in

0^thand 1^stgeneration 1,4-phenylene-based carbosilane dendri- CH₂Cl₂solutions at ambient temperature (Scheme 1, Experi-

mer-functionalized porphyrins and zinc(^II)-porphyrins. The mental section). The appropriate porphyrins H₂TPP(4-SiRR′-

single-crystal X-ray structure determination of five samples is Me)₄(3a, R = R′ = Me; 3b, R = Me, R′ = CH₂CHvCH₂; 3c, R =

reported as well showing diﬀerent interporphyrin interactions.

R′ = CH₂CHvCH₂; TPP = tetraphenyl porphyrin) were isolated

as dark red solids with yields of between 25 and 30% (see the

Experimental section). The corresponding zinc(^II)-porphyrins

Zn-TPP(4-SiRR′Me)₄(4a, R = Me, R′ = CH₂CHvCH₂; 4b, R =

R′ = CH₂CHvCH₂) were obtained in virtually quantitative

yields upon treatment of 3b or 3c with zinc(^II) acetate in a

mixture of CHCl₃–MeOH (ratio 5 : 1, v/v) (Scheme 1, see the

Experimental section).

Results and discussion

Synthesis

For the preparation of the carbosilane dendrimer-based por-

phyrins 3a–c (Scheme 1) the synthetic methodology developed

Scheme 1 Synthesis of 2–6.^21–24

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Porphyrins 3b and 3c, respectively, with their terminal (Scheme 2). The therefore necessary key aldehyde starting

SiCH₂CHvCH₂units could successfully be converted to the materials 1-H(O)C–C₆H₄-4-Si(C₆H₄-1,4-SiRR′Me)₃(8a, R = R′ =

corresponding Si-propanolic-functionalized porphyrins 5a and Me; 8b, R = Me, R′ = CH₂CHvCH₂; 8c, R = R′ = CH₂CHvCH₂)

5b by

a consecutive hydroboration–oxidation procedure were obtained with a two-step synthesis procedure from 1-Br-

(Scheme 1, see the Experimental section). Hydroboration of C₆H₄-4-Si(C₆H₄-1,4-SiRR′Me)₃(7a, R = R′ = CH₃; 7b, R = CH₃,

the appropriate end-grafted allyl groups with [BH₃·dms] R′ = CH₂CHvCH₂; 7c, R = R′ = CH₂CHvCH₂).

(dms = dimethyl sulfoxide) in thf gave the corresponding

After appropriate work-up, aldehydes 8a–c were obtained in

BH₂-functionalized systems, which on addition of hydrogen excellent yield, and porphyrins 3, 5 and 9 in yields between 25

peroxide were oxidized to the respective alcohols H₂TPP- and 40%, while the formation of the respective zinc(^II)-por-

(4-SiRR″Me)₄(5a, R = Me, R″ = CH₂CH₂CH₂OH; 5b, R = R″ = phyrins 4, 6 and 10 was quantitative (see the Experimental

CH₂CH₂CH₂OH) (Scheme 1). These porphyrins produce, when section). All carbosilane-functionalized (metallo)porphyrins

reacted with the transition metal salt [Zn(OAc)₂·2H₂O], the are, as the aldehyde starting materials, dark red colored solids

expected zinc(^II) species Zn(II)-TPP(4-SiRR″Me)₄(6a, R = Me, soluble in most common polar organic solvents. They are air-

R″ = CH₂CH₂CH₂OH; 6b, R = R″ = CH₂CH₂CH₂OH) in virtually and moisture-stable with decomposition or melting points

quantitative yield (Scheme 1, see the Experimental section). between 200 and 350 °C (see the Experimental section). Alde-

Zinc porphyrins 6a and 6b dissolve in most common organic hydes 8 and porphyrins 3–6 and 9–10 were characterized by

solvents.

elemental analysis, IR, UV-Vis and NMR spectroscopy (¹H,

The synthesis procedure used in the preparation of 3–6 ¹³C{¹H}, ²⁹Si{¹H}) (see the Experimental section). ESI-TOF

(Scheme 1) could successfully be transferred to the synthesis of mass spectrometric measurements were additionally carried

the 1^stgeneration carbosilane-based porphyrins 9a–c and 10a–c out with selected metal-free and zinc(^II) metallated samples

Scheme 2 Synthesis of 8–10.^18a,24

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(2c, 3b,c, 4a,b, 5a,b, 6a,b and 8a,c). The identity of 3b,c, 4a, 6a and 8b,c were measured. For example, the ²⁹Si{¹H} NMR

and 9b in the solid state was confirmed by single X-ray diﬀrac- spectra of 9 and 10 (in CDCl₃) show, as expected, two reson-

tion studies (vide infra).

ance signals at ca. −14.5 ppm and between −3.9 and

The IR spectra of the newly synthesized allyl carbosilane- −5.7 ppm, which can be assigned to the core and terminal

based porphyrins (Schemes 1 and 2) show a characteristic silicon atoms (see the Experimental section).²⁴The values for

ν_CvCvibration at ca. 1630 cm⁻¹together with one or two the inner silicon atoms are in good agreement with tetraphe-

typical absorptions in the range of 800–840 cm⁻¹for the Si–C nyl silane (−14.98 ppm).²⁹

stretching vibrations (see the Experimental section). The CH₃

ESI-TOF mass spectrometric studies were carried out for all

bending vibration of the SiMe_nentities (n = 1, 2, 3) is observed aldehyde derivatives and the 0^thgeneration porphyrins. Com-

at ca. 1250 cm⁻¹. These findings are in agreement with allyl- pounds 2c, 3b,c and 5a show the protonated molecular ion

functionalized carbosilanes, i.e. Si(CH₂CHvCH₂)₄(ref. 25). peak [M + H]⁺, while for 4a,b [M]⁺is characteristic. Com-

Further characteristic broad absorptions are observed at ca. pounds 5b, 6a,b and 8a,c could successfully be ionized by

3315 and 3400 cm⁻¹, which can be assigned to the NH as well doping with KSCN and hence the ion [M + K]⁺could be

as OH groups. The aldehyde functionalities present in 2 and 8 detected (see the Experimental section).

gave characteristic bands at 2732 and 2820 cm⁻¹for the CH

UV-Vis absorption spectra were additionally recorded for

and at 1705 cm⁻¹for the CO moieties. In addition, IR spec- porphyrins 3b,c, 4a,b, 5a,b, 6a,b, 9a–c and 10a–c, in order to

troscopy can be applied to monitor the progress of the hydro- analyze the eﬀect of the dendritic branches on the optical pro-

boration of 3 with [BH₃·SMe₂], since the ν_CvCvibration of the perties of the porphyrin ring. The spectra were measured in

allylic units in the respective starting compounds (ca. CH₂Cl₂and thf as solvents (Table 1). The porphyrin core of 3b

1630 cm⁻¹) disappears in the course of the reaction. After shows one Soret band at 420 nm in CH₂Cl₂and four Q bands

H₂O₂treatment new bands for the terminal hydroxyl function- at 517, 552, 592 and 648 nm (Fig. 1a).³⁰Metallation of 3b with

alities in 5a and 5b are found at ca. 3400 cm⁻¹, which is zinc(^II) did not influence the position of the soret band (4a,

typical for primary alcohols.²⁶Solely broad absorptions are 421 nm, in CH₂Cl₂) (Fig. 1b) but has a significant impact on

observed in the IR spectra; hydrogen-bridge formation and the shape of the Q band pattern. Two characteristic bands at

hence formation of molecular networks are the most 549 and 588 nm are observed in CH₂Cl₂, which is typical for

obvious.²⁷

metallo-porphyrins.³¹Fig. 1 also shows the diﬀerence between

The ¹H and ¹³C{¹H} NMR spectra of all compounds are the UV-Vis spectra of the corresponding 0^thand 1^stgeneration

characterized by well-resolved resonance signals for the dendritic porphyrins. Conspicuous is that the transitions

organic groups present (see the Experimental section). Most typical for the 1^stgeneration dendritic porphyrins, for

typical for aldehydes 2b,c and 8a–c is the resonance signal at example, 9b, are nearly meeting the shape of the bands of the

10.07 ppm. This functionality allows the monitoring of the appropriate 0^thgeneration systems, as, for example 3b, with

progress of the appropriate porphyrin formation because this just little enhancement of the band intensities and a very

signal disappears during the course of the reaction. Further small red shift in the Soret band (Fig. 1a). Similar observations

evidence for the successful formation of the porphyrins is the were made for zinc porphyrins 4a and 10b (Fig. 1b). The

appearance of a singlet at 8.92 ppm, which can be assigned to increasing shielding eﬀect of growing dendrons around the

the pyrrole hydrogen atoms.²⁸Also very distinctive is the reson- porphyrin core as, for example, described by Aida and co-

ance signal of the NH units at −2.8 ppm, while zincation leads workers for an aryl ether scaﬀold^30b,cdoes not appear in the

to the disappearance of this signal and hence this unit can case of our systems. The reason therefore is apparent when

also be used to monitor the formation of the appropriate zinc looking at the molecular structure of the 1^stgeneration 9b

porphyrins. Further indicative groups are the SiMe, (Fig. 10/11). Compared to aryl ether dendrons, the here

Si(CH₂)₃Me, and SiCH₂CHvCH₂entities (see the Experi- reported aryl silyl dendrons (e.g. 9b) are more rigid. A back-

mental section). Particularly the latter group is best suited to folding, as observed for the aryl ether dendrons, is impossible

study the progress of the consecutive hydroboration–oxidation and that implies that the porphyrin core plane is even in the

processes since new resonances for the Si(CH₂)₃OH building 1^stgeneration type compounds easily accessible from above

blocks are found (see the Experimental section). Similar to the and below by solvents. A dendritic eﬀect is therefore not

IR spectra, the representative resonance signals for the observed by comparing the UV-Vis data of the 0^thand 1^stgene-

SiCH₂CHvCH₂groups in 3b and 3c at ca. 2.0 (SiCH₂), ration molecules. The data correlate well with reported litera-

5.0 (H₂Cv) and 6.0 ppm (CHv) (in CDCl₃) disappear on ture spectra for silyl-functionalized porphyrins.³²

hydroboration and after oxidation with H₂O₂new signals can

X-ray investigations

be found at 0.9 (SiCH₂CH₂CH₂OH), 1.7 (SiCH₂CH₂CH₂OH),

3.5 (SiCH₂CH₂CH₂OH) and 4.5 ppm (SiCH₂CH₂CH₂OH) for Single crystals of 3b (as 3b·1/4CH₂Cl₂), 3c, 4a and 9b (as

alcohols 5a and 5b (in dmso-d₆), respectively. Similar obser- 9b·3.5EtOH) were grown by slow diﬀusion of CH₂Cl₂into EtOH

vations were made in the ¹³C{¹H} NMR spectroscopic studies solutions containing the respective compounds, while single

(see the Experimental section).

crystals of 6a (as 6a·2thf) were obtained by layering a thf solu-

n

Additionally, the ²⁹Si{¹H} spectra of the carbosilane-based tion containing 6a with pentane at ambient temperature. The

porphyrins 3b,c, 4a,b, 9b,c and 10a,b and the aldehydes 2b,c molecular structures of 3b,c, 4a and 6a are displayed in Fig. 2,

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Table 1 UV-Vis absorptions of porphyrins 3–6, 9 and 10

Compound (solvent)

λ_max(nm) (log ε)

Soret band (nm) (log ε)

Q bands (nm) (log ε)

3b (CH₂Cl₂)

3b (thf)

3c (CH₂Cl₂)

3c (thf)

4a (CH₂Cl₂)

4a (thf)

4b (CH₂Cl₂)

4b (thf)

9a (CH₂Cl₂)

9a (thf)

9b (CH₂Cl₂)

9b (thf)

9c (CH₂Cl₂)

9c (thf)

10a (CH₂Cl₂)

10a (thf)

10b (CH₂Cl₂)

10b (thf)

10c (CH₂Cl₂)

10c (thf)

5a (CH₂Cl₂)

5a (thf)

5b (CH₂Cl₂)

5b (thf)

420 (5.73)

419 (5.68)

420 (5.78)

419 (5.72)

421 (5.75)

425 (5.83)

421 (5.83)

426 (5.83)

421 (5.76)

420 (5.76)

421 (5.80)

420 (5.74)

421 (5.73)

420 (5.72)

422 (5.92)

427 (5.82)

422 (5.81)

427 (5.82)

422 (5.82)

427 (5.85)

420 (5.66)

419 (5.68)

420 (5.66)

419 (5.62)

421 (5.84)

426 (5.69)

426 (5.75)

517 (4.35)

515 (4.28)

517 (4.39)

515 (4.32)

552 (4.09)

592 (3.87)

648 (3.77)

648 (3.67)

648 (3.85)

649 (3.70)

550 (4.01)

552 (4.14)

550 (4.05)

549 (4.33)

558 (4.36)

549 (4.42)

558 (4.36)

552 (4.14)

550 (4.09)

552 (4.16)

550 (4.10)

552 (4.09)

550 (4.10)

550 (4.52)

558 (4.38)

550 (4.39)

559 (4.39)

550 (4.44)

559 (4.40)

552 (3.97)

550 (4.02)

552 (4.05)

550 (4.03)

550 (4.24)

558 (4.24)

558 (4.31)

593 (3.73)

592 (3.92)

593 (3.77)

588 (3.67)

598 (3.98)

588 (3.76)

597 (3.97)

592 (3.91)

592 (3.80)

592 (3.91)

592 (3.82)

592 (3.85)

592 (3.81)

588 (3.92)

598 (4.06)

588 (3.78)

598 (4.07)

588 (3.87)

598 (4.08)

594 (3.69)

593 (3.73)

594 (3.81)

594 (3.71)

588 (3.81)

598 (3.91)

598 (4.00)

402 (4.61)

405 (4.68)

402 (4.71)

405 (4.67)

517 (4.38)

515 (4.32)

517 (4.40)

515 (4.34)

517 (4.34)

516 (4.32)

648 (3.84)

648 (3.75)

648 (3.83)

648 (3.76)

648 (3.75)

649 (3.75)

403 (4.79)

406 (4.69)

403 (4.67)

406 (4.70)

403 (4.70)

407 (472)

516 (4.24)

516 (4.28)

517 (4.28)

517 (4.25)

648 (3.69)

650 (3.71)

648 (3.78)

650 (6.77)

6a (CH₂Cl₂)

6a (thf)

6b (thf)

403 (4.72)

405 (4.59)

Fig. 1 Absorption spectra of 3b (–) vs. 9b (⋯) (a) and 4a (–) vs. 10b (⋯) (b) in CH₂Cl₂.

6, 3 and 8. In the case of 9b the asymmetric unit comprises

It should be emphasised that meso-tetraphenylporphyrins

two crystallographically independent centrosymmetric halves carrying at the para position any kind of Si-containing groups

of 9b, denoted as 9bA and 9bB. Their molecular structures are have been sparingly characterised by single crystal X-ray diﬀ-

depicted in Fig. 10 and 11. Crystal and intensity collection raction studies so far. The solid state structures of 5,10,15,20-

data of 3b·1/4CH₂Cl₂, 3c, 4a, 6a·2thf and 9b·3.5EtOH are sum- tetrakis(4-pentamethyldisilanyl)phenyl)porphyrin^32aand of

marized in Table S1,† while selected bond lengths and angles 5,10,15,20-tetrakis[4-(diethoxymethylsilyl)phenyl]porphyrin^32b

are given in Tables 2 and 3, respectively.

are already described in the literature.

As already mentioned for 9b, even 3c possesses in the solid

However, experimentally observed bond lengths and angles

state crystallographically imposed inversion symmetry, for the end-grafted carbosilane branches of all functionalized

whereby the inversion centres are located in the middle of the meso-tetraphenylporphyrins described here are in agreement

atoms N2/N2A (3c, Fig. 6), N1/N1A (9bA, Fig. 10) and N4/N4A with parameters typically found for phenylene-based

(9bB, Fig. 11). For all other crystallographically characterized carbosilanes.^24,33

porphyrins no crystallographically implied symmetry is

observed, thus 3b·1/4CH₂Cl₂, 4a, and 6a·2thf are C₁symmetric (3b) and its related

The molecular structures of H₂TPP(4-SiMe₂(CH₂CHvCH₂))₄

zinc(II) species Zn(II)-TPP(4-

in the solid state.

SiMe₂(CH₂CHvCH₂))₄(4a) in the solid state are depicted in

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Fig. 2 ORTEP diagram (50% ellipsoid probability) of the molecular

structure of 3b. All C-bonded hydrogen atoms are omitted for clarity. Of

disordered atoms only one atomic position is displayed. The sign ∢

refers to calculated interplanar angles between terminal C₆H₄groups

and the central C₂₀N₄H₂core.

Fig. 3 ORTEP diagram (50% ellipsoid probability) of the molecular

structure of 4a. All hydrogen atoms are omitted for clarity. Of disordered

atoms only one atomic position is displayed. The sign ∢ refers to calcu-

lated interplanar angles between terminal C₆H₄groups and the central

C

₂₀N₄Zn core.

Fig. 2 and 3. Both porphyrins crystallize in the tetragonal

space group P4₃with similar dimensions of their respective

unit cells (Table S1†). For 3b a partially occupied packing

solvent molecule of CH₂Cl₂is observed in the crystal structure,

which should be found for 4a as well. However, no electron

density peaks of 4a could be used for the refinement of an ana-

logous packing solvent molecule. Despite this, 3b and 4a can

be regarded as structurally isomorphic to each other.

The asymmetric unit of both 3b and 4a possesses one crys-

tallographically independent porphyrin molecule. Related

bond lengths and angles of the C₂₀N₄cores of 3b and 4a can

be considered as identical to each other within standard devi-

ations (Tables 2 and 3). Not surprisingly, the N⋯N distances of

opposite nitrogen atoms of 3b are significantly longer, when

compared with 4a (3B, N1⋯N3/N2⋯N4 = 4.160(5)/4.113(5) Å

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vs. 4a, N1⋯N3/N2⋯N4 = 4.080(5)/4.059(5) Å), which nicely

reflects the modification of the central C₂₀N₄core upon com-

plexation. The Zn(^II) ion of 4a can be furthermore considered

as being involved in an ideal quadratic planar ZnN₄coordi-

nation environment. Zn–N bond lengths of 4a cover a very

narrow range (Zn1–N4 = 2.019(3) to Zn1–N2 = 2.041(4) Å) and

N–Zn–N bond angles are very close to the ideal values of trans-/

cis-ligated N donor atoms (trans: N1–Zn1–N3/N2–Zn1–N4 =

177.9(3)/178.6(3)°; cis: N1–Zn1–N4 = 89.3(2) to N1–Zn1–N2 =

90.4(2)°). Furthermore, the Zn1 atom is located practically in

plane with respect to its N₄environment as it deviates by just

0.007(4) Å of the calculated mean plane of the atoms N1 to N4

(root-mean-square deviation from planarity (rmsd) = 0.030 Å,

highest deviation from planarity (hdp) observed for N4 with

0.031(2) Å).

Porphyrins 3b and 4a are structurally isomorphic to each

other (vide supra) and consequently their crystal structures are

identical. For both porphyrins a 3D network structure is

observed in the solid state of which a selected part has been

illustrated in Fig. 4 (3b) and Fig. 5 (4a). Thereby it is observed

that all four crystallographically diﬀerent C₆H₄rings are

involved in T-shaped π–π contacts³⁴with the respective C₂₀N₄

cores (Fig. 4 and 5). Geometrical features of these π–π contacts

of 3b and 4a (Fig. 4 and 5) are in good agreement with each

other, when comparing both molecules.

The molecular structure of H₂TPP(4-SiMe(CH₂CHvCH₂)₂)

(3c) in the solid state is depicted in Fig. 6. The replacement of

one methyl group of the carbosilane SiMe₂(CH₂CHvCH₂)

moiety in 3b by an allyl unit, as characteristic for 3c, induces

considerable changes. In contrast to 3b, porphyrin 3c crystal-

ˉ

lizes in the triclinic space group P1 with crystallographically

imposed inversion symmetry. Thus, the asymmetric unit of 3c

comprises just half of the molecule, while the 2^ndhalf is gene-

rated by an inversion center which is located at the crossing

point of the atoms N1/N1A and N2/N2A (Fig. 3). Furthermore,

it is astonishing to notice that related bond lengths of the

C₂₀N₄core of 3c, when compared with those of 3b and 4a and

those of 6a and 9b as well, are significantly elongated

(Table 2). As a wrongly determined space group may cause

such deviations the structural refinement of 3c was checked

with the utmost precision; however, there are no indications

that the unit cell dimensions and space group of 3c are not

accurate (Table S1†). For example, the N⋯N distances of oppo-

site N atoms of 3c (N1⋯N1A/N2⋯N2A = 4.325(5)/4.228(5) Å)

are by far the longest ones of the here described porphyrins

(Table 2). A possible explanation of this unexpected obser-

vation for 3c might be drawn from the crystal structure of 3c,

which is illustrated in Fig. 7. In contrast to the observation of

3D network structures for 3b and 4a (Fig. 4 and 6) which are

induced by T-shaped π–π interactions, for 3c the formation of

2D layers has been noted. The 2D layers are formed along the

crystallographic a- and b-axes, but not along the crystallo-

graphic c-axes as depicted in Fig. S1 and S2.† Moreover, only

the C₆H₄aromatic group comprising the atoms C11 to C16

and symmetry generated analogues is involved in T-shaped π–π

interactions with the C₂₀N₄core of adjacent molecules.

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Fig. 4 Above: Graphical illustration of a selected part of the 3D network formed by 3b due to intermolecular π–π interactions. Labels A–C refer to a

1^st–3^rdsymmetry generated molecule of 3b. All hydrogen atoms and terminal substituents at the silicon atoms are omitted for clarity. Below: graphi-

cal illustration of the four diﬀerent types of intermolecular π–π interactions between the aromatic C₆H₄groups with respective parts of the por-

phyrin core. The sign ∢ refers to calculated interplanar angles between diﬀerently colored functionalities. Dotted lines indicate the shortest

observed distances between the geometrical centroids of the C₆H₄groups and the respective centroids/atoms of the porphyrin core with D1 = cen-

troid of C21–C26, D3 = centroid of C27–C32, D4 = centroid of C33–C38, D6 = centroid of C39–C44, D2 = centroid of N1 and C2, D5 = centroid of

C12–C14 and symmetry generated related atoms/fragments.

Thereby, comparatively large centroid-to-centroid distances are of the intermolecular O(H)–Zn bond formation the Zn1 atom

observed (Fig. 7). To deduce that the diﬀerent crystal structure of 6a is significantly moved out of the basal plane into the

of 3c is responsible for the observation of significantly direction of the coordinated O donor atom. Thus, the Zn1

diﬀerent bond lengths of 3c, when compared to those of 3b atom is located 0.255(2) Å above the calculated mean plane of

and 4a, is certainly a more qualitative description. Hence, the atoms N1 to N4 (rmsd = 0.022 Å, hdp observed for N3 with

further work, e.g. quantum chemical calculations, is required 0.022(2) Å).

to figure out the origin of this remarkable phenomenon.

The exchange of the terminal allyl groups of 4a by 3-propyl-

The molecular structure of Zn(^II)-TPP(4-SiMe₂((CH₂)₃OH))₄oxy functionalities, as present in 6a, resulted in a completely

(6a) is depicted in Fig. 8. Porphyrin 6a crystallizes in the tri- diﬀerent packing mode. There are no π–π interactions of any

ˉ

clinic system P1 with one molecule of 6a in the asymmetric kind observed for 6a in the solid state. Instead, the crystal

unit cell. As indicated before, bond lengths and angles of the structure is exclusively governed by reciprocal formation of

central C₂₀N₄core of 6a compare well with those of 3b, 4a and intermolecular O(H)–Zn contacts along the crystallographic

9b (Tables 2 and 3). Due to formation of an intermolecular a-axes together with formation of intermolecular O(H)⋯O

O(H)–Zn bond (Zn1–O1 = 2.155(3) Å), the Zn(^II) ion of 6a is hydrogen bonds along the crystallographic b-axes. Fig. S3 and

involved in an approximate square-based pyramidal ZnN₄O Table S2† show bond lengths and angles for the characteristic

coordination environment. Not surprisingly, as a consequence intermolecular hydrogen bonds. A part of the thus formed 2D

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Fig. 5 Above: graphical illustration of a selected part of the 3D network formed by 4a due to intermolecular π–π interactions. Labels A–C refer to a

1^stto the 3^rdsymmetry generated molecule of 4a. All hydrogen atoms and terminal substituents at the silicon atoms are omitted for clarity. Below:

graphical illustration of the four diﬀerent types of intermolecular π–π interactions between the aromatic C₆H₄groups with the respective parts of

the porphyrin core. The sign ∢ refers to the calculated interplanar angles between diﬀerently colored functionalities. Dotted lines indicate the short-

est observed distances between the geometrical centroids of the C₆H₄groups and the respective centroids/atoms of the porphyrin core with D1 =

centroid of C21–C26, D3 = centroid of C32–C37, D4 = centroid of C43–C48, D6 = centroid of C54–C59, D2 = centroid of N2 and C6, D5 = centroid

of C16–C18, D7 = centroid of C12–C14 and symmetry generated related atoms/fragments.

layers is furthermore graphically illustrated in Fig. 9. It is sur- molecules of 9b, denoted as 9bA and 9bB. Both 9bA and 9bB

prising to note that the formation of 1D chains, as a part of possess in the solid state crystallographically imposed inver-

the 2D network structure, due to mutual intermolecular O(H)– sion symmetry, whereby the molecular structures of both indi-

Zn contacts as observed for 6a, has not been observed so far vidual molecules are depicted in Fig. 10 and 11. The bond

for any kind of O-functionalised metalloporphyrins possessing distances and angles of the C₂₀N₄cores of 9bA and 9bB do not

3d transition metal ions. Related metalloporphyrins functiona- only compare well with each other, they can be even con-

lised by any kind of O-donor atoms, with the oxygen atoms sidered as closely related to analogous data reported here for

belonging to alcohol, ether, carbonic acid and/or carbonyl 3b, 4a and 6a but not 3c (see above and Tables 2 and 3).

functionalities, form either dimers,³⁵trimers³⁶or polymeric

2D³⁷and 3D³⁸networks, respectively.

Due to the presence of sixteen crystallographically indepen-

dent C₆H₄aromatic rings of both 9bA and 9bB, determination

Porphyrin H₂TPP(4-Si(C₆H₄-4-Si(CH₂CHvCH₂)Me₂)₃)₄(9b) of the crystal structure of 9b with respect to possible π–π inter-

crystallises in the triclinic space group P1. The asymmetric actions is rather complicated.³⁹However, it was found that a

ˉ

unit contains half of two crystallographically independent 3D network is formed by 9b in the solid state due to T-shaped

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π–π interactions. This 3D network can be understood as being

formed of 2D layers of molecules of 9bA and 9bB of which a

part is illustrated in Fig. 12. Further descriptions of the indi-

vidual interactions are given in Fig. 14 and S4–S6.† The 2D

layers interact then with each other by means of T-shaped π–π

interactions exclusively between molecules of either 9bA or

9bB (Fig. 13). The respective π–π interactions being responsible

for the formation of the 2D layers and of the 3D network are

then separately illustrated in Fig. 14. The inter-layer distance

between 2D layers corresponds to 25.1408 Å (=b), (Fig. 13).

Diﬀerent types of non-planar distortions commonly

observed for porphyrins have been already explicitly dis-

cussed.⁴¹In the case of here structurally described porphyrins

it can be determined that the central C₂₀N₄porphyrin cores

can be regarded as planar which can be concluded from, for

example, the sum of angles around the 5,10,15,20-anellated

atoms of the C₂₀N₄cores (Table 3) and further data are

given in Table S3 and Fig. S7,† including accompanying

remarks.

Fig. 6 ORTEP diagram (25% ellipsoid probability) of the molecular struc-

ture of 3c. All C-bonded hydrogen atoms are omitted for clarity. Of dis-

ordered atoms only one atomic position is displayed. The sign ∢ refers to

the calculated interplanar angles between terminal C₆H₄groups and the

central C₂₀N₄H₂core. Symmetry code for A: −x, −y + 2, −z + 1.

In summary, the observation of the formation of 3D (3b, 4a

and 9b) or 2D networks (3c) resulting from intermolecular

Fig. 7 Above: graphical illustration of a selected part of one 2D layer formed by 3c due to intermolecular π–π interactions. Labels ’, ’’, * and # refer

to symmetry generated atoms of crystallographically independent molecules of the asymmetric unit of 3c, label A to symmetry generated atoms of

the asymmetric unit of 3c and labels B–E to symmetry generated atoms of A labelled atoms. All C-bonded hydrogen atoms and terminal substituents

at the silicon atoms are omitted for clarity. Below: graphical illustration of the intermolecular π–π interactions between the aromatic C₆H₄groups

with the respective parts of the porphyrin core. The sign ∢ refers to the calculated interplanar angles between diﬀerently coloured functionalities.

Dotted lines indicate the shortest observed distances between the geometrical centroids of the C₆H₄groups and the respective centroids/atoms of

the porphyrin core with D1 = centroid of C11–C16 and D2 = centroid of C6–C8, respectively, and symmetry generated related atoms/fragments.

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terminal Si-functionalities at the para-position of the phenyl

rings, namely 5,10,15,20-tetrakis(4-pentamethyldisilanyl)phenyl)-

porphyrin^32aand 5,10,15,20-tetrakis[4-(diethoxymethylsilyl)-

phenyl]porphyrin,^32bwhich can be regarded as closely related

to the here reported porphyrins. Bond lengths and angles of

the C₂₀N₄porphyrin cores of these two reported samples are

in very good agreement with the corresponding data observed

for 3b, 4a, 6a and 9b, respectively.

Especially for 5,10,15,20-tetrakis[4-(diethoxymethylsilyl)-

phenyl]porphyrin it is indicated that “no significant short

contacts such as π-stacking” could be observed, which is attri-

buted to the steric hindrance of the terminal silyl function-

alities.^32bIt seems, however, likely, that only sandwich type π–π

interactions have been ruled out.

In the discussion of the crystal structures of Zn(TPP) and

Ag(TPP),⁴²which are isomorphous to H₂TPP, T-shaped π–π

interactions have been explicitly mentioned. Interplanar

angles between interacting aromatic units are given, although

no centroid-to-centroid distances and the final type of assem-

blies formed have been mentioned.⁴²In the case of a report on

the crystallographic characterisation of Fe(TPP) as a toluene

solvate, the formation of 1D chains, due to sandwich type π–π

interactions, is observed.⁴³One can thus assume that for non-

functionalised M(TPP) (M = 3d metal ion) type porphyrins,

especially for those in which the central metal ion is not co-

ordinated by one and/or two donor molecules, π–π interactions

play a significant role in the crystal structures. Indeed, for

Fig. 8 ORTEP diagram (50% ellipsoid probability) of the molecular

structure of 6a. All C-bonded hydrogen atoms are omitted for clarity. Of

disordered atoms only one atomic position is displayed. The sign ∢

refers to the calculated interplanar angles between terminal C₆H₄

groups and the central C₂₀N₄Zn core.

T-shaped π–π interactions is not a specific feature of the

here reported porphyrins. There are already two crystallo-

graphically described meso-tetraphenylporphyrins known bearing

Fig. 9 Graphical representation of a part of one of the 2D layers formed by 6a in the solid state due to formation of intermolecular O–H⋯O hydro-

gen bonds and O(H)–Zn bonds. All C-bonded hydrogen atoms and packing solvent molecules are omitted for clarity. Of disordered atoms only one

atomic position is displayed. Labels A–E refer to a 1^st–5^thsymmetry generated molecule of 6a.

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Fig. 10 ORTEP diagram (20% ellipsoid probability) of the molecular structure of 9bA. All carbon-bonded hydrogen atoms are omitted for clarity. Of

disordered atoms only one atomic position is displayed. The sign ∢ refers to the calculated interplanar angles between the directly porphyrin

bonded C₆H₄groups and the central C₂₀N₄H₂core. Symmetry code for A: −x + 2, −y, −z.

Fig. 11 ORTEP diagram (20% ellipsoid probability) of the molecular structure of 9bB. All carbon-bonded hydrogen atoms are omitted for clarity. Of

disordered atoms only one atomic position is displayed. The sign ∢ refers to the calculated interplanar angles between the directly porphyrin

bonded C₆H₄groups and the central C₂₀N₄H₂core. Symmetry code for A: −x + 1, −y and for #:, −z + 1.^40a

Zn(TPP), being co-crystallized with diﬀerent guest molecules, a

Conclusions

review by Byrn et al.⁴⁴for over 200 diﬀerent cases mentions

explicitly the observation of intermolecular T-shaped π–π inter- The preparation of a series of 0^thand 1^stgeneration carbo-

actions, although no geometrical features or types of assem- silane dendrimer-based porphyrins of types H₂TPP(4-SiRR′Me)₄,

blies were given.

Zn(^II)-TPP(4-SiRR′Me)₄(R

=

R′

=

Me, CH₂CHvCH₂,

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Fig. 12 Selected part of one 2D layer formed by 9b in the solid state due to T-shaped π–π interactions between molecules of 9bA and 9bB.^40b

Fig. 13 Graphical illustration of the mutual T-shaped π–π interactions between molecules of 9bA and 9bB, being responsible for the connection of

the 2D layers of 9b to give a 3D network structure.^40b

CH₂CH₂CH₂OH; R = Me, R′ = CH₂CHvCH₂, CH₂CH₂CH₂OH; determined by single X-ray structure determination. The supra-

TPP

=

tetraphenyl porphyrin), H₂TPP(4-Si(C₆H₄-1,4-SiRR′ molecular structures of the allyl 0^thgeneration species 3b,c, 4a

Me)₃)₄, and Zn(II)-TPP(4-Si(C₆H₄-1,4-SiRR′Me)₃)₄(R = R′ = Me, and the 1^stgeneration carbosilane-containing porphyrin 9b are

CH₂CHvCH₂; R = Me, R′ = CH₂CHvCH₂) using the Lindsey primarily controlled by π–π interactions, while in the hydroxyl-

condensation methodology is described. Functionalization of functionalized porphyrin 6a the network formation is exclu-

TPP with the carbosilane dendrons leads to a slight bathochro- sively set by zinc–oxygen coordination and hydrogen bonding

mic shift of the Soret and Q bands in the UV-Vis spectra, intermolecular interactions. Conspicuously, porphyrin 3b

which is in agreement with the literature.³⁰The structures of and its analogous zinc-metallated system 4a possess an

five samples (3b,c, 4a, 6a, 9b) in the solid state have been identical 3D supramolecular structure as both compounds

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Fig. 14 Graphical illustration of the respective T-shaped π–π interactions observed in the solid state structure of 9b being responsible for the for-

mation of 2D layers (left and middle) and for the interaction of 2D layers to give a 3D network.^40b

can be regarded as isomorphic in the solid state. On the Instrumentation

other hand, the eight allyl groups in 3c, instead of the four

allyl units present in 3b, modify the 3D network into a 2D

network which might be responsible for the observation of

Infrared spectra were recorded with a Perkin Elmer FT-IR

spectrometer Spectrum 1000 (v in cm⁻¹). UV-Vis spectra were

˜

measured with a Thermo Electron Corporation Genesys 6

significantly larger bond lengths of its C₂₀N₄core in comparison

spectrometer. NMR spectra were recorded with a Bruker

with the related bond lengths of the other here described

Avance 250 spectrometer (¹H NMR at 250.12 MHz and ¹³C{¹H}

porphyrins.

NMR at 62.86 MHz) in the Fourier transform mode. Chemical

For meso-tetraphenylporphyrins bearing any kind of substi-

shifts are reported in δ units (parts per million) downfield

tuent at the phenyl rings it seems less likely that intermolecu-

from tetramethylsilane (δ = 0.00 ppm) with the solvent as the

lar sandwich type π–π interactions can be observed, although

T-shaped π–π interactions might be found. For such cases we

do not find, to the best of our knowledge, precise comments

for crystallographically described representatives. We assume,

however, that especially T-shaped π–π interactions should be

observed, as reported here for 3b, 3c, 4a and 9b, at least in

such cases where the central metal ions are not coordinated by

additional donor solvents or the two N(H)-protons of the

central porphyrin rings are not involved in hydrogen bridges

with protic donor solvents.

1

reference signal (CDCl₃: H NMR, δ = 7.26; ¹³C{¹H} NMR, δ =

77.16; DMSO-d₆: ¹H NMR, δ = 2.54; ¹³C{¹H} NMR, δ = 40.45;

1

thf-d₈: H NMR, δ = 1.72; ¹³C{¹H} NMR, δ = 24.45).⁴⁵The atom

numbering is depicted in the ESI (Fig. S8†). The assignment of

¹³C{¹H} and ²⁹Si{¹H} NMR spectroscopic signals is mainly

based on ¹³C-DEPT-135 spectra and 2D-correlation spectra

(gradient with sensitivity-enhanced heteronuclear multiple

quantum correlation (gs-HMQC) for carbon and silicon and

gradient with sensitivity-enhanced heteronuclear multiple

bond correlation (gs-HMBC) for carbon). Please note that the

resonance signal for the pyrrole-α-C unit could only be

detected for the zinc complexes under the measurement con-

ditions applied. ESI-TOF mass spectra were recorded using a

Mariner biospectrometry workstation 4.0 (Applied Biosystems).

Microanalyses were performed with a Thermo FlashAE 1112

instrument. Melting points of pure samples were measured

with Gallenkamp MFB 595 010 equipment.

Experimental section

General data

All reactions were carried out under an atmosphere of nitrogen

using standard Schlenk techniques. Tetrahydrofuran, toluene

and ⁿpentane were purified by distillation from sodium–benzo-

phenone ketyl; CH₂Cl₂and CHCl₃were purified by distillation

from calcium hydride. Diethylamine and diisopropylamine

Reagents

were distilled from KOH; absolute MeOH was obtained by dis- 1a, 2a, 3a,²¹1b,²²1c, 7a,c,²⁴2b²³and 7b, 8b, 9b^18awere pre-

tillation from magnesium.

pared according to published procedures. All other chemicals

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were purchased from commercial suppliers and were used as 1.1 Hz, 4 H, cis-H¹¹), 5.01 (ddt, J_HH= 10.1 Hz, J_HH= 2.4 Hz,

received.

J_HH= 1.1 Hz, 3 H, trans-H¹¹), 2.02 (dt, J_HH= 8.1 Hz, J_HH

=

1.1 Hz, 16 H, H⁹), 0.54 (s, 24 H, H⁸), −2.74 (brs, 2 H, NH). ¹³C

{¹H} NMR (CDCl₃): δ = 142.8 (4 C⁷), 137.8 (4 C⁴), 134.7 (4 C¹⁰),

4-Diallylmethylsilylbenzaldehyde (2c)

^tBuLi (1.7 M, 34.7 mmol, 20.4 mL, pentane) was added drop- 134.1 (8 C⁶), 132.0 (8 C⁵), 131.2 (br, 8 C¹), 120.1 (4 C³), 113.6

wise to a Et₂O (75 mL) solution containing 1c (17.37 mmol, (4 C¹¹), 24.0 (4 C⁹), −3.2 (8 C⁸). ²⁹Si{¹H} NMR (CDCl₃): δ = −4.1.

4.88 g) at −78 °C. After 1 h of stirring at this temperature the ESI-TOF: m/z = 1007.49 [M + H]⁺(calcd 1007.48). Anal. calcd

resulting solution was drop-wise transferred via a cannula to for C₆₄H₇₀N₄Si₄(1007.61): C, 76.29; H, 7.00; N, 5.56. Found: C,

dimethyl formamide (52.12 mmol, 3.81 g, 4.04 mL) in thf 76.03; H, 7.26; N, 5.30.

n

(50 mL) at 0 °C and the obtained reaction mixture was kept at

this temperature for 15 min. Afterwards, it was warmed to

meso-Tetrakis(4-diallylmethylsilylphenyl)porphyrin (3c)

ambient temperature, stirring was continued for 2 h, and then To aldehyde 2c (10.00 mmol, 2.301 g) and pyrrole

it was quenched with aqueous HCl (3 N, 80 mL). The obtained (10.00 mmol, 0.671 g, 0.69 mL) dissolved in CH₂Cl₂(1000 mL)

residue was extracted with Et₂O (100 mL) and the organic layer [BF₃·OEt₂] (1.00 mmol, 0.142 g, 0.13 mL) was added in a single

was washed with water (2 × 60 mL), saturated NaHCO₃(60 mL) portion. The reaction solution was stirred for 2 h and then 2,3-

and brine (60 mL) and was then dried over MgSO₄. Afterwards, dichloro-5,6-dicyanobenzoquinone (7.50 mmol, 1.703 g) was

all volatiles were removed in oil-pump vacuum. The crude added in a single portion and stirring was continued for 1 h.

n

product was purified by column chromatography (a) hexane, The reaction mixture was washed with saturated NaHCO₃

(b) 20 vol% CH₂Cl₂–ⁿhexane to aﬀord 2c as colorless oil (100 mL) and then with water (3 × 100 mL). The organic layer

(14.86 mmol, 3.42 g, 86% based on 1c).

was filtered through a pad of silica gel and afterwards all vola-

˜

IR (film): v = 3074, 3024, 2992, 2966, 2910, 2882, 2824 (w, tiles were removed in oil-pump vacuum. The crude product

CHO), 2732 (w, CHO), 1704 (s, CvO), 1630 (w, CvC), 1254 (w, was purified by column chromatography (a) ⁿhexane and (b) 20

1

CH₃bending), 808 (s, SiC). H NMR (CDCl₃): δ = 10.02 (s, 1 H, vol% CH₂Cl₂–ⁿhexane. Porphyrin 3c was obtained as a dark

CHO), 7.84 (dt, J_HH= 8.1 Hz, J_HH= 1.6 Hz, 2 H, H³), 7.68 (dt, red solid (0.69 mmol, 0.76 g, 27% based on 2c).

J_HH= 8.1 Hz, 1.6 Hz, 2 H, H⁴), 5.74 (ddt, J_HH= 17.6 Hz, J_HH

9.5 Hz, J_HH= 8.1 Hz, 2 H, H⁸), 4.89 (ddt, J_HH= 17.6 Hz, J_HH

2.0 Hz, J_HH= 1.1 Hz, 2 H, cis-H⁹), 4.88 (ddt, J_HH= 9.5 Hz, J_HH

=

Mp = 350 °C (dec). IR (KBr disc): v = 3314 (s, NH), 3070,

3006, 2994, 2966, 2912, 2880, 1628 (m, CvC), 1250 (m, CH₃

˜

bending), 800 (s, SiC). H NMR (CDCl₃): δ = 8.90 (s, 8 H, H¹),

1

2.0 Hz, J_HH= 1.1 Hz, 2 H, trans-H⁹), 1.84 (dt, J_HH= 8.1 Hz, J_HH8.26 (brd, J_HH= 7.9 Hz, 8 H, H⁵), 7.92 (brd, J_HH= 7.9 Hz, 8 H,

= 1.1 Hz, 4 H, H⁷), 0.34 (s, 3 H, H⁶). ¹³C{¹H} NMR (CDCl₃): δ = H⁶), 6.04 (ddt, J_HH= 17.0 Hz, J_HH= 10.1 Hz, J_HH= 8.1 Hz, 8 H,

192.4 (1 C¹), 145.5 (1 C⁵), 136.7 (1 C²), 134.4 (2 C⁴), 133.4 H¹⁰), 5.10 (ddt, J_HH= 17.0 Hz, J_HH= 2.0 Hz, J_HH= 0.9 Hz, 8 H,

(2 C⁸), 128.5 (2 C³), 114.4 (2 C⁹), 21.2 (2 C⁷), −6.1 (1 C⁶). cis-H¹¹), 5.06 (ddt, J_HH= 10.1 Hz, J_HH= 2.0 Hz, J_HH= 0.9 Hz,

²⁹Si{¹H} NMR (CDCl₃): δ = −5.0. ESI-TOF: m/z = 231.10 8 H, trans-H¹¹), 2.10 (dt, J_HH= 8.0 Hz, J_HH= 0.9 Hz, 32 H, H⁹),

[M + H]⁺(calcd 231.12). Anal. calcd for C₁₄H₁₈OSi (230.38): C, 0.58 (s, 24 H, H⁸), −2.69 (brs, 2 H, NH). ¹³C{¹H} NMR (CDCl₃):

72.99; H, 7.88. Found: C, 72.54; H, 7.51.

δ = 142.9 (4 C⁷), 136.1 (4 C⁴), 134.3 (8 C¹⁰), 134.1 (8 C⁶), 132.3

(8 C⁵), 131.1 (br, 8 C¹), 120.1 (4 C³), 114.1 (8 C¹¹), 21.8 (8 C⁹),

−5.6 (4 C⁸). ²⁹Si{¹H} NMR (CDCl₃): δ = −5.2. ESI-TOF: m/z =

meso-Tetrakis(4-allyldimethylsilylphenyl)porphyrin (3b)

To aldehyde 2b (6.00 mmol, 1.224 g) and pyrrole (6.00 mmol, 1111.50 [M + H]⁺(calcd 1111.54). Anal. calcd for C₇₂H₇₈N₄Si₄

0.403 g, 0.416 mL) dissolved in CH₂Cl₂(600 mL), [BF₃·OEt₂] (1111.53): C, 77.78; H, 7.07; N, 5.04. Found: C, 77.68; H, 6.59;

(0.60 mmol, 0.085 g, 0.076 mL) was added in a single portion. N, 4.80.

The reaction solution was stirred for 2 h at ambient temp-

erature and then 2,3-dichloro-5,6-dicyanobenzoquinone

(4.50 mmol, 1.224 g) was added in a single portion and stirring

meso-Tetrakis(4-allyldimethylsilylphenyl)porphyrinato zinc

(4a)

was continued for 1 h. The reaction mixture was washed with To 3b (0.050 mmol, 0.0504 g) dissolved in CHCl₃(15 mL), a

saturated NaHCO₃(100 mL) and then with water (3 × 100 mL). MeOH solution (10 mL) containing [Zn(OAc)₂·2H₂O]

The organic layer was filtered through a pad of silica gel and (0.100 mmol, 0.0219 g) was added in a single portion. The

afterwards all volatiles were removed in oil-pump vacuum. The reaction solution was stirred for 2 h at ambient temperature

obtained solid material was purified by column chromato- and was then washed with saturated NaHCO₃(15 mL) followed

graphy (a) ⁿhexane and (b) 20 vol% CH₂Cl₂–ⁿhexane. Porphyrin by washing with water (2 × 15 mL). The organic layer was dried

3b was obtained as a dark red solid (0.44 mmol, 0.44 g, 29% over Na₂SO₄. All volatiles were removed in oil-pump vacuum to

based on 2b).

Mp = 350 °C (dec). IR (KBr disc): v = 3315 (s, NH), 3069, on 3b).

3056, 3011, 2994, 2911, 2880, 1627 (w, CvC), 1251 (m, CH₃Mp = 350 °C (dec). IR (KBr disc): v = 3055, 3011, 2989, 2911,

aﬀord 4a as a dark red solid (0.495 mmol, 0.053 g, 99% based

˜

1

bending), 834, 818, 804 (s, SiC). H NMR (CDCl₃): δ = 8.87 (s, 2954, 2908, 2878, 1627 (w, CvC), 125 (m, CH₃bending), 836,

8 H, H¹), 8.23 (brd, J_HH= 7.9 Hz, 8 H, H⁵), 7.90 (brd, J_HH

7.9 Hz, 8 H, H⁶), 6.01 (ddt, J_HH= 17.0 Hz, J_HH= 10.1 Hz, J_HH

8.1 Hz, 4 H, H¹⁰), 5.04 (ddt, J_HH= 17.0 Hz, J_HH= 2.4 Hz, J_HH

=

820, 811, 796 (s, SiC). H NMR (CDCl₃): δ = 9.00 (s, 8 H, H¹),

8.25 (brd, J_HH= 7.9 Hz, 8 H, H⁵), 7.90 (brd, J_HH= 7.9 Hz, 8 H,

H⁶), 6.02 (ddt, J_HH= 17.0 Hz, J_HH= 10.1 Hz, J_HH= 8.1 Hz, 4 H,

1

7882 | Dalton Trans., 2014, 43, 7868–7888

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1

H¹⁰), 5.05 (brd, J_HH= 17.0 Hz, 4 H, cis-H¹¹), 5.02 (brd, J_HH

=

833, 803 (s, SiC). H NMR (dmso-d₆): δ = 8.85 (s, 8 H, H¹), 8.23

10.1 Hz, 4 H, trans-H¹¹), 2.03 (brd, J_HH= 8.1 Hz, 8 H, H⁹), 0.56 (d, J_HH= 7.4 Hz, 8 H, H⁵), 7.96 (d, J_HH= 7.3 Hz, 8 H, H⁶), 4.53

(s, 24 H, H⁸). ¹³C{¹H} NMR (CDCl₃): δ = 150.2 (4 C²), 143.4 (t, J_HH= 5.3 Hz, 4 H, OH), 3.51 (q, J_HH= 6.2 Hz, 8 H, H¹¹), 1.67

(4 C⁷), 137.5 (4 C⁴), 134.8 (4 C¹⁰), 133.9 (8 C⁶), 132.1 (8 C¹), (m, 8 H, H¹⁰), 0.96 (m, 8 H, H⁹), 0.50 (s, 24 H, H⁸), −2.87 (br, 2

131.8 (8 C⁵), 121.2 (4 C³), 113.6 (4 C¹¹), 24.0 (4 C⁹), −3.2 (8 C⁸). H, NH). H NMR (thf-d₈): δ = 8.84 (s, 8 H, H¹), 8.22 (d, J_HH

=

1

²⁹Si{¹H} NMR (CDCl₃): δ = −4.1 (4 Si). ESI-TOF: m/z = 1070.44 7.8 Hz, 8 H, H⁵), 7.95 (d, J_HH= 7.8 Hz, 8 H, H⁶), 3.58 (t, J_HH

=

[M]⁺(calcd 1070.40). Anal. calcd for C₆₄H₇₀N₄Si₄Zn (1073.00): 6.2 Hz, 8 H, H¹¹), 1.64 (m, 8 H, H¹⁰), 1.03 (m, 8 H, H⁹), 0.52 (s,

C, 71.64; H, 6.58; N, 5.22. Found: C, 71.44; H, 6.58; N, 4.98.

24 H, H⁸). ¹³C{¹H} NMR (thf-d₈): δ = 143.6 (4 C⁷), 139.4 (4 C⁴),

134.8 (8 C⁶), 132.7 (8 C⁵), 131.7 (br, 8 C¹), 120.9 (4 C³), 65.5

(4 C¹¹), 28.5 (4 C¹⁰), 12.5 (4 C⁹), −2.8 (8 C⁸). ²⁹Si{¹H} NMR

(dmso-d₆): δ −2.0. ²⁹Si{¹H} NMR (thf-d₈): δ = −4.0. ESI-TOF:

meso-Tetrakis[4-(diallylmethylsilyl)phenyl]porphyrinato zinc

(4b)

To porphyrin 3c (0.050 mmol, 0.0556 g) dissolved in CHCl₃m/z = 1079.60 [M + H]⁺(calcd 1079.52). Anal. calcd for

(15 mL), [Zn(OAc)₂·2H₂O] (0.100 mmol, 0.0219 g) dissolved in C₆₄H₇₈N₄O₄Si₄·thf (1150.57): C, 70.91; H, 7.53; H, 4.86. Found:

MeOH (10 mL) was added in a single portion. The reaction C, 70.63; H, 7.65; N, 4.98.

solution was stirred for 2 h at ambient temperature and after-

wards it was washed with saturated NaHCO₃(15 mL) and then

with water (2 × 15 mL). The organic layer was dried over

meso-Tetrakis[4-methyldi(3-hydroxypropyl)silylphenyl]-

porphyrin (5b)

Na₂SO₄and all volatiles were removed in oil-pump vacuum to To [BH₃·SMe₂] (2.0 M, 2.00 mmol, 1.00 mL) dissolved in thf

aﬀord 4b as a dark red solid (0.490 mmol, 0.0576 g, 98% (5.0 mL), porphyrin 3c (0.207 mmol, 0.230 g) in thf (30 mL)

based on 3c).

was added drop-wise over 10 min at 0 °C. After 2 h of stirring

˜

Mp = 350 °C (dec). IR (KBr disc): v = 3070, 3056, 3008, 2990, at this temperature aqueous NaOH (3 M, 0.75 mL) was added

2966, 2952, 2912, 2876, 1628 (m, CvC), 1252 (m, SiCH₃and stirring was continued for 15 min. Afterwards, H₂O₂(30%,

1

bending), 820 (s, SiC), 798 (s, SiC). H NMR (CDCl₃): δ = 8.98 0.75 mL) was added in a single portion and the appropriate

(s, 8 H, H¹), 8.24 (brd, J_HH= 7.9 Hz, 8 H, H⁵), 7.89 (brd, J_HH

7.9 Hz, 8 H, H⁶), 6.01 (ddt, J_HH= 17.0 Hz, J_HH= 10.1 Hz, J_HH

8.1 Hz, 8 H, H¹⁰), 5.07 (ddt, J_HH= 17.0 Hz, J_HH= 2.0 Hz, J_HH

=

reaction mixture was stirred at ambient temperature for

30 min. It was extracted with saturated aqueous K₂CO₃(20 mL)

and then with a Et₂O–thf mixture (ratio 1 : 1, v/v; 50 mL). The

0.9 Hz, 4 H, cis-H¹¹), 5.03 (ddt, J_HH= 10.1 Hz, J_HH= 2.0 Hz, organic layer was washed with brine and filtered through silica

J_HH= 0.9 Hz, 4 H, trans-H¹¹), 2.02 (dt, J_HH= 8.1 Hz, J_HH

=

gel (thf, column size 1 × 10 cm). All volatiles were removed in

0.9 Hz, 16 H, H⁹), 0.55 (s, 12 H, H⁸). ¹³C{¹H} NMR (CDCl₃): δ = oil-pump vacuum and the residue was washed with Et₂O (3 ×

150.1 (4 C²), 143.6 (4 C⁷), 135.8 (4 C⁴), 134.3 (8 C¹⁰), 133.9 15 mL) and then dried in oil-pump vacuum to give 5b as a

(8 C⁶), 132.2 (8 C⁵), 132.0 (8 C¹), 121.1 (4 C³), 114.1 (8 C¹¹), dark red solid (0.150 mmol, 0.186 g, 72% based on 3c).

˜

21.9 (8 C⁹), −5.6 (4 C⁸). ²⁹Si{¹H} NMR (CDCl₃): δ = −5.2.

Mp = 350 °C (dec). IR (KBr disc): v = 3393 (s, OH), 3314 (s,

ESI-TOF: m/z = 1174.48 [M]⁺(calcd 1174.46). Anal. calcd for NH), 3055, 3011, 2994, 2927, 2863, 1251 (m, CH₃bending),

C₇₂H₇₈N₄Si₄Zn (1177.15): C, 73.46; H, 6.68; N, 4.76. Found: C, 801 (s, SiC). H NMR (dmso-d₆): δ = 8.87 (s, 8 H, H¹), 8.26 (d,

1

73.24; H, 6.45; N, 4.68.

J_HH= 7.5 Hz, 8 H, H⁵), 7.97 (d, J_HH= 7.5 Hz, 8 H, H⁶), 4.56 (t,

J_HH= 5.3 Hz, 8 H, OH), 3.51 (q, J_HH= 6.1 Hz, 16 H, H¹¹), 1.67

meso-Tetrakis[4-dimethyl(3-hydroxypropyl)silylphenyl]-

porphyrin (5a)

To [BH₃·SMe₂] (2.0 M, 2.00 mmol, 1.00 mL) dissolved in thf 7.6 Hz, 8 H, H⁵), 7.96 (d, J_HH= 7.6 Hz, 8 H, H⁶), 3.58 (t, J_HH

(m, 16 H, H¹⁰), 1.00 (m, 16 H, H⁹), 0.51 (s, 12 H, H⁸), −2.86 (br,

1

2 H, NH). H NMR (thf-d₈): δ = 8.84 (s, 8 H, H¹), 8.22 (d, J_HH

=

(5.0 mL), 3b (0.397 mmol, 0.400 g) in thf (30 mL) was drop- 6.4 Hz, 16 H, H¹¹), 1.74 (m, 16 H, H¹⁰), 1.06 (m, 16 H, H⁹), 0.52

wise added over 10 min at 0 °C. The reaction solution was (s, 12 H, H⁸). ¹³C{¹H} NMR (thf-d₈): δ = 143.5 (4 C⁷), 138.6

stirred for 2 h at this temperature and afterwards it was (4 C⁴), 134.8 (8 C⁶), 133.1 (8 C⁵), 131.7 (br, 8 C¹), 121.0 (4 C³),

quenched with aqueous NaOH (3 M, 0.75 mL) and stirring was 65.6 (8 C¹¹), 28.5 (8 C¹⁰), 10.9 (4 C⁹), −4.8 (8 C⁸). ²⁹Si{¹H} NMR

continued for 15 min. Afterwards, H₂O₂(30%, 0.75 mL) was (dmso-d₆): δ = −0.8. ²⁹Si{¹H} NMR (thf-d₈): δ = −0.8. ESI-TOF:

added in a single portion, stirring was continued at ambient m/z = 1293.70 [M + K]⁺(calcd 1293.58). Anal. calcd for

temperature for 30 min and then the reaction mixture was C₇₂H₉₄N₄O₈Si₄·H₂O (1273.90): C, 67.88; H, 7.60; N, 4.40.

extracted with saturated aqueous K₂CO₃(20 mL) and with a Found: C, 67.68; H, 7.65; N, 4.31.

Et₂O–thf mixture (ratio 1 : 1, v/v; 50 mL). The organic layer was

washed with brine and filtered through a silica gel column

(thf, column size 1.0 × 10 cm). From the eluate, all volatiles

meso-Tetrakis[4-dimethyl(3-hydroxypropyl)silylphenyl]-

porphyrinato zinc (6a)

were removed in oil-pump vacuum and the residue was To 5a (0.0926 mmol, 0.100 g) dissolved in thf (30 mL) a solu-

washed with Et₂O (3 × 15 mL) and was then dried in oil-pump tion of [Zn(OAc)₂·2H₂O] (0.185 mmol, 0.0407 g) in MeOH

vacuum to give 5a (0.332 mmol, 0.358 g, 83% based on 3b) as (10 mL) was added in a single portion. The reaction solution

a dark red solid.

was stirred for 2 h at ambient temperature and afterwards was

˜

Mp = 350 °C (dec). IR (KBr disc): v = 3397 (s, OH), 3314 (s, concentrated in oil-pump vacuum to dryness. The residue was

NH), 3055, 3011, 2994, 2926, 2864, 1251 (m, CH₃bending), dissolved in thf (20 mL) and filtered through a pad of silica gel

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(thf) and then all volatiles were removed in oil-pump vacuum. NMR (CDCl₃): δ = 192.6 (1 C¹), 143.2 (1 C²), 142.4 (3 C⁹), 136.9

The remaining solid was washed with a Et₂O–ⁿpentane (2 C⁴), 135.5 (6 C⁷), 133.5 (3 C⁶), 132.8 (6 C⁸), 128.6 (2 C³),

mixture (ratio 1 : 4 v/v,(30 mL)) and then dried in oil-pump 127.8 (1 C⁵), −1.2 (9 C¹⁰). ²⁹Si{¹H} NMR (CDCl₃): δ = −14.7

vacuum to give the title compound as a dark red solid (1 Si¹), −3.9 (3 Si²). ESI-TOF: m/z = 619.24 [M + K]⁺(calcd

(0.0857 mmol, 0.0980 g, 93% based on 5a).

619.21). Anal. calcd for C₃₅H₄₄OSi₄(581.05): C, 70.28; H, 7.63.

˜

Mp = 350 °C (dec). IR (KBr disc): v = 3398 (m, OH), 3048, Found: C, 70.19; H, 7.45.

3004, 2945, 2927, 2863, 1246 (s, CH₃bending), 831, 798 (s,

1

4-[Tris-(4-diallylmethylsilylphenyl)silyl]benzaldehyde (8c)

SiC). H NMR (dmso-d₆): δ = 8.76 (s, 8 H, H¹), 8.16 (d, J_HH

=

7.5 Hz, 8 H, H⁵), 7.89 (d, J_HH= 7.5 Hz, 8 H, H⁶), 4.49 (t, J_HH

The same procedure as described for preparing 2b was applied

6.2 Hz, 4 H, OH), 3.46 (q, J_HH= 6.3 Hz, 8 H, H¹¹), 1.63 (m, 8 H, in the synthesis of 8c (see above): BuLi (1.7 M, 6.00 mmol,

t

H¹⁰), 0.92 (m, 8 H, H⁹), 0.47 (s, 24 H, H⁸). ¹³C{¹H} NMR (dmso- 3.60 mL, pentane), 7c (3.00 mmol, 2.361 g) in Et₂O (40 mL),

n

d₆): δ = 150.1 (4 C²), 144.2 (4 C⁷), 138.6 (4 C⁴), 134.7 (8 C⁶), dimethyl formamide (9.00 mmol, 0.658 g, 0.70 mL) in thf

132.6 (8 C⁵and 8 C¹), 121.2 (4 C³), 64.8 (4 C¹¹), 28.2 (4 C¹⁰), (20 mL) and aqueous HCl (3 N, 25 mL). After appropriate

12.4 (4 C⁹), −1.8 (8 C⁸). ²⁹Si{¹H} NMR (dmso-d₆): δ = −2.1. work-up, 8c was isolated as colorless oil (2.46 mmol, 1.81 g,

ESI-TOF: m/z = 1179.50 [M + K]⁺(calcd 1179.39). Anal. calcd for 82% based on 7c).

˜

C₆₄H₇₆N₄O₄Si₄Zn (1143.04): C, 67.25; H, 6.70; N, 4.90. Found:

C, 67.44; H, 7.12; N, 4.81.

IR (film): v = 3074, 3050, 2996, 2969, 2913, 2878, 2819 (w,

CHO), 2725 (w, CHO), 1705 (s, CvO), 1629 (w, CvC), 1252 (w,

CH₃bending), 1132, 821 (s, SiC), 802 (s, SiC). ¹H NMR (CDCl₃):

δ = 10.07 (s, 1 H, CHO), 7.89 (brd, J_HH= 8.1 Hz, 2 H, H³), 7.77

(brd, J_HH= 8.1 Hz, 2 H, H⁴), 7.55 (brs, 12 H, H⁷and H⁸), 5.80

meso-Tetrakis[4-methyldi(3-hydroxypropyl)silylphenyl]-

porphyrinato zinc (6b)

To porphyrin 5b (0.0805 mmol, 0.100 g) dissolved in thf (ddt, J_HH= 16.9 Hz, J_HH= 10.2 Hz, J_HH= 8.0 Hz, 6 H, H¹²), 4.91

(30 mL), [Zn(OAc)₂·2H₂O] (0.1611 mmol, 0.03536 g) in MeOH (ddt, J_HH= 16.9 Hz, J_HH= 2.1 Hz, J_HH= 1.1 Hz, 6 H, cis-H¹³),

(10 mL) was added in a single portion. The reaction solution 4.89 (ddt, J_HH= 10.2 Hz, J_HH= 2.1 Hz, J_HH= 1.1 Hz, 6 H, trans-

was stirred for 2 h at ambient temperature and afterwards all H¹³), 1.84 (brd, J_HH= 8.0 Hz, 12 H, H¹¹), 0.31 (s, 9 H, H¹⁰).

volatiles were removed in oil-pump vacuum. The obtained ¹³C{¹H} NMR (CDCl₃): δ = 192.5 (1 C¹), 142.8 (1 C²), 139.1

residue was dissolved in thf (50 mL) and filtered through a pad (3 C⁹), 137.0 (1 C⁵), 136.9 (2 C⁴), 135.4 (6 C⁸), 134.0 (6 C¹²), 133.9

of silica gel (thf). All volatiles were removed in oil-pump (3 C⁶), 133.4 (6 C⁷), 128.6 (2 C³), 113.5 (6 C¹³), 23.5 (6 C¹¹),

vacuum. The remaining residue was washed with Et₂O (30 mL) −3.6 (3 C¹⁰). ²⁹Si{¹H} NMR (CDCl₃): δ = −14.7 (1 Si¹), −5.7

and then dried in oil-pump vacuum to give 6b as a red solid (3 Si²). ESI-TOF: m/z = 775.01 [M + K]⁺(calcd 775.30). Anal.

(0.068 mmol, 0.089 g, 85% based on 5b).

calcd for C₄₆H₅₆OSi₄(737.28): C, 74.94; H, 7.66. Found: C,

˜

Mp = 350 °C (dec). IR (KBr disc): v = 3403 (m, OH), 3055, 74.93; H, 7.77.

1

3004, 2923, 2863, 1250 (w, CH₃bending), 858, 796 (s, SiC). H

meso-Tetrakis{4-[tris(4-trimethylsilylphenyl)silyl]phenyl}-

porphyrin (9a)

NMR (dmso-d₆): δ = 8.77 (s, 8 H, H¹), 8.18 (d, J_HH= 7.7 Hz, 8 H,

H⁵), 7.90 (d, J_HH= 7.7 Hz, 8 H, H⁶), 4.49 (t, J_HH= 6.2 Hz, 8 H,

OH), 3.46 (q, J_HH= 6.3 Hz, 8 H, H¹¹), 1.64 (m, 16 H, H¹⁰), 0.95 To 8a (4.00 mmol, 2.324 g) and pyrrole (4.00 mmol, 0.268 g,

(m, 16 H, H⁹), 0.47 (s, 12 H, H⁸). ¹³C{¹H} NMR (dmso-d₆): δ = 0.28 mL) dissolved in CH₂Cl₂(400 mL), [BF₃·OEt₂]

150.2 (4 C²), 144.2 (4 C⁷), 137.8 (4 C⁴), 134.8 (8 C⁶), 132.9 (0.400 mmol, 0.057 g, 0.05 mL) was added in a single portion.

(8 C⁵), 132.6 (br, 8 C¹), 121.3 (4 C³), 64.9 (4 C¹¹), 28.2 (4 C¹⁰), The reaction solution was stirred for 2 h and then 2,3-dichloro-

10.8 (4 C⁹), −3.8 (8 C⁸). ²⁹Si{¹H} NMR (dmso-d₆): δ = −0.9. 5,6-dicyanobenzoquinone (3.00 mmol, 0.681 g) was added in a

ESI-TOF: m/z = 1355.62 [M + K]⁺(calcd 1355.49). Anal. calcd for single portion and stirring was continued for 1 h. The reaction

C₇₂H₉₂N₄O₈Si₄Zn (1319.24): C, 65.33; H, 6.95; H, 4.29. Found: mixture was washed with saturated NaHCO₃(40 mL) and after-

C, 64.89; H, 7.11; N, 4.07.

wards with water (3 × 40 mL). The organic layer was filtered

through a pad of silica gel and then all volatiles were removed

in oil-pump vacuum. The crude product was purified by

4-[Tris(4-trimethylsilylphenyl)silyl]benzaldehyde (8a)

The synthetic procedure described for the preparation of 2b column chromatography (a) ⁿhexane and (b) 20 vol%

(see earlier) was applied to synthesize 8a: ^tBuLi (1.7 M, CH₂Cl₂–ⁿhexane. After all volatiles were removed in oil pump

13.00 mmol, 7.70 mL, ⁿpentane), 7a (6.50 mmol, 4.10 g) in vacuum, porphyrin 9a was obtained as a dark red solid

Et₂O (70 mL), dimethyl formamide (19.50 mmol, 1.43 g, (0.256 mmol, 0.643 g, 26% based on 8a).

˜

Mp = 350 °C (dec). IR (KBr disc): v = 3315 (s, NH), 3047,

1.51 mL) in thf (40 mL) and aqueous HCl (3 N, 40 mL). After

appropriate work-up, 8a could be isolated as a colorless solid 2995, 2952, 2932, 2894, 1249 (m, CH₃bending), 1133, 847 (s,

1

(5.93 mmol, 3.45 g, 91% based on 7a).

SiC), 839 (s, SiC), 803. H NMR (CDCl₃): δ = 8.94 (s, 8 H, H¹),

Mp = 212 °C. IR (film): v = 3048, 2996, 2953 (m), 2894, 2816 8.27 (brd, J_HH= 8.0 Hz, 8 H, H⁵), 8.02 (brd, J_HH= 8.0 Hz, 8 H,

(w, CHO), 2722 (w, CHO), 1706 (s, CvO), 1249 (w, CH₃H⁶), 7.85 (brd, J_HH= 8.0 Hz, 24 H, H⁹), 7.70 (brd, J_HH= 8.0 Hz,

bending), 1133, 838 (s, SiC). ¹H NMR (CDCl₃): δ = 10.06 (s, 1 H, 24 H, H¹⁰), 0.36 (s, 108 H, H¹²), −2.72 (br, 2 H, NH). ¹³C{¹H}

CHO), 7.87 (brd, J_HH= 8.2 Hz, 2 H, H³), 7.78 (brd, J_HH= 8.2 Hz, NMR (CDCl₃): δ = 143.3 (4 C⁴), 142.2 (12 C¹¹), 135.8 (24 C¹⁰),

2 H, H⁴), 7.55 (s, 12 H, H⁷and H⁸), 0.29 (s, 27 H, H¹⁰). ¹³C{¹H} 134.7 (8 C⁶), 134.6 (12 C⁸), 134.2 (8 C⁵), 133.5 (4 C⁷) 132.9

˜

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(24 C⁹), 120.1 (4 C³), −1.1 (36 C¹²). ²⁹Si{¹H} NMR (CDCl₃): δ = 121.1 (4 C³), −1.1 (36 C¹²). ²⁹Si{¹H} NMR (CDCl₃): δ = −14.3

−14.2 (4 Si¹), −4.5 (12 Si²). Anal. calcd for C₁₅₂H₁₈₂N₄Si₁₆(4 Si¹), −3.9 (12 Si²). Anal. calcd for C₁₅₂H₁₈₀N₄Si₁₆Zn·EtOH

(2514.47): C, 72.60; H, 7.30; N, 2.23. Found: C, 72.54; H, 6.93; (2619.02): C, 70.49; H, 7.14; N, 2.14. Found: C, 70.51; H, 6.95;

N, 2.13.

N, 1.86.

meso-Tetrakis{4-[tris(4-diallylmethylsilylphenyl)silyl]phenyl}-

meso-Tetrakis{4-[tris(4-allyldimethylsilylphenyl)silyl]phenyl]-

porphyrin (9c)

porphyrinato zinc (10b)

To 8c (1.81 mmol, 1.333 g) and pyrrole (1.81 mmol, 0.122 g, To 9b (0.0123 mmol, 0.0350 g) dissolved in CHCl₃(5 mL),

0.13 mL) dissolved in CH₂Cl₂(180 mL), [BF₃·OEt₂] (0.18 mmol, [Zn(OAc)₂·2H₂O] (0. 0308 mmol, 0.0067 g) in MeOH (2.5 mL)

0.026 g, 0.02 mL) was added in a single portion. The reaction was added in a single portion. The reaction solution was

solution was stirred for

2 h and then 2,3-dichloro-5,6- stirred for 2 h at ambient temperature and then all volatiles

dicyanobenzoquinone (1.36 mmol, 0.308 g) was added and were removed in oil-pump vacuum. The residue was extracted

stirring was continued for 1 h. The reaction mixture was with CHCl₃(10 mL) and then with water (5 mL). The organic

washed with saturated NaHCO₃(40 mL) and then with water layer was dried over MgSO₄and all volatiles were removed in

(3 × 40 mL). The organic layer was filtered through a pad oil-pump vacuum to aﬀord 10b as

of silica gel and afterwards all volatiles were removed in (0.0118 mmol, 0.336 g, 96% based on 9b).

a dark red solid

˜

Mp = 350 °C (dec). IR (KBr disc): v = 3074, 3047, 2994, 2953,

oil-pump vacuum. The crude product was purified by

column chromatography (a) ⁿhexane and (b) 20 vol% 2912, 1628 (m, CvC), 1249 (m, CH₃bending), 1132, 835 (s,

1

CH₂Cl₂–ⁿhexane. After removal of all volatiles in a vacuum, SiC), 799 (s, SiC). H NMR (CDCl₃): δ = 9.05 (s, 8 H, H¹), 8.29

porphyrin 9c was isolated as a dark red solid (0.143 mmol, (brd, J_HH= 8.0 Hz, 8 H, H⁵), 7.97 (brd, J_HH= 8.0 Hz, 8H, H⁶),

0.452 g, 32% based on 8c).

7.85 (brd, J_HH= 8.0 Hz, 24 H, H⁹), 7.70 (brd, J_HH= 8.0 Hz,

Mp = 350 °C (dec). IR (KBr disc): v = 3322 (S, NH), 3074, 24 H, H¹⁰), 5.88 (ddt, J_HH= 16.9 Hz, J_HH= 10.2 Hz, J_HH

3050, 2996, 2968, 2954, 2912, 2878, 1630 (m, CvC), 1252 (m, 8.1 Hz, 24 H, H¹⁴), 4.95 (ddt, J_HH= 16.9 Hz, J_HH= 2.1 Hz, J_HH

CH₃bending), 1132, 822 (s, SiC), 802 (s, SiC). ¹H NMR (CDCl₃): 1.1 Hz, cis-H¹⁵), 4.92 (ddt, J_HH= 10.2 Hz, J_HH= 2.1 Hz, J_HH

=

˜

δ = 8.94 (s, 8 H, H¹), 8.28 (brd, J_HH= 7.6 Hz, 8 H, H⁵), 7.99 1.1 Hz, trans-H¹⁵), 1.86 (dt, J_HH= 8.1 Hz, J_HH= 1.1 Hz, 24 H,

(brd, J_HH= 7.6 Hz, 8H, H⁶), 7.82 (brd, J_HH= 7.5 Hz, 24 H, H⁹), H¹³), 0.38 (s, 72 H, H¹²). ¹³C{¹H} NMR (CDCl₃): δ = 150.1

7.68 (brd, J_HH= 7.5 Hz, 24 H, H¹⁰), 5.86 (ddt, J_HH= 17.2 Hz, (8 C²), 144.0 (4 C⁴), 140.5 (12 C¹¹), 135.8 (24 C¹⁰), 134.9 (12 C⁸),

J_HH= 9.6 Hz, J_HH= 8.1 Hz, 24 H, H¹⁴), 4.95 (brd, J_HH= 17.2 Hz, 134.6 (12 C¹⁴and 8 C⁶), 134.1 (8 C⁵), 133.2 (24 C⁹), 133.0

24 H, cis-H¹⁵), 4.93 (brd, 9.6 Hz, 24 H, trans-H¹⁵), 1.90 (brd, (4 C⁷), 132.1 (8 C¹), 121.1 (4 C³), 113.5 (12 C¹⁵), 23.6 (12 C¹³),

8.00 Hz, 48 H, H¹³), 0.37 (s, 36 H, H¹²), −2.75 (s, 2 H, NH). −3.5 (24 C¹²). ²⁹Si{¹H} NMR (CDCl₃): δ = −14.2 (4 Si¹), −4.5

¹³C{¹H} NMR (CDCl₃): δ = 143.4 (4 C⁴), 138.9 (12 C¹¹), 135.7 (12 Si²). Anal. calcd for C₁₇₆H₂₀₄N₄Si₁₆Zn·2EtOH (2982.26): C,

(24 C¹⁰), 135.0 (12 C⁸), 134.8 (8 C⁶), 134.3 (8 C⁵), 134.2 (24 C¹⁴), 72.49; H, 7.30, N, 1.88. Found: C, 72.17; H, 7.10; N, 1.67.

133.5 (24 C⁹), 133.2 (4 C⁷), 120.1 (4 C³), 114.0 (24 C¹⁵), 21.6

meso-Tetrakis{4-[tris(4-diallylmethylsilylphenyl)silyl]phenyl}-

(24 C¹³), −5.8 (24 C¹²). ²⁹Si{¹H} NMR (CDCl₃): δ = −14.2 (4 Si¹),

porphyrinato zinc (10c)

−5.7 (12 Si²). Anal. calcd for C₂₀₀H₂₃₀N₄Si₁₆(3153.39): C, 76.52;

H, 7.38, N, 1.78. Found: C, 76.66; H, 7.17; N, 1.23.

To 9c (0.0317 mmol, 0.100 g) in CHCl₃(15 mL), a solution of

[Zn(OAc)₂·2H₂O] (0.0793 mmol, 0.017 g) in MeOH (5 mL) was

added in a single portion. The reaction solution was stirred for

2 h at ambient temperature and afterwards all volatiles were

meso-Tetrakis{4-[tris(4-trimethylsilylphenyl)silyl]phenyl}-

porphyrinato zinc (10a)

To 9a (0.0139 mmol, 0.0350 g) in CHCl₃(5 mL), removed in oil-pump vacuum. The residue was extracted with

[Zn(OAc)₂·2H₂O] (0.0347 mmol, 0.0076 g) in MeOH (2.5 mL) CHCl₃(20 mL) and then with water (10 mL). The organic layer

was added in a single portion. The reaction solution was was dried over MgSO₄and all volatiles were removed in oil-

stirred for 2 h at ambient temperature and afterwards was con- pump vacuum to aﬀord 10c (0.0308 mmol, 0.099 g, 97% based

centrated in oil-pump vacuum to dryness. The residue was on 9c).

˜

Mp = 350 °C (dec). IR (KBr disc): v = 3074, 3050, 2994, 2968,

extracted with CHCl₃(10 mL) and then with water (5 mL). The

organic layer was dried over MgSO₄and all volatiles were 2912, 2878, 1628 (m, CvC), 1252 (m, CH₃bending), 1132, 820

removed in oil-pump vacuum to aﬀord 10a as a dark red solid (s, SiC), 802 (s, SiC). ¹H NMR (CDCl₃): δ = 9.03 (s, 8 H, H¹),

(0.0135 mmol, 0.340 g, 97% based on 9a).

8.27 (brd, J_HH= 8.0 Hz, 8 H, H⁵), 7.97 (brd, J_HH= 8.0 Hz, 8H,

Mp = 350 °C (dec). IR (KBr disc): v = 3046, 2994, 2952, 2932, H⁶), 7.82 (brd, J_HH= 8.0 Hz, 24 H, H⁹), 7.67 (brd, J_HH= 8.0 Hz,

˜

2893, 1249 (m, CH₃bending), 1132, 845 (s, SiC), 839 (s, SiC), 24 H, H¹⁰), 5.85 (ddt, J_HH= 16.9 Hz, J_HH= 9.6 Hz, J_HH

=

803. ¹H NMR (CDCl₃): δ = 9.02 (s, 8 H, H¹), 8.25 (brd, J_HH8.1 Hz, 24 H, H¹⁴), 4.94 (ddt, J_HH= 16.9 Hz, J_HH= 2.1 Hz, J_HH

=

7.9 Hz, 8 H, H⁵), 7.99 (brd, J_HH= 7.9 Hz, 8 H, H⁶), 7.83 (brd, 1.0 Hz, cis-H¹⁵), 4.91 (ddt, J_HH= 9.9 Hz, J_HH= 2.1 Hz, J_HH= 1.0

J_HH= 7.8 Hz, 24 H, H⁹), 7.68 (brd, J_HH= 7.8 Hz, 24 H, H¹⁰), Hz, trans-H¹⁵), 1.89 (brd, J_HH= 8.1 Hz, 48 H, H¹³), 0.36 (s, 36

0.34 (s, 108 H, H¹²). ¹³C{¹H} NMR (CDCl₃): δ = 150.1 (8 C²), H, H¹²). ¹³C{¹H} NMR (CDCl₃): δ = 150.1 (8 C²), 144.1 (4C⁴),

144.0 (4 C⁴), 142.1 (12 C¹¹), 135.8 (24 C¹⁰), 134.7 (12 C⁸), 134.6 138.8 (12 C¹¹), 135.7 (24 C¹⁰), 135.1 (12 C⁸), 134.6 (8 C⁶), 134.2

(8 C⁶), 134.1 (8 C⁵), 133.2 (4 C⁷), 132.9 (24 C⁹), 132.1 (8 C¹), (24 C¹⁴), 134.1 (8 C⁵), 133.5 (24 C⁹), 132.9 (4 C⁷), 132.1 (8 C¹),

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121.1 (4 C³), 114.0 (24 C¹⁵), 21.6 (24 C¹³), −5.8 (12 C¹²). ²⁹Si cerning the definition of “saddle-shaped” deformed geome-

{¹H} NMR (CDCl₃): δ = −14.2 (4 Si¹), −5.7 (12 Si²). Anal. calcd tries of porphyrins.

for C₂₀₀H₂₂₈N₄Si₁₆Zn·2EtOH (3294.87): C, 74.36; H, 7.34; N,

1.70. Found: C, 74.21; H, 7.30; N, 1.78.

References

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9b were performed with a Bruker Smart 1k CCD diﬀractometer

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39 It needs to be emphasized that for 3b, 3c, 4a and 9b, π–π

interactions involving the terminal allylic side chains have

been left unattended. The allyl groups have been at least par-

tially refined disordered, if possible. Moreover, the respective

carbon atoms do have comparatively large U_ijvalues. Due to

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40 (a) Labelling code: symmetry generated equivalent atoms

of Si10, Si11–Si16/C101, C102–C188 are assigned as Si0#,

Si1#–Si6#/C1# and C2#–C88#. Of symmetry generated

carbon atoms only selected ones have been labelled. Atom

C126 is disordered on two positions of which only one is

displayed and labelled with C12A (b) The assignment of

symmetry generated atoms is for 9b more complicated

than in conventional cases, as four digits are allowed only

when working with crystallographic software. For example,

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7888 | Dalton Trans., 2014, 43, 7868–7888

Article Doi

Porphyrins with a carbosilane dendrimer periphery as synthetic components for supramolecular self-assembly

DOI: 10.1039/c3dt53535e

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Full text of DOI:10.1039/c3dt53535e

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