5,15-Bis(3,5-di-tert-butyl­phen­yl)-10,20-bis­(phenyl­ethyn­yl)porphyrin

Hee Jung Kim; Atul P Singh; Hee-Joon Kim

doi:10.1107/S1600536809045954

. 2009 Nov 7;65(Pt 12):o3004–o3005. doi: 10.1107/S1600536809045954

5,15-Bis(3,5-di-tert-butylphenyl)-10,20-bis(phenylethynyl)porphyrin

Hee Jung Kim ^a, Atul P Singh ^a, Hee-Joon Kim ^a,^*

PMCID: PMC2972159 PMID: 21578743

Abstract

In the centrosymmetric title compound, C₆₄H₆₂N₄, the two phenylethynyl groups lie at diagonal meso positions. The 24-membered porphyrin has in-plane distortion with respect to the mean plane of the macrocycle and two intra-ring bifurcated N—H⋯(N,N) hydrogen bonds occur. The dihedral angles between the phenyl rings in the phenylethynyl group and the 3,5-bis(tert-butyl)phenyl group with respect to the mean plane of the porphyrin are 17.2 (2) and 59.2 (3)°. The tert-butyl groups are disordered over two sets of sites in a 0.661 (13):0.339 (13) ratio.

Related literature

For background to porphyrin structures and electronic properties, see: Anderson et al. (1994 ▶, 1998 ▶); Fujita et al. (1995 ▶); Henari et al. (1997 ▶); Huuskonen et al. (1998 ▶); LeCours et al. (1996 ▶); Screen et al. (2002 ▶); Seo et al. (2008 ▶); Silvers & Tulinsky (1967 ▶). graphic file with name e-65-o3004-scheme1.jpg

Experimental

Crystal data

C₆₄H₆₂N₄
M _r = 887.18
Triclinic,
a = 9.9598 (19) Å
b = 10.496 (2) Å
c = 13.925 (3) Å
α = 86.236 (4)°
β = 80.266 (4)°
γ = 82.765 (4)°
V = 1421.8 (5) Å³
Z = 1
Mo Kα radiation
μ = 0.06 mm⁻¹
T = 213 K
0.45 × 0.10 × 0.05 mm

Data collection

Bruker SMART CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2003 ▶) T _min = 0.974, T _max = 0.997
6144 measured reflections
4136 independent reflections
2068 reflections with I > 2σ(I)
R _int = 0.101
θ_max = 23.5°

Refinement

R[F ² > 2σ(F ²)] = 0.107
wR(F ²) = 0.315
S = 0.99
4136 reflections
363 parameters
193 restraints
H-atom parameters constrained
Δρ_max = 1.13 e Å⁻³
Δρ_min = −0.30 e Å⁻³

Data collection: SMART (Bruker, 2003 ▶); cell refinement: SAINT (Bruker, 2003 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809045954/hb5134sup1.cif

e-65-o3004-sup1.cif^{(23.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809045954/hb5134Isup2.hkl

e-65-o3004-Isup2.hkl^{(202.7KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯N2	0.87	2.44	2.972 (6)	120
N1—H1A⋯N2ⁱ	0.87	2.35	2.891 (5)	121

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Symmetry code: (i) Inline graphic .

Acknowledgments

This work was supported by the Ministry of Education, Science Technology (MEST) and the Korean Institute for the Advancement of Technology (KIAT) through the Human Resource Training Project for Regional Innovation. We also acknowledge the New University for Regional Innovation funded by the Ministry of Education, Science Technology (MEST) for support. We thank Dr Hyunuk Kim for the data collection.

supplementary crystallographic information

Comment

The electronic and steric tunnings through surrogating various substituents on the meso- and beta-carbons play crucial role in the synthesis of diverse porphyrin systems. In this respect, meso-ethynyl porphyrins have attracted the attention due to their wide utilization for the development of conjugated electronic (LeCours et al., 1996; Anderson et al., 1994; Henari et al., 1997; Screen et al., 2002) and light harvesting materials. As an extension of our research on the conjugated photoelectronic materials (Seo et al., 2008), the title compound (I) was prepared and its crystal structure determined.

The molecular structure of C64H62N4 (I) is shown in Figure 1. The structure shows symmetric molecular system due to presence of inversion center (Ci) in the core of porphyrin macrocycle. On assuming all four nitrogen atoms of all pyrolic groups in a plane, it was observed that the meso-carbons were deviated with ± 0.072 Å from the least-squares plane and find analogy with earlier reported compound 5,15-bis(3,5-di-tert-butylphenyl) -10,20-bis(trimethylsilylethynyl)porphyrin (Huuskonen et al., 1998). The structural analysis of the porphyrin macrocycle reveals that the plane of phenyl rings in the phenylethynyl groups is slightly twisted with the dihedral angle of 17.17° with respect to the least-squares plane of the porphyrin, in contrast the plane of aryl rings associated with 3,5-bis(tert-butyl)phenyl groups (59.19°) (Figure 2). The dihedral angle associated with phenylethynyl groups (17.17°) is also much smaller with respect to phenyl planes slanting (61–63°) in tetraphenylporphyrin (Silvers et al., 1967). The comparison of this result with the tetraphenylporphyrin, it was observed that on increasing the conjugation with phenyl groups leads to release of steric strain. The distances between the nitrogen atoms (N1—N2 = 2.972, N1—N2' = 2.891, N1—N1' = 4.167, N2—N2' = 4.126 Å) involve in the formation of basal parallelogram based core along with the C—C (triple bond) (1.165 Å) bond lengths and C(meso)-C(alpha)-C(beta) angles (178.07°) involving ethynyl groups show the analogy with previous reports (Fujita et al., 1995; Huuskonen et al., 1998). In addition, the distances involving the diagonal meso-carbon atoms (C5—C5' = 6.815, C10—C10' = 6.994 Å) also differ to each other and correlate with the previous work (Huuskonen et al., 1998). The shortest intermolecular distances for the pi-pi and pi-H interactions are not observed less than 6.085 and 3.84 Å, respectively and imply the steric strain between aryl groups of adjacent porphyrin prevent the strong interactions in between adjacent molecular system (Anderson et al., 1998).

Experimental

The title compound was prepared from the corresponding dipyrromethane and phenylpropargyl aldehyde as follows. BF3.OEt2 (25 ML, 0.2 mmol) was added to a solution of meso-(3,5-di-tert-butylphenyl) dipyrromethane (0.669 g, 2.0 mmol) and phenylpropargyl aldehyde (245 ML, 2.0 mmol) in dry CH2Cl2 (200 ml). The reaction mixture was stirred for 10 min at room temperature.

2,3-Dichloro-5,6-dicyano-p-benzoquinone (340 mg, 0.15 mmol) was added and further stirred for 30 min. After evaporation of solvent to dryness, the title compound was separated by column chromatography (SiO2, CH2Cl2:n-hexane = 1:4). Recrystallization from a CH2Cl2/CH3CN solution afforded purple crystalline solid. Yield: 124 mg (14%). 1H NMR (200 MHz, CDCl3): Δ 9.70 (d, 4H), 8.89 (d, 4H), 8.06 (s, 4H), 8.00 (t, 2H), 7.82 (s, 2H), 1.55 (s, 36H), -1.92 (br, 2H). UV-vis (CH2Cl2): Λmax (log E) 443 (6.04), 554 (4.38), 594(4.92), 623 (4.25), 681 (4.61) nm.

Purple needles of (I) were grown by slow diffusion of CH₃CN to a CH₂Cl₂ solution of the title compound.