[5,10,15,20-Tetrakis(2-thienyl)porphyrinato]zinc(II)

In the title complex, [Zn(C₃₆H₂₀N₄S₄)], the Zn^II ion occupies a special position on an inversion centre with four-coordinate geometry. The porphyrin ring shows a wave-like conformation, with the closest interporphyrin plane separation being 3.60 (6) Å. The two disordered thienyl groups are inclined with respect to the porphyrin plane at angles of 70 (4) and 67 (2)°.

S1. Comment

Meso-tetrathienylporphyrins are of growing interest owing to their unique energy transfer (Vollmer et al., 1998) and electrochemical (Ono et al., 1998) properties. Oligomeric (Shimidzu et al., 1995) and polymeric (Maruyama et al., 1998) thienylporphyrin films show interesting physicochemical properties. Here, we present the crystal structure of the title [meso-tetra(2-thienyl)porphyrinato]zinc(II) complex, (I). \sch

The molecular structure of (I) is shown in Fig. 1. The Zn^II ion is free of axial ligands, with no solvate molecules in the crystal lattice. The closest Zn^II to a thienyl S of an adjacent molecule is at a distance of 5.245 (3) Å. The observed bond lengths of the 24-atom core of (I) are similar to those of the four-coordinate [meso-5,10,15,20-tetraphenylporphinato]zinc(II), (II) (Scheidt & Lee, 1987).

Selected dihedral angles and bond lengths for (I) and (II) (Scheidt et al., 1986) are given in Table 1. The comparison is made to illustrate the effect of the thienyl groups on the stereochemical features of the porphyrin ring system. Notably, the central Zn to the meso carbon shows a shorter distance in (I) than in (II), indicative of a contraction of the porphyrin core. This is further reflected in the contraction of the Zn—N bond lengths (Table 1).

The deviations of the atoms of the 24-atom porphyrin core from the mean plane passing through the core are shown in Fig. 2. The porphyrin plane of (I) displays a wave-like conformation (Senge, 1999), with an interplanar porphyrin separation of 3.60 (6) Å, indicative of minimal interporphyrin interactions. The porphyrin molecules pack in a slipped-stack orientation.

It can be seen from Table 1 that the dihedral angles in (I) are higher than those found in (II). The thienyl groups in (I) are inclined with respect to the porphyrin plane at angles which differ by 3°. This is similar to (II), in which the difference between the two angles is 2.8°. The third C and the S atoms of the thienyl groups of (I) show disorder. In this structure, the Zn^II ion is free of five- or six-coordination, possibly due to steric hindrance by the 2-thienyl groups.

Related literature

For related literature, see: Adler et al. (1967, 1970); Maruyama et al. (1998); Ono et al. (1998); Scheidt & Lee (1987); Scheidt et al. (1986); Senge (1999); Shimidzu et al. (1995); Vollmer et al. (1998).

S2. Experimental

5,10,15,20-Tetrakis(2-thienyl)porphyrin was synthesized using the procedure of Adler et al. (1967) and recrystallized from CHCl₃/CH₃OH (1:1 v/v). Metallation of the porphyrin was carried out using zinc(II) acetate dihydrate as the metal carrier (Adler et al., 1970). The compound was purified by column chromatography using CHCl₃ as the eluant and the yield of (I) was almost quantitative. Single crystals of (I) suitable for X-ray analysis were obtained by slow evaporation of a chloroform solution over a period of 4 d. Spectroscopic analysis: ¹H NMR (CDCl₃, p.p.m.): 9.15 (s, 8H, pyrrole-H), 7.90 (dd, 4H, thienyl-3H), 7.85 (dd, 4H, thienyl-4H), 7.50 (dd, 4H, thienyl-5H); elemental analysis calculated for C₃₆H₂₂N₄S₄: H 3.15, C 61.40, N 7.96%; found: H 3.01, C 61.12, N 8.01%; FAB mass spectrum (m/z), calculated for C₃₆H₂₀N₄S₄Zn: 702.2; found: 702.8.

S3. Refinement

The thienyl groups exhibit twofold rotational disorder about the C5—C6 and C14—C15 bonds, which was noticed at the structure-solution stage itself. The occupancies of the two components refined to unequal values in both cases [0.615 (5) and 0.386 (5) for S1/S1ⁱ, and 0.719 (6) and 0.281 (6) for S2/S2ⁱ; symmetry code: (i) 1 - x, 1 - y, -z]. Apart from the disordered thienyl groups, H atoms were fixed geometrically and were treated as riding on their parent atoms, with C—H distances of ?

Computing details

Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: MolEN (Fair, 1990); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON97 query; software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. The molecular structure (ORTEP; Johnson, 1965) of (I), with the atom-numbering scheme and 50% probability displacement ellipsoids. H atoms have been omitted for clarity.
	Fig. 2. The perpendicular deviation of atoms (in units of 0.001 Å) from the mean plane of the 24-atom porphyrin core. Only the Zn^II ion and the N atoms are labelled [symmetry code: (i) 1 - x, 1 - y, -z].

[5,10,15,20-Tetrakis(2-thienyl)porphyrinato]zinc(II)

Crystal data

[Zn(C36H20N4S4)]	F(000) = 716
Mr = 702.17	Dx = 1.590 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 6.6009 (11) Å	Cell parameters from 25 reflections
b = 10.9678 (17) Å	θ = 10–15°
c = 20.278 (5) Å	µ = 1.16 mm^−1
β = 92.704 (16)°	T = 293 K
V = 1466.4 (5) Å^3	Plate, black
Z = 2	0.2 × 0.2 × 0.1 mm

Data collection

Enraf-Nonius CAD4 diffractometer	2163 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.037
Graphite monochromator	θmax = 25.6°, θmin = 2.1°
ω/2θ scans	h = 0→7
Absorption correction: ψ scan (North et al., 1968)	k = 0→13
Tmin = 0.75, Tmax = 0.86	l = −24→24
2879 measured reflections	2 standard reflections every 60 min
2637 independent reflections	intensity decay: none

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.040	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.121	H-atom parameters constrained
S = 1.15	w = 1/[σ^2(Fo^2) + (0.0438P)^2 + 2.6353P] where P = (Fo^2 + 2Fc^2)/3
2637 reflections	(Δ/σ)max = 0.005
239 parameters	Δρmax = 0.44 e Å^−3
8 restraints	Δρmin = −0.40 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Zn	1/2	1/2	0	0.03316 (19)
S1	0.5960 (9)	0.8250 (7)	0.2303 (3)	0.0565 (11)	0.615 (5)
S1'	0.250 (2)	0.9269 (11)	0.1579 (6)	0.056 (2)	0.386 (5)
S2	−0.0579 (4)	0.2251 (3)	0.16214 (13)	0.0564 (6)	0.719 (6)
S2'	−0.2896 (13)	0.2522 (12)	0.0532 (6)	0.080 (4)	0.281 (6)
N1	0.3080 (4)	0.5291 (3)	0.07163 (13)	0.0324 (6)
N2	0.6625 (4)	0.6516 (3)	0.02761 (14)	0.0324 (6)
C1	0.1453 (5)	0.4585 (3)	0.08613 (17)	0.0349 (8)
C2	0.0372 (6)	0.5163 (4)	0.13648 (19)	0.0436 (9)
H2	−0.0805	0.4878	0.1547	0.052*
C3	0.1360 (6)	0.6190 (3)	0.15267 (18)	0.0406 (9)
H3	0.0996	0.6750	0.1844	0.049*
C4	0.3072 (5)	0.6276 (3)	0.11260 (17)	0.0342 (8)
C5	0.4525 (5)	0.7211 (3)	0.11547 (16)	0.0340 (8)
C6	0.4296 (5)	0.8162 (3)	0.16527 (18)	0.0373 (8)
C7	0.279 (5)	0.903 (3)	0.1713 (13)	0.052 (6)	0.614 (6)
C7'	0.536 (5)	0.818 (4)	0.2225 (19)	0.056 (8)	0.386 (6)
C8	0.3097 (8)	0.9800 (4)	0.2284 (2)	0.0604 (12)
C9	0.4658 (8)	0.9354 (5)	0.2630 (2)	0.0615 (13)
C10	0.6131 (5)	0.7326 (3)	0.07504 (17)	0.0346 (8)
C11	0.7439 (6)	0.8373 (4)	0.0726 (2)	0.0451 (9)
H11	0.7422	0.9049	0.1003	0.054*
C12	0.8668 (6)	0.8200 (4)	0.0240 (2)	0.0456 (9)
H12	0.9669	0.8730	0.0107	0.055*
C13	0.8159 (5)	0.7035 (3)	−0.00424 (17)	0.0350 (8)
C14	0.0912 (5)	0.3470 (3)	0.05731 (17)	0.0350 (8)
C15	−0.0724 (6)	0.2758 (3)	0.08605 (18)	0.0378 (8)
C16	−0.256 (2)	0.2399 (14)	0.0557 (7)	0.045 (3)*	0.719 (6)
C16'	−0.026 (5)	0.204 (3)	0.1462 (16)	0.074 (13)*	0.281 (6)
C17	−0.3764 (7)	0.1705 (5)	0.1016 (3)	0.0707 (14)
C18	−0.2752 (9)	0.1552 (5)	0.1570 (3)	0.0724 (15)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn	0.0319 (3)	0.0352 (3)	0.0325 (3)	−0.0051 (2)	0.0031 (2)	−0.0070 (2)
S1	0.065 (3)	0.0603 (18)	0.0423 (15)	−0.0068 (18)	−0.0166 (17)	−0.0095 (13)
S1'	0.061 (4)	0.047 (4)	0.061 (5)	0.007 (3)	0.005 (4)	−0.016 (4)
S2	0.0664 (13)	0.0633 (13)	0.0393 (11)	−0.0168 (11)	0.0004 (10)	0.0099 (10)
S2'	0.036 (4)	0.101 (6)	0.101 (5)	−0.020 (4)	−0.011 (3)	0.032 (4)
N1	0.0326 (15)	0.0340 (16)	0.0307 (14)	−0.0036 (12)	0.0007 (12)	−0.0016 (12)
N2	0.0296 (14)	0.0338 (16)	0.0338 (15)	−0.0024 (12)	0.0001 (11)	−0.0066 (12)
C1	0.0350 (18)	0.0355 (18)	0.0343 (18)	−0.0019 (15)	0.0039 (14)	0.0005 (15)
C2	0.044 (2)	0.044 (2)	0.044 (2)	−0.0048 (17)	0.0152 (16)	−0.0052 (17)
C3	0.047 (2)	0.038 (2)	0.0371 (19)	−0.0017 (16)	0.0115 (16)	−0.0076 (16)
C4	0.0384 (19)	0.0310 (18)	0.0330 (18)	0.0012 (14)	0.0009 (14)	−0.0033 (14)
C5	0.0386 (19)	0.0321 (18)	0.0308 (17)	0.0014 (15)	−0.0027 (14)	−0.0027 (14)
C6	0.040 (2)	0.036 (2)	0.0360 (19)	−0.0029 (16)	0.0012 (15)	−0.0061 (15)
C7	0.055 (11)	0.054 (13)	0.046 (8)	−0.005 (8)	−0.002 (6)	−0.001 (6)
C7'	0.063 (19)	0.051 (9)	0.053 (15)	−0.001 (13)	−0.007 (12)	−0.032 (9)
C8	0.077 (3)	0.051 (3)	0.055 (3)	−0.007 (2)	0.027 (2)	−0.011 (2)
C9	0.083 (3)	0.059 (3)	0.044 (2)	−0.021 (3)	0.012 (2)	−0.013 (2)
C10	0.0352 (18)	0.0336 (19)	0.0347 (18)	−0.0027 (15)	−0.0013 (14)	−0.0066 (14)
C11	0.044 (2)	0.038 (2)	0.054 (2)	−0.0081 (17)	0.0065 (18)	−0.0158 (18)
C12	0.043 (2)	0.039 (2)	0.055 (2)	−0.0129 (17)	0.0089 (18)	−0.0115 (18)
C13	0.0304 (18)	0.0372 (19)	0.0371 (18)	−0.0032 (15)	−0.0010 (14)	−0.0032 (15)
C14	0.0330 (18)	0.0364 (19)	0.0353 (18)	−0.0017 (15)	0.0001 (14)	0.0005 (15)
C15	0.039 (2)	0.0372 (19)	0.0373 (19)	−0.0028 (16)	0.0040 (15)	−0.0018 (16)
C17	0.050 (3)	0.056 (3)	0.108 (4)	−0.012 (2)	0.018 (3)	0.003 (3)
C18	0.099 (4)	0.052 (3)	0.070 (3)	−0.013 (3)	0.036 (3)	0.004 (2)

Geometric parameters (Å, º)

Zn—N1^i	1.998 (3)	C4—C5	1.403 (5)
Zn—N1	1.998 (3)	C5—C10	1.376 (5)
Zn—N2^i	2.043 (3)	C5—C6	1.465 (5)
Zn—N2	2.043 (3)	C6—C7'	1.33 (3)
S1—C9	1.642 (10)	C6—C7	1.39 (3)
S1—C6	1.679 (6)	C7—C8	1.44 (3)
S1'—C8	1.577 (13)	C7'—C9	1.61 (4)
S1'—C6	1.700 (12)	C8—C9	1.314 (7)
S2—C18	1.625 (6)	C10—C11	1.439 (5)
S2—C15	1.639 (4)	C11—C12	1.319 (5)
S2'—C17	1.465 (14)	C12—C13	1.434 (5)
S2'—C15	1.574 (9)	C13—C14^i	1.379 (5)
N1—C4	1.363 (4)	C14—C13^i	1.379 (5)
N1—C1	1.367 (4)	C14—C15	1.474 (5)
N2—C13	1.352 (4)	C15—C16	1.391 (14)
N2—C10	1.361 (4)	C15—C16'	1.47 (4)
C1—C14	1.395 (5)	C16—C17	1.466 (17)
C1—C2	1.422 (5)	C16'—C18	1.75 (3)
C2—C3	1.335 (5)	C17—C18	1.291 (8)
C3—C4	1.426 (5)
N1^i—Zn—N1	180	C6—C7—C8	113.5 (18)
N1^i—Zn—N2^i	90.79 (11)	C6—C7'—C9	108 (2)
N1—Zn—N2^i	89.21 (11)	C9—C8—C7	106.7 (10)
N1^i—Zn—N2	89.21 (11)	C9—C8—S1'	120.3 (6)
N1—Zn—N2	90.79 (11)	C7—C8—S1'	15.1 (11)
N2^i—Zn—N2	180	C8—C9—C7'	105.2 (11)
C9—S1—C6	91.4 (4)	C8—C9—S1	118.1 (4)
C8—S1'—C6	92.3 (6)	C7'—C9—S1	15.0 (10)
C18—S2—C15	95.0 (3)	N2—C10—C5	125.3 (3)
C17—S2'—C15	101.2 (7)	N2—C10—C11	109.4 (3)
C4—N1—C1	107.0 (3)	C5—C10—C11	125.1 (3)
C4—N1—Zn	126.2 (2)	C12—C11—C10	107.5 (3)
C1—N1—Zn	126.7 (2)	C11—C12—C13	106.7 (3)
C13—N2—C10	105.8 (3)	N2—C13—C14^i	125.1 (3)
C13—N2—Zn	127.4 (2)	N2—C13—C12	110.5 (3)
C10—N2—Zn	125.8 (2)	C14^i—C13—C12	124.4 (3)
N1—C1—C14	126.5 (3)	C13^i—C14—C1	124.3 (3)
N1—C1—C2	109.2 (3)	C13^i—C14—C15	117.2 (3)
C14—C1—C2	124.3 (3)	C1—C14—C15	118.5 (3)
C3—C2—C1	107.2 (3)	C16—C15—C16'	111.1 (16)
C2—C3—C4	107.9 (3)	C16—C15—C14	127.9 (7)
N1—C4—C5	125.6 (3)	C16'—C15—C14	118.9 (14)
N1—C4—C3	108.7 (3)	C16—C15—S2'	7.2 (10)
C5—C4—C3	125.7 (3)	C16'—C15—S2'	114.4 (15)
C10—C5—C4	125.9 (3)	C14—C15—S2'	126.1 (5)
C10—C5—C6	116.9 (3)	C16—C15—S2	109.4 (7)
C4—C5—C6	117.1 (3)	C16'—C15—S2	15.7 (12)
C7'—C6—C7	105 (2)	C14—C15—S2	122.7 (3)
C7'—C6—C5	123.1 (17)	S2'—C15—S2	110.7 (5)
C7—C6—C5	130.4 (13)	C15—C16—C17	110.7 (10)
C7'—C6—S1	9.3 (19)	C15—C16'—C18	96.2 (19)
C7—C6—S1	109.7 (13)	C18—C17—S2'	117.4 (6)
C5—C6—S1	119.8 (4)	C18—C17—C16	110.3 (7)
C7'—C6—S1'	113.8 (18)	S2'—C17—C16	10.3 (8)
C7—C6—S1'	10.3 (14)	C17—C18—S2	114.4 (4)
C5—C6—S1'	122.9 (5)	C17—C18—C16'	107.5 (12)
S1—C6—S1'	117.2 (5)	S2—C18—C16'	14.9 (10)

Symmetry code: (i) −x+1, −y+1, −z.