Crystal structure of di-n-butyl-bis(benzothiazole-2-thionato)tin(IV), Sn(C4H9)2(C7H4NS2)2

C22H26N2S4Sn, monoclinic, P121/c1 (no. 14), a = 10.821(1) Å, b = 18.663(2) Å, c = 12.712(2) Å, . = 91.731(3)°, V = 2566.0 Å, Z = 4, Rgt(F) = 0.054, wRref(F) = 0.142, T = 298 K. Source of material A mixture of dibutyltin oxide (1.5 g; 5 mmol) and 2-mercaptobenzthiazole (1.7 g, 10 mmol) was suspended in 100 ml of methanol in a 250 mL spherical flask. The mixture is refluxed for 3 h. A clear solution was then formed. Single crystals of the title compound are obtained by slow evaporation of a solution of this complex. Elemental analysis — found: C, 46.81 %; H, 4.34 %; N, 4.75 %. Calculated for C22H26N2S4Sn: C, 46.73 %; H, 4.63 %; N, 4.95 %. Experimental details One ethyl group was disordered and modeled in three positions (30, 40, 30 % occupied) and various restraints were applied to maintain geometry while maintaining disordered atoms isotropic. All other non-hydrogen atoms were refined anisotropically. Discussion The structure of the title compound has been reported previously by Xanthopoulou et. al. in the space group C2/c [1] with the structure determined at 173 K. In this paper we report a polymorph of the same compound determined in the space group P21/c at 298.K. The coordination is basically the same for both polymorphs with shorter bond distances for the low temperature determinationas expected. In both determinations the Sn atoms fall in general positions. There are also variations in the packing of the molecular units. The volume of the C2/c (Z = 8) cell determined at 173 K is 4879.0(4) Å compared with 2566(5) Å for this 298 K determination as P21/c (Z = 4). The title crystal structure contains a six-coordinate tin atom. Two deprotonated 2-mercapto-benzthiazole ligands via sulfur (d(Sn1—S1) = 2.524(2) Å, d(Sn1—S3) = 2.530(2) Å) and the two trans butyl groups (d(Sn1—C14A) = 2.127(8) Å, d(Sn1—C10) = 2.123(6) Å) are covalently linked to the metal. Weak Sn-N interactions (d(Sn-N) = 2.697 Å) complete the coordination sphere around the metal center via the nitrogen atoms N19 and N3 of the benzothiazole ring. The two chelating nitrogens occupy cis positions, as it is the case for the sulfur bonding. The Sn—C bond lengths are quite close to the ones previously described in the literature [2]. The same can be noted for the Sn—N bond distances, which are totally in agreement with [3]. The average Sn—N distance (2.697 Å) is midway between the sums of the van der Waals and covalent radii of Sn and N, 3.74 and 2.15 Å, respectively [4]. Z. Kristallogr. NCS 224 (2009) 293-294 / DOI 10.1524/ncrs.2009.0129 293 © by Oldenbourg Wissenschaftsverlag, München Crystal: colorless plate, size 0.07 × 0.21 × 0.36 mm Wavelength: Mo K0 radiation (0.71073 Å) &: 13.32 cm−1 Diffractometer, scan mode: Bruker SMART APEX, 1 2"max: 50.5° N(hkl)measured, N(hkl)unique: 27470, 4636 Criterion for Iobs, N(hkl)gt: Iobs > 2 !(Iobs), 2910 N(param)refined: 263 Programs: SHELXS-97 [5], SHELXL-97 [6], SHELXTL [7] Table 1. Data collection and handling. H(5) 4e 0.1639 0.3907 0.6595 0.114 H(6) 4e 0.0415 0.4657 0.7551 0.123 H(7) 4e −0.1512 0.4970 0.6919 0.128 H(8) 4e −0.2251 0.4566 0.5309 0.123 H(10A) 4e 0.3202 0.4001 0.3867 0.144 H(10B) 4e 0.4183 0.3708 0.4686 0.144 H(11A) 4e 0.4588 0.3729 0.2506 0.214 H(11B) 4e 0.5583 0.3518 0.3377 0.214 H(12A) 4e 0.4534 0.4924 0.3249 0.281 H(12B) 4e 0.5633 0.4702 0.4028 0.281 H(13A) 4e 0.6457 0.5209 0.2500 0.443 H(13B) 4e 0.5750 0.4639 0.1804 0.443 H(13C) 4e 0.6837 0.4400 0.2568 0.443 C(14A) 4e 0.30 0.261(4) 0.175(1) 0.487(2) 0.086 Table 2. Atomic coordinates and displacement parameters (in Å). Atom Site Occ. x y z Uiso