Crystal structure of catena-poly[dibenzyl-dichlorido-(μ2-[4,4′-bipyridine]1,1′-dioxide-κ2O:O′)tin(IV)], C24H22Cl2N2O2Sn

Abstract C24H22Cl2N2O2Sn, monoclinic, P21/n (no. 14), a = 12.6418(1) Å, b = 13.2422(1) Å, c = 13.6364(1) Å, β = 104.6370(10)°, V = 2208.72(3) Å3, Z = 4, Rgt(F) = 0.0292, wRref(F2) = 0.0778, T = 100(2) K.

CrysAlis PRO [1], SHELX [2,3], WinGX/ORTEP [4] Source of material General: The melting point of the compound was measured on a Electrothermal digital melting point apparatus and was uncorrected.The elemental analysis was performed on a Perkin-Elmer EA2400 CHN analyser.The 1 H NMR spectrum was recorded in DMSO-d 6 solution on a Jeol JNM-ECA 400 MHz NMR spectrometer with chemical shifts relative to tetramethylsilane.Synthesis: Dibenzyltin dichloride was synthesized by the direct reaction of benzyl chloride (Merck) and metallic tin powder (Merck) in toluene according to a literature procedure [5].Dibenzyltin dichloride (0.37 g, 1 mmol) and 4,4′bipyridine N,N′-dioxide di-hydrate (Sigma Aldrich, 0.11 g, 0.5 mmol) were dissolved in methanol (25 mL) and the mixture was refluxed for 2 h.After filtration, the filtrate was evaporated slowly until pale-yellow crystals were formed.The crystals were filtered, washed with a minimum amount of ethanol and air-dried.Yield: 0.34 g (60.7%).M.pt: 469-471 K.

Experimental details
The C-bound H atoms were geometrically placed (C-H = 0.95-0.99Å) and refined as riding with U iso (H) = 1.2Ueq(C).

Comment
Crystal structure determinations of neutral organotin compounds of 4,4′-bipyridine N,N′-dioxide (L; systematic name: [4,4′-bipyridine]1,1′-dioxide) are rare, being restricted to the cis-and trans-isomers of octahedral (4-fluorobenzyl) 2 SnCl 2 (L) [6].Each of these is a one-dimensional coordination polymer with the topology being dependent on the specific isomer.Thus, while trans-isomer gives rise to a linear chain, the topology of the chain formed by the cis-isomer is helical [6].In continuation of these structural studies, the title compound, also a coordination polymer, [benzyl 2 SnCl 2 (L)]n, (I), was investigated by X-ray crystallographic methods.
The molecular structure of the asymmetric unit of (I) is shown in the upper view of the figure (70% displacement ellipsoids).The coordination geometry is based on an octahedron with the donor set defined by two methylenecarbon atoms of the benzyl substituents, two chlorido ligands and two oxido-oxygen atoms derived from two different 4,4′bipyridine N,N′-dioxide molecules, each of which is bidentate bridging.The cis-disposed Sn-Cl bond lengths are disparate with Sn-Cl1 of 2.5007(8) Å being shorter than Sn-Cl2 of 2.5101(8) Å.This is despite the oxido-oxygen atoms are each trans to a chloride [Cl1-Sn-O1 = 172.02(6)°andCl2-Sn-O2 i = 172.33(6)°for symmetry operation (i) 1 + x, y, z] form experimentally equivalent Sn-O bonds, i.e.Sn-O1 = 2.306(2) Å and Sn-O2 i = 2.317(2) Å.In the same way, non-systematic variations are noted in the Sn-C bond lengths, with Sn-C1 of 2.157(3) Å being shorter than Sn-C8 of 2.196(3) Å; C1-Sn-C8 = 170.03(14)°.Non-systematic variations in geometric parameters are notorius in organotin chemistry and DFT calculations indicate these arise as a result of the crystalline manifold rather than any chemical reasons [7,8].The maximum deviation from a regular octahedral geometry in terms of cis-angles is seen in the O1-Sn-O2 i angle of 80.18(8)°.As seen from the lower part of the figure, the resulting supramolecular chain has a linear topology, being propagated by translational symmetry.
The crystal of (I) features pyridyl-C-H interactions to sustain a three-dimensional architecture.

Table 1 :
Data collection and handling.