Ladder-like Organostannoxane: Synthesis and Crystal Structure of the Second Polymorph {[(C6H5)2Sn]2[(C6H5)2ClSn]2(μ3-O)2(μ2-OH)2}∙[DMF]2

A ladder-like organostannoxane identified as a polymorph of bis-[chloro-(m2-hydroxo)-(m3-oxo)-tetraphenyl-di-tin] dimethylformamide solvate, {[(C6H5)2Sn]2[(C6H5)2ClSn]2(μ3-O)2(μ2-OH)2}[DMF]2 (1), has been synthesized and structurally characterized by means of single-crystal X-ray diffraction analysis. Compound 1 crystallizes in the monoclinic space group P21/c with a = 23.4137(12) Å, b = 11.2525(6) Å, c = 20.2719(11) Å, β = 100.461(2)°, V = 5252.1(5) Å3, Z = 4 and Z’ = 1. The XRD discloses that the polymorph reported in this work is the full molecule which does not crystallize about any inversion center. Complex 1 exhibits a tetranuclear organotin(IV) ladder-like structure containing two external chlorides. The tetranuclear structure is comprised of a three-rung-staircase Sn4O4 cluster which consists of a ladder of four Sn2O2 units. The central Sn2O2 core forms dihedral angles of 4.00(7)° and 1.62(8)° with its two fused four-membered rings, describing a slightly bent ladder. This folding is further noticed with the dihedral angle between the two external Sn2O2 cores of 4.65(8)°. In the structure, two types of distorted trigonal bipyramid geometry at tin centers like-arrangement are disclosed. The most Sn–O bridges bond lengths describe a static trans effect affording dissymmetrical bonds. The dimethylformamide solvate molecules form a dihedral angle of 74.5(2)° and are interlinked to the tetranuclear organotin(IV) ladder via O–H···O hydrogen bond patterns. Additional inner C–H···Cl and C–H···O hydrogen bonds as well the C–H···O interactions are present. Moreover, the intermolecular C–H···O hydrogen bonds do not contribute to direct the crystal structure framework; they do not play an important function in forming a supramolecular architecture.