Syntheses and characterization of organostannoxanes derived from 2-chloroisonicotinic acid: Tetranuclear and hexanuclear

Abstract

Three types of ladder-like organostannoxanes, [(Me2Sn)2(μ3-O)L2]2 (1), [(n-Bu2Sn)2(μ3-O) (μ-OH)L]2 (2), [(Ph2Sn)2(μ3-O) (μ-OH)L]2 (3), [(Bz2Sn)2(μ3-O) (μ-OH)L]2 (4) and [(Me2Sn)2(μ3-O) (μ-OSnMe3)L]2 (5) (LH=2-chloroisonicotinic acid), have been synthesized by the treatment of 2-chloroisonicotinic acid and the corresponding diorganotin(IV) dichloride or trimethyltin(IV) chloride with sodium ethoxide in methanol. All of the complexes have been fully characterized by elemental analysis and FT-IR, NMR (1H, 13C, and 119Sn) spectroscopy, and particularly for 1, 2, 4 and 5, by X-ray crystallography. The structural analyses of 1, 2 and 4 reveal them to be tetranuclear, possessing two different ladder-like structures. Complexes 5 is also a ladder-like structure, but the essential difference from 1 to 4 is that complex 5 is a hexanuclear complex containing mixed tri- and dimethyltin units, where the central tetranuclear Sn4O4 motif is bridged by two μ-OSn(Me)3 groups. A series of O–H⋯O, O–H⋯N and C–H⋯Cl intermolecular hydrogen bonds in these complexes play an important function in the supramolecular aggregation, and 2D network structures are formed by these interactions.