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

Three types of ladder-like organostannoxanes, [(Me2Sn)(2)(mu(3)-O)L-2](2) (1), [(n-Bu2Sn)(2)(mu(3)-O) (mu-OH)L](2) (2), i(Ph2Sn)(2)(mu(3)-0) (mu-OH)L](2) (3), [Bz(2)Sn)(2)(mu(3)-O) (mu-OH)L](2) (4) and [Me2Sn)(2)(mu(3)-O)(mu-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 (H-1, C-13, and Sn-119) 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 Sn404 motif is bridged by two mu--OSn(Me)(3) groups. A series of O-H center dot center dot center dot O, O-H center dot center dot center dot N and C-H center dot center dot center dot Cl intermolecular hydrogen bonds in these complexes play an important function in the supramolecular aggregation, and 2D network structures are formed by these interactions. (C) 2014 Published by Elsevier Ltd.