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

Three types of ladder-like organostannoxanes, [(Me 2 Sn) 2 ( μ 3 -O)L 2 ] 2 ( 1 ), [(n-Bu 2 Sn) 2 ( μ 3 -O) ( μ -OH)L] 2 ( 2 ), [(Ph 2 Sn) 2 ( μ 3 -O) ( μ -OH)L] 2 ( 3 ), [(Bz 2 Sn) 2 ( μ 3 -O) ( μ -OH)L] 2 ( 4 ) and [(Me 2 Sn) 2 ( μ 3 -O) ( μ -OSnMe 3 )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 ( 1 H, 13 C, and 119 Sn) 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 Sn 4 O 4 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. [ABSTRACT FROM AUTHOR]