Self-assembly of triorganotin(IV) or diorganotin(IV) moieties and 2-methylpyrazine-5-acid: Syntheses, characterizations and crystal structures of monomeric, polymeric or tetranuclear macrocyclic compounds

A series of diorganotin(IV) and triorganotin(IV) compounds of the type [R2Sn(pca)2ClSnR3]2 (Rdouble bond; length as m-dashPhCH21, 2-ClC6H4CH22, 2-FC6H4CH23, 4-FC6H4CH24, 4-CNC6H4CH25, 4-ClC6H4CH26, 2,4-Cl2C6H3CH27; Hpcadouble bond; length as m-dash2-methylpyrazine-5-acid), [(nBu)3Sn(pca)]∞8, [(CH3)2Cl2Sn(pca)Sn(CH3)2(pca)]∞9, {[(nBu)2Sn(pca)]2O}210 and {[Ph2Sn(pca)]3O2[Ph2Sn(OCH3)]} 11 have been obtained by reactions of 2-methylpyrazine-5-acid with triorganotin(IV) chloride, diorganotin(IV) dichloride, and diorganotin(IV) oxide. All compounds were characterized by elemental, IR, and NMR spectra analyses. The crystal structure of compounds 1, 8–11 were determined by X-ray single crystal diffraction, which revealed that compound 1 was tetranuclear macrocyclic structures with seven-coordinate and five-coordinate tin atoms, compounds 8 and 9 were polymeric chain structures with five-coordinate and seven-coordinate tin atoms, compounds 10 and 11 were monomeric structures with six-coordinate and five-coordinate tin atoms.