Hexameric organotincarboxylates with cyclic and drum structures

The interaction of 3,5-diisopropylsalicylic acid (DIPSA) with [(Bu2Sn)-Bu-n(O)] in benzene proceeds with elimination of water to produce stannoxane [(Bu2Sn)-Bu-n(3,5-(Pr2C6H2)-Pr-i(O)(COO))](6) (1), while an analogous reaction of DIPSA with [(BuSn)-Bu-n(O)(OH)] leads to the isolation of [nBuSn(O)(3,5-(Pr2C6H2)-Pr-i(OH)(COO))](6) (2). The new products have been characterized by elemental analysis and EI-MS, IR, and NMR (H-1, C-13, and Sn-119) spectroscopy. The molecular structure of 1 determined by single-crystal X-ray diffraction studies reveals a rare cyclic hexameric structure. The tin atoms are pentacoordinated with distorted trigonal-bipyramidal geometry. Complex 2 is also a hexameric cluster, but existing in a more common drum-like structure where the tin centers are hexacoordinated.