Synthesis and characterization of bidentate organotin Lewis acid derivatives containing bis(pyrazol-1-yl)alkanes: X-ray crystal structure of PhBr2(L)SnCH2SnPhBr2 (L = bis(4-chloropyrazol-1-yl)methane)

摘要

The reaction between bis(dibromophenylstannyl)methane, [CH2(SnPhBr2)(2)], with bis(pyrazol-1-yl)alkanes, [(CH2)(n)Pz(2)] (n = 1 or 2; Pz = substituted pyrazole) in a 1: 1 or 1:2 ratio yields only 1: 1 adducts of PhBr2[(CH2)(n)Pz(2)]SnCH2SnPhBr2, which have been confirmed by elemental analysis, H-1 NMR and IR spectroscopy. The electronic and steric characteristics of substituents on the pyrazole rings markedly influence the donating ability of bis(pyrazol-1-yl)alkanes to the bidentate organotin Lewis acid acceptor. The investigations on the reaction of the adducts with DMSO and NMR spectra of the adducts show the weak interactions between ligands and the bidentate organotin Lewis acid acceptor. X-Ray analysis of PhBr2(CH2(4-ClPZ)(2))SnCH2SnPhBr2 showed that bis(4-chloropyrazol-1-yl)methane acts as a chelating bidentate ligand to only one tin atom. (C) 2002 Elsevier Science Ltd. All rights reserved. [References: 30]