Synthesis, structure and hydrolysis studies of pseudostannatranes: Kinetic studies of a hexanuclear tin(IV) hydroxo-cluster formed via reverse Kocheshkov reaction and partial hydrolysis of pseudostannatrane

Abstract

The structural and synthetic aspects of novel mononuclear pseudostannatranes and a hexanuclear tin(IV) hydroxo-cluster have been reported. The reaction of the bis-phenolate aminoethanol tripodal ligand N(CH2CH2OH){CH2(2,4-di-t-Bu-C6H2OH)}2 (H3L) with BuSnCl3, PhSnCl3 and SnCl4 yielded the mononuclear pseudostannatranes [N(CH2CH2O){CH2(2,4-di-t-Bu-C6H2O)}2Sn(n-Bu)H2O] (1), [N(CH2CH2O) {CH2(2,4-di-t-Bu-C6H2O)}2Sn(Ph)EtOH] (2) and [N(CH2CH2OH){CH2(2,4-di-t-Bu-C6H2O)}2Sn(Cl)2] (3), respectively. The reaction of the ligand with PhSnCl3 using triethylamine as a base produced the reverse Kocheshkov product [N(CH2CH2OH){CH2(2,4-di-t-Bu-C6H2O)}2Sn(Cl)2].1/3NEt3 (3.1/3NEt3), which on partial hydrolysis yielded the hexanuclear tin(IV) hydroxo-cluster [N(CH2CH2O){CH2(2,4-di-t-BuC6H2O)}2SnCl]2{(OH)3SnPh(OH)2SnPh(OH)3}[SnN(CH2 CH2O){CH2(2,4-di-t-Bu-C6H2O)}2]2 (4). The synthesized compounds were characterized by elemental analysis, infrared spectroscopy, multi-nuclear NMR spectroscopy, electrospray ionization mass spectrometry and single-crystal X-ray diffraction. In addition, vital facts regarding the kinetics of the partial hydrolysis of the reverse Kocheshkov product to form the hydroxo cluster were explained by 119Sn NMR spectroscopy.