Synthesis, characterization and hydrolytic stability of diorganotin(IV)bis(O-alkyl alkylphosphonate)s

Abstract

Diorganotinbis(O-alkyl alkylphosphonate)s, R2Sn(O2P(OR1)R1)2 [R1 = Me, R = Me (1), Et (2), n-Bu (3); R1 = Et, R = Me (4), Et (5), n-Bu (6)] have been synthesized from the reaction between dimethyl/diethyl/di-n-butyltin dichloride and dialkyl alkylphosphonates, (R1O)2P(O)R1, in a solvent-free medium (120 °C, 18 h). X-ray crystal structure of 1 reveals two independent molecules in the unit cell that form one-dimensional polymeric motifs by virtue of bridging bidentate phosphonate groups. The structural attribute of each polymeric chain represents an orderly infinite array of -[Sn-O-P-O-]2 8-membered puckered cyclic rings with hexa-coordinated tin atoms. The structure of 2 resembles that of 1 and exhibits nearly identical structural parameters. The presence of C–H···O hydrogen bonding interactions involving P-OMe and (or) phosphonate (P=O) groups in both 1 and 2 afford the formation of two- and three-dimensional structural motifs, respectively. The phase purity and structural integrity of the bulk sample of 1 upon exposure to water has been ascertained by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). All the compounds reported herein have been characterized by IR and multinuclear (1H, 13C, 31P, 119Sn) NMR spectral studies.