title: Synthesis, characterization and selective de-esterification of diorganotinbis(O-methylphosphite)s.
abstract: A one-pot reaction between di-n-butyl/diethyl/dimethyltin dichloride and dimethylphosphite (MeO)2P(O)H in a solvent free medium (120 °C, 18 h) proceeds smoothly to yield the corresponding diorganotinbis(O-methylphosphite)s, [R2Sn(OP(O)(OMe)H)2]n [R = n-Bu (1), Et (2), Me (3)]. The identity of 1-3 has been established by IR, multinuclear ((1)H, (13)C, (31)P, (119)Sn) NMR, powder X-ray diffraction (PXRD) and X-ray crystallography. The coordination framework in each case adopts a one-dimensional structural motif comprising an infinite array of eight-membered [Sn-O-P-O]2 cyclic rings, with the phosphite ligands acting in a bridging bidentate mode. The structures are extended to two- (for 1) and three-dimensional (for 2, 3) assemblies by virtue of C-H···O hydrogen bonding interactions. The stability and bulk properties of 1-3 have been investigated upon exposure to humid laboratory conditions using (1)H NMR, PXRD and SEM studies. The results conform to a unique chemical modification of 1-3 involving selective de-esterification of P-OMe bonds and the formation of corresponding diorganotinbis(phosphite)s, [R2Sn(OP(O)(OH)H)2]n (1a-3a), as insoluble solids. The results obtained from impedance studies (σ = 10(-4)-10(-6) S cm(-1); E(a) = 0.33-0.42 eV) reveal potential application of 1a-3a as proton conducting materials.
authors.affiliation: Department of Chemistry, Indian Institute of Technology, Hauz Khas, New Delhi, India. shankar@chemistry.iitd.ac.in.
authors.forename: Ravi
authors.initials: R
authors.lastname: Shankar
authors.forename: Meenal
authors.initials: M
authors.lastname: Asija
authors.forename: Nisha
authors.initials: N
authors.lastname: Singla
authors.forename: Suddhastwa
authors.initials: S
authors.lastname: Basu
authors.forename: Gabriele
authors.initials: G
authors.lastname: Kociok-Köhn
authors.forename: Kieran C
authors.initials: KC
authors.lastname: Molloy