SYNTHESIS AND CHARACTERIZATION OF ALKYLTIN(IV) AND ARYLTIN(IV) MONOTHIOCARBAMATES

The preparation of dialkyl- and diaryltin(IV) N,N′-dialkylmonothiocarbamates from the alkylammonium salt of the ligand and the appropriate diorganotin(IV) chlorides is described. The compounds R2Sn(R′2mtc)2 and Ph3Sn(R′2 mtc) (R = alkyl, aryl; R′2 = Me, Et; mtc = monothiocarbamate anion) are monomeric in dichloromethane or chloroform and are non-electrolytes in nitromethane. 1H spectra of CDCl3 CD2Cl2 and benzene solutions of R2Sn(R′2mtc)2 indicate that the dialkyltin(IV) moiety is non-linear (J119Sn-1HCH3 ca. 80 Hz) and that the N-alkyl substituents in the monothiocarbamate ligand are magnetically non-equivalent. Stereochemical non-rigidity of Me2Sn(Me2mtc)2 in CD2Cl2 is observed in the 1H nmr spectrum. Two isomeric species are observed with coalescence occurring at -30° to give a single species that shows restricted rotation of the N-methyl substituents. Further coalescence of these two equal intensity N-methyl signals occurs at 55 °C. A value of J119Sn--CH3(1J = 552 Hz) for the carbon bonded directly to tin in Et2Sn(Me2mtc)2 suggests that this type of compound involves six-coordination of the tin atom with SnS bonding being stronger than Sn-O bonding. The Ph3Sn(R′2mtc) species have distorted trigonal bipyramidal geometry with the oxygen of the bidentate monothiocarbamate in one of the axial positions. © 1979.