Synthesis, spectroscopic characterization and crystal structures of diorganotin (IV) complexes of 2-N-propyl and 2-N-benzyl-amino-1-cyclopentene-1-carbodithioates

Six new diorganotin (IV) complexes, [Ph2Sn(Pr-ACDA)2] 1, [Bu2Sn(Pr-ACDA)2] 2, [Ph2Sn(Bz-ACDA)2] 3, [Bu2Sn(Bz-ACDA)2] 4, [Me2Sn(Bz-ACDA)2] 5, [t-Bu2Sn(Bz-ACDA)2] 6 are reported (where ACDA is the 2-amino-1-cyclopentene-1-carbodithioic anion). The diorganotin complexes were prepared from reactions between sodium N-propyl and N-benzyl-2-amino-1-cyclopentene-1-carbodithioate with R2SnCl2 (R=Ph, Bu, Me, tBu) in a 2:1 ratio. All complexes were characterized by elemental analysis, IR, multinuclear NMR (1H, 13C, and 119Sn), FAB+ mass spectrometry and in the case of 2, 3 and 5 by single-crystal X-ray diffraction. Both solution and solid state studies show that dithioacid ligands are coordinated to tin in an aniso-bidentate manner. In all complexes coordination takes place only through the carbodithioate moieties. 119Sn NMR data indicate pentacoordination of tin in solution. The tin coordination geometry, in all three structures is a highly distorted octahedral geometry, where tin is bonded to the four sulfur atoms of the two aniso-bidentate carbodithioate ligands in the equatorial plane and the organic substituents on tin atom in trans-positions. In addition, the crystal structures show the presence of N-H...S hydrogen bonding contacts.