CRYSTAL AND MOLECULAR STRUCTURE OF TRIS(N-METHYLAMINOETHANOLDITHIOCARBAMATO)ANTIMONY(III), BISMUTH(III) AND BIS(IODOBIS(N-METHYLAMINOETHANOLDITHIOCARBAMATO)ANTIMONY(III) AND VBS CALCULATIONS

摘要

Syntheses, crystal structures and VBS calculations for Sb(nmedtc)(3) (2), Bi(nmedtc)3 (2) and Sb-2(nmedtc)(4)I-2 (3) complexes (where nmedtc=N-methylaminoethanoldithiocarbamate) are reported. Crystallographic data: 1: C12H24N3O3S6Sb, monoclinic, P2(1)/c, a=11.352(2), b=17.674(3), c=11.272(2) Angstrom, beta=101.53(4)degrees, Z=4; 2: C12H24N3O3S6Bi, monoclinic, P2(1)/c, a=11.225(2), b=17.953(1), c=11.346(2) Angstrom, beta=102.28(3)degrees, Z=4; 3:C10H20I2N2O4Sb, triclinic, P1, a=10.356(3), b=11.047(2), c=10.009(3) Angstrom, alpha=80.12(4), beta=51.49(3), gamma=67.41 (3)degrees, Z=2. The present study has conclusively proved the presence of intermolecular hydrogen bonding in complexes 1 and 2 and ruled out the intramolecular hydrogen bonding predicted on the basis of an IR study. The anisobidenticity associated with the dithiocarbamate ligand is due to the presence of a lone pair of electrons on the central ion and the stereochemical requirements. Complex 3 exists as a dimer (Sb-I=3.359(5), Sb-I'=3.280(5) Angstrom) unlike its diethyl analogue which is a single polymeric strand with iodine bridges (Sb-I=3.516(2) Angstrom)). The valence bond sums (VBS) for all the complexes have been calculated and were found to be equivalent to 3.0+/-0.2 indicating the compromise between the steric and electronic requirements of the ligand and the central ion. [References: 23]