Five-coordinated Trigonal Bipyramidal Geometry Research Articles

Synthesis of organotin complexes with ligands of biological significance

A series of new 1:1 complexes of formula Ph 3SnCl·L for a range of ligands L, where L 1 = 2-HOC 6H 4CHNCH 2CO 2Et, L 2 = 2-HOC 6H 4C(CH 3)NCH 2CO 2Et, L 3 = 2HOC 6H 4CHNCH(CH 3)CO 2Me and L 4 = 2-HOC 10H 6CHNCH 2CO 2Et, have been prepared and characterized. A full X-ray crystal structure analysis of the compound chlorotriphenyl(ethyl N-salicylideneglycinate)tin(IV) (Ph 3SnCl·L 1) has been performed. The crystals are monoclinic, space group P21/ n, a = 8.191(4), b = 18.575(5), c = 17.983(7) Å, β = 101.41(4)°, V = 2682.1(18) Å 3, Z = 4, D calc = 1.455 Mg m −3, μ = 1.08 mm −1, final R = 4.3% for 1174 unique observed reflections. It was found that the ligand behaves as a unidentate and binds to the tin via the phenolic oxygen atom. The complexes have a five-coordinated trigonal bipyramidal geometry with the phenyl groups taking up the equatorial position around the tin atom.

Stereochemical Studies on Nickel(II) Complexes of N-O and N-S Donor Ligands

Abstract Nickel (II) complexes of benzylmethylketone semicarbazone (BMSC) and thiosemicarbazone(BMTSC) have been synthesised and characterised by elemental analysis, magnetic susceptibility measurements, i.r. and electronic spectral studies. All the semicarbazone complexes have been assigned six-coordinated octahedral geometry except Ni(BMSC)2SO4, which has five-coordinated trigonal bipyramidal geometry. Nickel(II) complexes with thiosemicarbazone show stereochemical variations depending upon the anion involved. The thiocynato complex possesses six-coordinated octahedral geometry whereas the chloro, bromo and iodo complexes posses five-coordinated trigonal bipyramidal geometry. The acetate and sulphato complexes are four-coordinated square planar and tetrahedral, respectively.

Copper(II) complexes of isobutyl methyl ketone semicarbazone

Copper(II) complexes of isobutyl methyl ketone semicarbazone have been prepared and characterised by magnetic moments, i.r., electronic and e.s.r. spectral studies. The complexes were found to have CuL2X2 and CuL2X2 · 2H2O compositions. The electronic and e.s.r. spectra suggest a five-coordinated trigonal bipyramidal geometry, for the CuL2X2 complexes, (X=Cl−, Br−, NO 3 − , and 1/2 SO 4 2− ) and six-coordinate octahedral geometry has been suggested for CuL2X2 · 2H2O (X=Cl−, Br−, NO 3 − , SO 4 2− ).