Complexes of TaOCl3 and TaSCl3 with Neutral N- and O-donor ligands - synthesis, properties and comparison with the niobium analogues

The white complexes, [TaOCl3(OPPh3)2], [TaOCl3(L-L)] (L-L = 1,10-phenanthroline, 2,2’-bipyridyl, Ph2P(O)CH2P(O)Ph2, Ph2P(O)CH2CH2P(O)Ph2 and o-C6H4(P(O)Ph2)2), have been prepared from TaCl5, O(SiMe3)2 and the ligands in anhydrous CH2Cl2 solution. The corresponding yellow [TaSCl3(OPPh3)2] and [TaSCl3(L-L)] were made similarly using S(SiMe3)2. The complexes have been characterised by microanalysis, IR and NMR (1H, 31P{1H}) spectroscopy. X-ray crystal structures have been obtained for [TaOCl3(1,10-phen)], [TaSCl3(1,10-phen)], [TaOCl3{o-C6H4(P(O)Ph2)2}], [TaSCl3(OPPh3)2], [TaSCl3{Ph2P(O)CH2CH2P(O)Ph2}] and [TaSCl3(MeCN)2], which all contain mer-chlorines and with the neutral ligands trans to O/Cl or S/Cl. The structure of the Ta(V) dimer [Cl2S(1,10-phen)Ta(µ-O)Ta(1,10-phen)SCl2], formed by trace hydrolysis, is also reported. Comparisons between the complexes of TaOCl3 and TaSCl3 and their niobium analogues are discussed