Syntheses, NMR (~1H, ~(31)P) Spectroscopy And Crystal Structures Of Complexes Of Copper(I) Halides With Isatin-3-Thiosemicarbazones

摘要

Isatin-3-thiosemicarbazones (H_2itsc) react with copper(I) bromide or iodide in a 1: 1 mol ratio in acetonitrile in the presence of two moles of Ph3P to form tetrahedral monomeric complexes of composition [CuX(eta~1-S-H_2itsc)(Ph_3P)_2], X = Br (I), I (2). These complexes, which have been characterized by single-crystal structure determinations, are unlike the iodo-bridged dinuclear complex of copper(I) iodide of pyrrole-2-carbaldehydethiosemicarbazone (Hptsc), namely [Cu_2(mu-I)_2(eta'-S-Hptsc)_2(PPh_3)_2] (3). In both 1 and 2, the geometry around Cu is distorted tetrahedral with P-Cu-P bond angles being 121.97(3) (1) and 124.09(5)deg (2). Proton NMR confirms that thiosemicarbazone coordinates to the Cu atom as a neutral ligand, and ~(31)PNMR shows that there is no dissociation of the complexes in solution; coordination shift values suggest that Ph_3P stabilizes the Cu(I) oxidation state.