Copper(I) and silver(I) tertiary phosphines complexes: Synthesis, X-ray structures and spectroscopic characterization

Six new complexes, [Cu4I4(PPh2Cy)4]·2H2O (1), [CuI(PPhCy2)2] (2), [CuCl(PPhCy2)2] (3), and [CuBr(PPh3)3]·CH3CN (4), [Ag(PPhCy2)2(NO3)] (5), [Ag(PCy3)(NO3)]2 (6) [where Ph = phenyl, Cy = cyclohexyl], have been synthesized and structurally characterized by X-ray diffraction, IR absorption spectra and NMR spectroscopic studies (except complex 4). The X-ray diffraction analysis of complex (1), pseudo polymorph of complex [Cu4I4(PPh2Cy)4], reveals a stella quadrangula structure. The four corners of the cube are occupied by copper(I) atoms and four I atoms are present at the alternative corners of the cube, further more the copper(I) atoms are coordinated to a monodentate tertiary phosphine. Complexes (2) and (3) are isostructural with trigonal planar geometry around the copper(I) atom. The crystal structure of complex (4) is a pseudo polymorph of complex [CuBr(PPh3)3] and the geometrical environment around the copper(I) centre is distorted tetrahedral. In the AgI complexes (5) and (6), the central metal atoms have pseudo tetrahedral and trigonal planar geometry, respectively. Spectroscopic and microanalysis results are consistent with the single crystal X-ray diffraction studies.

Spectroscopic and X-ray diffraction studies of silver(I) and Cu(I) tertiary phosphine complexes reveal different geometrical environments around the central metal(I) ion. In the case of Cu(I), the geometry has been found to be highly dependent on the type of solvent of crystallization and to some extent on the type of the ligand. The Ag(I) complexes show either pseudo trigonal planar or pseudo tetrahedral geometry. The presence of hydrogen bonding interactions results in the formation of one- and two-dimensional chains and sheet-like structures.Figure optionsDownload as PowerPoint slide