Structure, spectra and electrical conductivity of copper(I) and silver(I) phosphino bridging mixed ligand complexes with coumarinyl Schiff base

Coordination polymers, [-M(L)(mu-dppp/dppb/dpph)-](n)(X)(n), (M = Cu(I), Ag(I); L, N-{(2-pyridyl)methyliden}-6-coumarin; X = NO3 or ClO4 ; dppp, 1,3-bis(diphenylphosphino) propane; dppb, 1,4-bis(diphenylphosphino)butane; dpph, 1,6-bis(diphenylphosphino)hexane) have been spectroscopically characterised and one of the complexes, [-Ag(L)(mu-dpph)-](n)(NO3)(n) has been structurally supported by single crystal X-ray diffraction measurement. The current(I)-voltage(V) characteristics of the coordination polymer lies in the semiconductor range (similar to 10(-3) S m(-1)) and non-ohmic in nature; the band gap lies below 3.0 eV. The complexes are emissive in the visible region (509-522 nm) and solid phase emission is more intensive than solution phase. The cyclic voltammetry shows Cu(II)/Cu(I) couple at 0.8-0.9 V and ligand reductions at -0.59 to -0.69 V and -0.92 to -1.38 V. The spectral and conducting properties have been explained by DFT computation of molecular functions using optimised structures. (C) 2017 Published by Elsevier B.V.