Dinuclear and polynuclear copper(II) complexes with 3,3′-thiodipropionate and unprecedented coordination mode

Abstract

Three new coordination compounds, {[Cu(μ3-tdp)(phen)]·2H2O}n (1), {[Cu(μ3-tdp)(bipy)]·H2O}n (2), [Cu2(μ2-tdp)(phen)4](NO3)2·2H2O (3) [tdpH2=3,3′-thiodipropionic acid, phen=1,10-phenanthroline, bipy=2,2′-bipyridine] were synthesized and characterized by the IR spectroscopy, elemental analysis, magnetic measurements and single crystal X-ray diffraction. Thermal behaviors and thermochromic properties of the complexes were investigated in detail. Complexes 1 and 2 are 1D coordination polymers while complex 3 is dinuclear structure. In complexes 1 and 2, the tdp acts as a tridentate bridging ligand to coordinate the two different Cu(II) centers to form 1D chain, which are extended into a 3D networks by hydrogen bonding and π⋯π interactions. The 3,3′-thiodipropionate ligand adopts a new coordination mode in 3. Furthermore, complex 3 changed the color from blue to green at 140°C at solid state.