Cyano-bridged heterometallic complexes directed by binuclear copper units

Abstract

A tridentate N,O-donor, 1,3-bis(3,5-dimethylpyrazol-1-yl)propan-2-ol (HL), has been employed to synthesize cyano-bridged complexes and six heterometallic complexes with [Cu2L2] or [Cu2L2(H2O)] have been generated by using slow diffusion. With slightly different synthetic conditions, subtle variations in the crystal structures of the complexes occur. [Cu2L2][Fe(CN)5NO]⋅2CH3CN (1) and [Cu2L2][Fe(CN)5NO]⋅H2O (2), synthesized in different solvents with the same precursor, exhibit a very similar 1-D zig-zag chain motif in different space groups, P21 and P-1, respectively. Similarly, [Cu2L2(H2O)][Ni(CN)4]·H2O (3) and [Cu2L2][Ni(CN)4]⋅H2O (4), synthesized with different diffusion methods, feature trinuclear and 1-D zig-zag chain structures, which indicates a solvent effect of water. [Cu2L2(H2O)]2[Cu2L2][W(CN)8]2·8H2O (5) is composed of two [W(CN)8]3− and three [Cu2L2]2+ units. In the octanuclear structure, [W(CN)8]3− and one [Cu2L2]2+ bridge and the other two [Cu2L2]2+ are terminal to stop extending the 1-D structure. [CuL][Ag2.24Cu0.76(CN)4] (6) exhibits a discrete structure, in which the complex anion forms a unique 2-D 63 network and the complex cations are inserted in the space between two adjacent networks. Magnetic properties of 1 and 4 are discussed.