First Example of Equatorial−Equatorial Disposition of End-to-End Thiocyanate Bridges in a Polynuclear Copper(II) Complex and Its Relation to the Very Efficient Transmission of the Magnetic Interaction

Abstract

The preparation, X-ray structure, and spectroscopic and magnetic properties of [Cu(NCS)(μ-NCS)(Hmtpo)(H2O)]2 (where Hmtpo= 4H,7H-5-methyl-7-oxo[1,2,4]triazolo[1,5-a]pyrimidine) are described. This compound crystallizes in triclinic space group P1, with unit cell dimensions a = 8.408(2) A, b = 10.581(3) A, c = 7.927(2) A, α = 89.45(2)°, β = 77.44(2)°, γ = 69.75(2)°, and Z = 1 (binuclear unit). The structure was refined to final R = 0.033 for 2143 data with I ≥ 3.0σ(I). The structure is comprised of polymeric 1-D copper(II) complexes supported by two different kinds of thiocyanate bridges. The coordination geometry around each of the metal centers is a distorted octahedron (N3S + O + S*). The equatorial positions are occupied by a monodentate Hmtpo ligand, coordinated via N3, two bridging thiocyanate groups coordinated in a “symmetric” end-to-end fashion, and the N-donor atom of an asymmetric end-to-end thiocyanate bridge. Finally, a water molecule and a weakly bonded S-donor atom from the asymmetric end-t...