Crystal structure and properties of bis(benzimidazol-2-ylmethanol-N′O)(nitrato-NO)copper(II) nitrate monohydrate

Abstract

The crystal and molecular structures of the title complex, [Cu(Hbim)₂(NO₃)][NO₃]·H₂O, have been determined by single-crystal X-ray diffraction using counter methods. Crystal data: space group P, a= 8.562(4), b= 9.990(4), c= 13.546(1)Å, α= 90.16(2), β= 100.86(2)γ= 118.29(4)°, and Z= 2. Refinement carried out by full-matrix least squares has reached a conventional R factor of 0.025. The ligand environment of the copper atom corresponds approximately to a tetragonally distorted octahedron. The two Hbim ligands are bidentate, bonding via one of the nitrogen atoms and the methanol oxygen. A co-ordinated bidentate nitrate group completes the octahedron. Hydrogen-bonding interactions between the other, unco-ordinated, nitrate group, the water of crystallisation, and the [Cu(Hbim)₂(NO₃)]⁺ cations form an extensively linked polymeric network. High-precision magnetic-susceptibility measurements show that the polymeric structure is strictly magnetically dilute down to liquid-helium temperatures. This contrasts with literature data that imply slight antiferromagnetic interactions in this complex and three of its structural analogues.