CRYSTAL AND MOLECULAR-STRUCTURE AND MAGNETISM OF THYL)SALICYLIDENAMINATO)COPPER(II)]-WATER-METHANOL

The crystal and molecular structure of hyl)salicylidenaminato)copper-( II)-water-methanol, [Cu2(SalNEt2)2(C8H4O4)].H2O.CH3OH, where SalNEt2 = N-(2-(diethylamino)ethyl)-salicylidenaminate, has been determined by single-crystal X-ray analysis. The compound crystallizes in the monocl inic system, space group P2(1)/c, with a = 7.379(1) angstrom, b = 7.54 6(2) angstrom, c = 33.783(6) angstrom, and beta = 100.40(1)-degrees. I n the molecular structure of this centrosymmetric compound the two equ ivalent copper(II) ions are bridged by the terephthalato ligand coordi nated in an amphimonodentate mode. The local geometry around both copp er(II) ions is square planar, whereas two noncoordinated molecules, na mely a water and a methanol molecule, are also present. The fitting of the variable-temperature magnetic susceptibility data to the HDVV (H = 2JS1S2), S1 = S2 = 1/2, spin exchange model yields a 2J value of 0.6 cm-1. The results of extended Huckel calculations on a model compound are consistent with the existense of accidental orthogonality between the magnetic orbitals.