111905-45-4Relevant articles and documents
Crystal structure, magnetic properties, and orbital interactions of the [(μ-terephthalato)(ethylenediamine)diaquocopper(II)] zigzag chain
Bakalbassis, Evangelos G.,Bozopoulos, Anastasios P.,Mrozinski, Jerzy,Rentzeperis, Panayotis J.,Tsipis, Constantinos A.
, p. 529 - 532 (2008/10/08)
The crystal structure of [Cu(en)(H2O)2(TA)]n, where TA2- is the dianion of terephthalic acid and en is ethylenediamine, has been determined by direct X-ray methods. The complex crystallizes in the monoclinic space group P2/c with two formula units in a unit cell of dimensions a = 5.726 (1) ?, b = 8.806 (2) ?, c = 12.866 (4) ?, and β = 101.12 (1)° and densities d(calcd) = 1.693 × 103 kg·m-3 and d(exptl) = 1.694 × 103 kg·m-3. The structure was refined to conventional discrepancy factors of R = 0.041 and Rw = 0.049 for 1404 observed reflections. A crystallographic inversion center is located at the center of the benzene ring of the TA bridging ligand. The Cu centers, lying on 2-fold axes, are bridged by TA in a bis-unidentate fashion. Thus, infinite zigzag chains along the b axis and parallel to (102) are formed. The environment of each metal ion is distorted-elongated octahedral. Variable-temperature (4.2-295 K) magnetic susceptibility data are consistent with a chain structure, the intrachain exchange parameter J being 4.0 cm-1 and the interchain exchange parameter zJ′ being -7.0 cm-1. The EPR spectrum does not exhibit any evidence for a triplet state. An orbital interpretation of the coupling is proposed.
