Structural and magnetic properties of copper(II) dimers bridged by oxalate, azide, and cyanide ions; X-ray structures of [Cu2{EtN(CH2CH2NEt2)2}2(C2O4)][BPh4]2 and [Cu2{MeN(CH2CH2NMe2)2}2(N3)2][BPh4]2. The role of the transition-metal ion ground state in magnetic exchange interactions
Abstract
Variable-temperature (4·2–270K) magnetic susceptibility, e.s.r., and single-crystal X-ray crystallographic data are presented to show that a predominantly dz2 CuII ground state can lead to appreciable magnetic exchange interactions via the extended bridges in [Cu2(Et5dien)2(C2O4)][BPh4]2, [Cu2(Me5dien)2(N3)2][BPh4]2, and [Cu2(tren)2(CN)][PF6]3[Et5dien = EtN(CH2CH2NEt2)2, Me5dien = MeN(CH2CH2NMe2)2, and tren = N(CH2CH2NH2)3].