Structural and Magnetic Properties of Dimorpholinium Hexahalodicuprate(II) Salts: Study of two Planar Cu2X62- Dimers

The chloride and bromide analogues of the title compound were synthesized, and the X-ray crystal structure of the former compound was determined. Magnetic susceptibility and EPR studies were carried out on both compounds. The crystal structure of the chloride salt yielded a triclinic structure, space group P̅1, with a = 7.414 (2) Å,b = 8.686 (2) Å, c = 14.766 (4) Å, α = 79.16 (2)°, β = 82.20 (2)°, γ = 74.19 (2)°, Z = 2, dcalcd = 1.94 g/cm3, and R = 0.0527. The structure consists of isolated planar dimers with each copper atom semicoordinated to two oxygen atoms in what may be described, on the average, as a 4+2 elongated octahedral geometry. The magnetic exchange interaction in the two compounds is predominantly antiferromagnetic with a singlet-triplet splitting energy of J/k = -43.5 (1) K for the chloride and J/k = -131 (2) K for the bromide. EPR and magnetic studies on both compounds indicate that magnetically these compounds are not isolated dimers. EPR studies supplement both the structural and magnetic studies. © 1988, American Chemical Society. All rights reserved.