Spin density maps in the triplet ground state of Cu-2(t-Bupy)(4)(N-3)(2) (ClO4)(2) (t-bupy = p-tert-butylpyridine): A polarized neutron diffraction study
Artikel i vetenskaplig tidskrift, 1998

This paper is devoted to the determination of the spin distribution in the spin triplet ground state of [Cu-2(t-Bupy)(4)(N-3)(2)](ClO4)(2), With t-Bupy = p-tert-butylpyridine. The crystal structure, previously solved at room temperature from X-ray diffraction, has been redetermined at 18 K from unpolarized neutron diffraction. The structure consists of binuclear cations in which Cu2+ ions are doubly bridged by azido groups in the 1,1-fashion, and noncoordinated perchlorate anions. The experimental spin distribution has been determined from polarized neutron diffraction (PND) at 1.6 K under 50 kOe. The spin populations have been found to be strongly positive on the Cu2+ ions, weakly positive on the terminal and bridging nitrogen atoms of the azido groups as well as on the nitrogen atoms of the t-Bupy ligands, and weakly negative on the central nitrogen atoms of the N-3(-) bridges. The PND results have been discussed. The spin distribution in [Cu-2(t-Bupy)(4)(N-3)2](ClO4)(2) has been analyzed as resulting from a spin delocalization from the Cu2+ ions toward the azido bridges, to which a spin polarization effect within the azido pi orbitals is superimposed. The experimental data have been compared to the results of DFT calculations. The spin density map is qualitatively reproduced; however, the DFT calculations overestimate the spin delocalization from the Cu2+ ions toward the peripheral and bridging ligands.

magnetostructural correlations








bridging ligand

copper(ii) dinuclear complex


M. A. Aebersold

B. Gillon

O. Plantevin

L. Pardi

O. Kahn

P. Bergerat

I. von Seggern

F. Tuczek

Lars Öhrström

Institutionen för oorganisk kemi

A. Grand

E. Lelievre-Berna

Journal of the American Chemical Society

Vol. 120 5238-5245