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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

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 (1998), 21, p. 5238-5245.
[Artikel, refereegranskad vetenskaplig]

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.

Nyckelord: copper(ii) dinuclear complex; electron-paramagnetic-res;, magnetostructural correlations; crystal-structures; bridging ligand;, azido; compound; end; perchlorate; exchange

Denna post skapades 2006-08-28. Senast ändrad 2014-11-10.
CPL Pubid: 10035


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