Ferromagnetic Interaction in an Asymmetric End-to-End Azido Double-Bridged Copper(II) Dinuclear Complex: A Combined Structure, Magnetic, Polarized Neutron Diffraction and Theoretical Study
✍ Scribed by Christophe Aronica; Erwann Jeanneau; Hani El Moll; Dominique Luneau; Béatrice Gillon; Antoine Goujon; Alain Cousson; Maria Angels Carvajal; Vincent Robert
- Publisher
- John Wiley and Sons
- Year
- 2007
- Tongue
- English
- Weight
- 243 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0947-6539
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
A new end‐to‐end azido double‐bridged copper(II) complex [Cu~2~L~2~(N~3~)~2~] (1) was synthesized and characterized (L=1,1,1‐trifluoro‐7‐(dimethylamino)‐4‐methyl‐5‐aza‐3‐hepten‐2‐onato). Despite the rather long CuCu distance (5.105(1) Å), the magnetic interaction is ferromagnetic with J= +16 cm^−1^ (H=−JS~1~S~2~), a value that has been confirmed by DFT and high‐level correlated ab initio calculations. The spin distribution was studied by using the results from polarized neutron diffraction. This is the first such study on an end‐to‐end system. The experimental spin density was found to be localized mainly on the copper(II) ions, with a small degree of delocalization on the ligand (L) and terminal azido nitrogens. There was zero delocalization on the central nitrogen, in agreement with DFT calculations. Such a picture corresponds to an important contribution of the d orbital and a small population of the d orbital, in agreement with our calculations. Based on a correlated wavefunction analysis, the ferromagnetic behavior results from a dominant double spin polarization contribution and vanishingly small ionic forms.