Experimental Charge Density Analysis of a Gallium(I) N-Heterocyclic Carbene Analogue

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• 作者：Jacob Overgaard ; Cameron Jones ; Deepak Dange ; James A. Platts
• 刊名：Inorganic Chemistry
• 出版年：2011
• 出版时间：September 5, 2011
• 年：2011
• 卷：50
• 期：17
• 页码：8418-8426
• 全文大小：1085K
• 年卷期：v.50,no.17(September 5, 2011)
• ISSN：1520-510X

文摘

The experimental electron density of the only known example of a four-membered Ga(I) N-heterocyclic carbene analogue has been determined by multipole modeling of 90 K X-ray diffraction data and compared to theoretical data. In order to obtain a satisfactory model, it is necessary to modify the radial dependency of the core electrons of Ga using two separate scaling parameters for s,p- and d-electrons. Evidence for significant lone-pair density on Ga is found in the electron density and derived properties despite the partial positive charge of this atom. Static deformation density and molecular electrostatic potential clearly show a directional lone pair on Ga, whereas the Laplacian of the total electron density does not; this feature is, however, present in the Laplacian of the valence-only density. The Ga center also acts as an acceptor in four intramolecular C鈥揌路路路Ga contacts, whose nature is probed by density properties. Substantial covalent character is apparent in the Ga鈥揘 bonds, but no sign of donation from filled N p-orbitals to empty Ga p-orbitals is found, whereas 蟺-delocalization over the organic ligand is evident. This study highlights the utility of experimental charge density analysis as a technique to investigate the unusual bonding and electronic characteristics of low oxidation state/low coordinate p-block complexes.