Electronic Structure of Complexes of the Ligand o-Phenylenebisdimethylarsine
<p>Various studies have been carried out to elucidate the detailed electronic structure of the unusual spin doublet complex [Ni(diars)<sub>2</sub>X<sub>2</sub>]Y (X = Cl, Br, -NCS; Y = CL, Br, -NCS, ClO<sub>4</sub><sup>-</sup>). An X-ray cryst...
| Summary: | <p>Various studies have been carried out to elucidate the detailed
electronic structure of the unusual spin doublet complex
[Ni(diars)<sub>2</sub>X<sub>2</sub>]Y (X = Cl, Br, -NCS; Y = CL, Br, -NCS, ClO<sub>4</sub><sup>-</sup>). An
X-ray crystallographic study has been done which confirmed its
coordination number of six. U.v. and visible spectra have been taken
of it and of other closely related cobalt and nickel complexes. Assignments
for the charge transfer and ligand field spectra are suggested.
ESR studies have been done in solution, powder, and single crystal
to extract the components of the ligand superhyperfine splitting
tensors. A semi-quantitative MO scheme, consistent with these
tensor values, has been used to explain some of the unusual properties
of this complex.</p>
<p>We have concluded from these studies that the energy level
ordering in Ni(diarsine)<sub>2</sub>X<sub>2</sub><sup>+</sup> is x<sup>2</sup> - y<sup>-</sup> < xz, yz < z<sup>2</sup> < xy
and that the ground state is <sup>2</sup>A<sub>g</sub>. The ground state is highly delocalized, consisting
of approximately 50% ligand character distributed over all six ligands.
The tipping of the benzene rings and the distortion of the axial ligands
permits an admixture of chlorine p<sub>x</sub> orbitals into the ground state
molecular orbital which serves to further stabilize this system.</p> |
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