Some nickel(II) complexes containing the ligands cyclohexyldiphenylphosphine, dicyclohexylphenylphosphine and tricyclohexylphosphine
1971; Elsevier BV; Volume: 5; Linguagem: Inglês
10.1016/s0020-1693(00)95959-0
ISSN1873-3255
Autores Tópico(s)Organometallic Complex Synthesis and Catalysis
ResumoThe properties and structural characterization of some nickel(II) complexes of the general type Ni[PPhnCy3−n]X2 (where Cy=Cyclohexyl, Ph=phenyl and X=Cl−, Br−, I−, NCS−) are reported. The thiocyanate complexes are diamagnetic both in solution and in the solid state and have been assigned trans-planar configuration. Spectral and magnetic evidence that with the halo complexes, planar⇆htetrahedral equilibrium is established in solution. In general, the amount of the paramagnetic tetrahedral isomer follows the order PPh3>PPh2Cy>PPhCy2>PCy3 for a given halide, and I−>Br−>Cl− for a given phosphine. In addition, the tetrahedral form is favored in polar solvents. In the solid state, depending on the condition of crystallization, several of the halo complexes were isolated both as the paramagnetic tetrahedral isomer, and the diamagnetic square-planar isomer. These results are discussed in terms of the electronic and steric effects of the phosphine ligands.
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