Preparation, Crystal Structures, and Spectroscopic and Redox Properties of Nickel(II) Complexes Containing Phosphane–(Amine or Quinoline)‐Type Hybrid Ligands and a Nickel(I) Complex Bearing 8‐(Diphenylphosphanyl)quinoline

Autor: Masaaki Kojima, Takayoshi Suzuki, Akira Hashimoto, Kazuo Kashiwabara, Hiroshi Yamaguchi, Hideo D. Takagi
Rok vydání: 2009
Předmět:
Zdroj: European Journal of Inorganic Chemistry. 2010:39-47
ISSN: 1099-0682
1434-1948
DOI: 10.1002/ejic.200900767
Popis: Nickel(II) complexes containing P―N-type bidentate hybrid ligands of 2-aminoethylphosphanes (RR'Pea; RR' = Ph 2 or MePh) or 8-quinolylphosphanes (RR'Pqn), namely [Ni(P―N) 2 ]-(BF 4 ) 2 [P―N = Ph 2 Pea (1), MePhPea (2), Ph 2 Pqn (3), or MePhPqn (4)] have been prepared, and their structural, spectroscopic, and electrochemical properties determined. The crystal structure analysis indicates that the 2-aminoethyl-phosphane complexes (1 and 2) have a square-planar coordination geometry around the Ni II center with a cis(P,P) configuration, whereas the 8-quinolylphosphane complexes (3 and 4) exhibit a severe tetrahedral distortion because of the steric repulsion between the ortho-H atoms in the mutually cis-positioned quinolyl rings. Complexes 1 and 2 maintain their diamagnetic square-planar four-coordinate structure on acetonitrile solution, whereas complexes 3 and 4 show paramagnetic behavior. Spectroscopic and electrochemical measurements suggest that the ligand-field strengths of these four P-N-type ligands increase in the order Ph 2 Pqn (3) < MePhPqn (4) < Ph 2 Pea (1) < MePhPea (2). The Ph 2 Pqn complex 3 is readily reduced by Zn powder to afford the corresponding nickel(I) complex [Ni(Ph 2 Pqn) 2 ]BF 4 (5). The crystal structure of complex 5 reveals that the Ni I ion adopts a distorted tetrahedral coordination geometry with slightly longer (= 0.05 A) Ni-P and Ni―N bond lengths than those in the corresponding Ni II complex 3.
Databáze: OpenAIRE
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