| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1991: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1990: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Research Abstract |
Electrochemical reductionsof isocyanide. complexes of platinum and palladium [M(RNC)_2(diphos)]^<2+> (1) (M = Pt, Pd ; diphos = PP_2P(CH_2)_nPPh_2, n = 1, 2, 3, 4) containing bidentate phosphine ligands were carried out. One electron reduction of (1) gave [M_2(RNC)_2(diphos)_2]^<2+>. The dppm (n = 1) complex has a trans-dppm structure, containing a mu-coordination to two metals and other diphosphine complexes (n = 2, 3, 4) have a chelate structure. A 1.5 electron reduction of (1) gave tri-nuclear complexes, [M_3(RNC)_4(diphos)_2]^<2+> (M = pt. Pd ; ri = 1, 2, 4) (2) and [Pt_3(RNC)_2(diphos)_2]^<2+> (n = 3) (3), depending on diphosphine ligands. In the complex (2), the dppm (n = 1) complex has a A-frame structure and other ones have a linear structure which two diphosphines chelated to two outer metals. The remarkable feature of (3) is the central platinum atom, which is bound only to other Pt atoms. To our knowledge, this is the first example of an electron-deficient tri-platinum compound. The electronic structure of the naked platinum of (3) was estimated by EHMO calculations of the model complexes, in which the charge separation of outer and central atoms was observed. This was confirmed by ESCA of (3). Reactions of dinuclear complexes with d^<10> ML_2 fragments led to an insertion of ML_2 one into a metal-metal bond to give homo-, heteronuclear or A-frame complexes. Reaction with RNC was also carried out.
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