Electrosynthesis and Reactions of Platinum Triad Metal Cluster Containing Bidentate Phosphine

异氰化物的电化学还原合成了含双齿膦配体的铂钯配合物[M（RNC）_2（diphos）]^<2+>（1）（M = Pt，Pd ; diphos = PP_2P（CH_2）_nPPh_2，n = 1，2，3，4）。（1）的单电子还原得到[M_2（RNC）_2（diphos）_2]^<2+>。dppm（n = 1）配合物具有反式-dppm结构，含有与两种金属的μ配位，并且其它二膦配合物（n = 2，3，4）具有螯合结构。（1）经1.5电子还原得到三核配合物[M_3（RNC）_4（diphos）_2]^<2+>（M = pt. Pd ; ri = 1，2，4）（2）和[Pt_3（RNC）_2（diphos）_2]^2+（n = 3）（3），取决于二膦配体。在配合物（2）中，dppm（n = 1）配合物具有A-骨架结构，其它配合物具有两个双膦配位于两个外金属的线型结构。（3）的显著特征是中心铂原子，它只与其他铂原子结合。据我们所知，这是缺电子三铂化合物的第一个例子。用EHMO方法计算了模型配合物的电子结构，观察到中心原子和外层原子的电荷分离。ESCA（3）证实了这一点。双核配合物与d^<10>ML_2片段反应，导致ML_2酮插入金属-金属键，得到同、异或A-框架配合物。还与RNC进行了反应。

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.