Synthesis, Structure, and Electrochemistry of Di- and Zerovalent Nickel, Palladium, and Platinum Monomers and Dimers Derived from an Enantiopure (<i>S</i>,<i>S</i>)-Tetra(tertiary Phosphine)
作者:Heather J. Kitto、A. David Rae、Richard D. Webster、Anthony C. Willis、S. Bruce Wild
DOI:10.1021/ic700912q
日期:2007.9.1
degrees C were interpreted according to reversible coordination of acetonitrile to the nickel(I) and nickel(0) complexes. The divalent palladium and platinum complexes [M(R,R)-tetraphos}](PF6)2 and [M2(R,R)-tetraphos}2](OTf)4 have been prepared. The reduction potentials for the complexes [M(R,R)-tetraphos}](PF6)2 increase in the order nickel(II) < palladium(II) < platinum(II). The reaction of (S,S)-tetraphos
(S,S)-1,1,4,7,10,10-六苯基-1,4,7,10-四磷烷(S,S)-tetraphos与六(水)镍(II)反应在三氟甲磺酸三甲基甲硅烷基酯(TMSOTf)的二氯甲烷溶液中氯化,得到黄色方形-平面络合物[Ni (R,R)-tetraphos}](OTf)2,在晶体学上已表征为方形-金字塔形乙腈加合物[Ni(NCMe)(R,R)-tetraphos}] OTf。在20°C的二氯甲烷和乙腈中的镍(II)配合物的循环伏安图显示,在负电势下,氧化(E(p)(ox))和还原(E(p)(red))峰分离的二次还原过程类似于在相同条件下观察到的二茂铁/二茂铁的那些,表明两个单电子步骤。根据乙腈与镍(I)和镍(0)配合物的可逆配位,解释了低于-20摄氏度的温度下乙腈中二价镍配合物的循环伏安数据。已经制备了二价钯和铂络合物[M (R,R)-四磷}](PF6)2和[M2 (R,R-四磷}