Bimetallic Cluster Complexes: The Synthesis, Structures, and Bonding of Ruthenium Carbonyl Cluster Complexes Containing Palladium and Platinum with the Bulky Tri-tert-butyl-phosphine Ligand

The bis-phosphine compounds M(PBut3)2, M = Pd and Pt, readily eliminate one PBut3 ligand
and transfer MPBut3 groups to the ruthenium−ruthenium bonds in the compounds Ru3(CO)12, Ru6(CO)17(μ6-C), and Ru6(CO)14(η6-C6H6)(μ6-C) without displacement of any of the ligands on the ruthenium complexes.
The new compounds, Ru3(CO)12[Pd(PBut3)]3, 10, and Ru6(CO)17(μ6-C)[Pd(PBut3)]2, 11, Ru6(CO)17(μ6-C)[Pt(PBut3)]n, n = 1 (12), n = 2 (13), and Ru6(CO)14(η6-C6H6)(μ6-C)[Pd(PBut3)]n, n = 1 (15), n = 2 (16), have
been prepared and structurally characterized. In most cases the MPBut3 groups bridge a pair of mutually
bonded ruthenium atoms, and the associated Ru−Ru bond distance increases in length. Fenske−Hall
calculations were performed on 10 and 11 to develop an understanding of the electron deficient metal−metal bonding. 10 undergoes a Jahn−Teller distortion to increase bonding interactions between neighboring
Ru(CO)4 and Pd(PBut3) fragments. 11 has seven molecular orbitals important to cluster bonding in accord
with cluster electron-counting rules.

双膦化合物M(PBut3)2，其中M代表钯(Pd)和铂(Pt)，能够轻易地消除一个PBut3配体，并将MPBut3基团转移到化合物Ru3(CO)12、Ru6(CO)17(μ6-C)和Ru6(CO)14(η6-C6H6)(μ6-C)中的钌-钌键上，而不会替换任何钌复合物上的配体。新制备的化合物，包括Ru3(CO)12[Pd(PBut3)]3、10，以及Ru6(CO)17(μ6-C)[Pd(PBut3)]2、11，Ru6(CO)17(μ6-C)[Pt(PBut3)]n，其中n=1 (12)、n=2 (13)，以及Ru6(CO)14(η6-C6H6)(μ6-C)[Pd(PBut3)]n，其中n=1 (15)、n=2 (16)，均已制备并进行了结构表征。在大多数情况下，MPBut3基团连接了一对相互键合的钌原子，并导致相关的Ru−Ru键距离延长。对化合物10和11进行了Fenske−Hall计算，以增进对电子缺乏的金属-金属键合的理解。化合物10经历了Jahn−Teller畸变，以增强相邻的Ru(CO)4和Pd(PBut3)片段之间的键合作用。化合物11具有七个对簇键合至关重要的分子轨道，符合簇电子计数规则。