Chemistry of Polynuclear Metal Complexes with Bridging Carbene or Carbyne Ligands. Part 85. Synthesis of Chain and Ring Compounds Containing Molybdenum

摘要

We have recently developed rational procedures for preparing heteropolynuclear metal complexes with structures based on chains of metal atoms, and in which the metal-metal bonds are bridged by alkylidyne groups. In the majority of these species Tungsten-Platinum or Tungsten-Nickel bonds form the spine of the molecules, and compounds with up to seven metal atoms in the chain have been characterised. A few complexes in which Mo replaces W in the chains have also been described. In attempts to extend the length of the chains beyond seven metal atoms cyclisation reactions were observed, affording metallacycles which we have termed star clusters. In this paper we report several other compounds in which Molybdenum atoms are present in the spines of the molecules, thus placing the initial observation on a firmer basis. We have also established that 'star clusters' can be prepared having Mo atoms in the metallacycle. Moreover, an interesting form of isomerism occurs which is related to different metal atom sequences within the metal cluster framework. In a subsequent paper we shall show that the presence of molybdenum atoms in these systems allows the synthesis of compounds having structures with chains of more than seven metal atoms. Reprints. (AW)