Iridium clusters containing eta(1) organic ligands: the synthesis and the solid state structure of [Ir-4(CO)(11)(CPh = CHPh)](-) and [Ir-6(CO)(14)(COOMe)(2)](2-)

The cluster [Ir-4(CO)(11)(CPh=CHPh)](-) was obtained by reaction of [HIr4(C O)(11)](-) and diphenylacetylene by refluxing in tetrahydrofuran (THF), wit h yields approaching 80%. The solid state structure was determined on the [ NEt4](+) salt, the cluster possesses a tetrahedral metallic framework, with three edge bridging carbonyls. The Vinyl fragment, having two phenyl rings in cis, is bound in axial position and donates only one electron to the cl uster, since the C=C double bond (1.34 Angstrom) does not interact with any iridium atom. The C-13-NMR of the cluster, recorded at -90 degrees C, allo ws full assignment of the signals. The cluster [Ir-6(CO)(14)(COOMe)(2)](2-) was obtained by nucleophilic attack of MeONa on [Ir-6(CO)(16)], in anhydro us methanol at room temperature. The solid state structure was determined o n its [N(PPh3)(2)](+) salt. Two methoxycarbonyl fragments are on adjacent m etal vertices of the octahedral framework. (C) 2000 Elsevier Science S.A. A ll rights reserved.