TRANS-[(MO6CL8)(C7H7)(4)(P(N-C4H9)(3))(2)] AND NS-[(MO6CL8)(C8H5)(4)(P(N-C5H11)(3))(2)].2C(7)H(8)

The title compounds, tetrabenzyl-2 kappa C,3 kappa C,4kC,5 kappa C-oct a-mu 3 -chloro-bis(tributylphosphine)-1 kappa P,6 kappa P-octa-hedro - hexamolybdenum(12Mo-Mo), (1), and tetrakis(phenylethynyl)-2 kappa C,3 kappa C,4 kappa C,5 kappa C -octa-mu 3-chloro-bis(tripentylphosphine)- 1 kappa P,6 kappa P-octahedro-hexamolybdenum (12Mo-Mo)-toluene (1/2), (2), containing octahedral Mo clusters with four sigma-C ligands, wer e prepared by the reaction of trans-[(Mo6Cl8)Cl-4(PR3)(2)] with triben zylaluminium and tris(phenylethynyl)aluminium, respectively, and their structures determined. The octahedral Mo-6 cores of both compounds ar e on inversion centres and are almost regular. Average interatomic dis tances in the clusters for (1) are Mo-Mo-edge 2.618, Mo...Mo-opposite 3.703, Mo-Cl 2.477 and Mo-C 2.26 Angstrom, and for (2) are Mo-Mo-edge 2.626, Mo...Mo-opposite 3.714 and Mo-C 2.13 Angstrom.