.mu.2-.eta.2:.eta.1-Benzylidene(diphenylphosphino)maleic Anhydride Mediated PMe3 Addition to the Tricobalt Cluster Co3(CO)6[.mu.2-.eta.2:.eta.1-C(Ph)C:C(PPh2)C(O)OC(O)](.mu.2-PPh2). Structure and Redox Properties of the Arachno Cluster Co3(CO)4(PMe3)2[.mu.2-.eta.2:.eta.1-C(Ph)C:C(PPh2)C(O)OC(O)](.mu.2-PPh2) - Simon Bott (Organometallics, 1995)