[Ru 4 (CO) 10 (µ-CO)(µ 4 -PPh)(µ 4 -η 2 -PhNNPh)]: the first example of an azobenzene molecule coordinated on a square metal face

Reaction of azobenzene, under photolytic conditions, with the 62-electron butterfly cluster [Ru4(CO)13(µ3-PPh)]1 affords the first example of a 64-electron square-planar cluster containing a coordinated azobenzene ligand; a single crystal X-ray analysis of [Ru4(CO)10(µ-CO)(µ4-PPh)(µ4-η2-PhNNPh)]2 has revealed a novel capped trigonal prismatic Ru4PN2 skeleton.