Reaction of the dinuclear cobalt complex [Co2{μ-PPh2CHCHC(O)CHCHPPh2}(CO)4] with two-electron donor ligands; the stabilisation of cobalt-alkene bonds by incorporation of alkenes into a bridging diphosphine ligand

Abstract The thermal reaction of [Co 2 {μ-PPh 2 CHCHC(O)CHCHPPh 2 }(CO) 4 ] ( 2 ) with two-electron donor ligands, L, leads to the mono- bis-substituted complexes [Co 2 {μ-PPh 2 CHCHC(O)CHCHPPh 2 }(CO) 3 (L)] (L = PPhMe 2 ( 3a ), PPh 2 H ( 3b ), P(OMe) 3 ( 3c ). CN t Bu ( 3d ) and [Co 2 {μ-PPh 2 CHCHC(O)CHCHPPh 2 }(CO) 2 (L) 2 ] (L = PPhMe 2 ( 4a ), PPh 2 H ( 4b ), P(OMe) 3 , ( 4c ), CN t Bu ( 4d )), in which CO groups rather than bound alkenes have been displaced from the metal centres. Single crystal X-ray diffraction has been used to determine the structure of [Co 2 {μ-PPh 2 CHCHC(O)CHCHPPh 2 }(CO) 2 (PPhMe 2 ) 2 ]·0.25[C 6 H 14 ] ( 4a ) (which crystallises i monoclinic space group P 2 t / c with a = 15.932(2), b = 12.608(4), c = 23.847(3) A , β = 98.87(3)°, Z = 4 ).