PHOTOLYTIC PREPARATION OF (BENZYLIDENEACETONE)CARBONYLPHOSPHINEIRON(0) COMPLEXES. THE MOLECULAR STRUCTURES OF Fe(CO)2(PEt3)(bda) AND Fe(CO)2(PPhMe2)(bda) (bda = benzylideneacetone)

Article abstract of DOI:10.1016/S0022-328X(00)99303-3

The (benzylideneacetone) carbonylphosphine iron(0) complexes, Fe(CO)2L(bda), Fe(CO)L2'(bda) and Fe(CO)(dpe)(bda) (L = PEt3, PPhMe2, PPh2Me; L' = PPhMe2, PPh2Me; dpe = 2) have been prepared by irradiating the corresponding tetracarbonylmonophosphine iron(0), tricarbonyldiphosphine iron(0) or tricarbonyl-1,2-bis(diphenylphosphine)ethane iron(0) complexes in benzene in the presence of benzylideneacetone.The X-ray crystal structures of the complexes with L = PEt3 (A) and PPhMe2 (B) have been determined, and show that the Fe atom adopts a distorted octahedral coordinated geometry in which three of the sites are occupied by the bda ligand.The bond parameters in the bda ligand suggest that this coordinated group is intermediate between its ground and first excited states.The complex Fe(CO)2(PEt3)(bda) crystallises in the monoclinic space group P2₁/c with a 10.203(3), b 12.964(4), c 16.960(6) Angstroem, β 120.00(2) deg, and Z = 4.The structure was solved by a combination of Patterson and Fourier difference techniques and refined by blocked full matrix least squares to R = 0.035 for 3351 unique observed diffractometer data.The complex Fe(CO)2(PPhMe2)(bda) also crystallises in space group P2₁/c, with a 8.134(3), b 21.394(8), c 11.658(5) Angstroem, β 108.12(2) deg and Z = 4.The structure was solved and refined as above to R = 0.036 for 3498 diffractometer data.The IR and 1H NMR data for all the complexes studied agree with the observed structures.