Reaction of the dicobalt alkyne compound Co2(CO)6( -dmad) with the diphosphine ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd). Spectroscopic properties, X-ray diffraction data, and thermal reactivity of the chelating isomer of Co2(CO)4(bpcd)( -dmad) - Simon Bott (Journal of Chemical Crystallography, 2004)