Formation of 3,5-Dithio-cyclopentenyl Ligand on Fe2(CO)6 Support from Photochemical Reaction of Internal Acetylenes with [Fe(CO)5] in Presence of CS2

Photolytic reaction of internal acetylenes, RC≡CR’ (R = Ph, Fc and R’ = C≡CPh, C≡CFc, CHO) with iron pentacarbonyl, in presence of CS2, in hexane yields a 3,5-dithiacyclopentene ligand system supported on a Fe2(CO)6 framework. On reaction with diacetylenes substituted cis- and trans-3,5-dithiacyclopentene ligand, formed by the coupling of two molecules of the diacetylenes are observed, while, with 3-ferrocenylpropynal, along with coupled 3-ferrocenylpropynal products, cis-3,5-dithiacyclopentene ligand, formed by the coupling of one 3-ferrocenylpropynal and one ferrocenylacetylene is also observed. All compounds have been characterized by IR, 1H NMR and 13C NMR spectroscopy, mass spectrometry, and structures of 4a and 4c have been established by single crystal X-ray diffraction technique. In addition, DFT computational analyses of compounds 4a and 4c have been investigated in order to understand the bonding in complexes 4a and 4c.