Photochemical reactions of Fe(CO)5 with FcCCH in the presence of S-powder and CS2: Synthesis and characterization of [{μ-SC(H)C(Fc)S}(CO)6Fe2], [μ-SC(O)C(H)C(Fc)S}(CO)6Fe2]; cis-[μ-η1:η2:η1:η1-{C(Fc)C(H)CS2C(H)C(Fc)}(CO)6Fe2] and trans -[μ-η1:η2:η1:η1-{C(Fc)C(H)CS2C(Fc)C(H)}(CO)6Fe2]