BEITRAEGE ZUR CHEMIE DES BORS. CLXXII. DARSTELLUNG, STRUKTUR UND REAKTIONEN VON μ-(BORANDITHIOLATO)BIS(TRICARBONYLEISEN)-VERBINDUNGEN, XBS22

Article abstract of DOI:10.1016/S0022-328X(00)99530-5

Li2S2Fe2(CO)6 and M2S2Fe2(CO)6nBEt3 (M=Li, Na) have been used to prepare a wide range of the compounds XBS2Fe2(CO)6 (X=NR2, R, Hal) as well as the μ-(bis(dimethylamino)diborane(4)di-thiolato) derivative (4).Reaction of Li2S2Fe2(CO)6 with 2-chloro-1,3-dimethyl-1,3,2-diazaborolidine yields a spirocyclic product.The Me2N group in the Me2NBS2Fe2(CO)6 can be readily exchanged for chlorine or bromine using the respective boron halides as electrophilic reagents.Similarly, 4 can be transformed into the dimethylamino-chloro or -bromo derivatives.Further substitution, using BCl3 and Me2N(Cl)B2S2Fe2(CO)6 leads to Cl2B2S2Fe2(CO)6, which can be de tected by 11B NMR at low temperature, but the compound decomposes at ambient temperature to produce ClBS2Fe2(CO)6.Nucleophilic displacement of Cl^- for O^tBu^- or R^- is readily achieved by treating ClBS2Fe2(CO)6 with KO^tBu or LiBu.Attack at the B-S bond has not been observed.The electron density at the iron atoms is only influenced marginally by the various boron substituents as shown by ν(CO); therefore electronic effects are not transduced via the sulfur atoms to the metal atoms.The X-ray structures, which have been determined for tmpBS2Fe2(CO)6 (3), (Me2NB)2S2Fe2(CO)6 (4) and <(CH2NMe)2B>2S2Fe2(CO)6 (6b) show only slight variations in the S2Fe2 units; a larger S...S separation results in 4 due to the bridging diborane(4) unit.