title: Chemistry of N,S-Heterocyclic Carbene and Metallaboratrane Complexes: A New η(3)-BCC-Borataallyl Complex.
abstract: A high-yielding synthetic route for the preparation of group 9 metallaboratrane complexes [Cp*MBH(L)2], 1 and 2 (1, M=Rh, 2, M=Ir; L=C7H4NS2) has been developed using [{Cp*MCl2}2] as precursor. This method also permitted the synthesis of an Rh-N,S-heterocyclic carbene complex, [(Cp*Rh)(L2)(1-benzothiazol-2-ylidene)] (3; L=C7H4NS2) in good yield. The reaction of compound 3 with neutral borane reagents led to the isolation of a novel borataallyl complex [Cp*Rh(L)2B{CH2C(CO2Me)}] (4; L=C7H4NS2). Compound 4 features a rare η(3)-interaction between rhodium and the B-C-C unit of a vinylborane moiety. Furthermore, with the objective of generating metallaboratranes of other early and late transition metals through a transmetallation approach, reactions of rhoda- and irida-boratrane complexes with metal carbonyl compounds were carried out. Although the objective of isolating such complexes was not achieved, several interesting mixed-metal complexes [{Cp*Rh}{Re(CO)3}(C7H4NS2)3] (5), [Cp*Rh{Fe2(CO)6}(μ-CO)S] (6), and [Cp*RhBH(L)2W(CO)5] (7; L=C7H4NS2) have been isolated. All of the new compounds have been characterized in solution by mass spectrometry, IR spectroscopy, and (1)H, (11)B, and (13)C NMR spectroscopies, and the structural types of 4-7 have been unequivocally established by crystallographic analysis.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036 (India).
authors.forename: Dipak Kumar
authors.initials: DK
authors.lastname: Roy
authors.affiliation: Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036 (India).
authors.forename: Anangsha
authors.initials: A
authors.lastname: De
authors.affiliation: Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036 (India).
authors.forename: Subhankar
authors.initials: S
authors.lastname: Panda
authors.affiliation: Sophisticated Analytical Instruments Facility, Indian Institute of Technology Madras, Chennai 600036 (India).
authors.forename: Babu
authors.initials: B
authors.lastname: Varghese
authors.affiliation: Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036 (India). sghosh@iitm.ac.in.
authors.forename: Sundargopal
authors.initials: S
authors.lastname: Ghosh
keywords: N,S-heterocyclic ligands; borataallyl; coordination modes; metallaboratrane; rhodium; vinylborane