title: New Routes to a Series of σ-Borane/Borate Complexes of Molybdenum and Ruthenium.
abstract: A series of agostic σ-borane/borate complexes have been synthesized and structurally characterized from simple borane adducts. A room-temperature reaction of [Cp*Mo(CO)3 Me], 1 with Li[BH3 (EPh)] (Cp*=pentamethylcyclopentadienyl, E=S, Se, Te) yielded hydroborate complexes [Cp*Mo(CO)2 (μ-H)BH2 EPh] in good yields. With 2-mercapto-benzothiazole, an N,S-carbene-anchored σ-borate complex [Cp*Mo(CO)2 BH3 (1-benzothiazol-2-ylidene)] (5) was isolated. Further, a transmetalation of the B-agostic ruthenium complex [Cp*Ru(μ-H)BHL2 ] (6, L=C7 H4 NS2 ) with [Mn2 (CO)10 ] affords a new B-agostic complex, [Mn(CO)3 (μ-H)BHL2 ] (7) with the same structural motif in which the central metal is replaced by an isolobal and isoelectronic [Mn(CO)3 ] unit. Natural-bond-orbital analyses of 5-7 indicate significant delocalization of the electron density from the filled σBH orbital to the vacant metal orbital.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036 (India).
authors.forename: Rongala
authors.initials: R
authors.lastname: Ramalakshmi
authors.affiliation: Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036 (India).
authors.forename: Koushik
authors.initials: K
authors.lastname: Saha
authors.affiliation: Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036 (India).
authors.forename: Dipak Kumar
authors.initials: DK
authors.lastname: Roy
authors.affiliation: SAIF, Indian Institute of Technology Madras, Chennai 600 036 (India).
authors.forename: Babu
authors.initials: B
authors.lastname: Varghese
authors.affiliation: Department of Chemical Sciences, Tezpur University, Tezpur 784 028 (India).
authors.forename: Ashwini K
authors.initials: AK
authors.lastname: Phukan
authors.affiliation: Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036 (India). sghosh@iitm.ac.in.
authors.forename: Sundargopal
authors.initials: S
authors.lastname: Ghosh
keywords: agostic boranes; heterocyclic carbene; molybdenum; ruthenium; σ-borates