title: Thermal Dehydrogenation of Base-Stabilized B2H5(+) Complexes and Its Role in C-H Borylation.
abstract: Thermally induced dehydrogenation of the H-bridged cation L2B2H5(+) (L=Lewis base) is proposed to be the key step in the intramolecular C-H borylation of tertiary amine boranes activated with catalytic amounts of strong "hydridophiles". Loss of H2 from L2B2H5(+) generates the highly reactive cation L2B2H3(+), which in its sp(2)-sp(3) diborane(4) form then undergoes either an intramolecular C-H insertion with B-B bond cleavage, or captures BH3 to produce L2B3H6(+). The effect of the counterion stability on the outcome of the reaction is illustrated by formation of LBH2C6F5 complexes through disproportionation of L2B2H5(+) HB(C6F5)3(-) .
authors.affiliation: Department of Chemistry, University of Michigan, 930 N. University Ave, Ann Arbor, MI 48109 (USA). aprokofj@umich.edu.|Current address: Department of Chemistry, Northwestern University, 2145 Sheridan Rd, Evanston, IL 60208 (USA). aprokofj@umich.edu.
authors.forename: Aleksandrs
authors.initials: A
authors.lastname: Prokofjevs
mesh_terms: D001880:Boranes / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D006865:Hydrogenation; D058115:Lewis Bases / Q000737:chemistry*; D015394:Molecular Structure; D013696:Temperature
chemical_list: D001880:Boranes; D058115:Lewis Bases; D006859:Hydrogen
keywords: CH activation; Lewis bases; boron; density-functional calculations; homogeneous catalysis