title: Mononuclear Schiff base boron halides: synthesis, characterization, and dealkylation of trimethyl phosphate.
abstract: A series of mononuclear boron halides of the type LBX(2) [LH = N-phenyl-3,5-di-tert-butylsalicylaldimine, X = Cl (2), Br (3)] and LBX [LH2 = N-(2-hydroxyphenyl)-3,5-di-tert-butylsalicylaldimine, X = Cl (7), Br (8); LH2 = N-(2-hydroxyethyl)-3,5-di-tert-butylsalicylaldimine, X = Cl (9), Br (10); and LH2 = N-(3-hydroxypropyl)-3,5-di-tert-butylsalicylaldimine, X = Cl (11), Br (12)] were synthesized from their borate precursors LB(OMe)2 (1) (LH = N-phenyl-3,5-di-tert-butylsalicylaldimine) and LB(OMe) [LH2 = N-(2-hydroxyphenyl)-3,5-di-tert-butylsalicylaldimine (4), N-(2-hydroxyethyl)-3,5-di-tert-butylsalicylaldimine (5), N-(3-hydroxypropyl)-3,5-di-tert-butylsalicylaldimine (6)]. The boron halide compounds were air and moisture sensitive, and upon hydrolysis, compound 7 resulted in the oxo-bridged compound 13 that contained two seven-membered boron heterocycles. The boron halide compounds dealkylated trimethyl phosphate in stoichiometric reactions to produce methyl halide and unidentified phosphate materials. Compounds 8 and 12 were found to be the most effective dealkylating agents. On reaction with tert-butyl diphenyl phosphinate, compound 8 produced a unique boron phosphinate compound LB(O)OPPh2 (14) containing a terminal phosphinate group. Compounds 1-14 were characterized by 1H, 13C, 11B, 31P NMR, IR, MS, EA, and MP. Compounds 5, 6, and 11-14 also were characterized by single-crystal X-ray diffraction.
authors.affiliation: Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, USA.
authors.forename: Amitabha
authors.initials: A
authors.lastname: Mitra
authors.forename: Lauren J
authors.initials: LJ
authors.lastname: DePue
authors.forename: Jeffrey E
authors.initials: JE
authors.lastname: Struss
authors.forename: Bijal P
authors.initials: BP
authors.lastname: Patel
authors.forename: Sean
authors.initials: S
authors.lastname: Parkin
authors.forename: David A
authors.initials: DA
authors.lastname: Atwood