250245-49-9Relevant academic research and scientific papers
Synthesis, structure, and reactivity of β-diketiminate boron(III) complexes
Qian, Baixin,Baek, Sung W.,Smith III, Milton R.
, p. 2405 - 2414 (2008/10/09)
The chemistry of boron supported by the β-diketiminate ligand, tolylnacnac (tolylnacnacH=2-N-p-tolylamino-4-N-p-tolylimino-2-pentene), has been investigated. (tolylnacnac)Li reacted with one equivalent of BF3·OEt2 to afford (tolylnacnac)BF2 (1) in 46% yield. The structure of compound 1 was solved indicating that the diketiminate ligand is η2-bound to B to form a six-membered heterocycle. While alkylation of compound 1 can be effected with alkyl lithium or Grignard reagents, nucleophilic addition to the diketiminate ligand occurred in the reaction between compound 1 and MeLi to afford [η2-(Me)2C(Ntolyl)CH=C(Ntolyl)Me]BMe (2). For Me3SiCH2Li, deprotonation of the diketiminate ligand afforded [η2-CH2=C(Ntolyl)CH=C(Ntolyl)Me]BCH 2SiMe3 (3). Conversely, alkyl Grignard reagents selectively delivered two alkyl groups to the boron center, and several pseudo-tetrahedral (tolylnacnac)BR2 (4a-d; a, R=Me, b, R=nPr, c, R=vinyl, d, R=allyl) complexes have been prepared. The structures of compounds 2, 3, and 4a were solved, and variations in B-N and B-C metrical data for compounds 2 and 4a were correlated to bond order, inductive effects of the co-ligands, and hybridization of the boron center. The reaction between compound 4a and tris(pentafluorophenyl)boron gave [(tolylnacnac)BMe]+[MeB(C6F5)3] - (5). Compound 5 reacted with pyridine to give an adduct, [(tolylnacnac)B(py)Me]+[MeB(C6F5) 3]- (6). Elsevier Science Ltd.
