Light group 13 chloride diazadiene complexes: consequences of varying substituent bulk

摘要: BCl3 cyclizes diazadiene (2,6-Pri2C6H3NCH)21 through a dichloroborated intermediate [(2,6-Pri2C6H3NCHCl)2BCl] 3 to give, in polar aprotic solvents, spontaneously dehyrochlorinated C-chloro diazaborole 4. In contrast, reaction of AlCl3 with 1 forms only acyclic mono- or di-adducts 5a/b and 6. Alkali metal reductions gave mixtures 4 [(2,6-Pri2C6H3NCH)2BCl] 7. Pd(0) reduction cleanly Reduction 6 low yield the closed shell C–C coupled dimer 8 putative radical anion 1·AlCl2 complex monomer. An alternative synthesis for (2,6-Pri2C6H4NCPh)2, 2, is reported. 2/BCl3, which additional phenyl groups on C-2 C-3 atoms hinder coupling observed 8, predominantly 2·BCl, (9a) contaminated 2·BCl2, (9b) first such stable boron. All compounds 2–9 were characterized by X-ray diffraction NMR spectroscopy. Stable 9b was additionally EPR spectroscopy density functional computation.