320780-02-7Relevant academic research and scientific papers
Structural studies of organoboron compounds. LVI.1 1-Benzyl-7-methyl-3,5-diphenyl-2,4,6-trioxa-1-azonia-3-bora-5-boratabicyclooctane and 1,4,6,9-tetramethyl-2,7-diphenyl-3,8,11,12-tetraoxa-1,6-diazonia-2,7-diboratatricyclo2,6>dodecane
Kliegel, Wolfgang,Lubkowitz, Gottfried
, p. 2809 - 2817 (2007/10/02)
The preparation of the N-(2-hydroxypropyl)-N-alkylhydroxyamines, 6a (R = CH3) and 6b (R = CH2Ph) and their reactions with phenylboronic acid are described.Regardless of the molar ratios of the reactants employed, the reaction with 6b leads to the 1:2 condensate 1-benzyl-7-methyl-3,5-diphenyl-2,4,6-trioxa-1-azonia-3-bora-5-boratabicyclo-octane, 7, while that with 6a give rise to the 1:1 condensate 1,4,6,9-tetramethyl-2,7-diphenyl-3,8,11,12-tetraoxa-1,6-diazonia-2,7-diboratatricyclo2,6>dodecane, 11 (the cyclic BONBON dimer of 4,6-dimethyl-2-phenyl-1,3-dioxa- 4-aza-2-boracyclohexane, 9).Compounds 7 and 11 both crystallize in the triclinic space group P: for 7; a = 13.126(1), b = 15.337(1), C = 10.9469(5) Angstroem, α = 91.727(5), β = 104.647(5), γ = 72.922(7) deg, Z = 4 and for 11; a = 9.0807(4), b = 9.1653(3), c = 6.4876(2) Angstroem, α = 97.708(3), β = 108.830(3), γ = 89.188(4) deg, Z = 1.The structures were solved by direct methods and were refined by full-matrix least-squares procedures to R = 0.038 and 0.032 for 5879 and 1827 reflections with I 3 ? (F2), respectively.Compound 7 has the expected bicyclic pyroboronate structure, but represents the first reported N-substituted example of this type of compound.Bond lenghs involving boron in 7 are (C)O-B(sp3) = 1.428(2) and 1.420(2), (B)O-B(sp3) = 1.472(2) and 1.468(2), N-B(sp3) = 1.737(2) and 1.762(2), C(phenyl)-B(sp3) = 1.588(2) and 1.584(2), (N)O-B(sp2) = 1.402(2) and 1.404(2), (B)O-B(sp2) = 1.331(2) and 1.329(2), C(phenyl)-B(sp2) = 1.555(3) and 1.553(2) Angstroem.The X-ray analysis establishes a centrosymmetric, twofold N -> B coordinated, dimeric structure in the solid state for 11 in which each B-O-N segment of a central six-membered BONBON ring is bridged by an O-C-C moiety.Compound 11 represents the first fully characterized example of a new type of "BONBON" compound.Bond distances involving the boron atom are (N)O-B = 1.465(1), (C)O-B = 1.428(1), N-B = 1.695(2), and C(phenyl)-B = 1.607(2) Angstroem.Spectroscopic evidence indicates that in solution and in the gas phase this material exists predominantly as the monomer 9.
