Structural studies of organoboron compounds. LII. N-Ethylhydroxylamine- (O-B)1,7-diethyl-3,5-diphenyl-2,4,6-trioxa-7-aza-1-azonia-3-bora-5- boratabicyclo[3.3.0]octane

Abstract

The reaction of N,N′-diethyl- N,N′-dihydroxymethanediamine with oxybis(diphenylborane) in absolute ethanol yields N-ethylhydroxylamine(O-B)1,7-diethyl-3,5-diphenyl-2,4,6-trioxa-7-aza-1-azonia-3-bora-5-boratabicyclo[3.3.0]octane [3-(1-oxa-2-azoniabutyl)-1,7-diethyl-3,5-diphenyl-2,4,6-trioxa-7-aza-1-azonia-3,5-diboratabicyclo[3.3.0]octane], 7b, in good yield. Crystals of this material are monoclinic, a = 16.396(2), b = 11.303(2), c = 22.898(4) Å, β = 92.78(1)°, Z = 8 (two molecules per asymmetric unit), space group P21/a. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.041 and Rw = 0.050 for 3602 reflections with I ≥ 3σ(I). The product 7b is formed by O→B coordination between N-ethylhydroxylamine and the bicyclic bis-phenylboronate of N,N′-diethyl-N,N′-dihydroxymefhanediamine. Compound 7b is only the second structurally characterized example of an N-alkylhydroxylamine(O-B)boron complex having an open-chain B,N-betaine structure. Bond lengths about boron are: B—O(N) = 1.467(4)–1.527(4), B—O(B) = 1.433(4)–1.451(4), B—N = 1.688(4) and 1.707(4), B—C = 1.586(4)–1.606(5) Å.