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

TriphenylboroxinN,N-diethylhydroxylamine adduct (dimethylformamide solvate)

“…This resembles the geometry of other boroxin ring systems containing one tetracoordinated B atom (Kliegel et al, 1985). The exocyclic O4ÐB1 bond length [1.508 (3) A Ê ] is similar to the OÐB distances (1.492±1.511 A Ê ) of other N-alkylhydroxylamine O±B adducts to cyclic phenylboronates (Kliegel et al, 1992(Kliegel et al, , 1992a.…”

“…Since amide O±B adducts to boron compounds are generally known (Kliegel et al, 1989, and references therein) and amine N±B adducts to boroxins have been reported (Yalpani & Boese, 1983, and references therein; Ferguson et al, 1990), the dual addition product (I) had to be considered a likely structure. Also, an isomeric complex, (II), containing the O±B-coordinated N,N-diethylhydroxylamine in its N-oxide form, is suggested by already established structures of O±B-coordinated boron complexes of N-mono-alkylhydroxylamines (Kliegel et al, 1992(Kliegel et al, , 1992a and N,Ndialkylhydroxylamines (Kliegel et al, 1992b). The BOBON ring part in the alternative structure, (III), formed by twofold N±B/O±B coordination of the hydroxylamine to the boroxin ring, is reminiscent of the BOBON heterocyclic ring part in the bicyclic compounds from N,N-dialkylhydroxylamines and phenylboronic acid (Kliegel et al, 1991(Kliegel et al, , 2002.…”