TETRADYDRO-ARYL-4H-1,3,6,2-DIOXAZABORACINE - CRYSTAL-STRUCTURE OF TETRAHYDRO-2-BIPHENYL-4H-1,3,6,2-DIOXAZABORACINE

Intramolecular B-N coordination occurs in etrahydro-2-biphenylyl-4H-1, 3,6,2-dioxazaboracine, (2: R = o-PhC6H4,R' = H) both in the solid stat e and in CDCl3 solution. Molecules are linked, in the solid state, int o spiral chains, via N-H---O hydrogen bonds utilising only one of the two oxygen atoms present in each molecule. Enantiomeric pairs of two d ifferent rotamers are present in the solid state structure. The intram olecular B-N bond length in the rotamers are 1.658(4) and 1.666(5) Ang strom; other geometric parameters are B-O bond lengths between 1.448(4 ) and 1.464(4) Angstrom, B-C bond lengths 1.612(5) and 1.620(5) Angstr om, and bond angles at B between 100.9(3) and 114.1(3)degrees. The del ta(11)B value for (2: R = o-PhC6H4, R' = H) at 25 degrees C = 10.7 ppm ): NMR spectra of other (2: R = aryl, R' = H) compounds are also repor ted.