30 The Vibrational Spectra and Structure of Some Tetrameric Borazynes J.
H.
S.
Downloaded by NORTHWESTERN UNIV on January 10, 2018 | http://pubs.acs.org Publication Date: January 1, 1964 | doi: 10.1021/ba-1964-0042.ch030
National
GREEN,
W.
KYNASTON,
Chemical Laboratory,
AND
H.
Teddington,
M.
PAISLEY
England
The infrared (5000 to 200 cm. ; solid, solutions in CS , CCl ) and Raman (solutions in CS , n-heptane) spectra of [(CH ) CNBCl] and [(CD ) CNBCl] have been measured; depolarization ratios of the Raman lines were measured for the former compound. Infrared data were also obtained (5000 to 420 cm. ) for [RNBX] , R = (CH ) C, (CD ) C; X = Br, NCS. Using complete assignments for (CH) CNH and (CD ) CNH , assignments have been made of the frequencies for R = (CH ) C, (CD ) C, X = Cl, associated principally with the tert-butyl group. The remaining frequencies have been considered in terms of four model structures for the ClBNC skeleton: (a) XIII (point group C ), (b) XIV (T ), (c) the chair conformation of XII (C ), and (d) XVI (S ). At least eight, and probably 11, polarized Raman lines have no infrared counterpart and the C and T models are therefore excluded. Unless several additional polarized Raman lines have escaped detection, the C model is also unlikely and the boat (S ) structure is that most consistent with the observed spectra. A Raman-active pair (species a for S ) of essentially B - N stretching modes can be assigned at 1313, 1305 cm. , with a similar infrared active pair (b or e) at 1370, 1396 cm. for [(CH ) CNBCl] . For [(CH ) CNBBr] the latter pair is at 1385, 1355, cm. , and for [(CH ) CNBNCS] at 1420, 1382 cm. . Other observed frequencies of the ClBNC skeleton cannot be ascribed with certainty to specific vibrations. -1
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301
Niedenzu; Boron-Nitrogen Chemistry Advances in Chemistry; American Chemical Society: Washington, DC, 1964.
