The N-lithioborazine LiH2N3B3Me3, 1, reacts with organoboron halides not only to the respective borazinyl organylboranes but also by Me/halogen exchange. (Me2N)2B-H2N3B3Me3 was obtained from 1 and (Me2N)2BCl. A new ten-membered B6N4 ring system, 5, results on treatment of Cl(Me2N)B-B(NMe2)Cl with 1. The B-N-borazinyl borazines 6 - 8 can be prepared from 1 and B-monohalo borazines. The synthesis of 2,4,6-trimethylborazinyl-aluminum and -titanium compounds is achieved only with mononuclear monohalides of Al(III) and Ti(IV). The 2,4,6-trimethylborazinyl- bis(piperidino)alane 9 and the tris(2,6-diisopropylphenoxo)-2,4,6-trimethylborazinyltitanium 10 were characterized by X-ray structure analysis.
The distortion of the borazine ring by B and N substitution is discussed. In case of the N-substituted borazines YH2N3B3Me3 the B-N bonds of the YNB2 units are elongated, e. g. for Y = PBr2 or (RO)3Ti, while N lithiation leads to a shortening of these B-N bond. These changes of bond lengths are also reflected by changes in the B1-N2 and B3-N3 bond lengths which become shorter in the presence of electron-withdrawing groups, but longer in case of Li substitution. Also, the bond angles B1-N2-B2 and B2-N3-B3 are affected by an increase of up to 128°.
通过B和N取代引起的硼氮杂环畸变进行了讨论。对于N取代的硼氮杂环YH2N3B3Me3,YNB2单元的B-N键被延长,例如对于Y = PBr2或(RO)3Ti,而N锂化导致这些B-N键的缩短。这些键长的变化也反映在B1-N2和B3-N3键长的变化上,在电子吸引基团存在时变短,但在锂取代的情况下变长。此外,键角B1-N2-B2和B2-N3-B3受到影响,最多增加128°。
B-Nitrosooxypentamethylborazine, B-nitrooxypentamethylborazine and B-trinitrooxy-N-trimethylborazine have been synthesized and characterized by 1H, 13C, 11B, and 14N NMR spectroscopy, mass spectrometry, vibrational spectroscopy and elemental analysis. The 11B NMR shifts were calculated and compared to the experimental results. The decomposition temperatures and the impact and friction sensitivities of these compounds have been determined as well.