Species Containing Two and Three Boron Atoms

3-Di-f-butyl-2,4-dimethyl-1,3,2,4-diazadiborolidine (24) is obtained from 18 (see p. 175) by treatment with dibromomethylborane by elimination of (CH3)2SnBr2. Mass spectral and NMR ( H, C) data are reported [9]. 

Compounds 25a to 25c are prepared by lithiation of the corresponding NH compounds with n-C4HgLi and subsequent treatment with CIB(C6H5)N(CH3)2 [11, 12]. 

4-diazadiborlne derivatives 26 have been prepared from CH3COOCCSCCOOCH3 and [-B(CH3)-N(C4H9-f)-]2 or [-B(C2H5)-N(C4H9-f)-]2, respectively, and were characterized by their mass spectral and NMR ( H, B, C) data. The molecular structure of 26a shows the six-membered ring in a twist conformation with Interplanar deviation angles of the individual atoms between 7° and 20°. The bond distances are (in pm) r(BC) = 154, r(CN) = 138, r(BN) from 145 to 146 (which excludes full aromaticity) [17]. 

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