Experimentelle und theoretische Untersuchungen zu Clustermolekülen mit dem NB 2 -, NB 3 -, CB 3 -, und B 4 -Gerüst
The reaction of Tri-tert-butylazadiboriridin with Halogenides of maingroup 3 and 5 elements leads to an opening of the BB-bond. Only in case of Trifluorophosphane a cyclic product was obtained. Nitrils and Isothiocyanats yield cyclic or bicyclic products, the structures of which were derived from comparison of experimental and calculated spectra. It was shown that H– reacts with NB2R3 to give a three-membered-ring consisting of a BN-double-bond and a BHtBu group. The reaction-path of H– with NB2H3 was calculated with ab initio-methods. Other anionic bases like R’O–, R’S–, R’2N–, R’2P– gave no reaction with NB2H3. This was explained by discussion of HOMO’s of these bases. For the reactions of NB2R3 with Lewis-acids R’BH2 was previously found that bicyclobutane-type products exhibit an equilibrium between the Cs exo-form and the chiral endo-form. The ab initio calculations show, that the reasonable isomerization path seems to be the inversion of the NB3 skeleton with partial opening of BB-bond. For the compound CB3H4R3, the structure of which was unknown, the DFT/GIAO-calculations revealed that it is bicyclobutane-type one, and hence, it can be considered as a nido-tetraborane.
info:eu-repo/classification/ddc/540, Chemie, Triboranderivate, Tetraboranderivate, Azaborane, Butylgruppe, Clusterverbindungen
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