Gas-Phase Structures of Dimethylboron Azide and Dimethylboron Isocyanate. Electron Diffraction and ab Initio Study

Publikations-Art

Zeitschriftenbeitrag

Autoren

Hausser-Wallis, R.; Oberhammer, H.; Einholz, W.; Paetzold, P.

Erscheinungsjahr

1990

Veröffentlicht in

Inorganic Chemistry

Band/Volume

29/18

Seite (von - bis)

3286-89

The gas-phase structures of (CH3)2BN3 and (CH3)2BNCO have been detd. by electron diffraction. Both mols. have planar heavy-atom skeletons with bent BN3 and BNCO moieties. Their geometries differ mainly in the BNY bond angle (Y = NN or CO), which is small (.apprx.120.degree.) in the azide and large (.apprx.150.degree.) in the isocyanate. Structure analyses with a large amplitude model for (CH3)2BNCO and a double min. potential for the BNCO in-plane bending motion suggest that the barrier at the linear configuration is .gtoreq.0.2 kcal/mol. HF calcns. with 6-31G* basis sets reproduce the exptl. structure of the azide satisfactorily. Relative to the ground state, a configuration with a linear BN3 group and one with the azide group pointing out of the plane are resp. 15.0 and 12.1kcal/mol less stable. For (CH3)2BNCO the ab initio method predicts a linear BNCO structure, which is at variance with the exptl. result.