Experimental and ab initio structure of BrN02

Competition and interplay between σ-hole and π-hole interactions: a computational study of 1:1 and 1:2 complexes of nitryl halides (O2NX) with ammonia

Quantum calculations at the MP2/cc-pVTZ, MP2/aug-cc-pVTZ, and CCSD(T)/cc-pVTZ levels have been used to examine 1:1 and 1:2 complexes between O(2)NX (X = Cl, Br, and I) with NH(3). The interaction of the lone pair of the ammonia with the σ-hole and π-hole of O(2)NX molecules have been considered. The 1:1 complexes can easily be differentiated using the stretching frequency of the N-X bond. Thus, those complexes with σ-hole interaction show a blue shift of the N-X bond stretching whereas a red shift is observed in the complexes along the π-hole. The SAPT-DFT methodology has been used to gain insight on the source of the interaction energy. In the 1:2 complexes, the cooperative and diminutive energetic effects have been analyzed using the many-body interaction energies. The nature of the interactions has been characterized with the atoms in molecules (AIM) and natural bond orbital (NBO) methodologies. Stabilization energies of 1:1 and 1:2 complexes including the variation of the zero point vibrational energy (ΔZPVE) are in the ranges 7-26 and 14-46 kJ mol(-1), respectively.

A Combined Matrix Isolation and ab Initio Study of Bromine Oxides

Bromine oxides have been generated by passing a mixture of Br(2)/O(2)/Ar through a microwave discharge. The products were stabilized at 6.5 K in an excess amount of argon. Infrared spectroscopy was used to analyze the species formed; experiments with enriched (18)O(2) and ab initio calculations were carried out to assist in the assignment of the spectra. Besides the known species BrO, OBrO, and BrBrO, spectroscopic evidence for BrOBrO, BrBrO(2), and a new isomer of Br(2)O(3) is reported for the first time. Extensive comparisons are drawn between the present studies and previous experimental and theoretical works. The chemistry involved in the production of the observed compounds is discussed. The assignments are corroborated by the good correlation between observed and calculated band positions and intensities.