Inter- and intramolecular electron transfer on formation of 15N2⋯BrCl determined from halogen nuclear quadrupole coupling in the rotational spectrumElectronic Supplementary Information available. See http://www.rsc.org/suppdata/cp/b1/b108824f/

Abstract

The ground-state rotational spectra of the four isotopomers 15N2⋯79Br35Cl, 15N2⋯81Br35Cl, 15N2⋯79Br37Cl and 15N2⋯81Br37Cl of a complex formed between 15N2 and bromine monochloride were observed by pulsed-jet, Fourier-transform microwave spectroscopy. Observed spectra were characteristic of a linear or quasi-linear molecule, with Br involved in the weak interaction, and were analysed to give the rotational constant B0, the centrifugal distortion constant DJ, the nuclear quadrupole coupling constants χaa(X) (X=Br or Cl) and the Br spin–rotation coupling constant Mbb(Br) for each isotopomer. Interpretation of χaa(X) values showed that the intermolecular electron transfer δ(Ni→Br)e on complex formation is negligible while its intramolecular counterpart δ(Br→Cl)e=0.012(2) e is also small. The electronic redistribution is consistent with a weak interaction of N2 and BrCl, as confirmed by the intermolecular stretching force constant kσ=4.40(2) N m−1. Values of r(N⋯Br), δ(Ni→Br)e, δ(Br→Cl)e, and kσ for 15N2⋯BrCl are compared with those for HCN⋯BrCl and H3N⋯BrCl, all of which involve weak binding of N to Br.