Sequential bond energies and structures of the Cr+•(N2)n, n=1-4

DFT calculations, with an effective core potential for the chromium ion and large polarized basis set functions have been used to calculate the sequential bond dissociation energies of the Cr+center dot(N-2)(n) (n = 1-4) complexes. A linear configuration was obtained for the Cr+center dot N-2 and Cr+center dot(N-2)(2) complexes with sequential bond dissociation energies of 14.6 and 16.4 kcal mol(-1), respectively. For the Cr+center dot(N-2)(3) and Cr+center dot(N-2)(4) complexes, distorted trigonal pyramidal and tetrahedral geometries were optimized with sequential bond dissociation energies of 6.5 and 5.5 kcal mol(-1), respectively. pi- back-donation in side-on approach of the Cr+center dot N-2 leads to the formation of a tilted structure with the Cr+ ion in central position. The di-ligated complex exhibits the strongest bond dissociation energy among these four Cr+center dot(N-2)(n) (n = 1-4) complexes since it has the largest Cr+-N bond order.