Pentacoordinated pyramidal structures and bonding properties of WN10-/0: anion photoelectron spectroscopy and theoretical calculations

Anion photoelectron spectroscopy and theoretical calculations were used to investigate the structural and bonding properties of WN10-/0. The electron affinity of WN10 is measured to be 1.582 +/- 0.030 eV. The frequency of the N=N stretch in WN10 is measured to be 2170 +/- 80 cm(-1), which is red-shifted with respect to that of the dinitrogen molecule indicating that the NN bonds are weakened in WN10. The theoretical adiabatic detachment energy (ADE) and vertical detachment energy (VDE) of WN10- obtained by calculations at the CCSD(T)/CBS level agree well with experimental results. The structures of WN10-/0 are C-4v symmetric pentacoordinated pyramidal structures with five end-on dinitrogen ligands. Our experiments show that the peak of WN10- is dominant in the mass spectrum of anionic WNn, whereas the mass peak of WN12+ is dominant in the mass spectrum of cationic WNn, implying that the stabilities of WNn clusters are strongly related to their charge states.