Photodissociative experiments were performed on Cu+−C5H5N and Ag+−C5H5N complexes in the gas phase. The dissociative ligand-to-metal charge-transfer fragments, pyridine+, were observed for both complexes. Photodissociation spectra were recorded as a function of laser wavelength. Two continuous, structureless bands were investigated in each complex. Because of the low-energy 2D state of the Cu atom, the Cu+−pyridine dissociative process is more complicated. Several possible mechanisms for this process have been discussed. The binding energies were determined experimentally to be 65.5 and 45.2 kcal/mol for Cu+−pyridine and Ag+−pyridine, respectively. M+−C5H5N (M = Cu or Ag) complexes also were studied theoretically using the HF, MP2, and B3LYP methods. All complexes under study show C 2 v symmetry. The binding energies predicted from the theoretical calculations were less than the experimental values, which were derived from the onset of the charge-transfer appearance combined with the IP (ionization potential). The complexes containing Cu+ and Ag+ are characterized predominantly by electrostatic interactions.

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A series of cyclic hydrocarbons were introduced to react with V(+) and Ta(+) using a pulsed beam expansion source in a time-of-flight mass spectrometer. The third-row metal Ta(+) displayed high reactivity in dehydrogenation to form benzyne complexes, whereas benzene complexes were the terminal products for V(+). M(+)-C(6)H(6) (M(+) = V(+) and Ta(+)) and Ta(+)-C(6)H(4) were selected to perform the photodissociation experiments. In contrast to the V(+) fragment formation via simple cleavage of the V(+)-C(6)H(6) bond, a photoinduced loss of C(2)H(2) occurred in both the Ta(+)-C(6)H(6) and Ta(+)-C(6)H(4) complexes. Plausible explanations involved in the formation of Ta(+)-C(6)H(6) and Ta(+)-C(6)H(4) complexes are given for observing such photo-induced dissociation. The observed photodissociation in Ta(+)-C(6)H(6) is analogous to the dissociative process previously investigated in metal ion-molecule reactions. The photodissociation spectrum of Ta(+)-C(6)H(4) was obtained by recording the appearance of Ta(+)-C(4)H(2) as a function of wavelength and yielded a dissociation energy of 91 +/- 1 kcal mol(-1).