Ag(+)(benzene) complexes are generated in the gas phase by laser vaporization and mass selected in a time-of-flight spectrometer. UV laser excitation at either 355 or 266 nm results in dissociative charge transfer (DCT), leading to neutral silver atom and benzene cation products. Kinetic energy release in translationally hot benzene cations is detected using a new instrument designed for photofragment imaging of mass-selected ions. Velocity-map imaging and slice imaging techniques are employed. In addition to the expected translational energy release, DCT of Ag(+)(benzene) produces a distribution of internally hot benzene cations. Compared with experiments at 355 nm, 266 nm excitation produces only slightly higher translational excitation and a much greater fraction of internally hot benzene ions. The maximum kinetic energy release in the photodissociation sets an upper limit on the Ag(+)(benzene) dissociation energy of 32.8 (+1.4/-1.5) kcal/mol.

Scandium and yttrium carbonyl cations produced in the gas phase via laser vaporization are mass selected and studied with infrared laser spectroscopy in the C-O stretching region. Mass spectra, ion fragmentation behavior, and infrared spectra, complemented by computational chemistry, establish the coordination numbers and structures of these complexes. Sc(+) does not form the eight-coordinate 18-electron complex but instead produces a 16-electron seven-coordinate species. However, Y(+) forms the anticipated eight-coordinate structure. Density functional theory computations provide structures and corresponding vibrational spectra for these complexes. Sc(CO)7(+) has a C3v capped octahedral structure, while Y(CO)8(+) forms a D4d square antiprism. The C-O stretches at 2086 and 2087 cm(-1) for Sc(CO)7(+) and Y(CO)8(+), respectively, are among the most red-shifted frequencies measured for any transition metal carbonyl cation.

The argon dimer cation is produced in a plasma generated by a laser spark in a supersonic expansion. The cold ions are mass selected and investigated by photodissociation at 355 nm, with velocity map imaging of the Ar + photofragment. Using the radius of the image, we determine the kinetic energy release and derive the ground state dissociation energy of Ar 2 + as D 0 " = 1.32 +0.03/-0.02 eV. Additionally, the angular distribution is described with β = 1.71-1.95, consistent with excitation of the parallel-type 2 Σ g + ← 2 Σ u + transition.

Protonated ions of acetylacetone, H(Hacac), and their argon-tagged analogues are produced via a pulsed discharge and cooled in a supersonic expansion. These ions are mass analyzed, selected in a time-of-flight spectrometer, and studied with infrared laser photodissociation spectroscopy using the method of rare-gas atom tagging. Computational studies at the DFT/B3LYP level are employed to elucidate the structures and spectra of these ions, which are expected to exist as either enol- or keto-based tautomers. The protonated acetylacetone ion is found to form a single enol-based isomer. Adding one or two water molecules to this ion, for example, H(Hacac)(HO), produces primarily enol-based structures, although a small concentration of keto structures also contribute to the spectra. The vibrational patterns resulting from hydrogen bonding in these systems are not well-described by theory. Addition of a third water molecule to form the H(Hacac)(HO) ion causes a significant change in the spectroscopy, attributed to proton transfer from the H(Hacac) ion into the water solvent.

The title compound, [Zn(C 6 H 5 S) 2 (C 18 H 12 N 2 )], was prepared as a model for future complexes that will be incorporated into light-harvesting arrays. The Zn II atom lies on a twofold rotation axis and the ligands are arranged tetra­hedrally around this atom. The benzene­thiol­ate ligand and the biquinoline ligand are nearly perpendicular to one another, making a dihedral angle of 84.09 (5)°. The biquinoline ligand is nearly planar, with a maximum deviation of 0.055 (3) Å from the mean plane of the ring system. In the crystal, the mol­ecules pack in a manner such that the biquinoline ligands are parallel to one another, with a π–π inter­action [interplanar distance = 3.38 (1) Å] with the neighboring biquinoline ligand.