Reactions of Laser-Ablated Platinum and Palladium Atoms with Dioxygen. Matrix Infrared Spectra and Density Functional Calculations of Platinum Oxides and Complexes and Palladium Complexes

Abstract

Platinum and palladium atoms produced by laser ablation were reacted with dioxygen diluted in argon during condensation at 10 K. Reaction products, including the M(O2) and (O2)M(O2) complexes prepared with thermal metal atoms, and the platinum oxides PtO, OPtO, PtO3, OOPtO, and (O2)PtO, were analyzed by matrix infrared spectroscopy. Absorptions due to PdO and OPdO were not identified. Density functional theory (B3LYP) calculations were performed on product molecules, which were identified on the basis of isotopic frequency shifts and correlation with density functional calculations. The most interesting new molecule produced here, linear OPtO, can also be produced by photolysis of the cyclic Pt(O2) complex.

Water Adsorption on Platinum Dioxide and Dioxygen Complex: Matrix Isolation Infrared Spectroscopic and Theoretical Study of Three PtO2–H2O Complexes

“…Calculations were first performed on the Pt(O 2 ) complex. Consistent with previous investigation, [29] although the triplet end-on bonded isomer was found to be 13.5 kcal mol À1 lower in energy than the singlet side-on bonded one, the calculated vibrational frequencies at 1042. . [29,30] Hence we refer to the cyclic closed-shell singlet Pt(O 2 ) complex with C 2v symmetry as the ground state platinum dioxygen complex, which is involved in the following reaction with water.…”

“…Consistent with previous investigation, [29] although the triplet end-on bonded isomer was found to be 13.5 kcal mol À1 lower in energy than the singlet side-on bonded one, the calculated vibrational frequencies at 1042. . [29,30] Hence we refer to the cyclic closed-shell singlet Pt(O 2 ) complex with C 2v symmetry as the ground state platinum dioxygen complex, which is involved in the following reaction with water. Note that the relative energy calculated by DFT methods might not be reliable enough to be compared with the experimental observations in some cases, which was recently demonstrated in a combined theoretical and experimental study on the [Pt,O 2 ] + cation.…”

“…The experiments were performed with approximately 13 mJ pulse À1 using different ratios ) are produced, which were previously identified in the reactions of platinum atoms and O 2 in solid argon. [29,30] formed via the aggregation of two water molecules upon sample annealing are also observed. [31] In addition, a series of new absorptions at 3699.3, 3521.9, 1603.0 and 924.0 cm À1 are produced (labeled as "A").…”

“…[29,30] The band position and isotopic frequency ratio imply that the 960.4 cm À1 absorption was due to an antisymmetric OÀPtÀO vibration of PtO 2 but slightly perturbed by another species in solid argon. Following the assignment of group B absorptions, the three infrared bands at 3726.4, 3629.6 and 1591.4 cm À1 are due to the antisymmetric stretching, symmetric stretching and bending vibrations of a perturbed water molecule, respectively.…”

A Critical Appraisal of the Experimental Data on the Molecular Structure and Spectra of Halides, Oxides, and Hydrides of the s-, d-, and f-Block Elements

“…IrO 2 [132] , RhO 2 , [133] and PtO 2 [134] are all reported as linear, while the more weakly bound YO 2 and LaO 2 are nonlinear [135] with n 1 showing an anomalously high intensity and frequency relative to n 3 . There are now data on all the lanthanide dioxides apart from Pm, Er, and Lu.…”