Infrared Spectra and Density Functional Calculations for the Sc(OH)_2,3 and HOScO Molecules and the Sc(OH)₂⁺ Cation in Solid Argon

Abstract

Reactions of laser-ablated Sc atoms with H2O2 molecules or H2 and O2 mixtures in excess solid argon gives four major new products, which are identified from concentration dependence, isotopic substitution, the effect of electron trap doping, and comparison to frequencies calculated by the B3LYP density functional. These are the Sc(OH)3 trihydroxide, the Sc(OH)2 dihydroxide, the Sc(OH)2+ cation, and the trihydroxide anhydride HOScO molecule. The Sc(OH)2+ cation forms a complex in solid argon that is effectively modeled by calculations for the [(Ar)4Sc(OH)2]+ cation including frequency shifts between the neutral and cation dihydroxides. Finally, the Sc(OH)4- anion is detected in H2O2 experiments.

Reactions of Th and U Atoms with C2H2: Infrared Spectra and Relativistic Calculations of the Metallacyclopropene, Actinide Insertion, and Ethynyl Products

“…Similar argon complexes have been observed and calculated recently for the UO 2 + and Group 3 M(OH) 2 + cations isolated in solid argon. [12,56] This is an interesting conclusion in its own right as it further underscores the principle that we are in fact dealing with argon complexes of guest molecules in the argon matrix environment, particularly guest molecules involving electropositive metal atoms.…”

Properties of Lanthanide Hydroxide Molecules Produced in Reactions of Lanthanide Atoms with H2O2 and H2 + O2 Mixtures: Roles of the +I, +II, +III, and +IV Oxidation States

“…The observed peaks shift slightly (0.3 cm –1 ) during this treatment, but they are reproduced within 0.2 cm –1 accuracy on deposition, first annealing and first photolysis. Parallel experiments employed hydrogen/oxygen mixtures to incorporate 18 O into the product molecules, and the frequencies from H 2 and O 2 mixtures were within 1 cm –1 of the H 2 O 2 values. − …”

“…The highest frequency product absorptions for La (3740.5 cm −1 ) and Ce (3742.7 cm −1 ) have already been identified as the antisymmetric OH stretching modes for the trihydroxides La(OH) 3 and Ce(OH) 3 , and their other major product absorptions in Table 1 have also been assigned previously. 20,27 The dihydroxide cations were the only products to exhibit resolved antisymmetric and symmetric OH and OD stretching modes (3−5 cm −1 , double arrows). The two OH stretching frequencies for Ln(OH) 2 (open arrows) were not resolved.…”

“…Laser-ablated lanthanide metal atoms were codeposited with H 2 O 2 molecules diluted in argon during condensation onto a 4 K cesium iodide window. − ,− Because it is more difficult to trap small reactive species in Ne than in Ar because of the much lower freezing temperature for Ne, particularly when the energy from laser ablation is added, we have chosen to study all of the Ln metals (excluding radioactive Pm) in argon only. A hydrogen peroxide complex with urea (Aldrich) at room temperature behind a Chemglass Pyrex-Teflon valve evaporated H 2 O 2 molecules into the flowing argon (4 mmol in 1 h) deposition stream directed at the cold window.…”

“…Another source of oxidative addition products is the reaction with hydrogen peroxide molecules, which has become straightforward through the use of a urea–hydrogen peroxide complex as a source of H 2 O 2 molecules at room temperature. − (In ref , the captions for Figures 8 and 9 should state La instead of Y.) Owing to the relatively weak O–O bond (50 kcal/mol) in H 2 O 2 , metal atom reactions to form M­(OH) 2 are highly exothermic.…”