ESR of matrix-isolated K+...HCl-

Abstract

transition for pyrene on silica gel may also reflect the importance of an asymmetric interaction on the molecule, part of which is in an environment approaching the vapor or inert solvent. This aspect of the photophysics of adsorbed species invites theoretical attention. ConclusionThe picture that emerges from these results can be summarized as follows. The distribution of pyrene molecules on the surfaces in question is not random: there appear to be preferred sites. The result is an inhomogeneous distribution which yields a multicomponent decay. Strong evidence exists for the formation of a very weakly bound ground-state bimolecular association product, particularly on silica gel, and the data suggest associating this phenomenon with particular sites at which an interaction stabilizes this bimolecular association. The data also indicate that this phenomenon may be related to some peculiarity of the hydrogen-bonding interaction with the x system of the aromatic hydrocarbon. It is suggested that the static and highly asymmetric interaction may cause pyrene to behave in a manner different from that in hydroxylic solvents where the interactions are rapidly averaged and, on the time scale of the lifetime of pyrene, the interactions are symmetric over the whole of the x system.If the silanol groups are blocked by a long-chain alcohol and polyalcohol, the pyrene molecules appear forced to be adsorbed in areas of weaker interactions where the tendency to form the bimolecular ground-state arrangement is diminished. The mobility during the lifetime also appears to be greatly enhanced, and dynamic excimer formation is then possible.

What is the ground electronic state of KO?

“…Early experiments on KO were inconclusive, with Herm and Herschbach initially concluding that the ground electronic state was 2 ⌺ ϩ on the basis of magnetic deflection experiments 20 and then concluding 21 that the nonobservation of an electron spin resonance ͑ESR͒ spectrum was consistent with its being 2 ⌸. Allison et al 19 calculated the ground state of KO to be 2 ⌸ ͑with the 2 ⌺ ϩ state lying 830 cm Ϫ1 above͒ using configuration interaction ͑CI͒ calculations and a double-basis set, with polarization functions on the oxygen atom.…”

Reactions between Li Atoms and HX (X = F, Cl) Molecules: Semiempirical SCF MO and Matrix Isolation ESR Studies

“…A photoassisted process was hence suggested for its formation. 3 It seemed that the reaction between an alkali metal atom and an HX molecule ought to proceed spontaneously driven initially by a three electron bonding scheme similar to that invoked above for the Li/RCN system. We therefore examined the (possible) reaction process between the Li atom and the HCl molecule and that between the Li atom and the HF molecule first by the semiempirical SCF molecular orbital method (AM1), 4 and then experimentally by matrix isolation ESR spectroscopy.…”

Partial Reduction and Selective Transfer of Hydrogen Chloride on Catalytic Gold Nanoparticles

“…And fourth, an inverse kinetic isotopic effect KIE H = 0.71 (1) was found for the hydrochlorination of phenylacetylene (PA) with DCl catalyzed by AuÀTiO 2 ,which strongly supports the idea that the Ha tom is bound to ah eavy atom, Au 0 in this case,during the reaction, in accordance to the location of the s* H-Cl LUMO of HCl on the Ha tom. [3,10] Density functional theory (DFT) calculations,s hown in Figure 2, support the Au···H À Cl electron transfer,since all the optimized geometries for HCl adsorbed on Au 38 NPs show the Hatom pointing to the Au surface,with the Cl atom far from the metal, and the HÀCl bond weakens and increases its length from 1.285 in the isolated molecule up to 1.344 when adsorbed on Au (Supporting Information, Figure S15). Once the Au···H À Cl interaction occurs,d issociation of H À Cl is an exothermic process by 8-10 kcal mol À1 ,w ith activation energy barriers of 5-7 kcal mol À1 depending on the presence or not of co-adsorbed alkyne (Figure 2; Supporting Information, Figure S15).…”

“…[9] UV/Vis measurements showed the expected absorption band for the excited reduced state of HCl at about 210-220 nm (ca. 5eVh igher than HCl;S upporting Information, Figure S1), [10] which is well differentiated from the 1,4-dioxane solvent (ca. 190 nm), HCl itself (ca.…”