Effects of intermolecular interaction on proton tunneling: Theoretical study on two-dimensional potential energy surfaces for 9-hydroxyphenalenone-CO2/H2O complexes

Abstract

Theoretical studies of the N2O van der Waals dimer: Ab initio potential energy surface, intermolecular vibrations and rotational transition frequencies Role of isomerization channel in unimolecular dissociation reaction H 2 CO→H 2 +CO : Ab initio global potential energy surface and classical trajectory analysisThe effects of binding of CO 2 or H 2 O with 9-hydroxyphenalenone ͑9HPO͒ on proton tunneling in the S 0 state have been theoretically investigated. High-level ab initio calculations predict that CO 2 is van der Waals-bonded to the CvO¯OH moiety of 9HPO in the most stable structure. This planar structure is more stable than the nonplanar structure where CO 2 is bonded above the aromatic rings of 9HPO. In the 9HPO-H 2 O complex, H 2 O is hydrogen-bonded to the carbonyl group in the most stable structure. Two-dimensional potential energy surfaces ͑PESs͒ for 9HPO-CO 2 and 9HPO-H 2 O have been calculated with the reaction surface method, and the contour plots of PESs for the complexes are compared with those for the 9HPO monomer. The binding of CO 2 with 9HPO induces slight asymmetry in the double-minimum potential well, whereas the asymmetry of the PES is very large for the binding of H 2 O. The transition state energy for 9HPO-CO 2 drastically decreases to be about a half that of 9HPO, while that for 9HPO-H 2 O is only slightly smaller than the transition energy for 9HPO. The vibrational wave function for in 9HPO-CO 2 is substantially delocalized over two potential minima, but that for 9HPO-H 2 O is completely localized around a single potential minimum. The calculated tunneling splitting of the zero-point level in 9HPO-CO 2 is only 10% smaller than the corresponding splitting of 9HPO, whereas proton tunneling is quenched in 9HPO-H 2 O. The calculated results are consistent with the prediction from the electronic spectra measured in a supersonic free jet.

Hydrogen Delocalization in an Asymmetric Biomolecule: The Curious Case of Alpha-Fenchol

“…Symmetric parents for other well investigated structural families with respect to (partial) localization by chemical or isotopic symmetry breaking include porphycen (tunneling splitting of 4.4 cm ) [ 37 , 38 , 39 , 40 , 41 ], malonaldehyde (21.6 cm ) [ 4 , 7 , 14 ] and 9-hydroxyphenalenone (69 cm ) [ 3 , 42 , 43 , 44 , 45 ].…”

A new luminescent molecular based terbium hybrid material containing both organic polymeric chains and inorganic silica networks

“…Thereby, lanthanide ions were rarely used alone as luminescent component. Among the various ligands, organic ligands especially b-diketone are peerless and much more effective due to the large delocalization of the p electrons which contribute to the strong absorption bands [4][5][6]. In the past decades, lanthanide complexes especially b-diketonates have been intensively studied due to their inherent extremely sharp emission peaks and high quantum efficiency [7].…”

Excited-state double-proton transfer dynamics of deuterated 7-azaindole dimers in a free jet studied by hole-burning spectroscopy

“…Thus, the ESDPT reaction of (7AI) 2 occurs in a highly vibrational-mode specific fashion as in the case of proton tunneling in tropolone and 9-hydroxyphenalenone. [18][19][20] Recent studies of (7AI) 2 have concentrated on the ESDPT mechanism, i.e., whether the two protons move simultaneously (concerted mechanism) or stepwise (sequential mechanism). In Scheme 1 a concerted double proton transfer (DPT) and a sequential single-proton transfer (SPT) is shown.…”