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101.
Santo M Giacomelli L Cattana R Silber J Blanco MM Schapira CB Perillo IA 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2003,59(7):1399-1407
The solvatochromism in 8-hydroxy-1,6-naphthyridin-5(6H)-one-7-carboxylic acid methyl ester (1), 5-hydroxy-1,7-naphthyridin-8(7H)-one-6-carboxylic acid methyl ester (2), and 4-hydroxy-2-methyl-1(2H)-isoquinolone-3-carboxylic acid methyl ester (3), has been studied in solvents of different polarity and hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA) ability. The relative stabilities of isomers for these naphthyridine derivatives and their interaction with the solvent are reported. Two intramolecular hydrogen-bonded structures contribute to the ground state of compound 1. Temperature effects on the absorption bands were recorded to analyse the possible equilibrium between covalent and zwitterionic forms. The formation of zwitterionic species was observed only in HBD solvents, from which is inferred the solvent assistance in the proton transference. AM1 and PM3 semi-empirical calculations were used in support of the proposed interpretations. 相似文献
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Dr. Alberto Verdini Dr. Prashant Shinde Dr. Gian Luca Montanari Dr. Simone Tommaso Suran‐Brunelli Dr. Marco Caputo Dr. Giovanni Di Santo Dr. Carlo A. Pignedoli Dr. Luca Floreano Prof. Daniele Passerone Dr. Andrea Goldoni 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(41):14672-14677
Herein the formation of water molecules in the intermediate step of the redox reaction of porphyrins self‐metalation on O/Cu(111) is demonstrated. Photoemission measurements show that the temperature on which porphyrins pick‐up a substrate metal atom on O/Cu(111) is reduced by about 185±15 K with respect to the pure Cu(111). DFT calculations clearly indicate that the formation of a water molecule is less expensive than the formation of H2 on the O/Cu(111) substrate and, in some cases, it can be also exothermic. 相似文献
105.
S. C. Shen L. Santo L. Genzel 《International Journal of Infrared and Millimeter Waves》2007,28(8):595-610
THz spectra for some amino acids, peptide and protein have been measured by use of commercial and optically compensated FTS
spectrometers. A lot of sharp spectral lines have been observed below 7 THz and attributed, tentatively and in general, to
hydrogen bonds and weak intermolecular interactions for the amino-acids and simple peptides, but the detailed explanation
is still lack and leaving a big room for further investigation.
For memory of Prof. Ludwig Genzel 相似文献
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In this paper, we consider two unidirectionally coupled time delayed systems with periodic delay time modulation. A new stability condition for synchronization is derived analytically with the help of the Krasovskii–Lyapunov approach for single and two time delays. The numerical calculations greatly support our analytical results. 相似文献
110.
Giuseppe Tresoldi Santo Di Pietro Dario Drommi Santo Lanza 《Transition Metal Chemistry》2010,35(2):151-158
The solvento species obtained by the treatment of cis-RuCl2(N,N-L)2 [L = di-2-pyridyl sulfide (dps), di-2-pyrimidyl sulfide (dprs)] with AgPF6, reacted with dithioethers L′ [L′ = 2,6-bis(2-pyridylthiomethyl)pyridine (pytmp), 2,6-bis(2-pyrimidylthiomethyl)pyridine (prtmp) and 2,6-bis{2-(4-methyl)pyrimidylthiomethyl}
pyridine (mprtmp)] to afford the compounds [Ru(N,N-L)2(N,S-L′)][PF6]2. The 1H NMR spectra indicate that L′ is chelated through S and N atoms with the formation of a four-membered ring. As a consequence, the ruthenium and sulfur
atoms are stereogenic centers with ∆ and Λ and (R) and (S) configurations, respectively. NMR spectra, at low temperatures, show that two invertomers, of similar abundance, as enantiomeric
couples ∆S, ΛR and ∆R, ΛS are present. In the methylene region, four AB systems are observed that in both the species contain
two non-equivalent methylene groups. Variable-temperature NMR spectra and EXSY experiments show that the sulfur inversion
produces an exchange between the invertomers. The one-dimensional band-shape analysis of the exchanging methylene signals
showed that the energy barriers for the process are in the 43–52 kJ mol−1 range. The possible mechanisms of the sulfur inversion are discussed. 相似文献