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Two excited state proton transfer mechanisms of 3-hydroxyisoquinoline (3HIQ) in cyclohexane and acetic acid (ACID) were investigated based on the time-dependent density functional theory (TDDFT), suggesting a different double-proton transfer mechanism from the one proposed previously (J. Phys. Chem. B, 1998, 102, 1053). Instead of the formation of keto-enol complexes for 3HIQ self-association in cyclohexane, our theoretical results predicted that 3HIQ self-association exists in two forms: the normal form (enol/enol) and the tautomer form (keto/keto) in cyclohexane. A high barrier (37.023 kcal mol(-1)) between the 3HIQ enol monomer and 3HIQ keto monomer form indicated that the 3HIQ keto monomer in the ground state should not exist. In addition, the constructed potential energy surfaces of the ground state and excited state have been used to explain the proton transfer process. Upon optical excitation, the enol/enol form is excited to the first excited state, then transfers one proton, in turn, transition to the ground state to transfer another proton. A relatively low barrier (8.98 kcal mol(-1)) demonstrates two stable structures in the ground state. In view of the acetic acid solvent effect, two protons of 3HIQ/ACID transfer along the dihydrogen bonds in the first excited state, which is a different transfer mechanism to 3HIQ self-association. In addition, the proton transfer process provides a possible explanation for the fluorescence quenching observed.

In this paper, we report experimentally and theoretically a surface photocatalysis reaction of 4-aminothiophenol (PATP) to p,p 0dimercaptoazobenzene (DMAB) on Au, Ag, and Cu colloids. Surface enhanced Raman scattering (SERS) spectra of PATP on Au and Cu colloids are significantly different from the normal Raman spectrum of PATP powder. Quantum chemical calculations reveal that PATP on Au and Cu colloids is converted to DMAB by a surface photocatalysis reaction, and all the strongly enhanced Raman peaks are the symmetric Ag vibrational mode by surface plasmon. The pH value effects on surface photocatalysis reaction were also investigated experimentally. It is found that plasmon-assisted surface photocatalysis reaction can be efficiently controlled by different pH values. The possibility of protonation of PATP adsorbed on Au and Ag nanoparticles at pH 3 is investigated theoretically. The molecular mechanism is proposed for controlling surface photocatalysis reaction by pH values.

For the first time, the experimental and theoretical evidence for the conversion of 4-nitrobenzenethiol (4-NBT) to p,pdimercaptoazobenzene (DMAB) in Ag and Cu sols by surface photochemistry reaction is obtained with surface-enhanced Raman scattering (SERS) spectroscopy. The SERS spectrum of 4-NBT in Cu sol is identical to that of DMAB produced from 4-aminothiophenol in Ag sol as reported in recent literature, thereby providing direct spectral evidence.

Key Points The Jak/Stat3 pathway promotes the expression of IL-17F in malignant CTCL cells. IL-17F is highly expressed in a subset of CTCL patients and associated with progressive disease.