Wagging motion of hydrogen-bonded wire in the excited-state multiple proton transfer process of 7-hydroxyquinoline·(NH3)3 cluster

A detailed theoretical study on the excited‐state hydrogen‐bonding dynamics and the proton transfer mechanism for a novel white‐light fluorophore

“…The positions of CPs were searched by the Newton method, and all the CPs could be found in this work, since our theoretical results satisfy the Poincaré-Hopf relationship (i.e., n NCP − n BCP + n RCP − n CCP = 1). [8][9][10][11][12][13][14][15][16][17][18][19] For the S 0 -state 1-keto structure, our calculated results show that the optimized form is the same as that of 1-enol. (the maximum threshold value proposed by Popelier to ensure the presence of a hydrogen bond [57] ).…”

“…It plays important roles in organic materials, organometallic molecules, biomolecules (proteins, nucleic acids, DNR, or RNA), and so on. [9][10][11][12][13][14][15] As one of the fundamental chemical reactions along with hydrogen bonding, proton transfer plays a decisive role in the chemical and biological fields because of its unique characters. With the development of experimental techniques, excited-state hydrogen-bonding dynamical processes have been explored in detail experimentally and theoretically.…”

Stepwise vs concerted excited state tautomerization of 2-hydroxypyridine: Ammonia dimer wire mediated hydrogen/proton transfer

“…For analogous systems such as 7-hydroxyquinoline-(NH 3 ) 3 , the enol-keto tautomerization mediated by the NH 3 wire has first been assigned to an excited state proton transfer reaction, 37 then to hydrogen transfer from Configuration Interaction Singles (CIS) calculations, 27 and lately to proton transfer from complete active space self-consistent field (CASSCF)/complete active space with second-order perturbation theory (CASPT2), 38 and time dependent-density functional theory (TD-DFT) 39,40 calculations. In a similar system, 7-azaindole with solvent molecules, CC2 calculations seem to show that the solvent-induced transfer should be a sequential proton transfer in the case of 7-azaindole-(NH 3 ) 2 41 and a concerted multiple proton transfer in the case of 7-azaindole-(methanol) 2 42-44 and 7-azaindole-(H 2 O) 2,3 clusters.…”

A DFT/TDDFT investigation of the excited state proton transfer reaction of fisetin chromophore

“…The geometric optimizations of fisetin-enol, fisetin-open and fisetin-enol were performed using DFT in the S 0 state and using TDDFT in the S 1 state. Especially, the TDDFT method has become a very useful tool to theoretically investigate the hydrogen bonding interaction that occurs in the excited-state of hydrogen-bonded systems [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. In addition, Becke's three-parameter hybrid exchange functional with Lee-Yang-Parr gradient-corrected correlation (B3LYP functional) was selected in both the DFT and TDDFT methods [69][70][71][72].…”

“…Up to now, many different sensing mechanisms, such as intramolecular charge transfer (ICT), photo-induced electron transfer (PET), fluorescence resonance energy transfer (FRET), and excited state proton transfer (ESPT) and so forth [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38], are relevant with hydrogen bonding. Particularly, the excited state interand intra-molecular proton transfer (ESIPT) reactions have been drawing great attention due to their unique photo-physical and photo-chemical properties.…”