Excited-State Proton Transfer of 5,8-Dicyano-2-naphthol in High-Temperature and High-Pressure Methanol: Effect of Solvent Polarity and Hydrogen Bonding Ability

2018 ◽  
Vol 122 (51) ◽  
pp. 12363-12374 ◽  
Author(s):  
Kaori Fujii ◽  
Megumi Aramaki ◽  
Yoshifumi Kimura
Keyword(s):  
High Pressure ◽  
Hydrogen Bonding ◽  
Excited State ◽  
High Temperature ◽  
Proton Transfer ◽  
Solvent Polarity ◽  
Effect Of Solvent ◽  
Excited State Proton Transfer

scholarly journals Femtosecond Dynamics on 2-(2′-Hydroxy-4′-diethylaminophenyl)benzothiazole: Solvent Polarity in the Excited-State Proton Transfer

ChemPhysChem ◽  
2006 ◽  
Vol 7 (6) ◽  
pp. 1372-1381 ◽  
Author(s):  
Yi-Ming Cheng ◽  
Shih-Chieh Pu ◽  
Chia-Jung Hsu ◽  
Chin-Hung Lai ◽  
Pi-Tai Chou
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Solvent Polarity ◽  
Femtosecond Dynamics ◽  
Excited State Proton Transfer

Excited-State Proton Transfer in Fluorescent Photoactive Yellow Protein Containing 7-Hydroxycoumarin

2014 ◽  
Vol 896 ◽  
pp. 85-88
Author(s):  
Dian Novitasari ◽  
Hironari Kamikubo ◽  
Yoichi Yamazaki ◽  
Mariko Yamaguchi ◽  
Mikio Kataoka
Keyword(s):  
Hydrogen Bonding ◽  
Excited State ◽  
Proton Transfer ◽  
Fluorescent Protein ◽  
Stokes Shift ◽  
Spectroscopic Studies ◽  
Photoactive Yellow Protein ◽  
Excited State Proton Transfer ◽  
Hydrogen Bonding Network ◽  
Green Fluorescent

Green fluorescent protein (GFP) has been used as an effective tool in various biological fields. The large Stokes shift resulting from an excited-state proton transfer (ESPT) is the basis for the application of GFP in such techniques as ratiometric GFP biosensors. The chromophore of GFP is known to be involved in a hydrogen-bonding network. Previous X-ray crystallographic and FTIR studies suggest that a proton wire along the hydrogen-bonding network plays a role in the ESPT. In order to examine the relationship between the ESPT and hydrogen-bonding network within proteins, we prepared an artificial fluorescent protein using a light-sensor protein, photoactive yellow protein (PYP). The native chromophore of p-coumaric acid (pCA) of PYP undergoes trans-cis isomerization after absorbing a photon, which triggers proton transfers within the hydrogen-bonding network comprised of pCA and proximal amino acid residues. Although PYP emits little fluorescence, we succeeded to reconstitute an artificial fluorescent PYP (PYP-coumarin) by substituting the pCA with its trans-lock analog 7-hydroxycoumarin. Spectroscopic studies with PYP-coumarin revealed that the chromophore takes an anionic form at neutral pH, but is protonated by lowering pH. Both the protonated and deprotonated forms of PYP-coumarin emit intense fluorescence, as compared with the native PYP. In addition, both the deprotonated and protonated forms show identical λmax values in their fluorescence spectra, indicating that ESPT occurs in the artificial fluorescent protein.

Effects of intermolecular hydrogen bonding on the excited-state proton transfer properties of the cinnamonitrile–methanol complex

2013 ◽  
Vol 91 (3) ◽  
pp. 229-234 ◽  
Author(s):  
Dapeng Yang ◽  
Ruiquan Qi
Keyword(s):  
Hydrogen Bonding ◽  
Excited State ◽  
Charge Transfer ◽  
Proton Transfer ◽  
Density Functional ◽  
Dft Method ◽  
Electronic Energy ◽  
Intermolecular Hydrogen Bonding ◽  
Excited State Proton Transfer ◽  
Hydrogen Bonded

The time-dependent density functional theory (TD-DFT) method was used to study the excited-state proton transfer (ESPT) properties of the hydrogen-bonded cinnamonitrile (3TPAN)–methanol (MeOH) complex (3TPAN–MeOH). The intermolecular hydrogen bonds N1···H11 in both the ground state S0 and the excited state S1 were demonstrated by the optimized geometric structures of the hydrogen-bonded 3TPAN–MeOH complex. While in the excited state S3, a new hydrogen bond H11···O1 was formed after the ESPT took place from the hydrogen-bonded MeOH molecule to the 3TPAN moiety. It was demonstrated that the electronic transitions of the S1 states for both the 3TPAN monomer (including the S3 state) and the hydrogen-bonded 3TPAN–MeOH complex should be of a localized-excited (LE) nature on the 3TPAN molecule, while the S3 state of the hydrogen-bonded 3TPAN–MeOH complex should be of charge transfer (CT) character from the hydrogen-bonded MeOH molecule (through O1···H11) to the 3TPAN moiety. The S3-state proton transfer and charge transfer due to the intermolecular hydrogen-bonding interaction should be the reasons for the remarkable redshift (0.91 eV) of the S3-state electronic energy for the hydrogen-bonded 3TPAN–MeOH complex compared with that of the 3TPAN monomer.

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