Effects of hydrogen bond on 2-aminopyridine and its derivatives complexes in methanol solvent.

In the present work, the time-dependent density functional theory (TD-DFT) method was adopted to investigate the excited state hydrogen-bond dynamics of 2-aminopyridine monomer (2AP) and its derivatives in hydrogen donating methanol solvent. The calculated steady-state absorption and fluorescence spectra agree well with the experimental results. Theoretical results state that the bond lengths of both O-H and N-H bands are lengthened, while the intermolecular hydrogen bond lengths are shortened in the excited state. Further, the intermolecular hydrogen bonds are proved to be strengthened according to the calculated binding energy. As a reasonable explanation, the hydrogen bonds binding energy increases with multiple hydrogen-bonding interactions in the electronically excited state. In addition, the hydrogen bonding dynamics in the excited state were visualized by the spectral shifts of vibrational modes. The calculated infrared spectra of both O-H and N-H stretching vibrational regions revealed that the O-H and N-H stretching bands red-shift.

[1]  T. Elsaesser,et al.  Femtosecond mid-infrared spectroscopy of condensed phase hydrogen-bonded systems as a probe of structural dynamics. , 2003, Faraday discussions.

[2]  Andrew G. Glen,et al.  APPL , 2001 .

[3]  Keli Han,et al.  Hydrogen bonding in the electronic excited state. , 2012, Accounts of chemical research.

[4]  S. Wallace,et al.  Solvation effects in jet-cooled 2-aminopyridine clusters: excited-state dynamics and two-color threshold photoionization spectroscopy , 1985 .

[5]  Shuo Chai,et al.  Reconsideration of the excited-state double proton transfer (ESDPT) in 2-aminopyridine/acid systems: role of the intermolecular hydrogen bonding in excited states. , 2009, Physical chemistry chemical physics : PCCP.

[6]  G. Leach,et al.  Structure and excited-state dynamics of 2-aminopyridine van der Waals molecules and hydrogen-bonded complexes , 1987 .

[7]  Suyong Re,et al.  Charge transfer and OH vibrational frequency red shifts in nitrate-water clusters. , 2008, The journal of physical chemistry. A.

[8]  Guang-Jiu Zhao,et al.  Role of intramolecular and intermolecular hydrogen bonding in both singlet and triplet excited states of aminofluorenones on internal conversion, intersystem crossing, and twisted intramolecular charge transfer. , 2009, The journal of physical chemistry. A.

[9]  A. Schäfer,et al.  Fully optimized contracted Gaussian basis sets of triple zeta valence quality for atoms Li to Kr , 1994 .

[10]  Ronghu Wu,et al.  Structure and Hydrogen Bonding of Different Isomers of 2-Aminopyridine·NH3 Studied by IR/R2PI Spectroscopy , 2004 .

[11]  R. A. Kydd,et al.  Microwave spectrum of 2-aminopyridine , 1972 .

[12]  Timothy S. Zwier,et al.  Electronic and Infrared Spectroscopy of Anthranilic Acid in a Supersonic Jet , 2003 .

[13]  Faraday Discuss , 1985 .

[14]  Filipp Furche,et al.  Adiabatic time-dependent density functional methods for excited state properties , 2002 .

[15]  Yufang Liu,et al.  Theoretical Study on Hydrogen Bonding of Mono‐ and Dihydrated Complexes of 7‐(3′‐Pyridyl)indole in Excited States , 2013 .

[16]  Henk Fidder,et al.  Ultrafast chemistry: using time-resolved vibrational spectroscopy for interrogation of structural dynamics. , 2005, Annual review of physical chemistry.

[17]  Ronghu Wu,et al.  Structure and hydrogen bonding of 2-aminopyridine·(H2O)n(n = 1, 2) studied by infrared ion depletion spectroscopy , 2004 .

[18]  W. Domcke,et al.  Intramolecular Hydrogen Bonding in the S1(ππ*) Excited State of Anthranilic Acid and Salicylic Acid: TDDFT Calculation of Excited-State Geometries and Infrared Spectra , 2004 .

[19]  T. Elsaesser,et al.  Probing solvation dynamics with femtosecond vibrational spectroscopy , 2000 .

[20]  E. Nibbering,et al.  Femtosecond pump–probe and grating scattering study of condensed-phase hydrogen-bonding dynamics of complexes of Coumarin 102 , 1999 .

[21]  Ronghu Wu,et al.  Infrared Depletion Spectroscopy and Structure of the 2-Aminopyridine Dimer† , 2004 .

[22]  Y. Nibu,et al.  Solvation effect on the NH stretching vibrations of solvated aminopyrazine, 2-aminopyridine, and 3-aminopyridine clusters. , 2012, The journal of physical chemistry. A.

[23]  R. Hochstrasser,et al.  Non-Markovian Dynamics of the Vibrations of Ions in Water from Femtosecond Infrared Three-Pulse Photon Echoes , 1998 .

[24]  Guang-Jiu Zhao,et al.  Effects of hydrogen bonding on tuning photochemistry: concerted hydrogen-bond strengthening and weakening. , 2008, Chemphyschem : a European journal of chemical physics and physical chemistry.

[25]  T. Elsaesser,et al.  Femtochemistry of Hydrogen Bonded Complexes after Electronic Excitation in the Liquid Phase: The Case of Coumarin 102 , 2000 .

[26]  J. Waluk.  Hydrogen-bonding-induced phenomena in bifunctional heteroazaaromatics. , 2003, Accounts of chemical research.

[27]  Mengtao Sun.  Control of structure and photophysical properties by protonation and subsequent intramolecular hydrogen bonding. , 2006, The Journal of chemical physics.

[28]  Graham R. Fleming,et al.  CHROMOPHORE-SOLVENT DYNAMICS , 1996 .

[29]  J. L. Whitten,et al.  Coulombic potential energy integrals and approximations , 1973 .