Excited-state hydrogen bonding dynamics of methyl isocyanide in methanol solvent: A DFT/TDDFT study

Abstract

Abstract:The time-dependent density functional theory (TDDFT) method was performed to investigate the hydrogenbonding dynamics of methyl cyanide (MeNC) as hydrogen bond acceptor in hydrogen donating methanol (MeOH) solvent. The ground-state geometry optimizations and electronic transition energies and corresponding oscillation strengths of the low-lying electronically excited states for the isolated MeNC and MeOH monomers, the hydrogen-bonded MeNC-MeOH dimer and MeNC-2MeOH trimer are calculated by the DFT and TDDFT methods, respectively. An intermolecular hydrogen bond N≡C· · · HO is formed between MeNC and methanol molecule. According to Zhao's rule on the excited-state hydrogen bonding dynamics, we find the intermolecular hydrogen bonds N≡C· · · HO are strengthened in electronically excited states of the hydrogen-bonded MeNC-MeOH dimer and MeNC-2MeOH trimer, with the excitation energy of a related excited state being lowered and electronic spectral redshifts being induced. Furthermore, the hydrogen bond strengthening in the electronically excited state plays an important role on the photophysics and photochemistry of MeNC in solutions

Sensing Mechanism of Excited‐State Intermolecular Hydrogen Bond for Phthalimide: Indispensable Role of Dimethyl Sulfoxide

“…[ 1 ] Since the excited‐state hydrogen bond enhancing mechanism was proposed by Han et al ., it has quickly become one of the hot spots in the international optical field. [ 2‐8 ] The hydrogen bonds between molecules are enhanced under the state of photoexcitation and promoted during the internal conversion process, which will have a significant influence on many processes of molecules, such as photophysics and photochemistry. [ 9‐13 ] However, it happens on the femtosecond scale so that the details of molecular‐level information, such as geometrical conformational changes, proton transfer and others, are difficult to be captured and analysed by spectroscopic experiments.…”

Physicochemical Properties of Derivatives ofN,N-Dimethylamino-cyclic-chalcones: Experimental and Theoretical Study

“…The phenomena of hydrogen bond (H-b) interaction in the ground-and excited-states play a crucial role in determining the structure, energetic and dynamics of different types of organic chromophores and biological biopolymers such as protein and nucleic acid. Thus, to understand such complications, numerous experimental [1][2][3][4][5][6][7][8][9][10][11][12] and theoretical [13][14][15][16][17][18][19][20] investigations were devoted to determine the nature of such intermolecular interactions. Accordingly, photophysical properties like fluorescence quantum yield (f), fluorescence life-time (t f ), absorption and fluorescence spectral shift, vibrational modes, transient absorption, etc., have been used in the H-b investigations.…”