STRUCTURAL AND SOLVENT EFFECTS ON THE n → π*(′U ← ′A) TRANSITIONS IN ALIPHATIC CARBONYL DERIVATIVES: EVIDENCE FOR HYPERCONJUGATION IN THE ELECTRONICALLY EXCITED STATES OF MOLECULES

1960 ◽  
Vol 38 (12) ◽  
pp. 2508-2513 ◽  
Author(s):  
C. N. R. Rao ◽  
G. K. Goldman ◽  
A. Balasubramanian
Keyword(s):  
Hydrogen Bonding ◽  
Carbonyl Group ◽  
Excited States ◽  
Solvent Effects ◽  
Electronically Excited States ◽  
Carbonyl Derivatives ◽  
Alkyl Groups ◽  
Electronically Excited

The n → π* transition of the carbonyl group has been studied in solvents of varying degree of polarity and hydrogen-bonding ability, in a number of aliphatic carbonyl derivatives. Evidence for hyperconjugation of the alkyl groups in the electronically excited states of molecules has been presented.

Solvent Effects on Electronically Excited States: QM/Continuum Versus QM/Explicit Models

2018 ◽  
Vol 122 (11) ◽  
pp. 2975-2984 ◽  
Author(s):  
Martina De Vetta ◽  
Maximilian F. S. J. Menger ◽  
Juan J. Nogueira ◽  
Leticia González
Keyword(s):  
Excited States ◽  
Solvent Effects ◽  
Electronically Excited States ◽  
Electronically Excited

A theoretical forecast of the hydrogen bond changes in the electronic excited state for BN and its derivatives

Open Physics ◽  
2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Dandan Wang ◽  
Ce Hao ◽  
Se Wang ◽  
Hong Dong ◽  
Jieshan Qiu
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Excited States ◽  
Electronic Spectra ◽  
Intermolecular Hydrogen Bond ◽  
Excitation Energies ◽  
Electronically Excited States ◽  
Electronically Excited ◽  
Accurate Forecast ◽  
Hydrogen Bonding Dynamics

AbstractThe relationship between electronic spectral shifts and hydrogen-bonding dynamics in electronically excited states of the hydrogen-bonded complex is put forward. Hydrogen bond strengthening will induce a redshift of the corresponding electronic spectra, while hydrogen bond weakening will cause a blueshift. Time-dependent density function theory (TDDFT) was used to study the excitation energies in both singlet and triplet electronically excited states of Benzonitrile (BN), 4-aminobenzonitrile (ABN), and 4-dimethylaminobenzonitrile (DMABN) in methanol solvents. Only the intermolecular hydrogen bond C≡N...H-O was involved in our system. A fairly accurate forecast of the hydrogen bond changes in lowlying electronically excited states were presented in light of a very thorough consideration of their related electronic spectra. The deduction we used to depict the trend of the hydrogen bond changes in excited states could help others understand hydrogen-bonding dynamics more effectively.

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

Open Physics ◽  
2011 ◽  
Vol 9 (3) ◽  
Author(s):  
Hongfei Wang ◽  
Meishan Wang ◽  
Mingliang Xin ◽  
Enfu Liu ◽  
Chuanlu Yang
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Excited State ◽  
Excited States ◽  
Intermolecular Hydrogen Bond ◽  
Hydrogen Bond Acceptor ◽  
Electronically Excited States ◽  
Electronically Excited ◽  
Hydrogen Bonding Dynamics ◽  
Hydrogen Bonded

AbstractThe 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

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