A DFT/TDDFT study on the excited-state hydrogen bonding dynamics of 6-aminocoumarin in water solution

Zhang, Mingzhen; Ren, Baiping; Wang, Yi; Chang-xin, Zhao

doi:10.1016/j.saa.2012.09.045

Cited by 18 publications

(7 citation statements)

References 49 publications

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“…5. [30][31][32][33] As CNT/ C@Fe/CS has visibly higher adsorption capacities for MO than MB which is in accordance with other CS-based magnetic materials, 28,34 indicating that it has better adsorption performance for negatively charged pollutants. Apparently, both the adsorption capacities of MB and MO increased rapidly when solution View Article Online pH is below 3 and then decreased at higher pH.…”

Section: Influences Of Ph On Adsorptionsupporting

confidence: 69%

“…Under alkaline solution, a large amount of OH À ions could compete with the dye anions. [30][31][32][33] As CNT/ C@Fe/CS has visibly higher adsorption capacities for MO than MB which is in accordance with other CS-based magnetic materials, 28,34 indicating that it has better adsorption performance for negatively charged pollutants. This may suggest that at low pH, free amino groups in CS are protonated which could be benefit for the attraction of an anionic dye.…”

Section: Influences Of Ph On Adsorptionsupporting

confidence: 69%

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Equilibrium, kinetic and thermodynamic adsorption studies of organic pollutants from aqueous solution onto CNT/C@Fe/chitosan composites

Zhuang

2015

New J. Chem.

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The adsorption of organic pollutants, including dyes (methylene blue (MB) and methyl orange (MO)), antibiotics (tetracycline (TC)), and organic arsenical compound (roxarsone (ROX)), has been studied on a new kind of CNT/C@Fe/CS nanocomposite. The effect of solution pH, contact time, and temperature on adsorption properties has been studied. The adsorption process follows the pseudo-second-order kinetic model very well, and equilibrium studies fit well with Langmuir, Freundlich, and Temkin adsorption isotherms. The maximum uptakes of MB, MO, TC and ROX on CNT/C@Fe/CS are found to be 111.1, 500.0, 125.0, and 142.9 mg g À1 , respectively. Parameters calculated from thermodynamic indicate that the adsorption process is exothermic, spontaneous and favorable. The removal of organic pollutants is obviously dependent on pH values and temperature. These results suggest that the CNT/C@Fe/CS nanocomposite could be effectively used for the removal of organic contaminants from wastewaters.

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Section: Influences Of Ph On Adsorptionsupporting

confidence: 69%

Section: Influences Of Ph On Adsorptionsupporting

confidence: 69%

Equilibrium, kinetic and thermodynamic adsorption studies of organic pollutants from aqueous solution onto CNT/C@Fe/chitosan composites

Zhuang

2015

New J. Chem.

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“…50 Krystkowiak et al 52 have also estimated the change in HBs energy of the 6AC molecule in protic solvents. Zhang et al 53 have studied the excited-state hydrogen bonding dynamics of 6-aminocoumarin with three water molecules, demonstrated that the A type HB is the strongest hydrogen bond among three ones in the S 0 state and in the S 1 state it is extremely weakened, which is significantly greater than the strengthening of the B and C type HBs. Additionally the hydrogen bond interaction and S 1 -exciplex formation may be responsible for the fluorescence of the dye in nitriles.…”

Section: Introductionmentioning

confidence: 99%

Change in energy of hydrogen bonds upon excitation of 6-aminocoumarin: TDDFT/EFP1 study

Ramegowda¹

2013

New J. Chem.

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Density functional theory (DFT)/time dependent density functional theory (TDDFT) calculations combined with the effective fragment potential (EFP) method have been carried out to study the electronic structure and the excited state properties of 6-aminocoumarin (6AC) with five water molecules (6AC-(H 2 O) 5 complex). Ground-state geometries are optimized using DFT with the B3LYP functional combined with cc-pVDZ basis sets and transition energies are computed with the same basis set and functional. One intermolecular hydrogen bond (HB) NÁ Á ÁH-O (type A) is formed between the amino group of 6AC and one water molecule, two intermolecular HBs CQOÁ Á ÁH-O (type B) are formed between the carbonyl group of 6AC and two water molecules, and two HBs of N-HÁ Á ÁO (type C), via participation of their amino hydrogen atoms, with the oxygen atoms of water molecules. The change in hydrogen bond energy, DE HB of the 6AC-(H 2 O) 5 molecule and DE HB for each HB of the 6AC-(H 2 O) 5 molecule are calculatedseparately. Upon excitation of the 6AC-(H 2 O) 5 complex, the A type HB is weakened with a decrease of 11.03 kJ mol À1 energy, whereas B and C type HBs are strengthened with increases of 5.28 and 18.14 kJ mol À1 energy, respectively. In this theoretical work, DE HB is calculated using the procedure proposed by T. Nagata et al. to calculate solute-solvent interaction energy in J. Chem. Phys., 2011, 134, 034110 and this study also confirmed again that intermolecular hydrogen bonds between the 6AC chromophore and aqueous solvents are strengthened, not cleaved upon electronic excitation, which is in accordance with Zhao's works Wiley Periodicals, Inc. J. Comput. Chem., 2011.

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“…The phenomenon of hydrogen bonding has been illustrious for its eminence in various fields like photo physics, photochemistry and biochemistry. The systematic study of hydrogen bonds is much essential for comprehending the photo-physical properties of some organic molecules which is having electron donor and acceptor demeanor at both ground and excited states [1][2][3][4].The EFP method furnishes a polarizable QM-based force field to characterize the inter-molecular interactions. To study the microsolvation effect on biological or organic molecule, EFP1 / DFT method was established explicitly for solvation and it interfaced with the polarizable continuum model (PCM) [5,6] and also EFP1 / TDDFT method has been fostered for characterizing the electronically excited states of solvated molecules [5,[7][8][9].…”

Section: Introductionmentioning

confidence: 99%

DFT / TDDFT insights into excited state intra-molecular hydrogen atom transfer mechanism in Liqcoumarin: an EFP1study

2021

Turk J Chem

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The theoretical calculations were carried out on Liqcoumarin (LC) and its water complex LC+(H 2 0) 4 -[LCH] at the ground (S 0 ) / first excited states (S 1 ) by employing density functional theory (DFT) / state specific time-dependent density functional theory (SS-TDDFT). In LC and LCH, there is an intra-molecular hydrogen bond between hydroxyl group and acetyl group along with four inter-molecular hydrogen bonds in the hydrated molecule. The computational studies of molecular structural parameters, electrostatic potential, NBO analysis, molecular orbital's and UV-Vis spectra of both molecules under polar solvents were explored by B3LYP / 6-31G (d,p) / PCM / EFP1 method. The intra-molecular hydrogen atom transpires between hydroxyl to 2 acetyl group in both pure and hydrated molecules confirm the ICT process and it affirms through potential energy surface (PES) scans.

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A DFT/TDDFT study on the excited-state hydrogen bonding dynamics of 6-aminocoumarin in water solution

Cited by 18 publications

References 49 publications

Equilibrium, kinetic and thermodynamic adsorption studies of organic pollutants from aqueous solution onto CNT/C@Fe/chitosan composites

Equilibrium, kinetic and thermodynamic adsorption studies of organic pollutants from aqueous solution onto CNT/C@Fe/chitosan composites

Change in energy of hydrogen bonds upon excitation of 6-aminocoumarin: TDDFT/EFP1 study

DFT / TDDFT insights into excited state intra-molecular hydrogen atom transfer mechanism in Liqcoumarin: an EFP1study

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