DFT and AIM studies of intramolecular hydrogen bonds in dicoumarols

Trendafilova, Natasha; Bauer, G.; Mihaylov, Tzvetan

doi:10.1016/j.chemphys.2004.03.021

Cited by 51 publications

(43 citation statements)

References 38 publications

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“…15 Our previous DFT study showed that the B3LYP functional with 6-31G(d) basis set is a suitable method for geometry and wavenumber predictions since it reproduced quite well the experimental geometry parameters and the intramolecular O-HÐ Ð ÐO hydrogen bonds in dicoumarol and PhDC (as obtained from X-ray diffraction analysis). 11 The geometries of o-, m-and p-PyDC were fully optimized without any constraints with the help of the analytical gradient procedure. The vibrational spectra of the compounds were calculated and discussed at the optimized geometries.…”

Section: Computational Proceduresmentioning

confidence: 99%

“…9,10 On the basis of B3LYP/6-31G(d) calculations in our previous study we estimated the hydrogen bond strength in PhDC as relatively high ( 55.46 kJ/mol and 52.32 kJ/mol). 11,12 The only difference between PhDC and o-, m-and p-PyDC is the type of the methylene substituent (it is phenyl in PhDC and pyridine in PyDCs), and therefore we suggest the same skeleton bis-coumarin structure for o-, m-and p-PyDC molecules stabilized by two intramolecular O-HÐ Ð ÐO hydrogen bonds ( Fig. 2(a)).…”

Section: Introductionmentioning

confidence: 99%

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Raman, FT‐IR and DFT studies of ortho‐, meta‐ and para‐pyridinomethylene substituted di(4‐hydroxy‐coumarin) and their Ce(III), La(III) and Nd(III) complexes

Georgieva

Kostova

Trendafilova

et al. 2006

J Raman Spectroscopy

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Vibrational spectra of ortho-, meta-and para-pyridinomethylene substituted di(4-hydroxycoumarin) (o-, m-, p-PyDC, (PyDCs)) and their Ce(III), La(III) and Nd(III) complexes were studied by Raman and Fourier transform infrared (FT-IR) spectroscopies. Density functional theory (DFT) at B3LYP/6-31G(d) level was used to determine the geometrical and vibrational characteristics of the neutral PyDC isomers and their dianionic forms. The experimental IR and Raman bands of PyDCs were assigned to the corresponding normal modes on the basis of DFT calculations. The effect of the intramolecular H-bonds in PyDCs as well as of the PyDCs deprotonation on the vibrational mode positions was estimated by comparison with the molecular vibrations of the H-bonding-free 4-hydroxycoumarin andPyDC dianionic forms. The characteristic IR and Raman bands of o-, m-and p-PyDC were specified and discussed. The comparative vibrational analysis of the neutral and the dianionic PyDCs and their Ln(III) complexes gave evidence that the PyDC ligands bound the lanthanide(III) through the carbonylic oxygens and the deprotonated hydroxylic oxygens.

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Section: Computational Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Raman, FT‐IR and DFT studies of ortho‐, meta‐ and para‐pyridinomethylene substituted di(4‐hydroxy‐coumarin) and their Ce(III), La(III) and Nd(III) complexes

Georgieva

Kostova

Trendafilova

et al. 2006

J Raman Spectroscopy

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“…De acordo com estudos teóricos 30 , a distribuição de carga nos átomos de oxigênio dos grupos carbonila e hidroxila pode ser afetada pela substituição, o que por razões eletrostáticas altera as distâncias O ... O, influenciando diretamente na força da ligação de hidrogênio. No entanto, tais propriedades não foram observadas para os compostos estudados quando se comparou o malonaldeído (1 HB ) e seus derivados.…”

Section: Cargas Atômicasunclassified

“…No entanto, as cargas de O(1) sofreram poucas variações ou mantiveram-se constantes. Para aos compostos 4 HB e 6 HB , que apresentam ligações de hidrogênio mais intensas e maior deslocalização dos elétrons π, esperava-se uma diminuição das cargas negativas nos oxigênios O(1) e O(3), porém o que se observou foi um aumento das mesmas, quando comparadas às cargas de 1 HB (Tabela 3), o que está em desacordo com os resultados de Trendafilova e colaboradores 30 . Os compostos que possuem oxigênios de carbonilas com pequena densidade eletrônica nem sempre são os que possuem ligações de hidrogênio estáveis.…”

Section: Cargas Atômicasunclassified

Efeitos de substituintes na ligação de hidrogênio do 3-hidroxipropenal

Rustici¹,

Caramori²,

Galembeck³

2006

Quím. Nova

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Recebido em 2/8/05; aceito em 21/2/06; publicado na web em 13/7/06 EFFECTS OF THE SUBSTITUENTS ON THE HYDROGEN BOND OF 3-HYDROXYPROPENAL. The effect of substituents on the energies and geometries of 3-hydroxypropenal was studied using the B3LYP/6-311++G(d,p) model. The hydrogen bond energies indicate that the strongest donors and the weakest acceptors present the highest and the weakest hydrogen bonds, respectively, indicating the validity of the Madsen RAHB model. Geometric parameters indicate that the intensity of the hydrogen bond is proportional to the resonance, as suggested by the RHAB model. The effect of substituents diverges from the model proposed by Gilli et al. Sometimes the results indicate that the donor or acceptor effect is more important than the point of substitution.Keywords: 3-hydroxypropenal; RAHB; effect of substituents. INTRODUÇÃOOs compostos β-dicarbonílicos, e particularmente as β-dicetonas despertaram o interesse de muitos pesquisadores em função de suas variadas aplicações. Os complexos metálicos formados por β-dicetonas têm sido bastante empregados como aditivos para combustíveis, fluidos supercríticos, em inúmeras reações de condensação principalmente reações orgânicas 1-3 , na manufatura de filmes supercondutores, na produção de catalisadores homogêneos e heterogêneos 4 e em química de polímeros 5 . Os complexos lantanídicos de compostos β-dicarbonílicos são usados como marcadores luminescentes em imunologia (fluoroimunoanálise) 6,7 . Os β-dicetonatos de lantanídeos possuem amplas aplicações na separação de misturas de lantanídeos com outros metais por sublimação fracionada, em cromatografia gasosa, em cromatografia líquida de adsorção, em análises espectrofotométricas, como oxidantes e como reagentes de deslocamento em espectroscopia de RMN 6,7 . Dentre estes compostos, um dos mais conhecidos é a 2,4-pentanodiona (acetilacetonato). Em estudos realizados por Verdenelli 8 , o acetilacetonato é empregado na síntese de dióxido de estanho que, posteriormente, é utilizado como condutor em células solares. Outros empregos, recentemente relatados, são na síntese de moléculas com propriedades farmacêuticas como analgésicos e antitérmicos 9 . É bem conhecido que o tautômero mais estável do composto β-dicarbonílico 1,3-propanodial é, na forma cetoenólica, o 3-hidroxipropenal (1 HB ), caracterizado por um sistema tipo anel fechado assimétrico estabilizado por uma ligação de hidrogênio muito intensa, O-H⋅⋅⋅O, intramolecular 10 (Figura 1). Gilli e colaboradores 11,12 propuseram o modelo de ligações de hidrogênio assistidas por ressonância, ("Resonance Assisted Hydrogen Bond", RAHB), para racionalizar o comportamento das ligações de hidrogênio O-H⋅⋅⋅O e N-H⋅⋅⋅O muito curtas em sistemas conjugados. Em uma primeira etapa desse modelo seqüencial, as cargas parciais existentes nos oxigênios da forma canônica dipolar levariam a uma atração entre esses dois átomos e, por conseqüência, a uma menor distância O⋅⋅⋅O. Em uma segunda etapa, o átomo de hidrogênio positivo que participa da ligação de hidrogên...

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“…This method also known as Bader's topological analysis, specifically studies (r) and ∇ 2 (r) at the bond critical points (BCP), a BCP being a region between a pair of nuclei, where ∇ (r) = 0. Generally, the character of a chemical interaction is determined based on the following criteria at the BCPs [35][36][37] Here, (r) is the kinetic energy density at the BCP (always positive), while v(r) is the potential energy density at the BCP (always negative). The above-mentioned criteria were exploited in this research endeavor to evaluate the characters of the M-O bonds.…”

Section: Qtaim Analysis Of the M-o Bond Charactersmentioning

confidence: 99%

Quantum Chemical Investigation on the Antioxidant Activity of Neutral and Anionic Forms of Juglone: Metal Chelation and Its Effect on Radical Scavenging Activity

Tamafo

Ghogomu

Nkungli

et al. 2017

Journal of Chemistry

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The chelation ability of divalent Mg, Ca, Fe, Co, Ni, Cu, Zn, and monovalent Cu ions by neutral and anionic forms of juglone has been investigated at DFT/B3LYP/6-31+G(d,p) level of theory in gas and aqueous phases. It is noteworthy that only the 1 : 1 stoichiometry was considered herein. The effects of these metals on the radical scavenging activity of neutral juglone were evaluated via the usual descriptors of hydrogen atom transfer. According to our results, metal chelation by the two forms of juglone was spontaneous and exothermic in both media. Based on the binding energies, Cu(II) ion showed the highest affinity for the ligands. QTAIM analyses identified the metal-ligand bonds as intermediate type interactions in all the chelates, except those of Ca and Mg. It was also found that the chelates were better radical scavengers than the ligands. In the gas phase, the scavenging activity of the compounds was found to be governed by direct hydrogen atom transfer, the Co(II) chelate being the most reactive. In the aqueous phase also, the sequential proton loss electron transfer was preferred by all the molecules, while the Cu(II) chelates were the most reactive.

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DFT and AIM studies of intramolecular hydrogen bonds in dicoumarols

Cited by 51 publications

References 38 publications

Raman, FT‐IR and DFT studies of ortho‐, meta‐ and para‐pyridinomethylene substituted di(4‐hydroxy‐coumarin) and their Ce(III), La(III) and Nd(III) complexes

Raman, FT‐IR and DFT studies of ortho‐, meta‐ and para‐pyridinomethylene substituted di(4‐hydroxy‐coumarin) and their Ce(III), La(III) and Nd(III) complexes

Efeitos de substituintes na ligação de hidrogênio do 3-hidroxipropenal

Quantum Chemical Investigation on the Antioxidant Activity of Neutral and Anionic Forms of Juglone: Metal Chelation and Its Effect on Radical Scavenging Activity

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