Ab initio and DFT investigations for the isatin dimer

Singh, Vipin Bahadur; Gupta, Ashutosh; Singh, Milind

doi:10.1016/j.theochem.2009.05.017

Cited by 5 publications

(4 citation statements)

References 11 publications

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“…47 It is worth mentioning that for N-H/O]C hydrogen bonds there are nice correlations between the magnitudes of the interaction energy components and the H/O distances. 48 In the isatin dimer 49 which also involves double N-H/O]C hydrogen bonds similar to the theophylline dimer IV, the hydrogen binding energy and H/O distance are found to be 15.52 kcal mol À1 and 1.855 Å respectively at the B3LYP/6-311++G(d,p) level of theory. The binding energy and the H/O distance for dimer IV at B3LYP/6-311++G(d,p) level are found to be 19.94 kcal mol À1 and 1.760 Å.…”

Section: Molecular Geometries Of Theophylline Dimersmentioning

confidence: 97%

Spectroscopic signatures and structural motifs in isolated and hydrated theophylline: a computational study

Singh

2015

RSC Adv.

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The spectra and structures of theophylline monomer and dimer and their hydrated complex have been investigated by MP2 and DFT methods. The ground state geometry optimization yield five lowest energy conformers of Tph 1 -(H 2 O) 1 complex at the M06-2X/6-311++G(d,p) level of theory for the first time. We investigated the low-lying excited states of bare theophylline by means of coupled cluster singles and approximate doubles (CC2) and TDDFT methods and a satisfactory interpretation of the electronic absorption spectra (Phys. Chem. Chem. Phys., 2012,14,10677-10682) is obtained. One striking feature is the coexistence of the blue and red shift of the vertical excitation energy of the optically bright state S 1 ( 1 ππ* ) of theophylline upon forming complex with a water at C 2 =O and C 6 =O carbonyl sites, respectively. The optimized structure of newly characterized theophylline dimer Form IV,computed the first time by MP2 and DFT methods. The binding energy of this dimer linked by double N-H…O=C hydrogen bonds was found to be 88 kj/mole at the MP2/6-311++G(d,p) level of theory. The geometry optimization of dimer Form M has also been performed and found that further stability is being conferred to the dimer IV after hydration. Computed IR spectra is found in remarkable agreement with the experiment (Cryst. Growth Des. 2010, 10, 3879-3886) and the out of phase (C=O) 2 stretching mode shows tripling of intensity upon dimerisation. The vertical excitation energy of the optically bright state S 1 ( 1 ππ* ) of theophylline monomer upon forming dimer IV is shifted towards red as well as blue.

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Section: Molecular Geometries Of Theophylline Dimersmentioning

confidence: 97%

Spectroscopic signatures and structural motifs in isolated and hydrated theophylline: a computational study

Singh

2015

RSC Adv.

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“…Isatin is a versatile compound and enjoys a chemical provenance due to its relationship with the pigment indigo. 9 In nature, isatin and its substituted derivatives can be found in plants and the human body because they are metabolic derivatives of adrenaline. 10 The synthetic versatility of isatin has stemmed from the biological and pharmacological properties of its derivativesl this has been confirmed by the crystal structure in, which isatin forms a centrosymmetric hydrogen-bonded dimer.…”

Section: Introductionmentioning

confidence: 95%

“…3-Substituted-3-hydroxy-2-oxindoles are heterocyclic organic compounds that contain a carbonyl group at the 2-position of the 5-membered ring and a quaternary carbon center at the 3-position of this ring, which could form the core units of many natural products and pharmaceutically important compounds possessing a wide range of biological activities. − As we all know, the most straightforward method to form 3-substituted-3-hydroxy oxindole is the nucleophilic addition of an appropriate nucleophile to isatin electrophiles, such as the aldol reaction or alkylation of isatin. Isatin is a versatile compound and enjoys a chemical provenance due to its relationship with the pigment indigo . In nature, isatin and its substituted derivatives can be found in plants and the human body because they are metabolic derivatives of adrenaline .…”

Section: Introductionmentioning

confidence: 98%

Exploring the Effects of Water on the Mechanism of the Catalyst-Free Reaction between Isatin and 3-Methyl-2-pyrazolin-5-one from the Mixed Implicit/Explicit Multiple Types of Water Clusters

Zhao

Zhang

et al. 2021

J. Phys. Chem. B

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Density functional theory calculations with implicit/explicit water cluster models were conducted to pursue deeper understandings about the mechanism and the water effects in the reaction of isatin with 3-methyl-2pyrazolin-5-one. The proposed preferential mechanistic scenario here undergoes three major steps: first, 3-methyl-2-pyrazolin-5-one converts to its enol form and then, the aldol addition reaction takes place between isatin and enol to generate the intermediate INT2, followed finally by the tautomerization of INT2 to become the product 3-pyrazolone. The computed results indicate that the direct aldol reaction without the water auxiliary is feasible in the second step and the remaining tautomerization steps (steps 1, 3, and 4) assisted by tri-, tri-, and six-water cluster models, respectively, are the most favorable cases. It is further noted that more hydrogen bonding interactions in the tri-water auxiliary reaction are essential for the reduction of the free energy barrier ΔG ⧧ in the proton transfer largely than those assisted by the other types of water cluster models. The origin of the more stable transition state in the rate-determining step of the tri-water cluster model is ascribed to smaller cyclic strain and more global electron density transfer associated to its structure than the other types of water cluster models.

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“…The best calculated wavelength presents a discrepancy of 23 nm. Considering the current performances of the TD-DFT, one can note much more satisfactory results in the literature [44][45][46], and it can be considered that a difference between theoretical and experimental values higher than 10 nm is not acceptable when the calculations are carried out with optimal conditions. Duncan et al [47] have shown that the Perdew-Wang (PW91) functional is well adapted to the electronic description of catechol.…”

Section: Free Ligandmentioning

confidence: 99%

Theoretical study of the Pb(II)–catechol system in dilute aqueous solution: Complex structure and metal coordination sphere determination

Lapouge¹,

Cornard²

2010

Journal of Molecular Structure

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Ab initio and DFT investigations for the isatin dimer

Cited by 5 publications

References 11 publications

Spectroscopic signatures and structural motifs in isolated and hydrated theophylline: a computational study

Spectroscopic signatures and structural motifs in isolated and hydrated theophylline: a computational study

Exploring the Effects of Water on the Mechanism of the Catalyst-Free Reaction between Isatin and 3-Methyl-2-pyrazolin-5-one from the Mixed Implicit/Explicit Multiple Types of Water Clusters

Theoretical study of the Pb(II)–catechol system in dilute aqueous solution: Complex structure and metal coordination sphere determination

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