Mapping of molecular electric potentials and fields

Mishra, Pankaj; Kumar, Anil

doi:10.1007/3-540-58672-5_22

Cited by 20 publications

(4 citation statements)

References 53 publications

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“…Note that the fluorescence peak position of DAPL bears an excellent correlation with the solvent polarity parameter, E T (30) in aprotic media. In protic solvents, a correlation can be observed between the wavenumbers of the fluorescence maxima and the hydrogen bond donating parameter, α, of the solvents (Figure ). In any given solvent, both the absorption and fluorescence maxima of DAPL are Stokes-shifted compared to those of APL.…”

Section: Resultsmentioning

confidence: 94%

The Fluorescence Response of a Structurally Modified 4-Aminophthalimide Derivative Covalently Attached to a Fatty Acid in Homogeneous and Micellar Environments

et al. 1999

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The photophysical properties of 11-(4-N,N-dimethylaminophthalimido)undecanoic acid (DAPL), a surfactant covalently labeled with a fluorophore, in homogeneous and micellar media are reported. The remarkable sensitivity of the fluorescence properties of DAPL to the polarity of the media is attributed to the existence of a low-lying nonfluorescent twisted intramolecular charge transfer (TICT) state. DAPL is found to be an excellent fluorescence sensor for following the micellar aggregation process. Although DAPL shows enhanced binding with the micelles, the quenching experiments and the fluorescence spectral and intensity data clearly indicate that the fluorescing moiety does not penetrate into the nonpolar core region of the micelles even though the fluorophore is covalently attached to the nonpolar end group of the fatty acid. It is unambiguously established from the fluorescence data that both of the terminal groups of DAPL are located in the interfacial region of the micelles by folding of the long polymethylene chain.

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Section: Resultsmentioning

confidence: 94%

The Fluorescence Response of a Structurally Modified 4-Aminophthalimide Derivative Covalently Attached to a Fatty Acid in Homogeneous and Micellar Environments

et al. 1999

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“…Many indices of reactivity like atomic charges, bond orders, free valences, frontier electron densities, Fukui functions, and the molecular electrostatic potentials (MEP) have been introduced. The shape of MEP is considered now as a standard tool in quantum chemistry for the analysis of the reactivity of molecules. ,,− Unlike many of the other quantities used as reactivity indices, the MEP is a real physical property which can be either determined experimentally by X-ray and electron diffraction methods − or calculated from the wave function. Its interpretation is simple in terms of classical electrostatics: The molecule provides a potential around itself which is felt by another approaching chemical species.…”

Section: Methodsmentioning

confidence: 99%

Prediction of the Coordination Scheme of Lanthanide N-Tetrasubstituted Tetraazamacrocycles: An X-ray Crystallography and Molecular Modeling Study

et al. 1997

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The synthesis and characterization of three lanthanide (Ce, Gd, Eu) complexes with the 1,4,8,11-tetrakis-(2-carboxyethyl)-1,4,8,11-tetraazacyclotetradecane ligand (TETP) are described. Crystal structures of [Ce(H2TETP)](OH)(H2O)·10H2O (1), [Gd(H3TETP)](OH)2(H2O)2 ·3H2O (2), and [Eu(H3TETP)](OH)2(H2O)2 ·3H2O (3) are reported. Crystal data: (1) monoclinic, C2/c, a = 29.523(4) Å, b = 17.492(3) Å, c = 8.509(1) Å, β = 98.72(1)°, V = 4344(1) Å3, Z = 4, R(|F|) = 0.057 for 2329 data (I/σ(I) ≥ 3), and 213 parameters; (2) monoclinic, C2/c, a = 15.378(2) Å, b = 14.172(2) Å, c = 14.264(2) Å, β = 99.10(1)°, V = 3069.5(7) Å3, Z = 4, R(|F|) = 0.075 for 1147 data (I/σ(I) ≥ 3), and 213 parameters; (3) monoclinic, C2/c, a = 15.32(1) Å, b = 14.19(1) Å, c = 14.130(3) Å, β = 99.41(3)°, V = 3031(3) Å3, Z = 4, R(|F|) = 0.085 for 1133 data (I/σ(I) ≥ 3) and 98 parameters. Complexes 2 and 3 are isotypes. In the three complexes, the centrosymmetric TETP macrocycle possesses a [3434] conformation; two propionate arms are extended, and the others are folded toward two protonated nitrogen atoms. The lanthanide coordination mode with the TETP ligand does not occur via the four nitrogen atom ring but only through carboxylic oxygen atoms belonging to four different ligands. Moreover, the four functionalized chains of the ligand are involved in the coordination polyhedron of the gadolinium and europium ions, but only extended propionate arms of TETP take part in the cerium ion coordination polyhedron, one of the oxygen atoms of asymmetric unit being bidentate between two metallic ions. In order to better understand the reactivity and the coordination scheme observed for these complexes, a theoretical study has been carried out using the molecular electrostatic potential as a tool to predict sites of the ligands where electrophilic attack should take place. The overall good agreement between calculated and observed structures permits us to explain the coordination scheme of this new class of complexes.

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“…These chemical shifts were calculated with the GIAO method [48] Molecular Electrostatic Potential Molecular electrostatic potential (MEP) has proved itself as an effective tool for quantitatively assessing various non-covalent interactions, such as hydrogen-bonding, halogen bonding, and cation-π interactions [51][52][53][54]. Electrostatic properties of molecules can be computed approximately using discrete point charges located on the atomic sites at the van der Waals surface or at surfaces farther away from the molecules [55][56][57][58][59].…”

Section: Chemical Shifts Of Nuclei Of Carbon and Hydrogen Atomsmentioning

confidence: 99%

N-[4-(3-Methyl-3-phenyl-cyclobutyl)-thiazol-2-yl]-N′-pyridin-2-ylmethylene-chloro-acetic acid hydrazide: Synthesis and configurational assignment based on X-ray, 1H, and 13C NMR and theoretical calculations

et al. 2017

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In this study, quantum chemical calculations based on the density functional theory have been carried out to examine the effects of N-[4-(3-methyl-3-phenyl-cyclobutyl)-thiazol-2-yl]-N'-pyridin-2-ylmethylene-chloro-acetic acid hydrazide. The calculated values are compared with the experimental data available for these molecules as a mean of validation of our proposed chemistry model. Aided by normal coordinate analysis and potential energy distributions, a confident vibrational assignment of all fundamentals is proposed herein. Additional support is given by 1 H and 13 C NMR spectra recorded with the sample dissolved in CDCl 3 and by predicted chemical shifts at the B3LYP/6-31G(d)/6-311G+(d) levels obtained using the gauge-invariant atomic orbital method. The calculated HOMO and LUMO energies also confirm that the charge transfer occurs within the molecule. Thiazole-based compounds are potential storehouse for exploiting CH•••O and CH•••N hydrogen bonding interactions for molecular self-assembly.

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Mapping of molecular electric potentials and fields

Cited by 20 publications

References 53 publications

The Fluorescence Response of a Structurally Modified 4-Aminophthalimide Derivative Covalently Attached to a Fatty Acid in Homogeneous and Micellar Environments

The Fluorescence Response of a Structurally Modified 4-Aminophthalimide Derivative Covalently Attached to a Fatty Acid in Homogeneous and Micellar Environments

Prediction of the Coordination Scheme of Lanthanide N-Tetrasubstituted Tetraazamacrocycles: An X-ray Crystallography and Molecular Modeling Study

N-[4-(3-Methyl-3-phenyl-cyclobutyl)-thiazol-2-yl]-N′-pyridin-2-ylmethylene-chloro-acetic acid hydrazide: Synthesis and configurational assignment based on X-ray, 1H, and 13C NMR and theoretical calculations

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