Calculation of Magnetic Couplings in Hydrogen-Bonded Cu(II) Complexes Using Density Functional Theory

2012 ◽  
Vol 116 (13) ◽  
pp. 3465-3473 ◽  
Author(s):  
Nuno A. G. Bandeira ◽  
Boris Le Guennic
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Functional Theory ◽  
Magnetic Couplings ◽  
Hydrogen Bonded

scholarly journals Spectroscopic, X-ray Diffraction and Density Functional Theory Study of Intra- and Intermolecular Hydrogen Bonds in Ortho-(4-tolylsulfonamido)benzamides

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 926
Author(s):  
Malose J. Mphahlele ◽  
Eugene E. Onwu ◽  
Marole M. Maluleka
Keyword(s):  
Density Functional Theory ◽  
Solid State ◽  
Hydrogen Bonds ◽  
Density Functional ◽  
Tetrahedral Geometry ◽  
Hindered Rotation ◽  
Hydrogen Bond Acceptor ◽  
Functional Theory ◽  
Vis Spectroscopy ◽  
Hydrogen Bonded

The conformations of the title compounds were determined in solution (NMR and UV-Vis spectroscopy) and in the solid state (FT-IR and XRD), complemented with density functional theory (DFT) in the gas phase. The nonequivalence of the amide protons of these compounds due to the hindered rotation of the C(O)–NH2 single bond resulted in two distinct resonances of different chemical shift values in the aromatic region of their 1H-NMR spectra. Intramolecular hydrogen bonding interactions between the carbonyl oxygen and the sulfonamide hydrogen atom were observed in the solution phase and solid state. XRD confirmed the ability of the amide moiety of this class of compounds to function as a hydrogen bond acceptor to form a six-membered hydrogen bonded ring and a donor simultaneously to form intermolecular hydrogen bonded complexes of the type N–H···O=S. The distorted tetrahedral geometry of the sulfur atom resulted in a deviation of the sulfonamide moiety from co-planarity of the anthranilamide scaffold, and this geometry enabled oxygen atoms to form hydrogen bonds in higher dimensions.

Theoretical Study on the Sensing Mechanism of Luminescent Metal-Organic Framework [Zn(3-tzba)(2,2′-bipy)(H2O)] · 3H2O for Formaldehyde Detection

2020 ◽  
Vol 17 (7) ◽  
pp. 2890-2896
Author(s):  
Yanhong Dong ◽  
Ning-Ning Wei ◽  
Liguo Gao ◽  
Juanyuan Hao ◽  
Dan Vasilescu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Internal Conversion ◽  
Rate Coefficient ◽  
Metal Organic Framework ◽  
Functional Theory ◽  
Metal Organic ◽  
Luminescent Mechanism ◽  
Organic Framework ◽  
Hydrogen Bonded

The sensing mechanism of luminescent metal-organic framework [Zn(3-tzba)(2,2′-bipy)(H2O)] -3H2O for formaldehyde detection was explored by using density functional theory and time-dependent density functional theory methods. Our investigation found that luminescent metal-organic framework [Zn(3-tzba)(2,2′-bipy)(H2O)] • 3H2O is able to interact with formaldehyde through hydrogen bonding to the framework. The luminescent mechanism of the hydrogen-bonded complex is photo-induced electron transfer; while the luminescent mechanism of luminescent metal-organic framework [Zn(3-tzba)(2,2′-bipy)(H2O)]-3H2O is ligand-to-ligand charge transfer. The intermolecu-lar hydrogen bond was found to be stronger in the excited state than that in the ground state by analyzing the geometry nuclear magnetic resonance, binding energy and infrared spectrum in different electronic states. Calculated fluorescence radiative rate coefficient and internal conversion rate coefficient qualitatively indicated a reduced radiative process and an enhanced internal conversion process of the hydrogen-bonded complex. The hydrogen-bonded complex exhibits luminescence weakening or even quenching due to the enhancement of the intermolecular hydrogen bond in the excited state compare with luminescent metal-organic framework [Zn(3-tzba)(2,2′-bipy)(H2O)]-3H2O. The variable luminescence demonstrated the potential of luminescent metal-organic framework [Zn(3-tzba)(2,2′-bipy)(H2O)]-3H2O as luminescent sensor for formaldehyde detection.

scholarly journals A Density Functional Theory Study on Paracetamol-Oxalic Acid Co-Crystal

2020 ◽  
pp. 11-18
Author(s):  
Punya Paudel ◽  
Krishna Raj Adhikari ◽  
Kapil Adhikari
Keyword(s):  
Density Functional Theory ◽  
Oxalic Acid ◽  
Molecular Orbital ◽  
Density Functional ◽  
Energy Gap ◽  
Lattice Energy ◽  
Stable Form ◽  
Functional Theory ◽  
Monoclinic Form ◽  
Hydrogen Bonded

Paracetamol (PCA) has two well-known polymorphic forms, monoclinic (form I) and orthorhombic (form II). The parallel packing of flat hydrogen bonded layers in the metastable form II results in compaction properties superior to the thermodynamic stable form I which contains corrugated hydrogen bonded layers of molecules. In this study, the structure of Paracetamol (PCA)-Oxalic acid (OXA) co-crystal has been analyzed and found layered structure similar to PCA form II which enhance ability to form tablet. The Density Functional Theory (DFT) has been conducted to find some physicochemical properties of co-crystal. It was observed that the lattice energy of co-crystal is more than that of PCA form II showing more stability on co-crystal. The energy gap between highest occupied molecular orbital and lowest unoccupied molecular orbital (HOMO-LUMO gap) in co-crystal was found less than PCA form II showing bigger enhancement of reactivity.

scholarly journals Stabilization of two conformers via intra- or inter-molecular hydrogen bonds in a dinuclear vanadium(v) complex with a pendant Schiff base: theoretical insight

RSC Advances ◽  
2019 ◽  
Vol 9 (60) ◽  
pp. 35165-35175 ◽  
Author(s):  
Snehasish Thakur ◽  
Michael G. B. Drew ◽  
Antonio Franconetti ◽  
Antonio Frontera ◽  
Shouvik Chattopadhyay
Keyword(s):  
Density Functional Theory ◽  
Schiff Base ◽  
Hydrogen Bonds ◽  
Dft Calculations ◽  
Molecular Hydrogen ◽  
Density Functional ◽  
Functional Theory ◽  
Theoretical Insight ◽  
Hydrogen Bonded

Two different hydrogen bonded conformers coexist in a synthesized dinuclear oxovanadium(v) Schiff base. Density functional theory (DFT) calculations were utilized to calculate the energies involved in two different conformers.

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