Differential Pulse Voltammetric Studies of Some Mixed-ligand Co(III) Complexes in Aquo-Organic Solvent Media Possessing Different Hydrogen Bonding Properties

2009 ◽  
Vol 64 (9) ◽  
pp. 1021-1026 ◽  
Author(s):  
Kumarasamy Sivaraj ◽  
Kuppanagounder P. Elango
Keyword(s):  
Hydrogen Bonding ◽  
Organic Solvent ◽  
Structural Parameters ◽  
Differential Pulse ◽  
Mixed Ligand ◽  
Solvent Interactions ◽  
Organic Solvent Media ◽  
Bonding Properties ◽  
Voltammetric Studies ◽  
The Difference

The electro-reduction of a series of Co(III) complexes of the type cis-β -[Co(trien)(4-R-Py)Cl]Cl2, where trien = triethylenetetramine and R = H, Me, Et, t-Bu, COMe, and CN, has been studied in propan-2-ol/water and 1,4-dioxane/water binary mixtures. The redox potential (E1/2) data were correlated with solvent and structural parameters with an aim to shed some light on the mechanism of these reactions. Correlation of E1/2 with macroscopic solvent parameters indicated that the reactivity is influenced by both specific and non-specific solute-solvent interactions. The reduction of Co(III) to Co(II) in these complexes was observed to become increasingly easier with an increase in the dipolarity/ polarizability of the medium as evidenced by the Kamlet-Taft correlation. The difference in the relative lenience of the reduction has been explained using the difference in H-bonding properties of the medium.

scholarly journals The Role of Hydrogen Bonding in Paracetamol–Solvent and Paracetamol–Hydrogel Matrix Interactions

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1842
Author(s):  
Marta Miotke-Wasilczyk ◽  
Marek Józefowicz ◽  
Justyna Strankowska ◽  
Jerzy Kwela
Keyword(s):  
Hydrogen Bonding ◽  
Dipole Moments ◽  
Release Kinetics ◽  
Spectroscopic Technique ◽  
Release Time ◽  
Solvent Interactions ◽  
Hydrogel Matrix ◽  
Matrix Interactions ◽  
The Difference

The photophysical and photochemical properties of antipyretic drug – paracetamol (PAR) and its two analogs with different substituents (acetanilide (ACT) and N-ethylaniline (NEA)) in 14 solvents of different polarity were investigated by the use of steady–state spectroscopic technique and quantum–chemical calculations. As expected, the results show that the spectroscopic behavior of PAR, ACT, and NEA is highly dependent on the nature of the solute–solvent interactions (non-specific (dipole-dipole) and specific (hydrogen bonding)). To characterize these interactions, the multiparameter regression analysis proposed by Catalán was used. In order to obtain a deeper insight into the electronic and optical properties of the studied molecules, the difference of the dipole moments of a molecule in the ground and excited state were determined using the theory proposed by Lippert, Mataga, McRae, Bakhshiev, Bilot, and Kawski. Additionally, the influence of the solute polarizability on the determined dipole moments was discussed. The results of the solvatochromic studies were related to the observations of the release kinetics of PAR, ACT, and NEA from polyurethane hydrogels. The release kinetics was analyzed using the Korsmayer-Peppas and Hopfenberg models. Finally, the influence of the functional groups of the investigated compounds on the release time from the hydrogel matrix was analyzed.

The hydrogen-bonding properties of a room temperature phosphorescence cellulose substrate

1986 ◽  
Vol 90 (21) ◽  
pp. 4941-4945 ◽  
Author(s):  
Georg W. Suter ◽  
Alan J. Kallir ◽  
Urs P. Wild ◽  
Tuan Vo-Dinh
Keyword(s):  
Hydrogen Bonding ◽  
Room Temperature ◽  
Room Temperature Phosphorescence ◽  
Cellulose Substrate ◽  
Bonding Properties

scholarly journals Theoretical Study of the Structures of 4-(2,3,5,6-Tetrafluoropyridyl)Diphenylphosphine Oxide and Tris(Pentafluorophenyl)Phosphine Oxide: Why Does the Crystal Structure of (Tetrafluoropyridyl)Diphenylphosphine Oxide Have Two Different P=O Bond Lengths?

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2778
Author(s):  
Joseph R. Lane ◽  
Graham C. Saunders
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Phosphine Oxide ◽  
Density Functional ◽  
Lone Pair ◽  
Diphenylphosphine Oxide ◽  
Functional Theory ◽  
Weak Hydrogen Bonding ◽  
Independent Molecules ◽  
The Difference

The crystal structure of 4-(2,3,5,6-tetrafluoropyridyl)diphenylphosphine oxide (1) contains two independent molecules in the asymmetric unit. Although the molecules are virtually identical in all other aspects, the P=O bond distances differ by ca. 0.02 Å. In contrast, although tris(pentafluorophenyl)phosphine oxide (2) has a similar crystal structure, the P=O bond distances of the two independent molecules are identical. To investigate the reason for the difference, a density functional theory study was undertaken. Both structures comprise chains of molecules. The attraction between molecules of 1, which comprises lone pair–π, weak hydrogen bonding and C–H∙∙∙arene interactions, has energies of 70 and 71 kJ mol−1. The attraction between molecules of 2 comprises two lone pair–π interactions, and has energies of 99 and 100 kJ mol−1. There is weak hydrogen bonding between molecules of adjacent chains involving the oxygen atom of 1. For one molecule, this interaction is with a symmetry independent molecule, whereas for the other, it also occurs with a symmetry related molecule. This provides a reason for the difference in P=O distance. This interaction is not possible for 2, and so there is no difference between the P=O distances of 2.

The Acidity Constants of Some Pyrimidine Bases in Various Water Organic Solvent Media

2004 ◽  
Vol 94 (11) ◽  
pp. 847-856 ◽  
Author(s):  
Iman T. Ahmed ◽  
Ekram S. Soliman ◽  
Ahmed A. A. Boraei
Keyword(s):  
Organic Solvent ◽  
Acidity Constants ◽  
Organic Solvent Media ◽  
Pyrimidine Bases

scholarly journals Linear Structural Trends and Multi-Phase Intergrowths in Helvine-Group Minerals, (Zn,Fe,Mn)8[Be6Si6O24]S2

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 325
Author(s):  
Sytle Antao
Keyword(s):  
Cell Parameter ◽  
Structural Parameters ◽  
Unit Cell ◽  
Fluid Composition ◽  
Ternary Solid Solution ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Difference ◽  
Multi Phase ◽  
And Diffusion

Synchrotron high-resolution powder X-ray diffraction (HRPXRD) and Rietveld structure refinements were used to examine the crystal structure of single phases and intergrowths (either two or three phases) in 13 samples of the helvine-group minerals, (Zn,Fe,Mn)8[Be6Si6O24]S2. The helvine structure was refined in the cubic space group P4¯3n. For the intergrowths, simultaneous refinements were carried out for each phase. The structural parameters for each phase in an intergrowth are only slightly different from each other. Each phase in an intergrowth has well-defined unit-cell and structural parameters that are significantly different from the three endmembers and these do not represent exsolution or immiscibility gaps in the ternary solid-solution series. The reason for the intergrowths in the helvine-group minerals is not clear considering the similar radii, identical charge, and diffusion among the interstitial M cations (Zn2+, Fe2+, and Mn2+) that are characteristic of elongated tetrahedral coordination. The difference between the radii of Zn2+ and Mn2+ cations is 10%. Depending on the availability of the M cations, intergrowths may occur as the temperature, pressure, fugacity fS2, and fluid composition change on crystallization. The Be–Si atoms are fully ordered. The Be–O and Si–O distances are nearly constant. Several structural parameters (Be–O–Si bridging angle, M–O, M–S, average <M–O/S>[4] distances, and TO4 rotational angles) vary linearly with the a unit-cell parameter across the series because of the size of the M cation.

Sequential microhydration of cationic 5-hydroxyindole (5HI+): infrared photodissociation spectra of 5HI+–Wn clusters (W = H2O, n ≤ 4)

2018 ◽  
Vol 20 (5) ◽  
pp. 3092-3108 ◽  
Author(s):  
Johanna Klyne ◽  
Mitsuhiko Miyazaki ◽  
Masaaki Fujii ◽  
Otto Dopfer
Keyword(s):  
Hydrogen Bonding ◽  
Infrared Spectroscopy ◽  
Dft Calculations ◽  
Bonding Properties

The hydrogen-bonding properties of the acidic OH and NH groups of the 5-hydroxyindole cation are probed by infrared spectroscopy and DFT calculations of its microhydrated clusters.

scholarly journals Synthesis of alkyl esters by cutinase in miniemulsion and organic solvent media

2009 ◽  
Vol 4 (5) ◽  
pp. 674-683 ◽  
Author(s):  
Dragana P. C. de Barros ◽  
Luís P. Fonseca ◽  
Joaquim M. S. Cabral ◽  
Clemens K. Weiss ◽  
Katharina Landfester
Keyword(s):  
Organic Solvent ◽  
Alkyl Esters ◽  
Organic Solvent Media

scholarly journals Mixed Ligand Complexes of Transition Metal Ions with Selective Bio-Ligands in Surfactant-Water Mixtures

2019 ◽  
Vol 8 (2S11) ◽  
pp. 3182-3190
Keyword(s):  
Hydrogen Bonding ◽  
Transition Metal ◽  
Metal Ions ◽  
Chemical Speciation ◽  
Transition Metal Ions ◽  
Ternary Complexes ◽  
Mixed Ligand ◽  
Stacking Interactions ◽  
Micellar Media ◽  
Chelate Effect

Chemical speciation of ternary complexes of L-arginine and L-aspartic acid with essential transition metal ions was studied pH metrically. The following MLX, MLXH and ML2X ternary species are detected and reported in this paper. The existence of different ternary species is established from modeling studies using the computer program MINIQUAD75. The relative concentrations (M: L: X=1:2:2, 1:2:4, 1:4:2) and stabilities of the ternary species are compared with those of binary species. The extra stability associated with the ternary complexes is attributed to factors such as charge neutralization, chelate effect, stacking interactions and hydrogen bonding. Trend in variation of stability constants with the change in the mole fraction of the surfactant in various micellar media is explained on the basis of electrostatic and non-electrostatic forces. Distribution diagrams in relation to pH and plausible structures were presented.

Sign in / Sign up

Export Citation Format

Share Document