Hydrogen Bonding Between FNO and H2O: Structure and Energetics

UV-Vis, FTIR, 1H, 13C NMR spectra and thermal studies of charge transfer complexes formed in the reaction of Gliclazide with π- and σ-electron acceptors

Charge transfer interactions (CT) between a gliclazide (GLC) donor and a picric acid (PA) π acceptor or iodine σ acceptor, were studied in a chloroform solution and in the solid state. UV-vis spectroscopy elucidated the formation of the complexes, and allowed determination of the stoichiometry, stability constants (K), and thermodynamic quantities (ΔG°, ΔH°, and ΔS°), and spectroscopic properties such as the molar extinction coefficient (ε_CT), oscillator strength (f), transition dipole moment (μ_EN), and ionization potential (I_p). Beer's law was obeyed over the 2-8 and 4-12 μg mL^-1 concentration ranges for GLC with PA (method A) and I₂ (method B), respectively, with correlation coefficients of 0.9986 and 0.9989. The limits of detection (LOD) and limits of quantification (LOQ) have also been reported. The 1:1 stoichiometric CT complexes were synthesized and characterized by FTIR, ¹H, and ¹³C NMR spectroscopy. The results indicated a favorable proton migration from PA to the donor molecule, and an interaction between the NH of GLC and iodine. Thermogravimetric analysis techniques (TGA/DTA) and differential scanning calorimetry (DSC) were used to determine the thermal stability of the synthesized CT complex. The kinetic parameters (ΔG*, ΔH*, and ΔS*) were calculated from thermal decomposition data using the Coats-Redfern method.

Charge transfer complexes of 4-isopropyl-2-benzyl-1,2,5-thiadiazolidin-3-one1,1-dioxide with DDQ and TCNE: experimental and DFT studies

We investigated the interaction between sulfahydantoin and two acceptors (DDQ and TCNE) in the liquid phase and in the solid state.

Synthesis, spectroscopic characterization and structural investigation of a new charge transfer complex of 2,6-diaminopyridine with 4-nitrophenylacetic acid: Antimicrobial, DNA binding/cleavage and antioxidant studies

A new hydrogen-bonded charge-transfer complex (CT) formed by the reaction between donor, 2,6-diaminopyridine and acceptor, 4-nitrophenylacetic acid in methanol at room temperature. The crystal was characterized by elemental analysis, IR, NMR spectroscopic studies and thermal studies. The elemental analysis of CT complex, obtained data revealed that the formation of 1:1 ratio CT complex was proposed. Infrared and NMR studies confirm the chemical constituents and molecular structure of the synthesized complex crystal. The high thermal stability is due to the molecular frame work through H-bonding interactions. Structural investigation indicates that cation and anion are linked through strong N(+)-H⋯O(-) type of hydrogen bond. The hydrogen bonded charge transfer crystal was screened for its pharmacology, such as antimicrobial, DNA binding/cleavage and antioxidant studies. The CT complex was screened for its antibacterial and antifungal activity against various bacterial and fungal species, which shows good antimicrobial activity. The DNA binding results indicated that the compound could interact with DNA through intercalation. It should have weak to moderate capacity of scavenging with DPPH.

Synthesis, spectral, structural characterization and biological investigation of m-Xylylenediaminium-bis (p-toluenesulfonate) monohydrate

Novel organic charge transfer complex, m-xylylenediaminium-bis (p-toluenesulfonate) monohydrate (XDPTS) have been synthesized and crystallized to the triclinic system with space group P-1 and the lattice parameters obtained are a=9.9265(7) Å, b=9.9676(6) Å, c=13.4948(10) Å, α=71.95(6)°, β=77.02(6)°, γ=76.851(5)°. The synthesized complex structure was confirmed by IR, (1)H NMR and (13)C NMR spectral analysis. Pharmacology activities of charge transfer complex were evaluated through antimicrobial, DNA binding/cleavage, antioxidant and cytotoxicity studies. The results reveal that the compound shows good antimicrobial activity against various antibacterial and antifungal species. The DNA interaction indicated that the compound could interact with DNA through intercalation, which is further confirmed by viscosity measurements. The compound should have weak to moderate capacity of scavenging with DPPH, Hydroxyl and ABTS radicals. The cytotoxicity has been evaluated by MTT assay method against MCF-7 cancer cell line.

A STUDY OF THE STRUCTURES AND VIBRATIONAL SPECTRA OF THE N2O⋯(HX)2 AND ON2⋯(HX)2 WITH X = F, Cl, Br AND CN

Theoretical calculations 6-311++G(d,p) have been performed in order to obtain binding energies and molecular properties of complexes involving nitrous oxide ( N2O ) and two HX (X = F, Cl, Br and CN ) molecules. Our calculations have revealed the existence of eleven stable structures. The vibrational changes which take place in the HX acid after complexation follow the usual behavior: the HX stretching frequency is shifted downward whereas its IR intensity is much enhanced. The new vibrational modes arising upon H-bond formation, were verified, especially, those associated with the out-of-plane and in-plane HX bending modes, which are pure rotations in the HX isolated molecule.

A spectrophotometric and thermodynamic study of the charge-transfer complexes of N-aryl-N'-isopropyloxycarbonylsulfamides with DDQ and TCNE

Molecular charge-transfer complexes of three N-aryl-N'-isopropyloxycarbonylsulfamides derivatives with π-acceptors tetracyanoethylene (TCNE), and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), were studied by using zero and second order derivative UV spectrophotometry in different solvents at four different temperatures within the range of 20-35 °C. The stoichiometries of the complexes were found to be 1:1 ratio between donors and acceptors using Job's method. The data were analyzed in terms of their stability constant (K), molar extinction coefficient (εCT), thermodynamic standard reaction quantities (ΔG°, ΔH°, ΔS°), oscillator strength (f), transition dipole moment (μEN) and ionization potential (ID). The results show that the stability constant (K) for the complexes was found to be dependant upon the nature of electron acceptor, electron donor, and polarity of used solvents.

Synthesis, spectroscopic investigations, antimicrobial and DNA binding studies of a new charge transfer complex of o-phenylenediamine with 3,5-dinitrosalicylic acid

A charge transfer complex of o-phenylenediamine (OPD) as donor with 3,5-dinitrosalicylic acid (DNSH) as acceptor, was synthesized and characterized by FTIR, (1)H NMR, (13)C NMR, mass spectroscopy, elemental analysis and X-ray crystallography. The structural investigations exhibit that the cation and anion are joined together by strong N(+)H⋯O(-) type hydrogen bonds and stoichiometry of CT complex was found to be 1:1. The CT (charge transfer) complex shows remarkable interaction with Calf thymus DNA, and the CT complex was also screened for its microbial activity such as antimicrobial and antifungal activities. A molecular frame work through H-bonding interactions via n→π(*) transitions between neighboring moieties is found which is responsible for high melting point of resulting CT complex. This has been attributed to the formation of 1:1 CT complex.

THEORETICAL STUDY OF THE HYDROGEN BOND CHARACTER BETWEEN THE FNO AND HO2 RADICAL

The hydrogen-bonding characters between FNO and HO2 radical are studied systematically with the MPWB1K method and 6-311++G (d, p), aug-cc-PVDZ as well as aug-cc-PVTZ basis sets. The relevant geometrical characteristics, energy properties, and the characters of the intramolecular hydrogen bonds have been reported in this work. In addition, the changes of electrostatic potential density are presented for further understanding the nature of hydrogen bonds and the preference of F atom as the hydrogen-bonding site.