scholarly journals Synthesis of New Schiff Base of 1,3-Oxazine and 1,3-Thiazine Derivatives Derived from 4-Phenyl Substituted Chalcones and Evaluation of their Antibacterial Activity

2021 ◽  
Vol 33 (3) ◽  
pp. 531-536
Author(s):  
Anupama Sharma ◽  
Sarita Khaturia ◽  
Har Lal Singh
Keyword(s):  
Schiff Base ◽  
Energy Gap ◽  
Biological Activities ◽  
Antibacterial Activities ◽  
Basis Set ◽  
Gram Negative Bacteria ◽  
Important Class ◽  
Lumo Energy ◽  
Homo Lumo

Oxazine and thiazine heterocycles have distinctive interests due to their important class of natural and non-natural products and exhibit high biological activities in the pharmaceutical and biological fields. This work was planned to synthesize Schiff base of 1,3-oxazine and 1,3-thiazine derivative from 4-phenyl substituted chalcones. The structures of the newly synthesized targeted compounds were established from UV, IR, 1H NMR, 13C NMR and DFT calculations. The molecular properties HOMO-LUMO energy, energy gap, softness and harness were calculated using DFT/B3LYP/6-311G (d,p) basis set. in vitro Antibacterial activities of Schiff bases of 1,3-oxazines and 1,3-thiazines derivatives were investigated against Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli) and compared with each other. It was found that thiazine derivatives showed higher activity.

SOLVENT EFFECTS ON THE ELECTRONIC STRUCTURE AND NON-LINEAR OPTICAL PROPERTIES OF PYRENE AND SOME OF ITS DERIVATIVES BASED ON DENSITY FUNCTIONAL THEORY

2021 ◽  
Vol 4 (4) ◽  
pp. 236-251
Author(s):  
A. S. Gidado ◽  
L. S. Taura ◽  
A. Musa
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Density Functional ◽  
Energy Gap ◽  
Chemical Reactivity ◽  
Basis Set ◽  
Lumo Energy ◽  
Functional Theory ◽  
Organic Optoelectronic ◽  
Homo Lumo

Pyrene (C16H10) is an organic semiconductor which has wide applications in the field of organic electronics suitable for the development of organic light emitting diodes (OLED) and organic photovoltaic cells (OPV). In this work, Density Functional Theory (DFT) using Becke’s three and Lee Yang Parr (B3LYP) functional with basis set 6-311++G(d, p) implemented in Gaussian 03 package was  used to compute total energy, bond parameters, HOMO-LUMO energy gap, electron affinity, ionization potential, chemical reactivity descriptors, dipole moment, isotropic polarizability (α), anisotropy of polarizability ( Δ∝) total first order hyper-polarizability () and second order hyperpolarizability (). The molecules used are pyrene, 1-chloropyrene and 4-chloropyrene  in gas phase and in five different solvents: benzene, chloroform, acetone, DMSO and water. The results obtained show that solvents and chlorination actually influenced the properties of the molecules. The isolated pyrene in acetone has the largest value of HOMO-LUMO energy gap of and is a bit closer to a previously reported experimental value of  and hence is the most stable. Thus, the pyrene molecule has more kinetic stability and can be described as low reactive molecule. The calculated dipole moments are in the order of 4-chloropyrene (1.7645 D) < 1-chloropyrene (1.9663 D) in gas phase. The anisotropy of polarizability ( for pyrene and its derivatives were found to increase with increasing polarity of the solvents.  In a nutshell, the molecules will be promising for organic optoelectronic devices based on their computed properties as reported by this work.

scholarly journals Molecular properties of polyvinyl alcohol/ sodium alginate composite

2019 ◽  
Vol 10 (1) ◽  
pp. 4734-4739
Keyword(s):  
Polyvinyl Alcohol ◽  
Sodium Alginate ◽  
Density Functional ◽  
Energy Gap ◽  
Heat Of Formation ◽  
Thermal Parameters ◽  
Basis Set ◽  
Lumo Energy ◽  
Model Structures ◽  
Homo Lumo

Molecular and bimolecular properties are important factors to judge the functionality of polymer/biopolymer composites. Accordingly, molecular modeling is conducted to study the electronic properties of Polyvinyl Alcohol (PVA); Sodium Alginate (SA) as well as their composites. Accordingly, Density functional theory (DFT) at B3LYB level using 6-311/G (d, p) basis set is utilized to study the model structures. Total dipole moment (TDM), HOMO/LUMO energy gap, electrostatic potential (ESP) are calculated at B3LYB level for all studied structures. The results of TDM, HOMO/LUMO energy gap and ESP indicated that the TDM increased, HOMO/LUMO energy gap decreased and electro-negativity increased for the structures under study. Thermal parameters at PM6 are calculated including final heat of formation; free energy; entropy; enthalpy and heat capacity as a function of temperature. Thermal parameters show a variation with changing the site of interaction which indicated that the coordination of PVA/SA is an important factor for describing PVA/SA composite.

A p–n fusion strategy to design bipolar organic materials for high-energy-density symmetric batteries

2021 ◽  
Author(s):  
Jihyeon Kim ◽  
Heechan Kim ◽  
Sechan Lee ◽  
Giyun Kwon ◽  
Taewon Kang ◽  
...  
Keyword(s):  
Energy Density ◽  
Organic Material ◽  
Energy Gap ◽  
High Energy ◽  
High Energy Density ◽  
Lumo Energy ◽  
Fusion Strategy ◽  
Redox Active ◽  
Bipolar Type ◽  
Homo Lumo

A new bipolar-type redox-active organic material with a wide HOMO–LUMO energy gap is designed though the ‘p–n fusion’ strategy.

scholarly journals In Vitro and In Vivo Antibacterial Activities of DW-224a, a New Fluoronaphthyridone

2006 ◽  
Vol 50 (6) ◽  
pp. 2261-2264 ◽  
Author(s):  
Hee-Soo Park ◽  
Hyun-Joo Kim ◽  
Min-Jung Seol ◽  
Dong-Rack Choi ◽  
Eung-Chil Choi ◽  
...  
Keyword(s):  
Antibacterial Activities ◽  
The Other ◽  
Vitro Activity ◽  
Gram Negative Bacteria ◽  
In Vitro Activity ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

ABSTRACT DW-224a showed the most potent in vitro activity among the quinolone compounds tested against clinical isolates of gram-positive bacteria. Against gram-negative bacteria, DW-224a was slightly less active than the other fluoroquinolones. The in vivo activities of DW-224a against gram-positive bacteria were more potent than those of other quinolones.

STRUCTURES, ABSORPTION SPECTRA, AND ELECTRONIC PROPERTIES OF POLYFLUORENE AND ITS DERIVATIVES: A THEORETICAL STUDY

2006 ◽  
Vol 05 (03) ◽  
pp. 595-608 ◽  
Author(s):  
KRIENGSAK SRIWICHITKAMOL ◽  
SONGWUT SURAMITR ◽  
POTJAMAN POOLMEE ◽  
SUPA HANNONGBUA
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Energy Gap ◽  
Level Energy ◽  
Excitation Energies ◽  
Lumo Energy ◽  
Functional Theory ◽  
Local Energy Minimum ◽  
Pi Systems ◽  
Homo Lumo

The structural and energetic properties of polyfluorene and its derivatives were investigated, using quantum chemical calculations. Conformational analysis of bifluorene was performed by using ab initio (HF/6-31G* and MP2/6-31G*) and density functional theory (B3LYP/6-31G*) calculations. The results showed that the local energy minimum of bifluorene lies between the coplanar and perpendicular conformation, and the B3LYP/6-31G* calculations led to the overestimation of the stability of the planar pi systems. The HOMO-LUMO energy differences of fluorene oligomers and its derivatives — 9,9-dihexylfluorene (DHPF), 9,9-dioctylfluorene (PFO), and bis(2-ethylhexyl)fluorene (BEHPF) — were calculated at the B3LYP/6-31G* level. Energy gaps and effective conjugation lengths of the corresponding polymers were obtained by extrapolating HOMO-LUMO energy differences and the lowest excitation energies to infinite chain length. The lowest excitation energies and the maximum absorption wavelength of polyfluorene were also performed, employing the time-dependent density functional theory (TDDFT) and ZINDO methods. The extrapolations, based on TDDFT and ZINDO calculations, agree well with experimental results. These theoretical methods can be useful for the design of new polymeric structures with a reducing energy gap.

Synthesis,Characterization and Evaluation of Biological Activity of Sulfonylhydrazide-Schiff Base" (E)- N’-(2,5-dimethoxybenzalidene) naphthalene-2-sulfonohydrazide"

2020 ◽  
Vol 8 (1) ◽  
pp. 01-11
Author(s):  
Sameer Amereih ◽  
Abd Daraghmeh ◽  
Ismail Warad ◽  
Mohammed Al-Nuri
Keyword(s):  
Schiff Base ◽  
Inhibitory Concentration ◽  
Condensation Reaction ◽  
Gram Negative Bacteria ◽  
Biological Applications ◽  
Bacteriostatic Effect ◽  
1H And 13C Nmr ◽  
13C Nmr Analysis ◽  
Ft Ir

Condensation reaction of naphthalene -2-Sulfonylhydrazide, as starting material with 2,5-dimethoxy benzaldehyde was used to produce (E)-N’-(2,5-dimethoxybenzalidene)naphthalene-2-sulfonohydrazide. The Schiff base product was isolated, purified and then spectrally characterized via UV-Vis, GC/MS, FT-IR, 1H and 13C NMR analysis, where strong evidences confirmed the formation of the desired product. Antimicrobial activity of Schiff base product was evaluated in vitro against several types of bacteria such as: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae and MRSA by Minimum Inhibitory Concentration (MIC) test using tetracycline (TE) as a standard antibiotic. The tests showed a promising bacteriostatic effect of this compound against gram negative bacteria such as P. aeruginosa and K. pneumoniae, such character is valuable for biological applications.

scholarly journals 5-Methyl-1,3-phenylene bis[5-(dimethylamino)naphthalene-1-sulfonate]: crystal structure and DFT calculations

2019 ◽  
Vol 75 (7) ◽  
pp. 1079-1083
Author(s):  
Tanwawan Duangthongyou ◽  
Ramida Rattanakam ◽  
Kittipong Chainok ◽  
Songwut Suramitr ◽  
Thawatchai Tuntulani ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Energy Gap ◽  
Rotation Axis ◽  
Three Dimensional ◽  
Hydrogen Atoms ◽  
Lumo Energy ◽  
Compound C ◽  
Dansyl Group ◽  
Weak Hydrogen Bonds ◽  
Homo Lumo

The title compound, C31H30N2S2O6, possesses crystallographically imposed twofold symmetry with the two C atoms of the central benzene ring and the C atom of its methyl substituent lying on the twofold rotation axis. The two dansyl groups are twisted away from the plane of methylphenyl bridging unit in opposite directions. The three-dimensional arrangement in the crystal is mainly stabilized by weak hydrogen bonds between the sulfonyl oxygen atoms and the hydrogen atoms from the N-methyl groups. Stacking of the dansyl group is not observed. From the DFT calculations, the HOMO–LUMO energy gap was found to be 2.99 eV and indicates n→π* and π→π* transitions within the molecule.

scholarly journals SYNTHESIS AND ANTITUMOR ACTIVITY OF NEW MULTIFUNCTIONAL COUMARINS

2020 ◽  
Vol 17 (36) ◽  
pp. 871-883
Author(s):  
Moath Kahtan BASHIR ◽  
Yasser Fakri MUSTAFA ◽  
Mahmood Khudhayer OGLAH
Keyword(s):  
Schiff Base ◽  
Antitumor Activity ◽  
Human Cancer ◽  
Biological Activities ◽  
Cell Viability Assay ◽  
Chemical Structures ◽  
Viability Assay ◽  
Schiff Base Formation ◽  
Mcf 7

Cancer constitutes one of the most severe public health menaces worldwide. It is imperative to synthesize new compounds and explore their antitumor activity to find a potential resolution to this health problem. Synthesis of new scaffolds and evaluating their antitumor activity is a relevant approach for combating cancer development. Coumarins can exhibit diverse biological activities, and one of these is the antitumor activity. This study aimed to synthesize new coumarins by grafting their precursors to the aromatic amines via Schiff base formation and evaluating their introductory antitumor activity. New multifunctional coumarins (MC1-MC9) were prepared by integrating a functionalized coumarin with different toluidine derivatives via a Schiff-base linkage. Spectral characterization inspired by FTIR, 1H- and 13C- NMR spectroscopies has established the chemical structures of the synthesized products. The antitumor activity was explored in vitro versus four dominant human cancer lines, including HeLa, SKG, MCF-7, and AMN3. The outcomes acquired from the cell viability assay inspected by applying MTT dye have revealed that the synthesized multifunctional coumarins, particularly MC3, have a hopeful activity. It can be concluded that a similar trend of activity against the test cell lines was observed for the synthesized coumarins, with the best action being versus MCF-7 and the least one versus AMN3. This study not only affords a new scaffold of a significant antitumor activity but also provides some insights into its structureactivity relationship.

scholarly journals Characterization of Novel Antimicrobial Peptoids

1999 ◽  
Vol 43 (6) ◽  
pp. 1429-1434 ◽  
Author(s):  
Bob Goodson ◽  
Anton Ehrhardt ◽  
Simon Ng ◽  
John Nuss ◽  
Kirk Johnson ◽  
...  
Keyword(s):  
Antibacterial Activities ◽  
Membrane Disruption ◽  
Infection Model ◽  
Gram Negative Bacteria ◽  
Positional Isomers ◽  
Bacterial Growth Inhibition ◽  
Alpha Carbon

ABSTRACT Peptoids differ from peptides in that peptoids are composed of N-substituted rather than alpha-carbon-substituted glycine units. In this paper we report the in vitro and in vivo antibacterial activities of several antibacterial peptoids discovered by screening combinatorial chemistry libraries for bacterial growth inhibition. In vitro, the peptoid CHIR29498 and some of its analogues were active in the range of 3 to 12 μg/ml against a panel of gram-positive and gram-negative bacteria which included isolates which were resistant to known antibiotics. Peptoid antimicrobial activity againstStaphylococcus aureus was rapid, bactericidal, and independent of protein synthesis. β-Galactosidase and propidium iodide leakage assays indicated that the membrane is the most likely target of activity. Positional isomers of an active peptoid were also active, consistent with a mode of action, such as membrane disruption, that does not require a specific fit between the molecule and its target. In vivo, CHIR29498 protected S. aureus-infected mice in a simple infection model.

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