scholarly journals Estimation of Bite Angle Effect on the Electronic Structure of Cobalt-Phosphine Complexes: A QTAIM Study

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Tamara Papp ◽  
László Kollár ◽  
Tamás Kégl
Keyword(s):  
Electronic Structure ◽  
Simple Model ◽  
Dft Calculations ◽  
Model Compound ◽  
Carbonyl Ligand ◽  
Reaction Conditions ◽  
Phosphine Complexes ◽  
Bite Angle ◽  
Angle Effect ◽  
Donor Character

The influence of bite angle in bisphosphine complexes has been modeled by DFT calculations employing the simple model compound HCo(CO)(PP) (PP = Xantphos or two monophosphine ligands). The increase of the bite angle increases the strength of the H–Co bond, whereas the C–O bond in the carbonyl ligand is weakened revealing an increase also in the donor character. The model compound cis-[HCo(CO)(PPh3)2] shows a flexibility both in terms of energy, and in terms of electronic structure upon the change of the P-Co-P angle, which can be a sign of the flexibility of PPh3 ligands in real reaction conditions.

DFT Study and Synthesis of Novel Bioactive Bispyrazole Using Mg/AlLDH as a Solid Base Catalyst

2020 ◽  
Vol 14 ◽  
Author(s):  
Soufiane Akhramez ◽  
Youness Achour ◽  
Mustapha Diba ◽  
Lahoucine Bahsis ◽  
Hajiba Ouchetto ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Experimental Finding ◽  
Biological Activities ◽  
Condensation Reaction ◽  
Aromatic Aldehydes ◽  
Mechanistic Study ◽  
Knoevenagel Reaction ◽  
Solid Base ◽  
Reaction Conditions ◽  
Aryl Aldehyde

Background: In this study, an efficient synthesis of novel bispyrazole heterocyclic molecules by condensation of substituted aromatic aldehydes with 1,3-diketo-N-phenylpyrazole by using Mg/Al-LDH as heterogeneous catalyst is reported. The attractive features of this protocol are as follows: mild reaction conditions, good yields and easiness of the catalyst separation from the reaction mixture. Further, a mechanistic study has been performed by using DFT calculations to explain the observed selectivity of the condensation reaction between aryl aldehyde and 1,3-diketo-N-phenylpyrazole via Knoevenagel reaction. The local electrophilicity/ nucleophilicity that allows explaining correctly the experimental finding. Methods: The bispyrazole derivatives 3a-m were prepared by condensation reaction of substituted aromatic aldehydes with 1,3-diketo-Nphenylpyrazole by using Mg/Al-LDH as heterogeneous catalyst under THF solvent at the refluxing temperature. Objective: To synthesize a novel bispyrazole heterocyclic molecule may be have important biological activities and thus can be good candidates for pharmaceutical applications. Results: This protocol describes the Synthesis of Bioactive Compounds under mild reaction conditions, good yields and easiness of the catalyst separation from the reaction mixture. Further, a mechanistic study has been performed by using DFT calculations to explain the observed selectivity of the condensation reaction between aryl aldehyde and 1,3-diketo-N-phenylpyrazole via Knoevenagel reaction. The local electrophilicity/ nucleophilicity that allows explaining correctly the experimental finding. Conclusion: In summary, the pharmacologically interesting bis-pyrazole derivatives have been synthesized through Mg/Al-LDH as a solid base catalyst, in THF as solvent. Thus, the synthesized bioactive compounds containing the pyrazole ring may be have important biological activities and thus can be good candidates for pharmaceutical applications. Therefore, the catalyst Mg/Al-LDH showed high catalytic activity. Besides, a series of bispyrazole molecules were synthesized with a good yield and easy separation of the catalyst by simple filtration. Moreover, DFT calculations and reactivity indexes are used to explain the selectivity of the condensation reaction between aryl benzaldehyde and 1,3-diketo-Nphenylpyrazole via Knoevenagel reaction, and the results are in good agreement with the experimental finding.

DFT calculations of electronic structure evaluation and intermolecular interactions of p53-derived peptides with cytotoxic effect on breast cancer

2021 ◽  
Vol 140 (8) ◽  
Author(s):  
Carolina Barrientos-Salcedo ◽  
Maricarmen Lara-Rodríguez ◽  
Linda Campos-Fernández ◽  
Martha Legorreta-Herrera ◽  
Isabel Soto-Cruz ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Electronic Structure ◽  
Dft Calculations ◽  
Intermolecular Interactions ◽  
Cytotoxic Effect ◽  
Structure Evaluation

scholarly journals Antibacterial and Photocatalytic Properties of ZnO Nanoparticles Obtained from Chemical versus Saponaria officinalis Extract-Mediated Synthesis

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2072
Author(s):  
Maria Antonia Tănase ◽  
Maria Marinescu ◽  
Petruta Oancea ◽  
Adina Răducan ◽  
Catalin Ionut Mihaescu ◽  
...  
Keyword(s):  
Microwave Irradiation ◽  
Zno Nanoparticles ◽  
Model Compound ◽  
Size Composition ◽  
Inorganic Nanoparticles ◽  
Bacterial Strains ◽  
X Ray Diffraction ◽  
Zno Nps ◽  
Reaction Conditions ◽  
Saponaria Officinalis

In the present work, the properties of ZnO nanoparticles obtained using an eco-friendly synthesis (biomediated methods in microwave irradiation) were studied. Saponaria officinalis extracts were used as both reducing and capping agents in the green nanochemistry synthesis of ZnO. Inorganic zinc oxide nanopowders were successfully prepared by a modified hydrothermal method and plant extract-mediated method. The influence of microwave irradiation was studied in both cases. The size, composition, crystallinity and morphology of inorganic nanoparticles (NPs) were investigated using dynamic light scattering (DLS), powder X-ray diffraction (XRD), SEM-EDX microscopy. Tunings of the nanochemistry reaction conditions (Zn precursor, structuring agent), ZnO NPs with various shapes were obtained, from quasi-spherical to flower-like. The optical properties and photocatalytic activity (degradation of methylene blue as model compound) were also investigated. ZnO nanopowders’ antibacterial activity was tested against Gram-positive and Gram-negative bacterial strains to evidence the influence of the vegetal extract-mediated synthesis on the biological activity.

Electronic structure and optical properties of Cs2HgI4: Experimental study and band-structure DFT calculations

2015 ◽  
Vol 42 ◽  
pp. 351-360 ◽  
Author(s):  
A.A. Lavrentyev ◽  
B.V. Gabrelian ◽  
V.T. Vu ◽  
P.N. Shkumat ◽  
G.L. Myronchuk ◽  
...  
Keyword(s):  
Experimental Study ◽  
Optical Properties ◽  
Electronic Structure ◽  
Band Structure ◽  
Dft Calculations

Halogenation of Butyl Rubber—A Model Compound Approach

1984 ◽  
Vol 57 (2) ◽  
pp. 275-283 ◽  
Author(s):  
R. Vukov
Keyword(s):  
Model Compound ◽  
Product Distribution ◽  
Butyl Rubber ◽  
Methyl Groups ◽  
Reaction Site ◽  
Model Compounds ◽  
Reaction Conditions ◽  
Basic Study ◽  
Rubber Model ◽  
Trisubstituted Alkenes

Abstract The study of the halogenation behavior of butyl rubber model compounds has brought about a better understanding of the behavior of these systems. It has been established that the presence of methyl groups, in a position B to the reaction site in the butyl rubber model compound, profoundly influences the course of halogenation. Due to the steric hindrance imposed by these groups, both the products of chlorination and bromination deviate from patterns typical of other trisubstituted alkenes. In the case of chlorination, this deviation is demonstrated by the absence of addition products of chlorine across the double bond. In the case of bromination reactions, the change in product distribution is even more dramatic. Thus, substitution products normally not observed in bromination reactions of other trisubstituted alkenes become predominant products found in yields of between 70–90% depending on the precise reaction conditions. The behavior of the butyl model compound appears to be entirely consistent with the behavior of butyl rubber itself; the model compound approach is therefore a valuable tool for use in the basic study of this type of system.

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