Current Physical Chemistry - Volume 9, Issue 1, 2019

Background: Earlier studies on the energetic molecule MTNPN show a small HOMO-LUMO energy gap. In general, the material which acquires small energy gap exhibits NLO response and identical counterparts in both IR and Raman spectra. Hence, the combined experimental and theoretical studies were performed to explore the fundamental properties of the molecule. Objective: The objective of this study was to explore the fundamental structural properties of an energetic molecule MTNPN in addition to its application as a nonlinear optical material. Methods: FT-IR technique and quantum chemical methods were used to analyze the vibrational normal modes and structural properties of the molecule. Kurtz and Perry technique is used to find second harmonic generation efficiency in comparison to the standard NLO reference material. Results: The potential energy distribution was used to assign the vibrational normal modes of the molecule. The second order perturbation energies between the lone pair and anti-bonding species were predicted to understand the driving forces of molecular stability. The chemical reactivity of the molecule was determined from the molecular electrostatic potential surface and global reactivity descriptor results. The second-order hyperpolarizability of MTNPN and SHG efficiency of MTNPN were studied to find its NLO response and it was found from the results that MTNPN exhibits high NLO response than the standard NLO reference material. Conclusion: The vibrational degrees of freedom of MTNPN molecule were assigned and the experimental FT-IR spectra were compared with the scaled harmonic frequencies. The predicted second-order hyperpolarizability of MTNPN was about 6.46 times greater than the standard NLO reference urea. The interacting species between the lone pair orbitals and antibonding orbitals such as n3O8→ π*(N7-O9), n3O11→ π*(N10-O12) and n3O14→ π*(N13-O15) stabilized the molecule to a greater extent.

Background: Thermal decomposition of iron-bearing organometallic complex acetyl ferrocene, (C5H4COCH3)Fe(C5H5), leads to hematite (α-Fe2O3) nanoparticles. Presence of maliec anhydride, C4H2O3 as co-precursor during thermal decomposition modifies the size of the particles as well as the quantity of the reaction product significantly. Objective: Kinetic analysis of the solid-state thermal reaction of acetyl ferrocene in the presence of varying amount of co-precursor maliec anhydride under inert reaction atmosphere has been studied in order to understand the reaction mechanism involved behind the formation of hematite and the role of co-precursor in the reaction process. For this purpose, reaction kinetic analysis of three mixtures of acetyl ferrocene and maliec anhydride has been carried out. Methods: Thermogravimetry under non-isothermal protocol with multiple heating rates has been employed. The data are analyzed using model-free iso-conversional kinetic techniques to estimate the activation energy of reaction and reaction rate. The most-probable reaction mechanism has been identified by master plot method. The kinetic triplets (activation energy, reaction rate, most probable reaction mechanism function) have been employed to estimate the thermodynamic triplets (ΔS, ΔH and ΔG). Observations: Acetyl Ferrocene (AFc) undergoes thermal decomposition in a four-step process leaving certain residual mass whereas maliec anhydride (MA) undergoes complete mass loss owing to melting followed by evaporation. In contrast, the (AFc1-x-MAx) mixtures undergo thermal decomposition through a two-step process, and the decompositions are completed at much lower temperatures than that in AFc. The estimated activation energy and reaction rate values are found strongly dependent on the extent of conversion as well as on the extent of mixing. Introduction of MA in the solid reaction atmosphere of AFc in one hand reduces the activation energy required by AFc to undergo thermal decomposition and the reaction rate, while on the other hand varies the nature of reaction mechanism involved. Result: The range of reaction rate values estimated for the mixtures indicate that the activated complexes during Step-I of thermal decomposition may be treated as ‘loose’ complex whereas ‘tight’ complex for the Step-II. From the estimated entropy values, thermal process of (AFc1-x-MAx) mixture for Steps I and II may be interpreted as ‘‘slow’’ stage. Conclusion: Variation of Gibb’s free energy with the fraction of maliec anhydride in the mixtures for Step-I and II indicate that the thermal processes of changing the corresponding activated complexes are non-spontaneous at room temperature.

Background: Triangular phase diagrams are important to understand the phase behaviors in ternary systems. The salting out of alcohol from water by kosmotropic salt has long been known, but the molecular interactions and the mechanism of bond breaking and making processes has not yet been fully understood. Objective: To understand the salting-out of 2-propanol from water using kosmotropic salts (Na2S2O3, Na2SO4 and Na2SO3). To study the phase equilibria of liquid-liquid, liquid-solid and liquid-liquid-solid system by constructing ternary phase diagrams. To determine the solute-solute, solute-solvent, and solvent-solvent molecular interactions to resolve the salting- out effect. Methods: The solubility data of Na2S2O3/Na2SO4/Na2SO3 salts have been reported in pure water, 2-propanol and water + 2-propanol mixtures in different concentrations at 298.15 ± 1 K. The ternary phase diagrams have been constructed from the obtained solubility data. The volumetric and acoustic data of binary and ternary systems of water + 2-propanol, water + salt and water + 2-propanol + salt has been determined using density meter and interferometer. Results: The ternary phase diagrams have been constructed for water+2-propanol+ Na2S2O3/Na2SO4/Na2SO3 system. The rise in sound velocity signifies more structural interactions in binary water-alcohol and water-salt systems, while the relation is rather change with the ternary system, as the water-alcohol sheath will be broken by the kosmotropic salt which results in to salt-water sheath. Conclusion: The density, sound velocity and adiabatic compressibility results suggest that phase separation phenomenon is due to the bond breaking and bond making process along with hydrophobic hydration and hydrophobic interactions. The anion S2O32-, SO42- and SO32- promote salting-out effect and the strength of these effects decreases in the order S2O32->SO42->SO32-.

Background: The azadirachtin is a triterpenoid associated with growth inhibition in several kinds of insects which cause epidemic diseases like Dengue, Chikungunya and Malaria. Azadirachtin acts by inhibiting the Ecdysone Receptor (EcR), which is responsible from larvae phase in insects. However, the interaction between the azadirachtin molecule and the Ecdysone Receptor is unknown. In this work, we used the program Dock Thor to generate several azadirachtin conformations inside the EcR binding site. The ten most stable conformations were optimized with the ONIOM approach present in the Gaussian 09 program. The interaction energy was calculated between the azadirachtin molecule and EcR receptor. Theoretical calculation shows that the azadirachtin molecule interacts with the same amino acids present in the ecdysone EcR interaction. These results will be useful to design new EcR inhibitors, which can be used in the control of some diseases based on insect proliferations. Objective: To understand the interaction between the natural insecticide azadirachtin and the Ecdysone Receptor. Methods: A combination of Dock Thor program with QM-MM calculation was used in order to obtain the most favorable molecular structures. Results: The hydrogens bond obtained by Dock Thor Program combined with QM-MM calculation suggest the azadirachtin interact with EcR in the same way that ecdysone molecule. Conclusion: The interaction mode that the molecule azadirachtin inhibits EcR in order to avoid insect proliferation was described.

Background: Surfactants most characteristic phenomenon of micellization in the bulk phase, as well as their ability to be accumulated at an interface are of immense theoretical, applied and biological interests as indicated by large number of publication of papers and reviews in last three decades. Particulars information about Copper (II) soaps derived from natural oils, play a vital role in its selection in specific phenomena such as foaming, wetting, detergency, emulsification etc. and also in their use as herbicides, fungicides, pesticides and insecticides etc. The tendency of Copper soaps have complex formation with compounds containing donor atoms like N, S, O, Br, etc. as benzothiazole and other related compounds play significant role in biological activities due to the presence of nitrogen and sulphur atoms, which are responsible for their pharmacological activities. Objective: The copper surfactants derived from various edible (Groundnut and Sesame oils) and non-edible oils (Neem and Karanj oils) and their complexes with nitrogen and sulphur containing ligands such as 2-amino-6-methyl-benzothiazole have been synthesized and studied for their structural aspects, which were confirmed using various techniques like IR, NMR and ESR spectroscopy. Thermogravimetric analysis of complexes which is derived from already synthesized copper (II) soaps with 2-amino-6-methyl benzothiazole was done to confirm the thermal decomposition. Methods: Thermo Gravimetric Analysis (TGA) has been used to study the thermal decomposition of copper surfactants complexes to evaluate their energy of activation and various thermodynamic parameters i.e. Gibbs free energy, enthalpy, entropy have been calculated. Copper surfactants and their benzothiazole complexes were studied to test the validity of various equations namely Freeman Carroll, Coats - Redfern, Horowitz - Metzger, Broido, and Piloyan-Novikova related to thermal degradation. Results: The degradation occurs in three steps and the value of activation energy is highest for third step and smallest for the first steps. CNB and CKB need higher energy to degrade than CGB and CSB. The all copper surfactants molecules have negative entropy, which indicates that the decomposition reactions proceed with a lower rate. Conclusion: Thermogravimetric degradation analysis will also provide significant information about the removal of the natural soap segment from the environment. The studies will be very important for pollution controlling and in the field of Green Chemistry.