Current Physical Chemistry - Volume 8, Issue 3, 2018

Background: The Colloidal-chemical behavior of Copper surfactants are gaining popularity on account of their utilitarian effect such as foaming, emulsification and fungicidal activities. The studies of various parameter derived from viscometric equations provide revealing interpretations of solute - solvent interaction and structural insight of micelle in binary and ternary system, which plays a vital role in its selection for industrial and biological applications. Objective: It is plan to study viscosity of copper neem soap solutions in benzene plus methanol mixture in different composition in order to understand the nature of critical micelle concentration and micellar characterization. Method: First we synthesized copper neem soap based upon their widest applicability performa. It was characterized by elemental analysis, melting points, IR, NMR, spectral studies. Benzene-methanol has been selected as co- solvents since mixed solvents show tendency to interact with complex molecules and result in affecting the aggregation of soap molecule. Results: The results were used to determine the Critical Micelle Concentration (CMC), soap complex-solvent interactions and the effect of chain length of the surfactant molecule on various parameters. The results with regard to solute-solute and solute- solvent interaction have been discussed in terms of well-known Moulik's and Jones- Dole equations. The effect of surfactant concentration on viscosity of the solution in non-polar solvent has been discussed. Conclusion: The viscosity parameters are important to understand the colloidal behavior, CMC characteristics and nature of the complexes. These studies indirectly help in identifying the structural insight, physical and biochemical properties of above metallic soaps. The above studies will definitely help future researchers to apply these novel soaps in multiple interlinked fields based on their widest applicability. Overall, the present course of study helps us to understand the characteristic nature and application of biological active copper soaps.

Background: Urea forms channel inclusion complexes with straight chain hydrocarbon, fatty acids, etc. The decomposition of urea is an interesting thermal induced solid state reaction yielding important by-products. Urea complexation with fatty acids has been successively used in the purification and separation of fatty acids, esters and alcohols. Objective: To study the thermal gravimetry analysis behaviour for inclusion complexes of urea with stearic acid, palmitic acid and neem oil. To compute specific heat capacity at constant pressure, as a function of temperature for the studied systems. Method: The thermal gravimetry analysis and differential scanning calorimetry techniques are used. Results: Thermal profiles of adduct of fatty acid with urea indicate shift in melting temperature of urea from 408 to 413 K. Thermal profiles of urea-neem oil adduct indicating that there is some incorporation of neem oil (inclusion compound formation) by lowering the melting temperature of urea. Conclusion: The data of the corresponding weight loss and enthalpy changes for urea, fatty acids, neem oil, urea-fatty acids adduct and urea-neem oil adduct as a function of temperature are reported. The urea-fatty acid inclusion complexes show congruent behavior in melting, while for urea-neem oil inclusion complex an incongruent melting behavior is observed.

Background: Metalloproteins and metal-protein complexes play key roles in all organisms. For example, certain metalloproteins are involved in metal homeostasis and detoxification, or oxidative stress protection; whereas, metals serve as essential cofactors in a large number of metal-protein complexes. Objective: Present work attempts to critically review methods for assessing the structure, characterization of the metal binding sites, with RNA involved in the various process of a living being are discussed. Method: The binding of Hg(II) and Mo (II) ions have been studied with RNA at different pH values and temperatures by the polarographic and spectrometric techniques. It is observed that binding data depend on pH and temperature. Results: The intrinsic association constants (k) and the number of binding sites (n) were calculated from Scatchard plots. The free energies of aggregation, ΔG associated with the binding interaction of the Hg (II) and Mo(II) and RNA were calculated. The negative values of the ΔG confirm the feasibility of interaction between the metals and RNA. Conclusion: All the observations recorded in this paper indicate that the Hg (II) and Mo (II) ions have a good affinity of binding with RNA and the number of binding sites is dependent on various physical and chemical factors. Both ions when bind with the RNA induce metabolic function at tissue level in fishes in the aquatic environment.

Background: The stability and molecular properties of 1H-indole-3- carbaldehyde (A) and its tautomer, (Z)-indol-3-ylidenemethanol (B) are examined using B3LYP/6-311++G(d,p), M06/6-311++G(d,p), wB97xD/6-311++G(d,p) and MP2/6- 311++G(d,p) methods. Method: The molecular reactivity indices calculated and discussed are the EHOMO, ELUMO, Δ(EHOMO-LUMO), dipole moment, softness (σ), chemical hardness (η), chemical potential (μ), ionization potential (IP), electron affinity (EA), nucleophilicity index (ω) and thermodynamics parameters. Observations: The band gap reveals that compound A is hard, more thermodynamically stable and less labile than B. This is in agreement with the total energy, chemical hardness and chemical softness calculated for the compounds. Result: The equilibrium constant calculation shows that the mixture of the tautomers in aqueous medium is 99.98 % and 0.12 % for compounds A and B respectively. This reveals that compound B is unstable in aqueous medium and is fast converted to compound A, this might explain the reason for compound B not to have been synthesized or reported in any literature. Conclusion: Critical analysis of the charge population distributions shows that charge distribution responded more to the basis sets rather than the computational methods used for the calculations.

Background: The conversion reactions of α -pinene involve mainly isomerization and hydration. These two competing reactions result in various terpenederivative products such as terpinene, limonene, terpineol and other derivatives. Objective: The reaction energy profile of the α-pinene conversion through a carbocation pathway has been studied. Method: The carbocation pathway was thoroughly studied by measuring conductivity and performing an infrared analysis of the liquid. The energy profile was computed by molecular modeling using the M062X XC functional with the 6-31G(d) basis set in IEFPCM continuum solvent model. Conclusion: By measuring the conductivity of the mixture and performing infrared analysis, one can conclude that the α -pinene reaction occurs through the presence of an intermediate carbocation molecule. The reaction mechanism covering various terpenederivative products has been explained/examined and thoroughly investigated in this paper.

Background: Ultrasonic speed and density parameters have been measured in binary and ternary systems containing complexes of copper surfactants (caprylate, caprate, and laurate) with 2-amino-6-methyl benzothiazolein 80 % and 40% benzene-methanol mixture at constant temperature using thermostatic water bath. Objective: From these values, the specific acoustic impedance Z, adiabatic compressibility β, intermolecular free length Lf, apparent molar compressibility φk, have been calculated. These parameters were used to know and compare the CMC value of the system observed by other physical parameters like apparent molar volume, viscosity, surface tension, etc. Method: Different plots were plotted and it has been observed that the synthesized molecule is acting as surfactant at particular concentrations CMC its behavior deviates. Result: The results have been explained on the basis of intermolecular interactions and indicate that there is sufficient solute–solvent interaction due to which micellar alignment is considerably affected. The decrease in adiabatic compressibility β and intermolecular free length Lf of the copper surfactant complex solution with increasing concentration of copper surfactant complex in 80% and 40% benzene−methanol has been observed which suggest that the non-polar long chains or lypophilic segment of the molecule in the solution are enveloped by a layer of solvent molecules bound and oriented towards lypophilic end. Conclusion: The orientation of the solvent molecules around the solutes may be due to the influence of electrostatic fields of solutes and results in the increase in the internal pressure and in lowering the compressibility of the solution i.e. the solution becomes harder to compress.