Effect of pyridine on cobalt phthalocyanine (CoPc) has been studied by the density functional theory and Raman spectroscopy. Thermal evaporation method has been used for the preparation of a thin film of CoPc and then Raman spectra of CoPc film have been recorded with and without exposure of pyridine. The molecular structure of CoPc and its coordinated complexes with pyridine have been computed using B3LYP/6-31(d,p) level of density functional theory calculations by employing Gaussian program package. Calculations show some in-plane and out-of-plane distortions in the structure of CoPc. Some noticeable changes have been observed in the Raman spectrum of CoPc thin film after its exposure with pyridine. Changes in wavenumbers and relative intensities of some of the bands have been observed. Most of the observed bands show downward shifts in the wavenumbers. These changes, are attributed to the weakening of some bonds and change of symmetry of CoPc, and confirm the coordination of pyridine molecule(s) with CoPc molecule

Nature has often provided valuable molecules either as lead compounds or for use in the fight against pests. Though a number of conference proceedings deal with the control of insects using natural products, there is no comprehensive account of what materials have been studied and what results have been obtained. Examining the material scattered across various disciplines, this book meets a recognized need by consolidating this information in one volume. The first section of the book covers chemistry and biological activity of major classes of naturally occurring pesticides, including the development of more potent insecticides based on natural lead-in structures. The second section consists of monographs on each compound by product.

The vibrational properties of glutathione have been investigated by infrared absorption and Raman spectroscopic techniques, and density functional theory calculations at the B3LYP/6-31+G(d,p) level. Assignments of all the experimentally observed vibrational bands have been done with the help of simulated vibrational spectra and potential energy distribution calculations of glutathione water cluster, which includes the effect of hydrogen bonding. Optimized molecular parameters of energy minimized structure have been compared with the available experimental values. Calculated molecular parameters of glutathione-water cluster match well with the experimental values. Some of the calculated molecular parameters and vibrational frequencies of vapor phase glutathione-water cluster suggest participation of some atoms of glutathione in hydrogen bonding. Experimentally observed UV-Visible absorption spectrum of glutathione has also been reported. Observed band at 203 nm has been assigned to electronic transitions calculated with time dependent density functional theory. (C) 2015 Elsevier B.V. All rights reserved.

Ashwagandha [Withania somnifera (L.) Dunal] is an important medicinal plant which is major source of alkaloids, viz., withanine, sominiferine, sominiferinine, somnine, withananine and withasomnine. The genetic variability, correlation and path analysis of dry root yield and its contributing traits were analyzed in twenty seven diverse genotypes of Ashwagandha. The highest magnitude of genotypic and phenotypic coefficient of variation was recorded for number of primary branches per plant. The heightest heritability was coupled with high genetic gain was recorded for total alkaloid content, which indicated the importance of additive gene effect, which could be therefore improved through selection. The plant height positively correlated with dry root yield and root diameter but negatively correlated with days to 75% maturity. Among the characters, maximum direct effect was recorded for plant height followed by total alkaloid content. Superior genotypes, viz., MPAS-6, MPAS-4, MPAS-10, MPAS-5, and MPAS-1 could be gainfully utilized in the improvement of dry root yield in Ashwagandha.

We report the infrared absorption and Raman spectra of melatonin recorded with 488 and 632.8 nm excitations in 3600-2700 and 1700-70 cm(-1) regions. Further, we optimized molecular structure of the three conformers of melatonin within density functional theory calculations. Vibrational frequencies of all three conformers have also been calculated. Observed vibrational bands have been assigned to different vibrational motions of the molecules on the basis of potential energy distribution calculations and calculated vibrational frequencies. Observed band positions match well with the calculated values after scaling except N-H stretching mode frequencies. It is found that the observed and calculated frequencies mismatch of N-H stretching is due to intermolecular interactions between melatonin molecules. (C) 2013 Elsevier B.V. All rights reserved.

We report the effects of methanol, pyridine, diethylamine, dichloromethane, acetonitrile, bromine and NO2 vapours on the Raman and infrared absorption spectra of zinc tetraphenylporphine thin films by recording their spectra before and after exposure with chemical vapours. Positions of some vibrational bands show detectable change on exposure. Changes in the intensity of some vibrational bands of the thin films have also been observed on exposure. Coordination of vapours molecules at the zinc ion and subsequent charge transfer are responsible for the shift in the vibrational bands. Density functional theory calculations have been carried out to determine the probable geometric structures of the porphyrin–vapour complexes. Calculated geometric structures show in-plane and out-of-plane distortions in the porphyrin macrocycle. Calculations also result in charge transfer between vapour and porphyrin molecules.

We report the effects of chemical vapours on the Raman and infrared absorption spectra of a crystalline nickel phthalocyanine thin films. Transmission electron micrograph of the thin films suggests presence of nano-sized particles of nickel phthalocyanine in the thin film. Some vibrational bands show changes in their positions and/or intensities on exposure of thin films with chemical vapours. These changes have been interpreted on the basis of interactions of the vapours molecule with the central nickel ion and other peripheral atoms of the phthalocyanine ring. Density functional theory (DFT) calculations have been carried out to determine the probable geometric structures of the complexes of vapour and phthalocyanine molecules. Calculated geometric structures show in-plane and out-of-plane distortions in the phthalocyanine molecule. Calculations further suggest charge transfer between vapour and phthalocyanine molecules. (C) 2011 Elsevier By. All rights reserved.

In the present work, we have studied the effect of pyridine on the zinc phthalocyanine by recording the infrared absorption and X-ray diffraction spectra with and without pyridine. In the presence of pyridine phase of the crystalline zinc phthalocyanine changes from beta to alpha. Some infrared bands show changes in their positions and/or intensities. These changes have been interpreted on the basis of coordination of the pyridine molecule with the central zinc ion. Coordinated pyridine transfers some of its charge to the pi electron system of the phthalocyanine ring through zinc ion. Pyridine molecule also distorts the phthalocyanine molecule by pulling zinc ion out of the phthalocyanine plane. Density functional theory also confirms the ligation of pyridine molecule at the fifth coordination site of the central metal ion. (C) 2010 Elsevier B.V. All rights reserved.

The present work reports vibrational spectra and density functional theory calculations for chloranil, imidazole and their complexes. The experimentally observed infrared and Raman bands have been assigned with the help of calculated vibrational frequencies and potential energy distribution analysis. Some bands of chloranil and imidazole have been found to shift on the complex formation due to partial electronic charge transfer from imidazole to chloranil. The charge transfer between these molecules is also corroborated by the electronic absorption spectroscopy and calculations. The theoretical values of the interaction energy of various possible chloranil–imidazole interactions suggest that the two molecules interact preferably via N and H atoms of imidazole and CO group of chloranil with their molecular planes almost perpendicular to each other.

Usage of natural substances as therapeutic agents in modern medicine has sharply declined from the predominant position held in the early decades of last century, but search for bioactive molecules from nature (plants, animals, microflora) continues to play an important role in fashioning new medicinal agents. With the advent of modern techniques, instrumentation and automation in isolation and structural characterisation, we have on hand an enormous repository of natural compounds. In parallel to this, biology has also made tremendous progress in expanding its frontiers of knowledge. An interplay of these two disciplines constitutes the modern thrust in research in the realm of compounds elaborated by nature. The purpose of this article is to underline how natural products research continues to make significant contributions in the domain of discovery and development of new medicinal products. It is proposed to present the material under several heads, each of which has made natural products research relevant in the search for new and better medication.

Sodium dispersed on alumina is described and evaluated as a convenient off-the-shelf reagent (in a wax- coated form) for reduction of ketones , esters and oximes. While isopropanol is the preferred proton donor for the reduction of ketones and oximes, t-butanol is the alcohol of choice for the reduction of esters.

AbstractThe enol‐lactone (V), obtained via two routes from (+)‐car‐3‐ene (I), is used for the construction of the title compound (VI) and the dimethylacetal (VIII).

General Remarks on the Use of this Book General Introduction Skeletal-Type Index Pentacyclic Compounds Hexacyclic Compounds References Index

(+)-Car-3-ene has been converted by a simple route into (-)-cis-caronaldehydic acid hemiacetal, an important intermediate in the commercial production of certain synthetic pyrethroids.