SINDO1 II. Application to ground states of molecules containing carbon,nitrogen and oxygen atoms

Molecular geometries, binding energies, ionization potentials and dipole moments are calculated by the SINDO1 method for a large number of molecules containing C, N and O atoms. Comparison is made with MINDO/3, MNDO and where possible with STO-3G results. The explicit data and an error statistics show the relative merits of SINDO1.     

Using non-Gaussian density functional fits to improve relative free energy calculations

The accurate and reliable computation of relative free energy differences remains an important long-term goal. Major stumbling blocks for achieving this goal reflect the difficulty of sampling in a known fashion along the reaction coordinate and of maximally combining information that has been collected from the simulation along the reaction coordinate. In this paper we examine the utility of a probability density functional type fit to the distribution of work events collected during a nonequilibrium sample along the reaction coordinate. This approach can readily be generalized to equilibrium sampling and has the potential to estimate the quality of a relative free energy estimate as data are being collected. The method may have the greatest utility for nonequilibrium sampling where non-Gaussian work distributions are generally present that are strongly dominated by rare event sampling in the tail region. We believe that the approach can be used to augment the design and the error analysis of relative free energy computations thus improving the ability to reliably and with known accuracy compute a relative free energy.     

Kinetics of acid and base catalysed hydrolysis ofcis-α- andcis-β2-[Co(trien)(aniline)Cl]2+ cations

Summary The rate of hydrolysis of the title cations obey the rate law:-d ln[Complex]/dt=k_obs=k₀+k₁[OH^–] in the range: 1pH3. The rate and activation parameters for acid and base hydrolysis (k₀ and k₁ paths respectively) are reported in the 40–60 °C range.     

Origin of 1,3-induction in the addition of alkyl lithium to imines bearing an N-stereogenic center

The origin of diastereoselectivity in the addition of alkyl lithium to chiral Schiff bases has been investigated experimentally and theoretically and the formation of the major diastereomer can be explained from the energy minimized structure of the Schiff base in which the phenyl group has been found to orient in such a manner that it posed lesser steric hindrance to the incoming nucleophile as compared to the alkyl group.     

Simultaneous Determination of Enalapril and Losartan in Pharmaceutical Preparations by UV Spectrophotometry and LC

The simultaneous determination of enalapril (Ena) and losartan (Los) in solid dosage forms were done by two methods. The first method involves spectrophotometric determination using the simultaneous equation method at 222 and 250 nm for Ena and Los, respectively. The second method involved an RP-LC method of analysis using methanol:water:acetonitrile (45:35:20% v/v) as the mobile phase. Both methods were satisfactorily validated as per ICH guidelines.     

A new methodology for crisp equivalent of fuzzy chance constrained programming problem

This paper deals with a chance constrained programming model, where both fuzziness and randomness are present in the objective function and constraints. The concept of fuzzy random variable, mean and variance of fuzzy random variable, minimum of fuzzy numbers are used in the model. The methodology is verified through a numerical example.     

Chemo-enzymatic asymmetric total synthesis of stagonolide-C

The naturally occurring phytotoxic noneolide stagonolide-C has been synthesized by a chemo-enzymatic approach. Two key intermediates have been synthesized by applying a metal–enzyme combined DKR (dynamic kinetic resolution) strategy, followed by RCM (ring-closing metathesis) to afford the target compound in an efficient way.     

Kinetics of aquation of pentaammine(substituted salicylato)cobalt(III) complexes by ferric ion

Summary The aquation of pentaammine (substituted salicylato) cobalt(III) complexes [(NH₃)₅CoO₂CC₆H₃(X)OH]²⁺,X = 5-SO₃, 5-Br, 5-NO₂, and 3-NO₂ in the presence of ferric ion was studied spectrophotometrically in the 65°–80° range. Ferric ion catalyses the aquation of the substratesvia formation of a reactive binuclear species.Reprints of this article are not available.     

A 1D Cu(II) coordination polymer exhibiting ferromagnetic interactions and a mononuclear Cu(II) complex of substituted pyrazole carboxylic acids: Synthesis, characterization and crystal structure

Reaction of 2 equiv. amount of copper(II) nitrate hexahydrate with 1 equiv. of 5-methyl-1-pyridin-2-yl-1H-pyrazole-3-carboxylic acid (PyPzCA) in presence of triethyl amine base afforded a 1D coordination polymeric compound [Cu₂(PyPzCA)₂(H₂O)₃(NO₃)]NO₃·H₂O (1). Whereas, the same reaction when repeated with 1-(4,6-dimethyl-pyrimidin-2-yl)-5-methyl-1H-pyrazole-3-carboxylic acid (PymPzCA) instead of PyPzCA, a mononuclear compound [Cu(PymPzCA)]·2H₂O·NEt₃ (2) is formed. Both the complexes are crystallographically characterized. In 1, both the copper atoms (Cu1 and Cu2) have distorted square pyramidal geometry with N₂O₃ chromophore while, in 2, the central copper atom has a distorted trigonal bipyramidal geometry with N₄O chromophore. Complex 1, is a 1D coordination polymer where the metal centers being far apart and are involved in a weak ferromagnetic interaction which is quite unexpected.