Research portfolio, Theoretical air stability of some random phosphine, Determining hygroscopicity from dynamic vapor sorption measurements

Abstract

Task 1: Theoretical air stability of some random phosphine Key Findings Presence of Heteroatom and Air Stability. The presence of heteroatoms may not ensure the stability of phosphine. Stearic effect on stability of phosphine Under Normal conditions, a compound with the same functionalities may show altered stability where as a slight change in constitution will alter the reactivity or stability pattern. In phosphine case the loan pair may or may not cause steric hindrance in the stability of the compound. Effect of Extended Conjugation on air stability Extended conjugation may stabilize the molecule, but on this single factor the stability of the molecules cannot be decided Air Stability Depending upon nature of Phosphine From the 1o to 2o and from 2o to 3o, the stability of phosphine decreases. In small phosphines the effect is smaller whereas in larger and complex phosphines the effect is more pronounces due to electronic repulsion as well as hindrance in umbrella-flipping of Phosphine. Criteria for Air stability/Stability Five significant parameters are taken as significant in determination of stability of a compound; energies of LUMO, Dipole moment μ, Polarizability α and molecular weight (MW). Skills: Skills: Task 3 : Key Findings: Energies of HOMO, Significance: This research provided me an opportunity to study the stability of phosphine compounds by using ChemDraw/ Gamess. Using this research experience, similar studies can be done for other compounds as well. Finding out the stabilities of compounds helps in determining shelf life for a compound but also the stability under different environments and solvents. From stability data, the label for the compound of interest is prepared to practice it under different conditions of heat, temperature or humidity for optimum results. From the current research and calculation I learned how to use ChemDraw/ Gamess to studying different phosphine compounds for their stability and factors which effects the stability. Task 2: Synthesis of 5-Hydroxy-2-methoxy-4-nitrobenzaldehyde (37) Key Findings: Preliminary study and research is very crucial before starting of any chemical reaction. It has been found that the reaction condition greatly affect the yield of a chemical reaction A successful reaction with high yield need great expertise in designing the route, setting the reaction condition and separation and purification of the products Significance: From this research, I have learned that how to set suitable condition for a chemical reaction for high percentage of the product. Moreover I had practice of extraction of synthesized product from aqueous solution into a organic solvent. Purification of final product is very important step of any synthetic procedure. Here I obtained theoretical knowledge practical expertise for purification of any compound by column chromatography. From the research I have learned how to set an assembly for a chemical reaction. Now I have expertise in setting the different condition of a reaction like uniform heating for temperature control, safe transfer of chemicals from one container into another container. Now I have skills of separating a compound from aqueous solution by solvent extraction techniques and purification of compounds by column chromatography.

The stabilities of compounds are greatly affected by different special orientation of groups present in the compounds. The presence of larger groups on same side will destabilize the molecule due to greater repulsive forces among them but the presence larger groups on opposite side to each other will lead to stability of molecule due minimum repulsive force. Significance: I t has been found that stable compound has greater concentration enantiomeric mixture which results more intense peaks in NMR spectra. Moreover I have also lear