Manganese has variable oxidation states and appears as Mn(III) with redox function. It plays an important role in numerous biological processes associated with utilization or generation of hydrogen peroxide or dioxygen. The functions of these type are known viz manganese superoxide dismutase, manganese catalase, manganese peroxidase, manganese ribonucleotide reductase and oxygen involving complex in photo system-II. This has prompted to under take the coordination of Mn(III) ions with ligands. The oxygen donar ligands used for the coordination are -diketones since -diketones anions are powerful chelating species and they give stable Mn(III) complex which can further be used for preparing other Mn(III) species that can be used as catalysts. The tris ( -diketonate) Mn(III) complex gives substitution as well as addition reactions with other ligands. Here nitrogen donar ligands used are ethylenediamine, propylenediamine and hexamethylenediamine. The nitrogen donar atom ligands ultimately result in the mixed ligand complexes for Mn(III) which are more stable in this oxidation state of manganese. In this way the aim of preparing stable Mn(III) complexes is achieved by the oxygen donor"

Ascorbic acid also known as vitamin C. Vitamin C is Ascorbic acid also known as vitamin C. Vitamin C is very essential for growth and maintenance of the human body. It is necessary for the normal formation of protein collagen, which is an important constituent of skin and connective tissue. The deficiency of vitamin C causes is known as disease "Scurvy." Vitamin C is present in all citrus fruits, gooseberry (Aonla), tomato, apple, pine apple, grapes and other foods. The vitamin C is very sensitive to heat, light, air and strong alkali. Most of the part of vitamin C is lost during heat treatment (processing) like blanching, boiling, cooking, cooking under pressure and sterilization of foods. The apple, lemon, pine apple, grapes, guava, ripe mango, was heated to 60 C, 70 C, 80 C, 90 C and 100 C for different time viz. 15, 30, 45, 60, 75, 90 and 105 minute in constant temperature. The loss of vitamin C is less at low temperature. As, the time of heating is increase, the loss of vitamin C increase. The maximum loss of vitamin C has been found in the first 15 minutes of heating at different temperature, then, further rate of loss of vitamin C becomes lesser due to presence surface oxyge"

This book targets a broad readership for young researchers(Postgraduate students) in X-ray crystallography and Quantum Chemistry as it contains a wide and comprehensive coverage of all important aspects of the subject including up-to- date survey of recent revolutionary advances. Molecular structure determination using crystallographic technique of pyrazolo 3,4-d] pyrimidines, naturally occurring drugs as well as synthetic molecular crystals has been discussed.The optimized structures and the electronic properties of the molecules using quantum mechanical methods have also been discussed and results have been compared with crystallographic data, which could enable one to understand and evaluate different quantum mechanical methods. It should be a valuable asset to established researchers in this area due to very detailed explanation of the behavior of aromatic - interactions on the basis of experimental and theoretical results. The crystallographic and theoretical investigations on some synthetic and natural drugs attract the research in the area of drug design using Molecular modeling of the reported compounds with suitable targets.