Pharmacological activity of compounds rarely principally on their interaction with biological matrices like proteins nucleic acids and bio membranes. All these matrices have complicated three-dimensional structures that are capable to acknowledge specifically the matter molecule in barely one amongst the various attainable arrangements within the three-dimensional area. It's the three-dimensional structure of the receptor drug target that determines that of the potential drug candidate molecules are certain among its cavity and with what affinity. It includes a combined term as well as enantiomers and diastereomers. Enantiomers are molecules associated with one another as a true object to its alikeness. Enantiomers are thus associated with one another through the reflection by the mirror plane, and don't seem to be congruentwith symmetry. Not all object mirror-image pairs represent enantiomers, however solely those that don't seem to be superimposable when any rotation/translation of the total object, or its alikeness. Enantiomeric relation doesn't bear the facet of energy; the conformational isomers existing within the quick interconversion are still thought of enantiomers. For the aim of the determination whether or not 2 conformations are enantiomeric, they're thought of to be rigid. The existence of enantiomers is typically related to a minimum of one chiral centre. Enantiomers have precisely the same energies, and so don't seem to be differentiated by physical measurements apart from optical rotation. Diastereomers are any molecules that have an even constitution, however don't seem to be connected through the mirror reflection operation. Diastereomers may well be compounds with two or a lot of chiral centres and analytical, within which not all chiral centres have opposite configuration to a corresponding chiral centers and structural isomerism in Another Diastereomers don't ought to possess chiral centre they solely have to be compelled to take issue by a spatial  distinction not associated with mirror reflection.

Stereochemistry is the study of the static and dynamic aspects of the three-dimensional shapes of molecules. It has long provided a foundation for understanding organic structure and reactivity. At the same time, stereochemistry constitutes an intrinsically interesting research field in its own right. Many chemists find this area of study fascinating due simply to the aesthetic beauty associated with use of chemical structures, and the intriguing ability to combine the fields of geometry, topology, and chemistry in the study of three-dimensional shapes. In addition, there are extremely important practical ramifications of stereochemistry. Nature is inherently chiral because the building blocks of life (-amino acids, nucleotides, and sugars) are chiral and appear in nature in enantiomerically pure forms. Hence, any substances created by humankind to interact with or modify nature are interacting with a chiral environment. This is an important issue for bioorganic chemists, and a practical issue for pharmaceutical chemists. The Food and Drug Administration now requires that drugs be produced in enantiomerically pure forms, or that rigorous tests be performed to ensure that both enantiomers are safe.

The importance of stereochemistry in drug analysis is gaining greater attention in medical biology practice, and a basic knowledge of the subject will be necessary for clinicians to make informed decisions regarding the use of single-enantiomer drugs.   Chirality the most important point is that chiral drugs have 2 structurally similar forms that can behave very differently in biological systems due to their different shapes in 3-dimensional space. These 2 possible forms are termed as enantiomers and the 2 enantiomers of a given chiral drug should be considered 2 different drugs. In biological synthesis chiral drugs synthesises enantiomers of a chiral drug have identical physical and chemical properties in an achiral environment. In a chiral environment, one enantiomer may display different chemical and pharmacology of cancer drug behaviour than the other enantiomer. Because living systems are themselves chiral, each of the enantiomers of a chiral drug can behave very differently in vivo. In other words, the R-enantiomer of a drug will not necessarily behave the same way as the S-enantiomer of the same drug when taken by a patient. The importance of chirality in camptothecin drugs and in all drugs approximately 50% of marketed drugs are chiral, and of these approximately 50% are mixtures of enantiomers rather than single enantiomers.  Racemization refers to the conversion of an enantiomerically pure mixture into a mixture where more than one of the enantiomers are present. If the racemization results in a mixture where the enantiomers are present in equal quantities, the resulting sample is described as racemic or a racemate. Mutarotation is the change in the optical rotation because of the change in the equilibrium between two anomers, when the corresponding stereocenters interconvert. Cyclic sugars show mutarotation as α and β anomeric forms interconvert. The optical rotation of the solution depends on the optical rotation of each anomer and their ratio in the solution. 

Stereoisomers occur once the ligands have equivalent bonds; however the bonds square measure in several orientations relative to one another. Structural state happens once the bonds square measure totally different. Isomers square measure distinct organic compounds which will have totally different physical properties like colour, crystal structure, and temperature. Molecules of the amino acids of that our proteins square measure designed have the property of being non superimposable on their alikeness. owing to this they're a aforementioned to be chiral or to possess handedness though each alikeness forms square measure on paper doable covalent bonds, such as those for the amino alkanoic acid amino acid higher than, life on earth has evolved in an exceedingly approach that amino acids square measure chiefly of the alikeness kind aforementioned to be left-handed. The reason that almost all amino acids square measure of the left-handed kind isn't famous, however. In the absence of associate degree influence that possesses imbalance like a living system, chemical reactions turn out associate degree equal mixture of each alikeness forms of polymers.

Molecular stereochemistry is a fundamental aspect of all areas of chemistry. It is especially important in inorganic chemistry where the coordination numbers are variable and occasionally quite high. The stereochemistry of co-ordi­nation compounds having both unidentate and multidentate ligands. Steric hindrance occurs when the large size of groups within a molecule prevents chemical reactions that are observed in related molecules with smaller groups. Steric effect in biomolecules arises from a fact that each atom within a molecule occupies a certain amount of space. If atoms are brought too close together, there is an associated cost in energy due to overlapping electron clouds and this may affect the molecule's preferred shape and reactivity. The Chan In gold Prelog priority rules , CIP system or CIP conventions are a set of rules used in polymer chemistry to name the stereoisomers of a molecule. A molecule may contain any number of stereocenters and any number of double bonds, and each gives rise to two possible configurations. The purpose of the CIP system is to assign an R or S descriptor to each stereo centre and an E or Z descriptor to each double bond so that the configuration of the entire molecule can be specified uniquely by including the descriptors in its systematic name. VSEPR theory is used to predict the arrangement of electron pairs around non-hydrogen atoms in molecules, especially simple and symmetric molecules, where these key, central atoms participate in bonding to 2 or more other atoms; the geometry of these key atoms and their non-bonding electron pairs in turn determine the geometry of the larger whole. The Ligand degeneracy is described as the solid angle formed with the metal at the vertex and the hydrogen atoms at the perimeter of the cone. Crystal Field Theory is a model that describes the breaking of degeneracies of electron orbital states, usually d or f orbitals, due to a static electric field produced by a surrounding charge distribution.  Stereospecificity is the property of a reaction mechanism that leads to different stereoisomeric reaction products from different stereoisomeric reactants, or which operates on only one of the stereoisomers.  Stereospecific polymerization leading to the synthesis of polymer chemistry having a highly ordered structure (stereo regular polymers).

Energy is usually utilized in several contexts, however rarely during a fastidiously outlined means. A rushing automobile has wide mechanical energy that is reworked into heat and work if the auto crashes into a fence. The accumulated snow on a steep mountain has wide Potential energy. that is reworked in AN avalanche, initial into mechanical enaergy, then into heat and work because the avalanche engulfs forests and cities and eventually involves a stop. In these examples the potential and mechanical energy square measure directed in area, whereas the warmth made consists of random molecular motion. Chemists square measure involved with each physical and chemical process, and therefore the energy related to every. Chemical reactions involve the creating and breaking of valence bonds, and these transformation energy consequences. Heat transfer is that the commonest variety of energy introduced into or free from chemical reactions, but light, electrical current and sound may additionally be concerned. Also if gases square measure made during a reaction, the work done on the environment by volume enlargement becomes a part of the energy balance, and in explosive reactions could also be the main consequenceThe science that investigates the passage of energy from one system to a different, and therefore the transformation of energy from one kind to a different is termed natural philosophy. Physical property isn't the sole physics perform that influences the energy changes, rates and equilibria of chemical and physical transformations.

A stereocenter or stereogenic center is an atom bearing groups such that an interchanging of any two groups leads to a stereoisomer. The most common stereocenters are chiral centers and the double-bonded carbon atoms in cis-trans alkenes. Stereoisomerisms  are isomeric molecules that have the same molecular formula and sequence of bonded atoms, but differ in the three-dimensional orientations of their atoms in space. This contrasts with structural isomers, which share the same molecular formula, but the bond connections or their order differs. By definition, molecules that are stereoisomers of each other represent the same structural isomer. Stereoisomers have the supramolecular type of chirality. Regioselectivity  is the preference of one direction of chemical bond making or breaking over all other possible directions. It can often apply to which of many possible positions a reagent will affect, such as which proton a strong base will abstract from an organic molecule, or where on a substituted benzene ring a further substituent will add.  Epimer refers to one of a pair of stereoisomers. The two isomers differ in configuration at only one stereogenic center. All other stereocenters in the molecules, if any, are the same in each. Chirotopicity terms enantiotopic and diastereotopic describe the relationship between a pair of atoms or groups in a molecule. Stereogenic control on industrial scale explains the development of the commercial Synthesis of drugs. Stereoselective synthesis of therapeutic C-Glycosides and also method of continuous variations in Organometallic Chemistry.  Chirality without stereogenic centers is the exceptions of some structure of molecules that have no chiral canters. A few are like Allenes, Biaryls, Hexahelicenes and etc. Steric hindrance occurs when the large size of groups within a molecule prevents chemical reactions that are observed in related molecules with smaller groups.

Supramolecular Chemistry is all concerning interactions between molecules however they'll recognise one another, assemble and performance on a molecular scale. It provides a bottom up approach to nano scale systems with applications starting from biology to materials science. Refers to the realm of chemistry beyond the molecules and focuses on the chemical systems created of adiscrete range of assembled molecular subunits or elements. The forces accountable for the special organization could vary from weak to strong valence bonding, only if the degree of electronic coupling between the molecular elements remains little with respect to relevant energy parameters of the element. While ancient chemistry focuses on the bond, supramolecular chemistry examines the weaker and reversible non covalent interactions between molecules. These forces include hydrogen bonding, metal coordination, hydrophobic forces, Vander Waals forces, pi-pi interactions and electricity effects. At intervals nanotechnology the active directional transport of molecules or charges is extremely necessary. Chemical reactions involve the creating and breaking of valence bonds, and these transformation energy consequences. Heat transfer is that the commonest variety of energy introduced into or free from chemical reactions, but light, electrical current and sound may additionally be concerned.

Carbon nanotubes of certain stereochemistry have been found to be conductive. Others have been found to be excellent transistors, and together Nano electronic devices have already been formed from them including logic gate circuits. Two synthetic approaches have been tried, in supramolecules namely plasma arcing in the presence of additives and ball milling. In plasma arcing, cathode deposits are altered by the presence of naphthalene in the Nano material. The mixture of nanotubes so formed has a larger average void size than that formed in the absence of naphthalene. The results support proposed mechanisms of nanotube formation which involve growth by incorporation of carbon atoms into open tubes. They also show that naphthalene can be directly incorporated into fullerene black and thereby increase the number of hexagonal sheet structure of  molecules in the carbon deposit. Work so far in ball milling has been confined to studies of the destruction of graphite crystalline phases. Carbon nanotubes are related to fullerenes ("Bucky balls") the spherical and oval shaped molecules. In the separation of carbon nanotubes ultracentrifuge technique was used. Single-walled carbon nanotubes (SWNTs) are high aspect ratio cylinders of carbon (~1 nm in diameter) whose walls are one atomic layer thick and have an atomic arrangement analogous to graphite. Plasma arcing and ball milling are also the electronic application ns of carbon nanotubes and it has many applications in hydrogen storage, in batteries, in electronics, in the high Young’s Modulus, as actuators, nano structures and in other Nano machines.

Enzymecatalyzed reactions are almost always completely stereoselective. In other words, enzyme catalyst reactions that form only a single stereoisomer.  The chemistry associated with living organisms is called biochemistry. The isolation and purification of an enzyme makes it possible to consider the reaction which it catalyses from standpoint of organic chemistry, it can be considered as a reaction between organic chemistry molecules in which the  catalyst happens to be a protein. Such a consideration allows the tools of physical organic chemistry to be applied to the study of enzyme mechanism. Stereospecificity in the enzymology  labilization of one of the 4-methylene protons of pyridoxamine has been demonstrated in the transamination of pyridoxamine catalysed by apoglutamate-oxaloacetate transaminase.  Spectrum analysis is analysis in terms of a spectrum of frequencies or related quantities such as energies, eigenvalues, etc.  Synthesis and identification of some enzymes was done by keto reductase activity.