ARTICLE IN ENGLISH - CHEMISTRY

ORGANIC CHEMISTRY Organic chemistry is a discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation (by synthesis or by other means) of chemical compounds that contain carbon. These compounds may contain any number of other elements, including hydrogen, nitrogen, oxygen, the halogens as well as phosphorus, silicon and sulfur. The original definition of "organic" chemistry came from the misconception that organic compounds were always related to life processes. However, organic molecules can be produced by processes not involving life. Life as we know it also depends on inorganic chemistry. For example, many enzymes rely on transition metals such as iron and copper; and materials such as shells, teeth and bones are part organic, part inorganic in composition. Apart from elemental carbon, only certain classes of carbon compounds (such as oxides, carbonates, and carbides) are conventionally considered inorganic. Biochemistry deals mainly with the natural chemistry of biomolecules such as proteins,nucleic, acids,and sugars. Because of their unique properties, multi-carbon compounds exhibit extremely large variety and the range of application of organic compounds is enormous. They form the basis of, or are important constituents of many products (paints, plastics, food, explosives, drugs, petrochemicals, to name but a few) and (apart from a very few exceptions) they form the basis of all earthly life processes. The different shapes and chemical reactivities of organic molecules provide an astonishing variety of functions, like those of enzyme catalysts in biochemical reactions of live systems.Current (as of 2008) trends in organic chemistry include chiral synthesis, green chemistry, microwave chemistry, fullerenes and microwave spectroscopy. Description and nomenclature Classification is not possible without having a full description of the individual compounds. In contrast with inorganic chemistry, in which describing a chemical compound can be achieved by simply enumerating the chemical symbols of the elements present in the compound together with the number of these elements in the molecule, in organic chemistry the relative arrangement of theatoms within a molecule must be added for a full description. One way of describing the molecule is by drawing its structural formula. Because of molecular complexity, simplified systems of chemical notation have been developed. The latest version is the line-angle formula, which achieves simplicity without introducing ambiguity. In this system, the endpoints and intersections of each line represent one carbon, and hydrogens can either be notated or assumed to be present by implication. Some disadvantages of chemical notation are that they are not easily described by words and they are not easily printable. These problems have been addressed by describing molecular structures using organic nomenclature. .Because of the difficulties arising from the very large number and variety of organic compounds, chemists realized early on that the establishment of an internationally accepted system of naming organic compounds was of paramount importance. The Geneva Nomenclature was born in 1892 as a result of a number of international meetings on the subject. It was also realized that as the family of organic compounds grew, the system would have to be expanded and modified. This task was ultimately taken on by the International Union on Pure and Applied Chemistry (IUPAC). Recognizing the fact that in the branch of biochemistry the complexity of organic structures increases, the IUPAC organization joined forces with the International Union of Biochemistry and Molecular Biology, IUBMB, to produce a list of joint recommendations on nomenclature. Later, as the numbers and complexities of organic molecules grew, new recommendations were made within IUPAC for simplification. The first such recommendation was presented in 1951 when a cyclic benzene structure was named a cyclophane. Later recommendations extended the method to the simplification of other complex cyclic structures, including heterocyclics, and named such structures phanes. For ordinary communication, to spare a tedious description, the official IUPAC naming recommendations are not always followed in practice except when it is necessary to give a concise definition to a compound, or when the IUPAC name is simpler (viz. ethanol versus ethyl alcohol). Otherwise the common or trivial name may be used, often derived from the source of the compound. In summary, organic substances are classified by their molecular structural arrangement and by what other atoms are present along with the chief (carbon) constituent in their makeup, whilst in a structural formula, hydrogen is implicitly assumed to occupy all free valences of an appropriate carbon atom which remain after accounting for branching, other element(s). JHON D. ROBERTS - Basic Principles of Organic Chemistry - 2006