Alexander Nikolayevich was one of the greatest organic chemists of the 20th century. He organised a number of fundamental works on the theory of the structure and reactivity of organic compounds. He created a new discipline lying on the border of inorganic and organic chemistry, which was called "chemistry of organoelement compounds". Also he has researched the production of synthetic food, the creation of new drugs and the synthesis of a number of technical materials.
Nesmeyanov's diazomethod (Nesmeyanov's reaction) Studying the decomposition of double salts of aryldiazonium halides with mercury halides by copper powder, in 1929 Nesmeyanov proposed a new method for obtaining arylmercury halides. Later, the diazo method was extended to the synthesis of organometallic compounds of thallium, germanium, tin, lead, arsenic, antimony, and bismuth. The features of the diazo method, which distinguish it from direct metalation methods, are the possibility of obtaining organometallic compounds with different functional groups in the carbon radical and the possibility of selectively introducing a metal atom into a certain position. In 1935 – 1948, Nesmeyanov, together with K. A. Kocheshkov, obtained organic derivatives of tin, lead, antimony and other metals. Due to mutual transitions from organic derivatives of some elements to organic compounds of other elements, organometallic compounds obtained by the diazo method have found new applications in synthesis.
Stereochemistry of unsaturated organometallic compounds The study by Nesmeyanov of the products of the addition of mercuric chloride to ethylene, acetylene and their derivatives led to the concept of the “dual reactivity” of a substance and the “transfer of the reaction center” along the chain π, π-, σ, π-, σ, σ- and p,π-conjugations in a molecule. Further research showed that these phenomena are fundamentally different from tautomerism. With the participation of his colleague A.E. Borisov, Nesmeyanov formulated the rule according to which electrophilic and homolytic substitution at the olefin carbon atom occurs with the preservation of the geometric configuration (Nesmeyanov – Borisov rule). Thanks to his research, which showed the enolate structure of ketone derivatives with alkali metals and magnesium, that is, the existence of O-derivatives of ketones, Nesmeyanov refuted Knorr 's concept of "pseudomerism ".
Metallotropy In the study of the structure of mercury b-, lead- and organotin derivatives of nitrosophenols, Nesmeyanov discovered the phenomenon of metallotropy, that is, a special tautomerism in which a reversible transfer of an organometallic group occurs. Joint studies by A. N. Nesmeyanov and I. F. Lutsenko discovered heteroatomic tautomerism (between carbon and oxygen atoms) in keto-enol systems of tin, o- and germanium compounds. Nesmeyanov, together with Yu. A. and N. A. Ustynyuk, discovered a new type of metallotropy: it was found that in fluorenylchromium tricarbonyl anions, η 6 -complexes are equilibrium and reversibly isomerized into η 5 -complexes.
Research on ferrocene and its derivatives In 1954, research into the chemistry of ferrocene began at the Department of Organic Chemistry at Moscow State University and at INEOS under the direction of Nesmeyanov. It turned out that the functional derivatives of ferrocene react similarly to aromatic compounds. However, it has been shown that the electronic effects of the substituents are transmitted through the metallocene core by an inductive mechanism, and therefore have a lesser effect than on benzene derivatives. Research on ferrocene and its derivatives made it possible to create a number of photosensitive compositions that allow obtaining a stable image on paper, fabric, plastics and metals, and also led to the creation of a new drug, ferrocerone, which fights diseases associated with iron deficiency. On the basis of cymantrene, Nesmeyanov proposed a new antiknock agent for motor gasoline.
Research in organic chemistry Nesmeyanov, together with N.K. Kochetkov and M.I. Rybinskaya, developed a method for the synthesis of various five- and six-membered
heterocycles, which is based on the high activity of carbonyl groups and the mobility of the β-substituent in compounds of the type RCOCH=CHX. The same group of scientists developed the method of "β-ketovinylation", which consists in introducing an RCOCH=CH group into the molecule. The reaction of β-substituted vinyl ketones with an azide ion made it possible to study the stereochemistry and propose a mechanism for
nucleophilic substitution at the activated double bond. In collaboration with other scientists, Nesmeyanov carried out a number of works in the field of radical telomerization and rearrangement
radicals. In addition to studies of already known reactions, thermal telomerization of ethylene and propylene with silicon hydrides has been developed and other new telomerization reactions. Also, new routes for the synthesis of compounds containing groups such as CCl3, CCl3CHCl, CCl3C 2=CH, CCl2=CHX and others. The study of compounds containing the CCl3-C=C3CBr=CH2 to CCl2=CClCH2Br under ultraviolet illumination. In continuation of the work related to the previously created
diazo method, Nesmeyanov and L. G. Makarova investigated the mechanism of decomposition of aryldiazonium and diaryliodonium salts. This made it possible to synthesize new types of onium compounds - diphenylbromonium, diphenylchloronium and triphenyloxonium salts. Together with T. P. Tolstaya and other scientists, Nesmeyanov showed that double salts of diphenylbromonium and diphenylchloronium halides with heavy metal halides are decomposed by powders of the corresponding metals with the formation of organometallic compounds. Thus, the diazo method began to be used to obtain σ-aryl complexes of transition metals and other organometallic compounds.
The scientific basis for obtaining new forms of food In 1961, Nesmeyanov formulated the idea of obtaining food by synthetic methods, bypassing agriculture. The idea was based on the works of D. I. Mendeleev and M. Berthelot, as well as an awareness of the modern possibilities of organic synthesis, the problems of preserving the environment and the efficiency of food production. The main areas of work were: the development of highly efficient methods for obtaining nutrients; reproduction of the appearance, taste, smell, color, shape, consistency and other properties of natural products in synthetic food substances. As a result of research at INEOS, processes have been developed for obtaining black caviar, new forms of potato products, pasta and cereals and combined meat products based on vegetable and animal proteins. ==Recognition==