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383
Section: Chemistry
On Solid Principles

On Solid Principles

Solid state chemistry at Novosibirsk State University As we are taught at school, chemistry is the science studying substances and their transformations. Solid state chemistry is the science studying transformations with participation (as reagents or reaction products) of substances, at least one of which is in solid state. The chemical nature of these substances can be very different - metals, inorganic compounds, organic substances or even biopolymers - nucleic acids and proteins. The only requirement is that they need to be solid, i. e. crystalline or amorphous, in glass state. Why is it necessary to distinguish transformations with participations of solids as a special branch of chemistry? The reason is that the solid state of a substance determines multiple specific features for its synthesis, analysis and investigation of its transformations

As we are taught at school, chemistry is the science studying substances and their transformations. Solid state chemistry is the science studying transformations with participation (as reagents or reaction products)of substances, at least one of which is in solid state. The chemical nature of these substances can be very different – metals, inorganic compounds, organic substances or even biopolymers – nucleic acids and proteins. The only requirement is that they need to be solid, i. e. crystalline or amorphous, in glass state. Why is it necessary to distinguish transformations with participations of solids as a special branch of chemistry? The reason is that the solid state of a substance determines multiple specific features for its synthesis, analysis and investigation of its transformations

What makes solids so specific that their study was singled out as a separate science? For a “conventional” chemist obtaining a substance means obtaining a molecule with a definite stoichiometric ratio of the elements (this is always a ratio of integer numbers, e.g. H2O – 2:1, C2H5OH – 2:6:1, etc.). In addition, it is necessary that the elements be bound to each other in a certain way. For instance, many substances have isomers, i. e. molecules with the same elemental composition but different structure.

This problem becomes much more complex in relation to solids.

From the content to the form

In addition to elemental composition and molecular structure, a substance in solid state is characterized by a certain structure of the crystal (or amorphous sample, glass), size and shape of the particles, presence, type and concentration of defects. Many polymorphs and polyamorphs (analogs of molecular isomers) can exist.

Ceramic composites from fibers and a ceramic matrix form a special class of materials capable of prolonged operation under extreme conditions, e.g. at temperatures above 1000° C and high mechanical loads in the oxidizing environment. Due to their low density, thermal stability, and mechanical strength they are used in different aircrafts. Although the matrix itself and the fibers are fragile, due to a nanoscale layer between them (interface) the composite acquires a new property, pseudoplasticity. Components of promising high-temperature ceramic composites reinforced with carbon and silicon carbide fibers are developed by the students working in the group of Candidate of Chemistry N. I. Baklanova (Institute of Solid State Chemistry and Mechanochemistry, SB RAS)

In this case the stoichiometric formula no longer requires integer values (the law of multiple proportions is not always fulfilled). The properties of a sample depend on its “biography” – synthesis method, storage time and conditions, and external impacts. Often it is enough to touch a crystal with tweezers or glue it, to change its properties drastically.

If a sample consists of several particles, which is typical for solid materials, it is important how the particles are located relative to each other, how they contact each other. For reactions of solids with gases and liquids it may even be important which side (crystal face) of the particle is turned to the gas or liquid.

Nanoheterogeneous systems with typical size of its components below 10 nm can be considered a special class of solid materials. Synthesis and investigation of these promising for the modern technology nanomaterials with a number of unique physicochemical properties are the area of studies by the group headed by the instructor of the SSC Chair Doctor of Chemistry N. F. Uvarov (Institute of Solid State Chemistry and Mechanochemistry SB RAS). The group includes the Chair’s undergraduates and postgraduates

Many properties of modern materials, for example, strength or ability of the surface to repulse moisture and self-clean, are determined by the sample “macrostructure” rather than by its internal composition. A material can have grooved surface, honeycomb structure; different particles can alter in a composite, etc.

Even the simplest description of a substance in the solid state is as complex as that of biochemical objects, e.g. proteins and DNAs that have, in addition to primary structure, secondary, tertiary and quarternary ones, which in turn are assembled into even more complex objects (membranes, cells, etc.).

Building material and medicines

The solids’ structural complexity makes working with them very complex too, it requires special solution of preparative and analytical problems. The same is true for investigation of chemical transformations with participation of solids and control of them, determination of interrelations between the structure of a substance and its properties. To achieve this, original methods and approaches are required.

Of great scientific interest and practical value are not only nanomaterials, but also the possibility of conducting multiple reversible photo and thermal transformations without destructing single crystals. This principle underlies operation of many solid state devices

As most substances in the surrounding world exist in solid state, solid state chemistry is not a science dealing only with some exotic objects. On the contrary, today it is the basis of materials science, and its achievements have made it possible to develop many modern technological processes.

Among the latter are both large-capacity processes, such as processing mineral raw materials, preparation of construction materials and catalysts, and less material-intensive technologies related to the preparation of very expensive pharmaceuticals, high-tech fibers, coatings and membranes, modern materials for electronics, batteries, sensors, fuel cells, etc.

A most important practical area of studies of solid-state chemists is the mechanochemical method for extraction of biologically active substances from vegetables with a small number of stages. The advantages of the new method are lack of organic solvents in the technological operation, ecological compatibility, safety and higher yield of desired products. These studies are carried out by Doctor of Chemistry O. I. Lomovskii, Candidate of Chemistry A. A. Politov, Candidates of Chemistry K. G. Korolev (Institute of Solid State Chemistry and Mechanochemistry, SB RAS) and N. A. Pankruchina (Novosibirsk Institute of Organic Chemistry, SB RAS), and students of the NSU Chair of Solid State Chemistry

Solid state chemistry finds applications both in simulation of biological processes and in imitation of natural materials. It is difficult to find an area where the knowledge of solid state chemistry would not be required. It is applied even in archeology, where it allows for recreating the technology of artifacts found during digs on the basis of results obtained in thermoanalytical, diffraction and microscopic studies. In this way it sheds light on the history of their creation – by whom, where, when, and from what materials these objects were made.

NSU in the vanguard

A special accomplishment of Novosibirsk State University (NSU) is that unlike all other Russian universities solid state chemistry has been taught here as a general course for several decades already.

A major application of solid state chemistry is development of new medicines. Molecular substances used in them often form a number of structurally different modifications (polymorphs). Polymorphs have different properties, e.g. solubility. As a result, a drug form can be highly efficient (optimum dissolution rate), have low efficiency (low solvability), be toxic or even lethal (too fast dissolution of a large dose).
Different polymorphs can also have different storage stability, different tabletting ability and other practically important properties. Knowledge of the existence of various polymorphs of drugs, their properties and synthesis conditions is necessary for the pharmaceutical industry. Also important are problems of patent protection and possibility of producing generics, i. e. medicines that are allowed equivalents of an original medicine.
The experience of Novosibirsk researchers in drug form modifications was highly appreciated by one of the leaders of the pharmaceutical business Pfizer, which collaborated with them in a joint research grant. The scientists hope that their work will be called for in Russia.
This area of research is being developed at the Institute of Solid State Chemistry and Mechanochemistry, SB RAS and NSU Chair of Solid State Chemistry under the guidance of RAS Member V. V. Boldyrev



Back in the Soviet times, it was NSU that opened the first chair of this profile at the Department of Natural Sciences (DNS). Before that, solid state chemistry (SSC) had been taught for almost 20 years as a special course for students of the Physics Department and DNS, and since the mid-1970s it has been given as a general course by the Chair of Physical Chemistry at DNS.

Initially, the Chair of Solid State Chemistry was created to prepare scientific brainpower for the Institute of Physicochemical Bases of Processing of Mineral Raw Materials, Siberian Branch of the Russian Academy of Sciences (SB RAS). Although this institute, which is now called the Institute of Solid State Chemistry and Mechanochemistry SB RAS, is still the base for the SSC chair, the latter went beyond the institute’s limits long ago.

During the last decades much has changed at the NSU Chair of Solid State Chemistry, but the enthusiasm and dedication of both researchers and students have remained the same

Today, its students are introduced to general concepts necessary not only to chemists but also to physicists and biologists. In addition to the constantly developing general courses and special courses for students majoring in chemistry and physics, the chair also prepares study units for courses and practical studies for geology and pharmacology students, methodological materials to be included in inorganic and organic chemistry courses for the first- and second-year undergraduates. Many of these courses and materials have been used at other universities, including foreign ones. The unit structure of all courses allows one to easily restructure and adapt them for a particular program.

One of the studies of the SSC Chair that has acquired international recognition is investigation of aminoacid crystals under extreme temperatures and pressures. Researchers of the chair headed by Doctor of Chemistry E. V. Boldyreva were the first in the world to examine crystalline structures of aminoacids under high pressures by diffraction methods and obtained a number of new polymorph modifications.
These studies are important for chemistry and physics, medicine and biology

Such a comprehensive coverage explains the fact that instructors teaching both general and special courses at the chair represent different research institutes of SB RAS: Institute of Solid State Chemistry and Mechanochemistry, Institute of Catalysis, Institute of Inorganic Chemistry, Novosibirsk Institute of Organic Chemistry, Institute of Fundamental Medicine and Bioorganic Chemistry, Institute of Geology and Mineralogy, as well as Schlumberger, which is a leading international oil-service company.

It is at this chair that the principle of connection between science and education declared by Mikhail Lavrentyev is adhered to as nowhere else: all its instructors without exception are part-time teachers. Note that the chair traditionally employs many young instructors together with a number of “living classics”, veterans of SB RAS.

Solid state chemistry not only makes it possible to create materials and technologies of the future, but also allows one to solve the mysteries of the distant past. Objective quantitative information on samples of ancient ceramics from Siberia and Russian Far East has been already obtained using the modern methods for investigation of composite materials (X-ray diffraction and thermal analysis). It has allowed the researchers to determine their function and production technology. These studies are carried out by the researchers of the Chair, Candidate of Chemistry V. A. Drebuschak and Candidate of Chemistry T. N. Drebuschak under the guidance of Academician V. V. Boldyrev and Academician V. I. Molodin in cooperation with archeologists from the Institute od Archaeology and Ethnography, SB RAS

The main areas of research done by the scientists of the chair are diverse: investigation of mechanisms of chemical reactions and phase transformations with participation of solids and search for methods of controlling their rate, development in space, composition, structure and properties of the products; synthesis of new materials with desired properties for various practical applications; investigation of substances and materials under extreme conditions of high temperatures and pressure; development of new methods for synthesis of biologically active substances based on renewable natural raw materials or industrial wastes.

Scientific studies of the chair researchers are well known in the world. This is proven by high citing ratings, international awards, invitations to give lectures at conferences and at leading foreign scientific centers and universities, election to the leading positions in international scientific unions and organizations.

Silver stearate is used in thermally developed photography, in medicine and in several technical areas. Novosibirsk scientists in cooperation with specialists from companies 3M and Kodak (USA) were the first to establish correlations between the structure of crystals and hidden photographic images formed in them.
Thermal decomposition of the same silver stearate and some other carboxylates under special conditions lead to the formation of “colloid crystals” constructed from silver nanoparticles of absolutely similar sizes and shapes. Such nanomaterials find many interesting applications

The eagerness of foreign researchers to collaborate with Novosibirsk scientists on joint international projects is no less demonstrative, which includes both hosting our young researchers and organizing trips of young academics to Siberia.

The interest of researchers in the special class of layered compounds is caused by their possible application as ion-exchange materials.
The escape of lithium ions into the interlayer space of layered aluminum hydroxides with addition of lithium makes it possible to:
– selectively extract lithium from natural highly mineralized waters;
– create mild antidepressants with prolonged action;
– use the interlayer space as a mini-reactor for carrying out unusual chemical reactions.
These studies initiated at the Institute of Solid State Chemistry and Mechanochemistry, SB RAS, by Academician V. V. Boldyrev have been successfully continued by the group of Doctor of Chemistry V. P. Isupov including undergraduates and postgraduates of the SSC Chair

Today we are optimistic about our future. During the many years of its existence, despite the very difficult 1990s, the Chair of Solid State Chemistry at NSU has not disintegrated or languished – on the contrary, it has gained second wind.

It is impossible even to compare the modern level of equipment with that the chair used once for research and instruction. We are full of ideas and plans. Furthermore, we are joined by young scientists capable of implementing these plans. The only thing that is needed is to work hard so that the words “solid state chemistry” and “Novosibirsk” continue to be associated with each other for the scientific community in Russia and abroad.

References
Boldyrev V. V., Shveikin G. P. Solid state chemistry // Znanie – Sila. – 1977. – Iss. 1. – P. 8—11.
Boldyrev V. V. Reactivity of solid substances. – SB RAS Publishing, Novosibirsk, 1997.
Boldyreva E. V. Between diamond anvils // Science First Hand. – 2007. – Iss. 2. – P. 78—85 .
Chupakhin A. P., Boldyrev V. V., Lyakhov N. Z. Solid state chemistry. – Znanie, Moscow, 1982.
Boldyreva E. V. An experience of teaching solid-state chemistry as a comprehensive course for chemistry students // J. Chem. Educ. – 1993. – V. 70. – P. 551—556.
Varnek A. A., Dietrich B., Wipff G., Lehn J.-M., Boldyreva E. V. Supramolecular Chemistry. Computer-Assisted Instruction in Undergraduate and Graduate Chemistry Courses. // J. Chem. Educ. – 2000. – V. 77. – P. 222—226.

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