Platinum Metals Rev., 1976, 20, (4), 126
Il’ya Il’ich Chernyaev’s Research on the Platinum Metals
This year marks the fiftieth anniversary of the trans effect, one of the most fundamental principles in the synthetic chemistry of the platinum metals, as well as the tenth anniversary of the death of its discoverer, Il’ya Il’ich Chernyaev, one of the Soviet Union’s most distinguished scientists and the man who was undisputedly this century’s most prolific worker on the coordination chemistry of platinum.
Il’ya Il’ich Chernyaev (1–9), late Academician of the Academy of Sciences of the U.S.S.R., was born on January 21, 1893 in the village of Spasskii in what was formerly Vologda province. After graduating from the Vologda Gymnasium (High School) with a gold medal in 1911, he entered the Natural Science Division of the Physico-Mathematical Faculty of St. Petersburg University where he studied under Lev Aleksandrovich Chugaev (1872–1922) (10). In 1915, he graduated with a first class diploma in chemistry, and at Chugaev’s suggestion he remained at the university for training as a university teacher. He also began war research and work on platinum complexes in Chugaev’s laboratory. His first published studies dealt with hydroxylamine (11) and aquo salts (12) of divalent platinum. In 1917, he became a contributor to the Platinum Division of the Commission for the Study of Russian Natural Productive Sources (KEPS) of the Russian Academy of Sciences. In 1918, he became Assistant in the Chair of Inorganic Chemistry at the Petrograd University and also became a research associate at Chugaev’s newly created Institute for the Study of Platinum and Other Precious Metals at Petrograd. Until his death on September 30, 1966, he remained at this institute, which was transferred to Moscow in 1934 and underwent several changes in name through the years. Upon Chugaev’s death in 1922, Nikolai Semenovich Kurnakov (1860–1941) (13) became director of the institute, and on Kurnakov’s death in 1941 it was renamed the N. S. Kurnakov Institute of General and Inorganic Chemistry of the Academy of Sciences of the U.S.S.R., with Chernyaev as its director, a post which he held until his death.
In 1923, Chernyaev became Assistant Lecturer at Petrograd University. In 1930, he became Docent in Inorganic Chemistry at the Leningrad Chemical-Technological University where he directed the Faculty of General Chemistry. In that same year he became Head Chemist of the Platinum Institute. In 1932, he was appointed Professor at Leningrad University, and in 1934, he took charge of the Section for the Chemistry of Complex Compounds in the newly created Institute of General and Inorganic Chemistry of the U.S.S.R. Academy of Sciences. From 1945 until his death he was Professor of the Chemistry of Complex Compounds at the Lomonosov State University in Moscow.
As Chugaev’s successor and most outstanding student, Chernyaev was at the time of his death in charge of the world’s largest school of chemists specialising in the chemistry of the platinum metals and one of the world’s principal centres for the systematic study of coordination compounds in general. His name, of course, is inextricably linked with the trans effect and with numerous researches on the compounds of divalent and tetravalent platinum, especially those containing nitro groups. Less well known, however, is his role as one of the creators of refining technology in the Soviet precious metals industry. As such, his name is associated with a new and advanced method for the purification of platinum, its separation in highest purity, the preparation of pure osmium, a method for extracting platinum metals from low grade ores, the development of a series of analytical methods for noble metals, and the solution of many other critical industrial problems. Among the subjects included in his more than 275 articles are the synthesis, reactions, structure-proof, thermochemistry, thermodynamics, photochemistry, spectroscopy, and optical properties of complexes of the platinum metals. In the last decade of his life he helped to establish the nuclear fuel industry in the U.S.S.R. by his extensive research on uranium and thorium complexes (7).
Chernyaev was the editor of many important monographs published by the Institute of General and Inorganic Chemistry. He was a co-editor of the Institute’s journal, Izvestiya Sektora Platiny i Drugikh Blagorodnykh Metallov (14) from 1947 until 1955, when it ceased publication. In that year he became editor-in-chief of its newly founded successor, the Zhurnal Neorganicheskoi Khimii. For his discovery and application of the trans effect, Chernyaev received numerous awards and prizes from the Soviet government, including the Stalin Prize, First Class in Chemistry in 1952, four Orders of Lenin, and two Orders of the Red Banner of Labour. He was made a Corresponding Member of the U.S.S.R. Academy of Sciences in 1933 and an Academician in 1943.
Almost every student of organic chemistry knows that most substitution reactions do not occur in a random manner, and in a similar manner, substitution reactions among coordination compounds are not random. However, the general principle underlying the directive influences of coordinated ligands was not enunciated until well into the third decade of the present century. Such influences are most pronounced and well investigated among square planar complexes, especially those of platinum(II).
The chemical behaviour of dipositive platinum complexes was studied by many of the early investigators in coordination chemistry, and the well-known regularities observed in substitution reactions were cited by Werner in his assignment of cis or trans configurations for platinum(II) complexes, to which he ascribed a square planar arrangement. The compounds chosen by Werner were among the simplest and longest known (1844) platinum isomers, viz., platosemidiammine chloride or Peyrone’s Salt and platosammine chloride or Reiset’s Second Chloride, both with the formula Pt(NH3)2Cl2. On the basis of transformation reactions, Werner assigned them the configurations:
The synthesis of each of these compounds involves directive influences, and the preparative reactions were known as Peyrone’s reaction and Jörgensen’s reaction, respectively and were said to exemplify Peyrone’s rule (cis orientation) (15) and Jörgensen’s rule (trans orientation) (16):
In 1893, a third important regularity was observed by the Russian chemist Nikolai Semenovich Kurnakov (13), who found that substitution by thiourea occurs with all the ligands of the cis compound but only with the acid radicals of the trans compound (17):
(A=NH3 or an amine, X=halogen or acid radical, tu=thiourea).
Since the two isomers yield different products, this reaction, known as Kurnakov’s reaction or Kurnakov’s test, may be used to differentiate cis from trans isomers of dipositive platinum or palladium.
In 1926, Chernyaev (18, 19) generalised that a negative group coordinated to a metal atom loosens the bond of any group trans to it and thus explained not only Peyrone’s, Jorgensen’s, and Kurnakov’s reactions but also many other features of the reactions of divalent and tetravalent platinum. He also investigated substitution reactions of complexes of chromium, cobalt, tellurium, and osmium. He postulated that the trans effects of atoms are inversely proportional to their metallic character, i.e., directly proportional to their electronegativities. Electronegative ligands such as NO2−, NCS−, F−, Cl−, Br−, and I− have a greater “trans influence” than neutral ligands such as NH3, amines, or H2O. Chernyaev’s original trans -directing series has been extended to include a variety of ligands: CN− ∼ CO ∼ C2H4 ∼ NO ∼ H− > CH3− ∼ SC(NH2)2 ∼ SR2 ∼ PR3 > SO3H− > NO2− ∼ I− ∼ SCN− > Br− > Cl− > C5H5N > RNH2 ∼ NH3 > OH− > H2O (20a).
Chernyaev’s trans effect has been useful not only in synthetic work but also in structure-proof. His discovery enabled him and his many students and research workers to prepare many complexes not only of platinum but also of palladium, rhodium, iridium, ruthenium, cobalt, and other metals. The rule made it possible for the first time to plan systematic routes for carrying out inner-sphere substitution reactions in order to prepare platinum complexes in which all the ligands are different. For example, Chernyaev’s early synthesis of the three possible geometric isomers of [Pt(NH3)-(C5H5N)(NH2OH)(NO2)]+ was cited as evidence for a square planar arrangement for platinum(II) (21). Among his syntheses of platinum(IV) complexes we may cite the following: [PtenNH3NO2Cl2]X (three out of four possible isomers and resolution of the two asymmetric compounds) (21, 22), [PtenNH3NO2BrCl]X (five out of six possible isomers) (23), [Pt(NH3)2(NO2)2Cl2] (all five possible isomers) (24).
Chernyaev’s concept is one of the fundamental principles of synthetic inorganic chemistry and has greatly stimulated the theoretical study of the reactivity and kinetics of coordination compounds, and a number of reviews have been devoted to it (25, 26). At present there are two theoretical viewpoints concerning the possible mechanism of the trans effect.
The first type of theory is primarily an electrostatic one that emphasises a weakening or labilisation of the trans bond, suggested by Chernyaev himself (19), Nekrasov (27), and Grinberg (28). The second type of theory emphasises the lowering of the activation energy of trans replacement and makes use of modern molecular orbital theory (29–33). Two π-bonding ligands competing for the d orbitals of the metal tend to labilise each other, compared to the more stable cis isomer where no competition takes place, and the stronger π-bonder will weaken the bonding of the ligand trans to it (20b). Several interpretations have also been made to explain the trans effect on the basis of σ-bonding only (34). It is currently uncertain what interpretation of the trans effect is the best.
- 1V. V. Lebedinskii, “Il’ya Il’ich Chernyaev,” Materialy k Biobibliografii Uchenykh S. S.S.R., publ. by Akademia Nauk S.S.S.R., Moscow, Leningrad, 1948 . This contains a bibliography of one hundred and one titles to early 1948 .
- 2V. V. Lebedinskii and A. M. Rubinshtein, Uspekhi Khim., 1953, 22, ( 3 ), 241
- 3A. V. Babaeva, Zh. Obshch. Khim., 1953, 23, ( 5 ), 713. This is a summary of Chernyaev’s work on the occasion of his 60th birthday.
- 4N. M. Zhavoronkov, Zh. Neorg. Khim., 1967, 12, ( 2 ), 291. This contains a list of one hundred and seventy-five of Chernyaev’s works from 1948 to 1966.
- 5I. A. Fedorov, in “Vydayushchiesya Sovetskie Khimiki Akademiki A. A. Grinberg i I. I. Chernyaev”, publ. by “Nauka”, Moscow, 1970, 39
- 6A. V. Babaeva, Ibid., 46
- 7V. A. Golovnya, Ibid., 58
- 8I. I. Chernyaev, “Izbrannye Trudy, Kompleksnye Soedineniya Platiny”, ed. Ya. K. Syrkin, publ. by “Nauka”, Moscow, 1973 . This contains seventy-six of Chernyaev’s articles on platinum complexes.
- 9D. N. Trifonov, “Dictionary of Scientific Biography”, ed. C. C. Gillispie, Charles Scribner’s Sons, New York, 1971, Vol. 3, 235
- 10G. B. Kauffman, J. Chem. Educ., 1963, 40, ( 12 ), 656; Platinum Metals Rev., 1973, 17, ( 4 ), 144
- 11L. A. Chugaev and I. I. Chernyaev, J. Russ. Phys. Chem. Soc., 1915, 47, 201; Compt. Rend., 1915, 161, 637
- 12L. A. Chugaev and I. I. Chernyaev, J. Russ. Phys. Chem. Soc., 1915, 47, 1806 ; Compt. Rend., 1915, 161, 792
- 13G. B. Kauffman and A. Beck, J. Chem. Educ., 1962, 39, ( 1 ), 44
- 14G. B. Kauffman, Platinum Metals Rev., 1974, 18, ( 4 ), 142
- 15M. Peyrone, Liebigs Ann. Chem. Pharm., 1844, 51, 1
- 16S. M. Jörgensen, J. Prakt. Chem., 1886, 33, (10–11), 489; Z. Anorg. Chem., 1900, 24, ( 2 ), 153
- 17N. S. Kurnakov, J. Russ. Phys. Chem. Soc., 1893, 25, 565; J. Prakt. Chem., 1894, 50, (11–12), 481
- 18I. I. Chernyaev, Izv. Inst. Izucheniiu Platiny i Drug. Blagorodn. Metall. (hereafter abbreviated Izv. ), 1926, 4, 243
- 19I. I. Chernyaev, Izv., 1927, 5, 118
- 20J. E. Huheey, “Inorganic Chemistry: Principles of Structure and Reactivity”, Harper and Row, New York, 1972, (a) p. 424; (b) p. 427
- 21I. I. Chernyaev, Izv., 1928, 6, 55
- 22I. I. Chernyaev, Izv., 1928, 6, 23 and 40
- 23I. I. Chernyaev and A. D. Adrianova, Izv., 1949, 23, 9
- 24I. I. Chernyaev and G. S. Muraveiskaya, Izv., 1955, 31, 5
- 25J. V. Quagliano and L. Schubert, Chem. Rev., 1952, 50, 201
- 26F. Basolo and R. G. Pearson, “Mechanisms of Inorganic Reactions”, John Wiley and Sons, New York, 1958, Chap. 4; Prog. Inorg. Chem., 1962, 4, 381
- 27B. V. Nekrasov, “Kurs Obshchei Khimii”, Moscow, Leningrad, 1935, Vol. 2, p. 777; rev. ed., Gosudarstvennoe Nauchnotekhnicheskoe Izdatel’stvo Khimicheskoi Literatury, Moscow, Vol. 2, p. 860; idem, Zh. Obshch. Khim., 1937, 7, ( 11 ), 1594
- 28A. A. Grinberg, Izv., 1932, 10, 47
- 29J. Chatt,, L. A. Duncanson and L. M. Venanzi, J. Chem. Soc., 1955, 4456 and 4461
- 30A. Pidcock,, R. E. Richards and L. M. Venanzi, J. Chem. Soc., A, 1966, ( 12 ), 1707
- 31L. E. Orgel, J. Inorg. Nucl. Chem., 1956, 2, ( 3 ), 137
- 32J. A. Wunderlich, and D. P. Mellor,, Acta Cryst., 1954, 7, 130; Ibid., 1955, 8, 57; P. R. H. Alderman, P. G. Owston and J. M. Rowe, Ibid., 1960, 13, 149
- 33F. Basolo,, J. Chatt,, H. B. Gray,, R. G. Pearson and B. L. Shaw, J. Chem. Soc., 1961, 2207
- 34C. H. Langford, and H. B. Gray,, “Ligand Substitution Processes”, W. A. Benjamin,, New York, 1965, p. 25; Ya. K. Syrkin,, Izv. Akad. Nauk S.S.S.R., Otdel. Khim. Nauk, 1948, ( 1 ), 69; L. M. Venanzi, Chem. Br., 1968, 4, ( 4 ), 162; R. S. Tobias, Inorg Chem., 1970, 9, ( 5 ), 1296
The present study resulted from research on the separation of inorganic geometric isomers supported by the Research Corporation, the National Science Foundation, and the Petroleum Research Fund, administered by the American Chemical Society. The author, a Visiting Scholar at the Office for History of Science and Technology, University of California, Berkeley, acknowledges the John Simon Guggenheim Memorial Foundation for a Guggenheim Fellowship. He is also indebted to Drs G. V. Bykov, V. A. Golovnya, T. N. Leonova, and L. A. Nazarova, and the late Academician Il’ya Il’ich Chernyaev, all of the U.S.S.R. Academy of Sciences, for the location of source material, to Dr Henry M. Leicester and Alexander Beck for assistance in translation, and to Elsie Taylor and Robert Michelotti for technical assistance.