Osmium naming

History. Osmium was discovered in 1803 by Smithson Tennant in the dark colored residue left when crude platinum is dissolved by aqua regia. This dark residue contains both osmium (named after the Greek osme, meaning odor) and iridium. It is a bluish-white, silvery, extremely hard brittle metal that is not malleable even at high temperatures. 

This is a chapter written entirely by a chemist named Rhodium (with guest speaker Osmium ). Rhodium is, as far as Strike is concerned, the world s leading underground scientist. Knowledgeable in nearly every aspect of drug chemistry, this chemist has been the savior for many a person that was lost. Here he has contributed some new reactions for your reading pleasure. Radical stuff that you can bet will become the next wave of synthesis protocol. The rest of this chapter is Rhodium s voice.]... 

A catalytic enantio- and diastereoselective dihydroxylation procedure without the assistance of a directing functional group (like the allylic alcohol group in the Sharpless epox-idation) has also been developed by K.B. Sharpless (E.N. Jacobsen, 1988 H.-L. Kwong, 1990 B.M. Kim, 1990 H. Waldmann, 1992). It uses osmium tetroxide as a catalytic oxidant (as little as 20 ppm to date) and two readily available cinchona alkaloid diastereomeis, namely the 4-chlorobenzoate esters or bulky aryl ethers of dihydroquinine and dihydroquinidine (cf. p. 290% as stereosteering reagents (structures of the Os complexes see R.M. Pearlstein, 1990). The transformation lacks the high asymmetric inductions of the Sharpless epoxidation, but it is broadly applicable and insensitive to air and water. Further improvements are to be expected. 

Another important reaction associated with the name of Sharpless is the so-called Sharpless dihydroxylation i.e. the asymmetric dihydroxylation of alkenes upon treatment with osmium tetroxide in the presence of a cinchona alkaloid, such as dihydroquinine, dihydroquinidine or derivatives thereof, as the chiral ligand. This reaction is of wide applicability for the enantioselective dihydroxylation of alkenes, since it does not require additional functional groups in the substrate molecule ... 

We have previously seen examples of the carbon-like formulas of mononuclear and dinuclear osmium compounds, namely the methane-like tetrahydride (4.50c), ethylene-like H20s=CH2 (4.51c) and H2Os = OsH2 (Table 4.15), acetylenelike HOs = CH (4.54c) and HOs = OsH (Table 4.15), allene-like H2C = Os = CH2 (4.55a), and so forth. While the coordination numbers and Lewis-like formulas are formally analogous, the actual structures of Os and C species may be quite similar (e.g., the Td structures of OsfL and CH4) or dissimilar (e.g the strongly bent Cs structure of H20s = CH2 [Fig. 4.13(c)] versus the planar D2h structure of H2C = CH2). 

Osmium (Os, [Xe + 4/ l4]5 /66.v2), name from the Greek oop/ij (osme, smell). Powdered Os slowly gives off 0s04 toxic and with a strong smell. Discovered with... 

About a decade after the discovery of the asymmetric epoxidation described in Chapter 14.2, another exciting discovery was reported from the laboratories of Sharpless, namely the asymmetric dihydroxylation of alkenes using osmium tetroxide. Osmium tetroxide in water by itself will slowly convert alkenes into 1,2-diols, but as discovered by Criegee [15] and pointed out by Sharpless, an amine ligand accelerates the reaction (Ligand-Accelerated Catalysis [16]), and if the amine is chiral an enantioselectivity may be brought about. 

Iridium - the atomic number is 77 and the chemical symbol is Ir. The name derives from the Latin Iris, the greek goddess of rainbows because of the variety of colors in the element s salt solutions . Iridium and osmium were both discovered in a crude platinum ore in 1803 by the English chemist Smithson Tennant. Iridium was discovered independently by the French chemist H. V. Collet-Descotils also in 1803. Descotils actually published one month before Tennant but Tennent is given credit for the discovery, perhaps because he alone also found osmium in the ore. 

Osmium - the atomic number is 76 and the chemical symbol is Os. The name derives from the Greek osme for smell because of the sharp odor of the volatile oxide. Both osmium and iridium were discovered simultaneously in a crude platinum ore by the English chemist Smithson Tennant in 1803. 

Iridium and its parmer osmium were discovered in 1803 by the Enghsh chemist Smithson Tennant (1761-1815). In essence, he employed the same technique to separate these elements from platinum ores that is used today to pmify iridium. He dissolved the minerals with aqua regia, which left a black residue that looked much like graphite. After analyzing this shiny black residue, he identified two new elements—Ir and Os. Tennant was responsible for naming iridium after the Latin word iris because of the element s rainbow of colors. 

In 1803 William Hyde Wollaston, a British physician who became famous for his research in metallurgy, mineralogy, and optics, succeeded in extracting a white metal from platinum. He named the new element palladium, after the asteroid Pallas, which had just been discovered the previous year. In the same year the English chemist Smithson Tennant obtained two new metals, which he named iridium and osmium, from platinum. And in 1828 the Russian chemist Karl Karlovich Klaus reported that he had obtained three new metals from platinum mined in the Urals. However, the existence of only one of them, which Klaus called ruthenium, was confirmed. 

Osmium was discovered by English chemist Smithson Tennant in 1804. The element was named osmium after the Greek word, osme, which means a smell, because of the pungent and peculiar odor of its volatde oxide. 

The powder was fused with NaOH, then treated with acid, and distilled. The acrid-smelling condensate contained a compound of a metal which was called osmium, and the residue contained a compound of a second metal which was called iridium. Os was named after the Greek word osme which means stench, and Ir was named after Iris, the Greek goddess of the rainbow. 

In the meantime Tennant continued his researches, and the results which he communicated to the Royal Academy in the spring of 1804 showed that the powder contains two new metals, which may be separated by the alternate action of acid and alkali. One of these he named iridium because its salts are of varied colors, and the other he called osmium because of its odor (20). 

Tennant gave the name iridium to the metal which Descotils and Vauquelin had observed, and the name osmium to the new one (20). In speaking of iridium, osmium, palladium, and rhodium, W. T. Braude stated in his lectures in 1817, Of these, the two former were discovered by the late Mr. Tennant and the two latter by Dr. Wollaston and bad we searched throughout chemistry for an illustrative instance of the delicacy of the modem art of analysis, it would be difficult to have found any one more notorious than the history of the discovery and separation of these bodies exhibits (46). During the entire course of the researches which led to ibe discovery of these four metals, Dr. Wollaston and Tennant had friendly intercourse with each other, and each kept in close touch with... 

In 1828 Berzelius and G. W. Osann (25), professor of chemistiy at the University of Dorpat, examined the residues left after dissolving crude platinum from the Ural mountains in aqua regia. Berzelius did not find in them any unusual metals except palladium, rhodium, osmium, and iridium, which had already been found by Wollaston and Tennant in similar residues from American platinum. Professor Osann, on the other hand, thought that he had found three new metals, which he named pluranium, ruthenium, and polinium (25, 36). In 1844, however, Professor Klaus, another Russian chemist showed that Osann s ruthenium oxide was very impure, but that it did contain a small amount of a new metal (26,33). 

In 1866 Friedrich Wohler discovered a ruthenium mineral. When he analyzed the shining black grains of what seemed to be an unusual platinum mineral which Herr Waitz of Cassel had brought back from Borneo, he found it to be a sulfide of ruthenium and osmium. Wohler stated that this mineral, which he named laurite, presented the first example of the natural occurrence of sulfur compounds of the platinum metals (129). 

In the course of investigating the production of platinum from its ores, Wollaston and Tennant found four new elements in 1803. Tennant isolated osmium and iridium Wollaston found rhodium and palladium. As was the contemporary habit, Wollaston named the latter after a newly discovered celestial body. Uranium gained its name this way after William Herschel s discovery of the planet Uranus, and palladium honoured the asteroid Pallas, found in 1802. 

Ferrocene is only one of a large number of compounds of transition metals with the cyclopentadienyl anion. Other metals that form sandwich-type structures similar to ferrocene include nickel, titanium, cobalt, ruthenium, zirconium, and osmium. The stability of metallocenes varies greatly with the metal and its oxidation state ferrocene, ruthenocene, and osmocene are particularly stable because in each the metal achieves the electronic configuration of an inert gas. Almost the ultimate in resistance to oxidative attack is reached in (C5H5)2Co , cobalticinium ion, which can be recovered from boiling aqua regia (a mixture of concentrated nitric and hydrochloric acids named for its ability to dissolve platinum and gold). In cobalticinium ion, the metal has the 18 outer-shell electrons characteristic of krypton. 

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