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Ferrocene
Ferrocene is an organometallic compound with the formula . The molecule is a complex consisting of two cyclopentadienyl rings bound to a central iron atom. It is an orange solid with a camphor-like odor, that sublimes above room temperature, and is soluble in most organic solvents. It is remarkable for its stability: it is unaffected by air, water, strong bases, and can be heated to 400 °C without decomposition. In oxidizing conditions it can reversibly react with strong acids to form the ferrocenium cation . The rapid growth of organometallic chemistry is often attributed to the excitement arising from the discovery of ferrocene and its many analogues, such as metallocenes. History Discovery Ferrocene was discovered by accident thrice. The first known synthesis may have been made in the late 1940s by unknown researchers at Union Carbide, who tried to pass hot cyclopentadiene vapor through an iron pipe. The vapor reacted with the pipe wall, creating a "yellow slu ...
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Metallocene
A metallocene is a compound typically consisting of two cyclopentadienyl anions (, abbreviated Cp) bound to a metal center (M) in the oxidation state II, with the resulting general formula Closely related to the metallocenes are the metallocene derivatives, e.g. titanocene dichloride, vanadocene dichloride. Certain metallocenes and their derivatives exhibit catalytic properties, although metallocenes are rarely used industrially. Cationic group 4 metallocene derivatives related to p2ZrCH3sup>+ catalyze olefin polymerization. Some metallocenes consist of metal plus two cyclooctatetraenide anions (, abbreviated cot2−), namely the lanthanocenes and the actinocenes ( uranocene and others). Metallocenes are a subset of a broader class of compounds called sandwich compounds. In the structure shown at right, the two pentagons are the cyclopentadienyl anions with circles inside them indicating they are aromatically stabilized. Here they are shown in a staggered conformation. ...
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Iron
Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in front of oxygen (32.1% and 30.1%, respectively), forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust. In its metallic state, iron is rare in the Earth's crust, limited mainly to deposition by meteorites. Iron ores, by contrast, are among the most abundant in the Earth's crust, although extracting usable metal from them requires kilns or furnaces capable of reaching or higher, about higher than that required to smelt copper. Humans started to master that process in Eurasia during the 2nd millennium BCE and the use of iron tools and weapons began to displace copper alloys, in some regions, only around 1200 BCE. That event is considered the transition from the Bronze Age to th ...
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Organometallic Chemistry
Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkali, alkaline earth, and transition metals, and sometimes broadened to include metalloids like boron, silicon, and selenium, as well. Aside from bonds to organyl fragments or molecules, bonds to 'inorganic' carbon, like carbon monoxide (metal carbonyls), cyanide, or carbide, are generally considered to be organometallic as well. Some related compounds such as transition metal hydrides and metal phosphine complexes are often included in discussions of organometallic compounds, though strictly speaking, they are not necessarily organometallic. The related but distinct term " metalorganic compound" refers to metal-containing compounds lacking direct metal-carbon bonds but which contain organic ligands. Metal β-diketonates, alkoxides, dialkylamides, and metal phosphine complexes are r ...
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Chromocene
Chromocene is the organochromium compound with the formula r(C5H5)2 Like structurally related metallocenes, chromocene readily sublimes in a vacuum and is soluble in non-polar organic solvents. It is more formally known as bis(η5-cyclopentadienyl)chromium(II). Synthesis Ernst Otto Fischer, who shared the 1973 Nobel Prize in Chemistry for work on sandwich compounds, first described the synthesis of chromocene. One simple method of preparation involves the reaction of chromium(II) chloride with sodium cyclopentadienide: :CrCl2 + 2 NaC5H5 → Cr(C5H5)2 + 2 NaCl Such syntheses are typically conducted in tetrahydrofuran. Decamethylchromocene, Cr 5(CH3)5sub>2, can be prepared analogously from LiC5(CH3)5. Chromocene can also be prepared from chromium(III) chloride in a redox process: :2 CrCl3 + 6 NaC5H5 → 2 Cr(C5H5)2 + C10H10 + 6 NaCl Structure and bonding The structure of chromocene has been verified by X-ray crystallography. The average Cr–C bond length is 215.1(13)&nbs ...
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Cyclopentadienyl Magnesium Bromide
Cyclopentadienyl magnesium bromide is a chemical compound with the molecular formula . The molecule consists of a magnesium atom bonded to a bromine atom and a cyclopentadienyl group, a ring of five carbons each with one hydrogen atom. The compound is a Grignard reagent, a type of organometallic compound that features a magnesium atom bonded to a halogen atom and to a carbon atom of some organic functional group. This compound is of historic importance as the starting material for the first published synthesis of ferrocene by Peter Pauson and Thomas J. Kealy in 1951. Preparation The compound can be prepared by reacting cyclopentadiene with magnesium and bromoethane in anhydrous benzene Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms .... References P. L. Pauson and T. J. Kealy ...
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Cobaltocene
Cobaltocene, known also as bis(cyclopentadienyl)cobalt(II) or even "bis Cp cobalt", is an organocobalt compound with the formula Co(C5H5)2. It is a dark purple solid that sublimes readily slightly above room temperature. Cobaltocene was discovered shortly after ferrocene, the first metallocene. Due to the ease with which it reacts with oxygen, the compound must be handled and stored using air-free techniques. Synthesis Cobaltocene is prepared by the reaction of sodium cyclopentadienide (NaC5H5) with anhydrous cobalt(II) chloride in THF solution. Sodium chloride is cogenerated, and the organometallic product is usually purified by vacuum sublimation. Structure and bonding In Co(C5H5)2 the Co centre is "sandwiched" between two cyclopentadienyl (Cp) rings. The Co–C bond lengths are about 2.1 Å, slightly longer than the Fe–C bond in ferrocene. Co(C5H5)2 belongs to a group of organometallic compounds called metallocenes or sandwich compounds. Cobaltocene has 19 valence ...
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Nickelocene
Nickelocene is the organonickel compound with the formula Ni( ''η''5-C5H5)2. Also known as bis(cyclopentadienyl)nickel or NiCp2, this bright green paramagnetic solid is of enduring academic interest, although it does not yet have any known practical applications. Structure and bonding Ni(C5H5)2 belongs to a group of organometallic compounds called metallocenes. Metallocenes usually adopt structures in which a metal ion is sandwiched between two parallel cyclopentadienyl (Cp) rings. In the solid-state, the molecule has D5d symmetry, wherein the two rings are staggered. The Ni center has a formal +2 charge, and the Cp rings are usually assigned as cyclopentadienyl anions (Cp−), related to cyclopentadiene by deprotonation. The structure is similar to ferrocene. In terms of its electronic structure, three pairs of d electrons on nickel are allocated to the three d orbitals involved in Ni–Cp bonding: d''xy'', d''x''2–''y''2, d''z''2. The two remaining d-electrons each res ...
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John A
Sir John Alexander Macdonald (January 10 or 11, 1815 – June 6, 1891) was the first prime minister of Canada, serving from 1867 to 1873 and from 1878 to 1891. The dominant figure of Canadian Confederation, he had a political career that spanned almost half a century. Macdonald was born in Scotland; when he was a boy his family immigrated to Kingston in the Province of Upper Canada (today in eastern Ontario). As a lawyer, he was involved in several high-profile cases and quickly became prominent in Kingston, which elected him in 1844 to the legislature of the Province of Canada. By 1857, he had become premier under the colony's unstable political system. In 1864, when no party proved capable of governing for long, Macdonald agreed to a proposal from his political rival, George Brown, that the parties unite in a Great Coalition to seek federation and political reform. Macdonald was the leading figure in the subsequent discussions and conferences, which resulted in the ...
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Grignard Reagent
A Grignard reagent or Grignard compound is a chemical compound with the general formula , where X is a halogen and R is an organic group, normally an alkyl or aryl. Two typical examples are methylmagnesium chloride and phenylmagnesium bromide . They are a subclass of the organomagnesium compounds. Grignard compounds are popular reagents in organic synthesis for creating new carbon-carbon bonds. For example, when reacted with another halogenated compound in the presence of a suitable catalyst, they typically yield and the magnesium halide as a byproduct; and the latter is insoluble in the solvents normally used. In this aspect, they are similar to organolithium reagents. Pure Grignard reagents are extremely reactive solids. They are normally handled as solutions in solvents such as diethyl ether or tetrahydrofuran; which are relatively stable as long as water is excluded. In such a medium, a Grignard reagent is invariably present as a complex with the magnesium atom co ...
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Cyclopentadiene
Cyclopentadiene is an organic compound with the formula C5H6.LeRoy H. Scharpen and Victor W. Laurie (1965): "Structure of cyclopentadiene". ''The Journal of Chemical Physics'', volume 43, issue 8, pages 2765-2766. It is often abbreviated CpH because the cyclopentadienyl anion is abbreviated Cp−. This colorless liquid has a strong and unpleasant odor. At room temperature, this cyclic diene dimerizes over the course of hours to give dicyclopentadiene via a Diels–Alder reaction. This dimer can be restored by heating to give the monomer. The compound is mainly used for the production of cyclopentene and its derivatives. It is popularly used as a precursor to the cyclopentadienyl anion (Cp−), an important ligand in cyclopentadienyl complexes in organometallic chemistry. Production and reactions Cyclopentadiene production is usually not distinguished from dicyclopentadiene since they interconvert. They are obtained from coal tar (about 10–20 g/tonne) and ...
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Fulvalene
Fulvalene (bicyclopentadienylidene) is the member of the fulvalene family with the molecular formula C10H8. It is of theoretical interest as one of the simplest non-benzenoid conjugated hydrocarbons. Fulvalene is an unstable isomer of the more common benzenoid aromatic compounds naphthalene and azulene. Fulvalene consists of two 5-membered rings, each with two double bonds, joined by yet a fifth double bond. It has D2h symmetry. History An earlier attempt at synthesis of fulvalene in 1951 by Pauson and Kealy resulted in the accidental discovery of ferrocene. Its synthesis was first reported in 1958 by E. A. Matzner, working under William von Eggers Doering. In this method, cyclopentadienyl anion is coupled with iodine to the dihydrofulvalene. Double deprotonation of dihydrofulvalene with ''n''-butyllithium gives the dilithio derivative, which oxidizes with oxygen. Fulvalene was spectroscopically observed at from photolysis of diazocyclopentadiene, which induces dimer ...
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Duquesne University
Duquesne University of the Holy Spirit ( or ; Duquesne University or Duquesne) is a private Catholic research university in Pittsburgh, Pennsylvania. Founded by members of the Congregation of the Holy Spirit , image = Holy Ghost Fathers seal.png , size = 175px , caption = The seal of the Congregation depicting the Immaculate Heart of Mary, and the Holy Spirit proceeding from the Trinity. , abbreviation ..., Duquesne first opened as the Pittsburgh Catholic College of the Holy Ghost in October 1878 with an enrollment of 40 students and a faculty of six. In 1911, the college became the first Catholic university-level institution in Pennsylvania. It is the only Spiritan institution of higher education in the world. It is named for an 18th-century governor of New France, Michel-Ange Duquesne de Menneville. Duquesne has since expanded to over 9,300 graduate and undergraduate students within a self-contained hilltop campus in Pittsbur ...
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