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F-block Metallocene
In organometallic chemistry, f-block metallocenes are a class of sandwich compounds consisting of an Block (periodic table)#f-block, f-block metal and a set of electron-rich ligands such as the cyclopentadienyl anion. History The first prepared and well-characterized f-block metallocenes were the tris(cyclopentadienyl) lanthanide complexes, (C5H5)3Ln (Ln = La, Ce, Pr, Nd, Sm and Gd).Wilkinson, G.; Birmingham, J. M. ''J. Am. Chem. Soc.'' 1954, ''76'', 6210.Birmingham, J. M.; Wilkinson, G. ''J. Am. Chem. Soc.'' 1956, ''78'', 42. However, their significance is limited more to their existences and structures than to their reactivity. The cyclopentadienyl ligands of f-block metallocenes were considered as inert ancillary ligands, only capable of enhancing their stability and solubility, but not their reactivity. In addition, only late and small metals in the lanthanide series, i.e., elements from Sm to Lu, are trivalent metallocene complexes, [(C5H5)2LnZ]nEvans, W. J.; Wayda, A. L. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organometallic
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 repres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The First (C5Me5)3M Synthetic Method
The First may refer to: * ''The First'' (album), the first Japanese studio album by South Korean boy group Shinee * ''The First'' (musical), a musical with a book by critic Joel Siegel * The First (TV channel), an American conservative opinion network * ''The First'' (TV series), a drama television series created by Beau Willimon * '' The First 48'', an American documentary television series on A&E * The First Evil (also "The First"), a fictional character created by Joss Whedon for the TV series ''Buffy the Vampire Slayer'' See also * Das Erste Das Erste (; "The First") is the flagship national television channel of the ARD association of public broadcasting corporations in Germany. ''Das Erste'' is jointly operated by the nine regional public broadcasting corporations that are member ..., the principal publicly owned television channel in Germany * La 1ère (other) (french: La Première, , The First), "Première" * First (other) {{DEFAULTSORT:Fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sterically Induced Reduction (SIR) Of The F-block Metallocene
In chemistry, a sterically induced reduction happens when an oxidized metal behaves as, and exhibits similar reducing properties to, the more reduced form of the metal. This effect is mainly caused by the surrounding ligands that are complexed to the metal and it is the ligands that are involved in the reduction chemistry instead of the metal due to electronic destabilization by being significantly distanced from the metal. Sterically induced reductions commonly involve metals found in the lanthanoid and actinoid series. Background Divalents Lanthanides are extremely reducing (can reduce alkali cations) compounds. Of these divalent lanthanides, Samarium(II) iodide, SmI2, is a common reducing agent that is used in a variety of synthetic applications, mainly because all other divalent lanthanides are unstable. Complexes of Sm(II) have also been investigated and used in similar applications. However, even though Sm(II) complexes and compounds have had tremendous success w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ligand Cleavage
In coordination chemistry, a ligand is an ion or molecule ( functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electron pairs, often through Lewis bases. The nature of metal–ligand bonding can range from covalent to ionic. Furthermore, the metal–ligand bond order can range from one to three. Ligands are viewed as Lewis bases, although rare cases are known to involve Lewis acidic "ligands". Metals and metalloids are bound to ligands in almost all circumstances, although gaseous "naked" metal ions can be generated in a high vacuum. Ligands in a complex dictate the reactivity of the central atom, including ligand substitution rates, the reactivity of the ligands themselves, and redox. Ligand selection requires critical consideration in many practical areas, including bioinorganic and medicinal chemistry, homogeneous catalysis, and environme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymerization Reaction
In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many forms of polymerization and different systems exist to categorize them. In chemical compounds, polymerization can occur via a variety of reaction mechanisms that vary in complexity due to the functional groups present in the reactants and their inherent steric effects. In more straightforward polymerizations, alkenes form polymers through relatively simple radical reactions; in contrast, reactions involving substitution at a carbonyl group require more complex synthesis due to the way in which reactants polymerize. Alkanes can also be polymerized, but only with the help of strong acids. As alkenes can polymerize in somewhat straightforward radical reactions, they form useful compounds such as polyethylene and polyvinyl chloride (PVC), whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Second (C5Me5)3MZ Synthetic Method
''The Second'' is the second studio album by Canadian-American rock band Steppenwolf, released in October 1968 on ABC Dunhill Records. The album contains one of Steppenwolf's most famous songs, " Magic Carpet Ride". The background of the original ABC LP cover was a shiny "foil", in contrast to later (MCA Records) LP issues and the modern CD sleeve. Featuring a style that incorporates psychedelic music and hard rock, the release has received critical acclaim both when it came out as well as in later years. For example, AllMusic critic Bruce Eder stated that, though "highly derivative" of their first album, ''The Second'' had "very hard and edgy" tracks with the band "in excellent form". It became the band's highest-charting album on the ''Billboard'' 200, reaching number three. The five tracks on side two after "Magic Carpet Ride" consist of a continuous medley. Track listing Personnel Steppenwolf * John Kay – lead vocals, rhythm guitar, harmonica * Michael Monarch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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