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In organic chemistry, an allyl group is a substituent with the structural formula −CH 2 −HC=CH 2. It consists of a methylene bridge (−CH 2 −) attached to a vinyl group (−CH=CH 2). [1] [2] The name is derived from the scientific name for garlic, Allium sativum. In 1844, Theodor Wertheim isolated an allyl derivative from garlic oil and ...
The allyl ligand is commonly in organometallic chemistry.Usually, allyl ligands bind to metals via all three carbon atoms, the η 3-binding mode.The η 3-allyl group is classified as an LX-type ligand in the Green LXZ ligand classification scheme, serving as a 3e – donor using neutral electron counting and 4e – donor using ionic electron counting.
Allyl halides react with Ni(CO) 4 to form pi-allyl complexes, (allyl) 2 Ni 2 Cl 2. [8] These compounds in turn are sources of allyl nucleophiles . In (allyl) 2 Ni 2 Br 2 and (allyl)Ni(C 5 H 5 ), nickel is assigned to oxidation number +2, and the electron counts are 16 and 18, respectively.
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Electrophilic additions to allyl- and vinylsilanes take advantage of this, and site selectivity generally reflects this property—electrophiles become bound to the carbon γ to the silyl group. The electron-donating strength of the carbon-silicon bond is similar to that of an acetamide substituent and equal to roughly two alkyl groups. [ 6 ]
Indenyl like effects are also observed in a number of non indenyl substituted metal complexes. In fluorenyl complexes, associative substitution is enhanced even further than indenyl compounds. The substitution rate of Mn(η 5 -C 13 H 9 )(CO) 3 is about 60 times faster than that of Mn(η 5 -C 9 H 7 )(CO) 3
BMW and Yamaha Motor have invested in U.S.-based rare earths processing startup Phoenix Tailings, the latest move by manufacturers to boost production of the strategic metals outside of China.
Some metal alkyls feature agostic interactions between a C-H bond on the alkyl group and the metal. Such interactions are especially common for complexes of early transition metals in their highest oxidation states. [18] One determinant of the kinetic stability of metal-alkyl complexes is the presence of hydrogen at the position beta to the metal.