metallocene
Noun
Meaning
English Wikipedia has an article on:metalloceneWikipedia
metallocene (plural metallocenes)
(organic chemistry) Any of a class of organic compounds containing two cyclopentadienyl anions and a transition metal whose bonding involves overlap of ns and np orbitals of the metal with molecular orbitals of appropriate symmetry of each cyclopentadienyl ring; the rings are parallel to each other, or sometimes canted.
Synonyms
Examples
1 H NMR chemical shifts for diamagnetic organotransition-metal compounds is usually observed between 25 and 40 ppm, but this range is much more narrow for diamagnetic metallocene complexes, with chemical shifts usually observed between 3 and 7 ppm.
According to the IUPAC definition, a metallocene contains a transition metal and two cyclopentadienyl ligands coordinated in a sandwich structure, i.e., the two cyclopentadienyl anions are on parallel planes with equal bond lengths and strengths.
Organoberkelium compounds Berkelium forms a trigonal (η 5 –C 5 H 5 ) 3 Bk metallocene complex with three cyclopentadienyl rings, which can be synthesized by reacting berkelium(III) chloride with the molten beryllocene ( Be (C 5 H 5 ) 2 ) at about 70 °C.
Derivatives main After the discovery of ferrocene, the synthesis and characterization of derivatives of metallocene and other sandwich compounds attracted researchers’ interests.
Mechanism of Ziegler–Natta polymerization The structure of active centers in Ziegler–Natta catalysts is firmly established only for metallocene catalysts.
The complexes are activated using MAO, as is done for metallocene catalysts.