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Ethylene Polymerization with Hydridotris(pyrazolyl)boratoniobium Complexes as Precursors
Author(s) -
Jaffart Joëlle,
Nayral Céline,
Choukroun Robert,
Mathieu René,
Etienne Michel
Publication year - 1998
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/(sici)1099-0682(199804)1998:4<425::aid-ejic425>3.0.co;2-l
Subject(s) - chemistry , catalysis , polymerization , toluene , ethylene , alkyl , niobium , electrochemistry , metal , ligand (biochemistry) , polymer chemistry , medicinal chemistry , inorganic chemistry , organic chemistry , polymer , receptor , electrode , biochemistry
Substituted hydridotris(pyrazolyl)borato (Tp′) niobium complexes of the type [Tp′NbMe 2 (PhC≡CMe)] polymerize ethylene (under 1 atm, at room temp. and in toluene) when treated with an equimolar amount of B(C 6 F 5 ) 3 . A clear relationship is observed between the stereoelectronic nature of the complex and catalytic activity. This is discussed on the basis of electrochemical data for the dichloro complexes [Tp′NbCl 2 (PhC≡CMe)], and the rates of alkyl migration in [Tp′Nb(Cl)(R)(PhC≡CMe)] (R = CH 2 Me, CH 2 SiMe 3 ). For a given electron density at the metal, the bulky Tp Me2,4‐Cl yields a catalyst which is more than 6 times as active as the unsubstituted Tp based catalyst.