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Preparation of Tungsten‐Based Olefin Metathesis Catalysts Supported on Alumina
Author(s) -
Yuan Jian,
Townsend Erik M.,
Schrock Richard R.,
Goldman Alan S.,
Müller Peter,
Takase Michael K.
Publication year - 2011
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201100200
Subject(s) - chemistry , catalysis , metathesis , tungsten , adsorption , olefin metathesis , pentane , selectivity , olefin fiber , calcination , salt metathesis reaction , medicinal chemistry , ring opening metathesis polymerisation , isopropyl , organic chemistry , polymerization , polymer
A new tungsten alkylidene complex, W(NAr)(CHCMe 2 Ph)(OHIPT‐NMe 2 )(pyrrolide) {Ar=2,6‐( i‐ Pr) 2 C 6 H 3 ; HIPT‐NMe 2 =2,6‐[2,4,6‐( i‐ Pr) 3 C 6 H 2 ] 2 ‐4‐NMe 2 ‐C 6 H 2 }, has been synthesized and shown to be highly selective for Z homocoupling metathesis of selected terminal olefins in pentane, as is W(NAr)(CH 2 CH 2 CH 2 )(OHIPT)(pyrrolide) ( 5 ). Both 5 and W(NAr)(CHCMe 2 Ph)(OHIPT‐NMe 2 )(pyrrolide) ( 6 ) are adsorbed onto calcined alumina. Control experiments and metathesis homocoupling of four substrates lead to the conclusions that 5 is largely adsorbed in a reaction that liberates HIPTOH, while 6 is adsorbed largely through an interaction between the dimethylamino group and an acidic site on the surface. There is no evidence that any adsorbed catalyst can give rise to Z selectivity of a magnitude equal to that found in a homogeneous reaction involving 5 or 6 .