Phosphine-substituted vinyl containing metallocene catlyst, preparation process and the application of the same
申请人:Yi Jianjun
公开号:US20080194854A1
公开(公告)日:2008-08-14
The invention relates to a phosphine-substituted vinyl containing metallocene catalyst, and also to the preparation process of the same as well as to the application of the catalyst. The catalyst has the general formula of Cp
2
(CR
1
═CR
2
(P(R
3
)
2
))MX, wherein Cp is a ligand containing cyclopentadiene having 1˜5 substitutions, of which two neighbors connecting to each other to form fused rings having more than two members; R
1
-R
3
is selected from the groups consisting of hydrogen, C
1
˜C
18
alkyl or perfluoro-alkyl, C
6
˜C
24
aralkyl or alkaryl; M is selected from the groups consisting of metals of the IVB group; and X is selected from the groups consisting of halogens, C
1
˜C
24
alkyl alkoxyl, silicone or alkaryl. With aluminoxane or modified aluminoxane, aluminum alkyl, halogenated aluminum alkyl or their mixture as the catalyst promoter the phosphine-substituted vinyl containing metallocene catalyst may be employed as the major catalyst for the polymerization or copolymerization of alpha-olefin. Due to its high activity, the polymerization may occur at both high and low temperatures with the polymer having higher molecular weight and broader molecular weight distribution.
The first manganese-catalyzed hydroboration of propargylic alcohols and amines as well as internal alkynes is reported. High regio- and stereoselectivity is achieved by applying 2 mol % of a manganese precatalyst based on the readily accessible bis(imino)pyridine ligand and MnCl2 as metal source. Propargylic alcohols and amines, as well as symmetric internal alkynes, were efficiently converted into
Electrochemical esterification reaction of alkynes with diols <i>via</i> cleavage of carbon–carbon triple bonds without catalyst and oxidant
作者:Pei-Long Wang、Hui-Zhi Shen、Hui-Hui Cheng、Hui Gao、Pin-Hua Li
DOI:10.1039/d0gc02193h
日期:——
as it is catalyst-free, oxidant-free, and additive-free and shows atom-economy. This is the first example of an electrochemical reaction via cleavage of carbon–carbon triple bonds. Meanwhile, this is also the first example of a carbon–carbon triple bond cleavage reaction of alkynes with diols.
poly(vinyl alcohol) (PVA) nanofiber mats prepared by means of electrospinning have been used for the immobilization of palladiumcatalyst. Thermal treatment of the palladium-loaded PVA nanofiber mats results in the cross-linking of the matrix PVA molecules as well as the reduction of the divalent palladium (Pd2+) into zerovalent palladium (Pd0) species. The palladium oxidation states were examined by X-ray
Re‐Catalyzed Annulations of Weakly Coordinating
<i>N</i>
‐Carbamoyl Indoles/Indolines with Alkynes via C−H/C−N Bond Cleavage
作者:Yunhui Yang、Congyang Wang
DOI:10.1002/chem.201901518
日期:2019.6.21
Described herein are rhenium‐catalyzed [3+2] annulations of N‐carbamoyl indoles with alkynes via C−H/C−N bondcleavage, which provide rapid access to fused‐ring pyrroloindolone derivatives. For the first time, the weakly coordinating O‐directing group was successfully employed in rhenium‐catalyzed C−H activation reactions, enabled by the unique catalytic trio of Re2(CO)10, Me2Zn and ZnCl2. Mechanistic