Catalyst systems suitable for tetramerizing ethylene to form 1-octene may include a catalyst including a chromium compound coordinated with a ligand and a co-catalyst including an organoaluminum compound. The ligand may have a chemical structure: (R.sub.1)(R.sub.2)A-X—C(R.sub.3)(R.sub.4). A and C may be phosphorus. X may be B(R.sub.5), Si(R.sub.5).sub.2, N(R.sub.5), wherein R.sub.5 is an aryl group substituted with a halogen, halogenated alkyl or a silyl group, and wherein B, or N, or Si is bound to A and C. R.sub.1, R.sub.2, R.sub.3, and R.sub.4 may be independently chosen hydrocarbyl groups or heterohydrocarbyl groups.

A tetraanionic OCO pincer ligand metal-oxo-alkylidene complex is prepared from a trianionic pincer ligand supported metal-alkylidyne. The metal can be tungsten or other group 5-7 transition metal. The tetraanionic pincer ligand metal-oxo-alkylidene complex, a trianionic OCO pincer ligand metal complex, or a trianionic ONO pincer ligand metal complex can be used to polymerize cycloalkenes. The poly(cycloalkene)s are predominantly cis-alkene macrocyclics.

Triaryl phosphine ligands, as shown in general formulae Ia and Ib, or a mixture thereof, and a preparation method therefor. The invention addresses the deficiencies of biaryl phosphine ligands invented by Buchwald et al. Also provided are a triaryl phosphine coordinated palladium complex, a system composed of triaryl phosphine ligand and a palladium salt or complex, and a use of the triaryl phosphine coordinated palladium complex in catalysing organic reactions, in particular a use in catalysis of coupling reactions involving (pseudo)halogenated aromatic hydrocarbon as substrate.

Disclosed is a method for preparing an organic carboxylic ester by using a combined catalyst of an aryl bidentate phosphine ligand. The method includes subjecting a terminal olefin, carbon monoxide, and an alcohol to a hydroesterification reaction in the presence of a combined catalyst of a palladium compound, an aryl bidentate phosphine ligand, and an acidic additive, to generate an organic carboxylic ester having one more carbon atom than the terminal olefin.

Provided are triaryl phosphine ligands, as shown in general formulae Ia and Ib, or a mixture thereof, and a preparation method therefor. The invention addresses the deficiencies of biaryl phosphine ligands invented by Buchwald et al. Also provided are a triaryl phosphine coordinated palladium complex, a system composed of triaryl phosphine ligand and a palladium salt or complex, and a use of the triaryl phosphine coordinated palladium complex in catalysing organic reactions, in particular a use in catalysis of coupling reactions involving (pseudo)halogenated aromatic hydrocarbon as substrate.

Described herein are compositions composed of frustrated Lewis pairs impregnated in porous materials such as, for example, metal-organic frameworks, and their uses thereof. These compositions may allow new applications of frustrated Lewis pairs in catalysis by sequestering and protecting the frustrated Lewis pair within the nanospace of the porous material. Also provided are methods of hydrogenating an organic compound having at least one unsaturated functional group comprising using the compositions described herein.

The present invention may provide an asymmetric hydrogenation catalyst capable of resolving enantiomers with excellent enantioselectivity from a carbon-carbon double bond-containing compound. The catalyst according to one embodiment of the present invention includes: an iridium cation; and a ligand bonded to the iridium cation.

The present invention relates to a process for preparing nitrile rubbers having reduced molecular weight by metathesis of a first nitrile rubber in the presence of specific ruthenium complex catalysts that have particular N-heterocyclic carbene ligands.

Catalyst systems suitable for tetramerizing ethylene to form 1-octene may include a catalyst including a chromium compound coordinated with a ligand and a co-catalyst including an organoaluminum compound. The ligand may have a chemical structure: (R.sub.1)(R.sub.2)A-X—C(R.sub.3)(R.sub.4). A and C may be phosphorus. X may be B(R.sub.5), Si(R.sub.5).sub.2, N(R.sub.5), wherein R.sub.5 is an aryl group substituted with a halogen, halogenated alkyl or a silyl group, and wherein B, or N, or Si is bound to A and C. R.sub.1, R.sub.2, R.sub.3, and R.sub.4 may be independently chosen hydrocarbyl groups or heterohydrocarbyl groups.

The invention relates to a method of forming an olefin from a first olefin and a second olefin in a metathesis reaction, comprising step (i): (i) reacting the first olefin with the second olefin in the presence of a compound that catalyzes said metathesis reaction such that the molar ratio of said compound to the first or the second olefin is from 1:500 or less, and the conversion of the first or the second olefin to said olefin is at least 50%, characterized in that as compound that catalyzes said metathesis reaction a compound of the following formula is used: ##STR00001## wherein M is Mo or W; R.sup.1 is aryl, heteroaryl, alkyl, or heteroalkyl; optionally substituted; R.sup.2 and R.sup.3 can be the same or different and are hydrogen, alkyl, alkenyl, heteroalkyl, heteroalkenyl, aryl, or heteroaryl; optionally substituted; R.sup.5 is alkyl, alkoxy, heteroalkyl, aryl, heteroaryl, silylalkyl, silyloxy, optionally substituted; and R.sup.4 is a residue R.sup.6—X—, wherein X═O and R.sup.6 is aryl, optionally substituted; or X═S and R.sup.6 is aryl, optionally substituted; or X═O and R.sup.6 is (R.sup.7, R.sup.8, R.sup.9)Si; wherein R.sup.7, R.sup.8, R.sup.9 are alkyl or phenyl, optionally substituted; or X═O and R.sup.6 is (R.sup.10, R.sup.11, R.sup.12)C, wherein R.sup.10, R.sup.11, R.sup.12 are independently selected from phenyl, alkyl; optionally substituted; and to the catalysts used in the method.