The present disclosure relates to a catalyst system comprising i) (a) a bicyclic 2-[(phosphinyl)aminyl] cyclic imine chromium salt or (b) a chromium salt and a bicyclic 2-[(phosphinyl)aminyl] cyclic imine and ii) an organoaluminum compound. The present disclosure also relate to a process comprising: a) contacting i) ethylene; ii) a catalyst system comprising (a) a 2-[(phosphinyl)aminyl] cyclic imine chromium salt complex or (b) a chromium salt and a bicyclic 2-[(phosphinyl)aminyl] cyclic imine; ii) an organoaluminum compound, and iii) optionally an organic reaction medium; and b) forming an oligomer product in a reaction zone.

Disclosed are a pincer-type ligand having a structurally rigid acridane structure and a metal complex consisting of the pincer-type ligand and a metal bound to each other, and exhibiting high reactivity and stability during a variety of bonding activation reactions. T-shaped complexes can be prepared from .sup.acriPNP(4,5-bis(diisopropylphosphino)-2,7,9,9-tetramethyl-9H-acridin-10-ide), which is a pincer-type PNP ligand having an acridane structure, and metal complexes, which can be structurally rigid and thus exhibit excellent reactivity and stability based on minimized structural change thereof, can be prepared by introducing an acridane structure into the backbone thereof. The PNP ligand is structurally stable and has novel chemical properties, as compared to conventional similar ligands, and thus can be utilized in a wide range of catalytic reactions and material chemistry.

Disclosed are a chiral multidentate ligand (I), a preparation, and an application thereof. In this method, compound (M1) is subjected to condensation with compound (M2) followed by amine deprotection in the presence of a deprotection reagent to obtain compound (M4). Compound (1) is subjected to deprotonation by butyl lithium and phosphorization followed by dimethylamino group substitution to produce compound (3). The compound (3) and the compound (M4) are reacted in the presence of triethylamine to produce chiral multidentate ligands.

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A cyclopropanation method includes reacting an alcohol, an ester, or an aldehyde with a sulfone in an organic solvent containing a base providing a counter cation to form a cyclopropane; and isolating the cyclopropane. When using the alcohol or ester, the organic solvent further contains a catalyst having an alcohol dehydrogenation activity.

The present disclosure relates to a catalyst system comprising i) (a) an N.sup.2-phosphinyl bicyclic amidine chromium salt or (b) a chromium salt and an N.sup.2-phosphinyl bicyclic amidine and ii) an organoaluminum compound. The present disclosure also relate to a process comprising: a) contacting i) ethylene; ii) a catalyst system comprising (a) an N.sup.2-phosphinyl bicyclic amidine chromium salt complex or (b) a chromium salt and an N.sup.2-phosphinyl bicyclic amidine; ii) an organoaluminum compound, and iii) optionally an organic reaction medium; and b) forming an oligomer product in a reaction zone.

The present disclosure relates to a catalyst system comprising i) (a) a bicyclic 2-[(phosphinyl)aminyl] cyclic imine chromium salt or (b) a chromium salt and a bicyclic 2-[(phosphinyl)aminyl] cyclic imine and ii) an organoaluminum compound. The present disclosure also relates to a process comprising: a) contacting i) ethylene; ii) a catalyst system comprising (a) a 2-[(phosphinyl)aminyl] cyclic imine chromium salt complex or (b) a chromium salt and a bicyclic 2-[(phosphinyl)aminyl] cyclic imine; ii) an organoaluminum compound, and iii) optionally an organic reaction medium; and b) forming an oligomer product in a reaction zone.

The present disclosure relates to a ligand compound, a catalyst system for oligomerization, and a method for olefin oligomerization using the same. The catalyst system for oligomerization using the ligand compound according to the present disclosure has excellent catalytic activity, exhibits high selectivity to 1-hexene and 1-octene, and greatly reduces the production of the by-products, thereby enabling efficient preparation of alpha-olefin.

The present disclosure relates to a catalyst system comprising i) (a) an N.sup.2-phosphinyl bicyclic amidine chromium salt or (b) a chromium salt and an N.sup.2-phosphinyl bicyclic amidine and ii) an organoaluminum compound. The present disclosure also relate to a process comprising: a) contacting i) ethylene; ii) a catalyst system comprising (a) an N.sup.2-phosphinyl bicyclic amidine chromium salt complex or (b) a chromium salt and an N.sup.2-phosphinyl bicyclic amidine; ii) an organoaluminum compound, and iii) optionally an organic reaction medium; and b) forming an oligomer product in a reaction zone.

Catalyst compositions and processes for the oligomerization of ethylene to 1-octene are described. The catalyst composition includes a triamino bisphospino (NPNPN) ligand system with specific phosphorous and nitrogen ligands. The terminal nitrogen atoms include linear alkyl hydrocarbons that differ in the number of carbon atoms by 3.

A catalyst system comprising i) a 2-[(phosphinyl)aminyl] cyclic imine transition metal compound complex and ii) an organoaluminum compound. A process comprising contacting i) ethylene, ii) a catalyst system comprising (a) a 2-[(phosphinyl)aminyl] cyclic imine transition metal compound complex, and (b) an organoaluminum compound, and iii) optionally hydrogen to form an oligomer product.