The present invention relates to the field of polymerisation catalysts, and systems comprising these catalysts for polymerising carbon dioxide and an epoxide, a lactide and/or lactone, and/or an epoxide and an anhydride. The catalyst is of formula (I): ##STR00001##
wherein at least one of M.sub.1 or M.sub.2 is selected from Ni(II) and Ni(III)-X. A process for the reaction of carbon dioxide with an epoxide; an epoxide and an anhydride; and/or a lactide and/or a lactone in the presence of the catalyst is also described.

Polymerisation catalysts and systems comprising said catalysts for polymerising carbon dioxide and an epoxide, a lactide and/or lactone, and/or an epoxide and an anhydride. The catalyst is of formula (I):

##STR00001##

Wherein M.sub.1 and M.sub.2 are independently selected from Zn(II), Cr(II), Co(II), Cu(II), Mn(II), Ni(II), Mg(II), Fe(II), Ti(II), V(II), Cr(III)-X, Co(III)-X, Ni(III)-X, Mn(III)-X, Fe(III)-X, Ca(II), Ge(II), AI(III)-X, Ti(III)-X, V(III)-X, Ge(IV)-(X).sub.2 or Ti(IV)-(X).sub.2. R.sub.3A is different from R.sub.3B; and/or at least one occurrence of E.sub.3, E.sub.4, E.sub.5 and E.sub.6 is different to a remaining occurrence of E.sub.3, E.sub.4, E.sub.5 and E.sub.6. A ligand, a process of asymmetric N-substitution of a symmetrical ligand and a process for the reaction of: (i) carbon dioxide with an epoxide; (ii) an epoxide and an anhydride; and/or (iii) a lactide and/or a lactone, in the presence of a catalyst is also described.

A process to form a cyclic olefin polymerization catalyst which includes contacting a metal alkoxide with a transition metal halide to form a transition metal precatalyst, and contacting the transition metal precatalyst with a metal alkyl activator to form the activated catalyst comprising a transition metal carbene moiety. A cyclic olefin polymerization process is also disclosed.

The present invention relates to the field of polymerisation catalysts, and systems comprising said catalysts for polymerising carbon dioxide and an epoxide, a lactide and/or lactone, and/or an epoxide and an anhydride. The catalyst is of formula (I): ##STR00001## Wherein M.sub.1 and M.sub.2 are independently selected from Zn(II), Cr(II), Co(II), Cu(II), Mn(II), Ni(II), Mg(II), Fe(II), Ti(II), V(II), Cr(III)-X, Co(III)-X, Ni(III)-X, Mn(III)-X, Fe(III)-X, Ca(II), Ge(II), Al(III)-X, Ti(III)-X, V(III)-X, Ge(IV)-(X).sub.2 or Ti(IV)-(X).sub.2. R.sub.3A is different from R.sub.3B; and/or at least one occurrence of E.sub.3, E.sub.4, E.sub.5 and E.sub.6 is different to a remaining occurrence of E.sub.3, E.sub.4, E.sub.5 and E.sub.6. A ligand, a process of asymmetric N-substitution of a symmetrical ligand and a process for the reaction of: (i) carbon dioxide with an epoxide; (ii) an epoxide and an anhydride; and/or (iii) a lactide and/or a lactone, in the presence of a catalyst is also described.

A new family of mononuclear organometallic complexes of a divalent metal bound to sequential tetradentate monoanionic {ONNN}-type ligands, and polymerization of cyclic esters such as lactides utilizing same are provided. Novel tetradentate monoanionic {ONNN}-type ligands usable for forming these complexes are also provided.

A hydroprocessing catalyst or catalyst precursor has been developed. The catalyst is a unique transition metal tungsten oxy-hydroxide material. The hydroprocessing using the transition metal tungsten oxy-hydroxide material or the decomposition product thereof may include hydrodenitrification, hydrodesulfurization, hydrodemetallation, hydrodesilication, hydrodearomatization, hydroisomerization, hydrotreating, hydrofining, and hydrocracking.

The present invention provides, inter alia, a multidentate ligand having the structure of:

##STR00001##

Also provided are methods of preparing metal complexes from the multidentate ligand, and the metal complexes prepared by such methods. Further provided are catalysts comprising such metal complexes, and various uses of such catalysts.

The present invention provides a process for preparing a water splitting catalyst containing [Mn.sub.4CaO.sub.4] core structure and use thereof. The present invention provides clusters containing [Mn.sub.4CaO.sub.4] core structure by a chemical synthesis using inexpensive metal ions (Mn.sup.2+, Ca.sup.2+ ions), simple carboxyl ligands and a permanganate, performed single crystal X-ray diffraction on their space structure, and characterized their physical and chemical properties with electron spectrum, electrochemical and electron paramagnetic resonance technologies and the like. These compounds can catalyze water splitting in the presence of oxidant to release oxygen and can also catalyze water splitting on the surface of an electrode to release electrons onto the surface of the electrode to form a current.

Provided is a production method whereby corresponding carboxylic acid esters can be obtained from a variety of carboxylic acids at a high yield, even under conditions using a simple reaction operation and little catalyst and even if the amount of substrate used is theoretical. A production method for carboxylic acid ester, whereby a prescribed diester dicarbonate, carboxylic acid, and alcohol are reacted in the presence of at least one type of magnesium compound and at least one type of alkali metal compound.

In one aspect, the present invention provides catalysts for the carbonylation of heterocycles. The inventive catalysts feature metal-ligand complexes having cationic functional groups tethered to the ligand, wherein the tethered cationic groups are associated with anionic metal carbonyl species. The invention also provides methods of using the inventive catalysts to affect the ring opening carbonylation of epoxides.