In one aspect, the present disclosure encompasses polymerization systems for the copolymerization of CO.sub.2 and epoxides comprising 1) a catalyst including a metal coordination compound having a permanent ligand set and at least one ligand that is a polymerization initiator, and 2) a chain transfer agent having one or more sites capable of initiating copolymerization of epoxides and CO.sub.2, wherein the chain transfer agent contains one or more masked hydroxyl groups. In a second aspect, the present disclosure encompasses methods for the synthesis of polycarbonate polyols using the inventive polymerization systems. In a third aspect, the present disclosure encompasses polycarbonate polyol compositions characterized in that the polymer chains have a high percentage of OH end groups, a high percentage of carbonate linkages, and substantially all polycarbonate chains having hydroxyl end groups have no embedded chain transfer agent.

A nanocage-confined catalyst has the formula: NC-m[M(Salen1)X]-n[M(Salen2)]. NC is a material having a nanocage structure, and M(Salen1)X and M (Salen2) are active centers, respectively; each occurrence of M is independently selected from the group consisting of Co ion, Fe ion, Ga ion, Al ion, Cr ion, and a mixture thereof. Each occurrence of M is independently selected from Cu ion, Ni ion and a mixture thereof, m is 0 to 100; n is 0 to 100, with the proviso that at least one of m and n is not 0; each occurrence of Salen1 and Salen2 is independently a derivative of Shiff bases; X is an axial anion selected from the group consisting of substituted or unsubstituted acetate, substituted or unsubstituted benzene sulfonate, substituted or unsubstituted benzoate, F, Cl, Br, I, SbF6-, PF6-, BF4-, and a mixture thereof.

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.

Aminoalcohol lipidoids are prepared by reacting an amine with an epoxide-terminated compound are described. Methods of preparing aminoalcohol lipidoids from commercially available starting materials are also provided. Aminoalcohol lipidoids may be prepared from racemic or stereochemically pure epoxides. Aminoalcohol lipidoids or salts forms thereof are preferably biodegradable and biocompatible and may be used in a variety of drug delivery systems. Given the amino moiety of these aminoalcohol lipidoid compounds, they are particularly suited for the delivery of polynucleotides. Complexes, micelles, liposomes or particles containing the inventive lipidoids and polynucleotide have been prepared. The inventive lipidoids may also be used in preparing microparticles for drug delivery. They are particularly useful in delivering labile agents given their ability to buffer the pH of their surroundings.

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.

The present invention provides unimolecular metal complexes having increased activity in the copolymerization of carbon dioxide and epoxides. Also provided are methods of using such metal complexes in the synthesis of polymers. According to one aspect, the present invention provides metal complexes comprising an activating species with co-catalytic activity tethered to a multidentate ligand that is coordinated to the active metal center of the complex.

The present invention provides a composite comprising at least one hydrophobic organic compound and a matrix of at least one metal; wherein said at least one hydrophobic compound is entrapped within said matrix, compositions comprising at least one composite and methods of its preparation.

The present disclosure relates to a transition metal based pro-catalyst represented by Formula I: wherein, the substituents have the meaning as defined in the specification. The present disclosure also relates to a process for preparing the transition metal based pro-catalyst represented by Formula I and the catalyst composition obtained therefrom. Further, the present disclosure relates to a process for polymerizing olefins by employing the catalyst composition comprising the transition metal based pro-catalyst represented by Formula I. ##STR00001##

The present invention encompasses catalysts for the carbonylation of heterocycles such as ethylene oxide, as well as methods for their use. The catalysts feature Lewis acidic metal complexes having one or more tethered metal-coordinating groups in combination with at least one metal carbonyl species. In preferred embodiments, the inventive catalysts have improved stability when subjected to product separation conditions in continuous ethylene oxide carbonylation processes.

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.