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.

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 disclosure provides novel methods of making aluminum complexes with utility for promoting epoxide carbonylation reactions. Methods include reacting neutral metal carbonyl compounds with alkylaluminum complexes, such as the alkylaluminum complexes represented by Formula I, where Q is a nitrogen atom and the four Q groups are part of a single porphyrin ligand and R.sup.q is selected from optionally substituted C.sub.1-12 aliphatic and optionally substituted aryl: ##STR00001##

The present invention relates to catalyst composition for cyclic carbonate production from CO.sub.2 and epoxides under mild conditions, which can effectively catalyze the cyclic carbonate synthesis and provides good selectivity to cyclic carbonate, wherein said catalyst composition comprising: a) the metal complex as shown in structure (I): ##STR00001## wherein, M represents transition metal atom; R.sub.1, R.sub.2, and R.sub.3 represent independent group selected from hydrogen atom, halogen atom, alkyl group, alkenyl group, alkynyl group, alkoxy group, amine group, phenyl group, benzyl group, cyclic hydrocarbon group comprising hetero atom, perfluoroalkyl group, or nitro group; R.sub.4 represents group selected from alkylene group, cycloalkylene group, or phenylene group; X represents group selected from hydrogen atom, acetate group, or triflate group; and b) the organic compound as the co-catalyst selected from compound containing nitrogen, compound of quaternary ammonium salts, or compound of iminium salts.