Disclosed is a method for preparing a borate ester on the basis of a tricyclopentadienyl rare earth metal complex, the method comprising the following steps: uniformly stirring and mixing a catalyst, a borane and a carbonyl compound for reaction to prepare a borate ester, wherein the catalyst is a tricyclopentadienyl rare earth metal complex; and the molecular formula of the tricyclopentadienyl rare earth metal complex can be expressed as: Ln(Cp).sub.3, wherein Ln represents a rare metal selected from one of lanthanide elements. The preparation method has a higher catalytic activity, mild reaction conditions, a product that is easy to post-treat, a short reaction time, a low catalyst consumption amount, and a good range of applicable substrates, and can be used for industrial production.

A molecular building block composition can include a metal ion component; and a ligand component including a core including at least one functional group associated with the metal ion component and the core.

Biodegradable polymers with advantageous physical and chemical properties are described, as well as methods for making such polymers. In one embodiment, a new chemical synthesis route to technologically important biodegradable poly(3-hydroxybutyrate) (P3HB) with high isotacticity and molecular weight required for a practical use is described. The new route can utilize racemic eight-membered cyclic diolide (rac-DL), meso-DL, or a rac-DL and meso-DL mixture, derived from bio-sourced dimethyl succinate, and enantiomeric (R,R)-DL and (S,S)-DL, optically resolved by metal-based catalysts. With a stereoselective racemic molecular catalyst, the ROP of rac-DL under ambient conditions produces rapidly P3HB with essentially perfect isotacticity ([mm]>99%), high crystallinity and melting temperature (T.sub.m=171 C.), as well as high molecular weight and low dispersity (M.sub.n=1.5410.sup.5 g/mol, =1.01).

Biodegradable polymers with advantageous physical and chemical properties are described, as well as methods for making such polymers. In one embodiment, a new chemical synthesis route to technologically important biodegradable poly(3-hydroxybutyrate) (P3HB) with high isotacticity and molecular weight required for a practical use is described. The new route can utilize racemic eight-membered cyclic diolide (rac-DL), meso-DL, or a rac-DL and meso-DL mixture, derived from bio-sourced dimethyl succinate, and enantiomeric (R,R)-DL and (S,S)-DL, optically resolved by metal-based catalysts. With a stereoselective racemic molecular catalyst, the ROP of rac-DL under ambient conditions produces rapidly P3HB with essentially perfect isotacticity ([mm] >99%), high crystallinity and melting temperature (T.sub.m=171 C.), as well as high molecular weight and low dispersity (M.sub.n=1.5410.sup.5 g/mol, =1.01).

An ethylene/butadiene copolymer comprising statistically distributed ethylene units and butadiene unit is provided. The molar fraction of the ethylene units in the copolymer is greater than or equal to 50%, relative to the total number of moles of ethylene and butadiene units. The microstructure of the copolymer is homogeneous. A process for preparing such a copolymer and also the uses of this copolymer, in particular in rubber compositions for tires is also provided.

An ethylene/butadiene copolymer comprising statistically distributed ethylene units and butadiene units is provided. The molar fraction of the ethylene units in the copolymer is greater than or equal to 50%, relative to the total number of moles of ethylene and butadiene units. The microstructure of the copolymer is homogeneous.

A process for preparing such a copolymer and also the uses of this copolymer, in particular in rubber compositions for tires is also provided.

A nanofibrous catalyst for in the electrolyzer and methods of making the catalyst. The catalysts are composed of highly porous transition metal carbonitrides, metal oxides or perovskites derived from the metal-organic frameworks and integrated into a 3D porous nano-network electrode architecture. The catalysts are low-cost, highly active toward OER, with excellent conductivity yet resistant to the oxidation under high potential operable under both acidic and alkaline environments.

A molecular building block composition can include a metal ion component; and a ligand component including a core including at least one functional group associated with the metal ion component and the core.

A nanofibrous catalyst for in the electrolyzer and methods of making the catalyst. The catalysts are composed of highly porous transition metal carbonitrides, metal oxides or perovskites derived from the metal-organic frameworks and integrated into a 3D porous nano-network electrode architecture. The catalysts are low-cost, highly active toward OER, with excellent conductivity yet resistant to the oxidation under high potential operable under both acidic and alkaline environments.

A molecular building block composition can include a metal ion component; and a ligand component including a core including at least one functional group associated with the metal ion component and the core.