Iron(III) Complexes with Pyridine Group Coordination and Dissociation Reversible Equilibrium: Cooperative Activation of CO and Epoxides into Cyclic Carbonates.

Herein, a series of [ONSN]-type iron(III) complexes were synthesized. A binary catalytic system in combination with iron complexes and tetrabutylammonium bromide (TBAB) exhibited high activity for the synthesis of cyclic carbonates from CO (1 atm) and terminal epoxides at room temperature. Additionally, single-component iron complexes without using additional TBAB as nucleophiles also showed high activity for the cycloaddition of CO and terminal epoxides under 80 °C and 0.

Organocatalytic Strategy for the Fixation of CO via Carboxylation of Terminal Alkynes.

An organocatalytic strategy for the direct carboxylation of terminal alkynes with CO has been developed. The combined use of a bifunctional organocatalyst and CsCO resulted in a robust catalytic system for the preparation of a range of propiolic acid derivatives in high yields with broad substrate scope using CO at atmospheric pressure under mild temperatures (60 °C). This work has demonstrated that this organocatalytic method offers a competitive alternative to metal catalysis for the carboxylation of terminal alkynes and CO.

[UV/Visible spectroscopic study of the beta-diketonate zirconium active species for olefin polymerization].

The method of UV/Visible absorption spectroscopy for olefin catalytic system was introduced in this paper, whose testing condition was much closer to the polymerization conditions. The actions of olefin polymerization catalyst (dbm)2 ZrCl2 with cocatalyst AlEt2 Cl (or MAO) were investigated by UV/visible absorption spectroscopy at atmosphere temperature. It was shown that the UV/Visible main absorption band of the zirconocenium, which can be related to the ligand to metal charge transfer bands (LMCT), varies greatly upon incremental addition of AlEt2 Cl or MAO.