A series of new octahedral bis-3,6-di-tert-butylcatecholates based on tin(IV) containing metal-coordinated N-donor ligands (substituted iminopyridines and diazabutadienes) has been synthesized and structurally characterized. The compounds, both solid and in solution, are intensely colored. They absorb in the visible region of the spectrum. Charge transfer between the catecholate donor and the diimine acceptor is responsible for the absorption. This observation is in good agreement with the DFT calculations and with the electrochemical studies carried out by CV.

Cyclohexane epoxide with highly active epoxy groups is an important intermediate in the preparation of fine chemicals. However, the epoxidation path of cyclohexene is difficult to be controlled due to the allyl oxidation of cyclohexene and the ring opening of cyclohexane epoxide in the process of cyclohexene epoxidation to cyclohexane oxide. This work mainly reviewed the structure-activity relationships and synthesis processes of a series of heterogeneous transition metal-based catalysts based on cyclohexene epoxidation reaction, including molybdenum(Mo)-based, tungsten(W)-based, vanadium(V)-based, titanium(Ti)-based, cobalt(Co)-based,, etc. catalysts. First, the mechanism of cyclohexene epoxidation by transition metal-based catalysts was collated from the perspective of catalytic active centers. Then, the current status of research on cyclohexene epoxidation catalysts was summarized from the perspective of catalyst support. At the same time, the differences between alkyl hydroperoxide, hydrogen peroxide (H2O2), and oxygen (O2) as oxidants were analyzed. Finally, the main factors affecting the catalytic performance were summarized and the reasonable opinions on the design of catalysts were put forward. The above work provided some scientific support for the development of olefin epoxidation industry.