The invention relates to oligomerization of olefins, such as ethylene, to higher olefins, such as a mixture of 1-hexene and 1-octene, using a catalyst system that comprises a) a source of chromium b) one or more activators and c) a phosphacycle-containing ligating compound. Additionally, the invention relates to a phosphacycle-containing ligating compound and a process for making said compound.

The present invention relates to carbazole derivatives, especially for use in electronic devices. The invention further relates to a process for preparing the compounds of the invention and to electronic devices comprising these.

The present invention relates to a compound comprising at least one phosphepine ring and having the phosphorus atom of the phosphepine ring substituted with at least one monovalent substituent R, a semiconducting material comprising the compound, and electronic device comprising the semiconducting material.

The present invention relates to new phosphaviologen derivatives, methods of making phosphaviologen derivatives, and uses thereof, including uses in electrochromic devices and organic battery materials. The phosphaviologen derivatives described herein have strong electron-accepting properties and can be used to provide phosphaviologen derivative-containing electronic materials. In certain embodiments, the phosphaviologen derivatives include dimeric phosphaviologens.

##STR00001##

The present disclosure relates to the field of organic electroluminescence, in particular to a compound, an organic electroluminescence device and a display device. The compound has a structure shown in a formula (I):

##STR00001##

and X is selected from O atom or S atom; X.sub.1-X.sub.8 are each independently selected from C atoms or N atoms, and at least one of X.sub.1-X.sub.8 is N atoms; A and B are each independently selected from any one or more of the substituted or unsubstituted C6-C40 aryl, and substituted or unsubstituted C4-C40 heteroaryl; R.sub.1 is selected from C1-C9 alkyl, substituted or unsubstituted C6-C18 aryl, substituted or unsubstituted C4-C30 heteroaryl.

An organic electroluminescent device contains an anode, a cathode, and an organic layer containing at least one luminous layer. The organic layer is disposed between the anode and the cathode. At least one luminous layer contains a -conjugated compound exhibiting no overlap between the electron density distributions of the HOMO and the LUMO in the molecule, such that electron transition between the HOMO and the LUMO occurs by a through-space interaction in the molecule. The -conjugated compound has a -conjugated aromatic ring at a moiety on which at least one of the HOMO and the LUMO is localized.

The present invention provides a thermally activated delayed fluorescence (TADF) material, which is composed of a molecular compound having an ultra-fast reverse intersystem crossing rate, and when the TADF material serves as a host material in light-emitting layers of electroluminescent devices, both the resulting blue light fluorescence device and phosphorescent electroluminescent device can achieve very high efficiency.

Tridentate platinum, palladium, and gold complexes of Formulas A-I and A-II and tridentate iridium and rhodium compounds of Formulas B-I, B-II, and B-III suitable for delayed fluorescent and phosphorescent or phosphorescent emitters in display and lighting applications.

##STR00001##

The present invention relates to innovative catalysts for producing oligomeric polyisocyanates. These catalysts comprise polyhedral silsesquioxanes to which cyclic phosphorus(III) or phosphorus(V) compounds have been coupled.

An acetylacetone derivative is useful for capturing a metal element by complexation. A convenient and very versatile synthesis method can be used to synthesize the derivative. The derivative can have the following formula: ##STR00001##