A novel polycyclic aromatic compound in which plural aromatic rings are linked via boron atoms, oxygen atoms and the like is provided, and therefore, the range of selection of the material for organic electroluminescent elements can be widened. Also, an excellent organic electroluminescent element is provided by using the novel polycyclic aromatic compound as a material for an organic electroluminescent element.

A novel polycyclic aromatic compound in which plural aromatic rings are linked via boron atoms, oxygen atoms and the like is provided, and therefore, the range of selection of the material for organic electroluminescent elements can be widened. Also, an excellent organic electroluminescent element is provided by using the novel polycyclic aromatic compound as a material for an organic electroluminescent element.

An organic electroluminescence device includes a first electrode, a hole transport region on the first electrode, an emission layer on the hole transport region, the emission layer including a condensed polycyclic compound of three or more six-membered rings, at least two six-membered rings among the six-membered rings including an electron donor moiety and an electron acceptor moiety at facing positions, respectively, the at least two six-membered rings not being immediately adjacent to each other, an electron transport region on the emission layer, and a second electrode on the electron transport region.

A method for forming 1,3,5,7-tetraalkyl-6-(2,4-dimethoxyphenyl)-2,4,8-trioxa-6-phosphaadamantane includes obtaining a solution comprising an ethereal solvent and an aluminum hydride, adding dichloro(2,4-dimethoxyphenyl)phosphine to the solution to produce 2,4-dimethoxyphenylphosphine, and reacting the 2,4-dimethoxyphenylphosphine with an acidic mixture comprising diones to produce 1,3,5,7-tetraalkyl-6-(2,4-dimethoxyphenyl)-2,4,8-trioxa-6-phosphaadamantane. The solution has a temperature from IN greater than 20 C. to 50 C. throughout the method. Another method for forming 1,3,5,7-tetraalkyl-6-(2,4-dimethoxyphenyl)-2,4,8-tri-oxa-6-phosphaadamantane includes obtaining dichloro(2,4-dimethoxyphenyl)phosphine, forming 2,4-dimethoxyphenylphosphine by adding the dichloro(2,4-dimethoxyphenyl)phosphine to a solution comprising at least one solvent and an aluminum hydride, reacting the 2,4-dimethoxyphenylphosphine with a mixture to produce 1,3,5,7-tetraalkyl-6-(2,4-dimethoxyphenyl)-2,4,8-trioxa-6-phosphaadamantane. The mixture includes an acid selected from the group consisting of Lewis acids, sulfonic Bronsted acids, and mixtures thereof, an aromatic or non-aromatic hydrocarbons; and acetylacetone.

Provided is an electrolyte solution for a lithium secondary battery and a lithium secondary battery including the electrolyte solution. The electrolyte solution includes an additive represented by a specific chemical formula, an organic solvent and a lithium salt. The lithium secondary battery including the electrolyte solution provide enhanced high-temperature properties.

An object t of the present invention is to proroaide crystal of a cyclic phosphonic acid sodium salt (2ccPA) with high purity and excellent storage stability and a method for producing the crystal. The present invention provides a crystal of a cyclic phosphonic acid sodium salt (2ccPA) represented by formula (1):

##STR00001##

A phosphorus-containing flame retardant, a preparation method thereof, a resin composition comprising the phosphorus-containing flame retardant and an article made therefrom are disclosed. The phosphorus-containing flame retardant is characterized by having the advantages of high phosphorus content, high resin compatibility, not increasing gel time of varnish and low water absorption rate, and is therefore suitable for use as a flame retardant of various resin materials.

Provided is an organic electroluminescent element having high efficiency, a long lifetime, and bending resistance. An organic electroluminescent element includes a light emitting layer and an electron transport layer adjacent to the light emitting layer between a positive electrode and a negative electrode. A host compound of the light emitting layer has an ionization potential deeper than that of a light emitting dopant of the light emitting layer by 0.3 eV or more. At least one organic compound contained in the electron transport layer has a molecular dipole moment of 6.0 debye or more.

An object of the present invention is to provide a crystal of a cyclic phosphonic acid sodium salt (2ccPA) with high purity and excellent storage stability and a method for producing the crystal. The present invention provides a crystal of a cyclic phosphonic acid sodium salt (2ccPA) represented by formula (1): ##STR00001##

A novel polycyclic aromatic compound in which plural aromatic rings are linked via boron atoms, oxygen atoms and the like is provided, and therefore, the range of selection of the material for organic electroluminescent elements can be widened. Also, an excellent organic electroluminescent element is provided by using the novel polycyclic aromatic compound as a material for an organic electroluminescent element.