Abstract: The object of the present invention addresses a problem of providing a novel hydrogen storage material containing a metal-organic framework that can effectively store hydrogen. Hydrogen can be effectively stored by use of a hydrogen storage material containing a metal-organic framework, the metal-organic framework comprising a carboxylate ion of formula (I) and a multivalent metal ion, wherein the carboxylate ion and the multivalent metal ion are bound to each other.

Abstract: Despite the fact that the amount and type of gas to be stored may vary in accordance with the type of substituent, metal-organic frameworks only using a terephthalic acid having substituents within the limited range have been produced conventionally. An object of the present invention is to provide a novel metal-organic framework using a 2,5-disubstituted terephthalic acid. A metal-organic framework comprising a carboxylate ion of formula (I) and a multivalent metal ion bound to each other is a novel metal-organic framework, enabling a gas such as hydrogen and nitrogen to be store efficiently.

Abstract: An object of the present invention is to provide a metal-organic framework capable of adsorbing a gas such as a hydrogen molecule or carbon dioxide at a practical level. The metal-organic framework is used for adsorbing a gas such as hydrogen or carbon dioxide and comprises a multivalent metal ion and a carboxylate ion of formula [I] [wherein in formula [I], X1 to X3 each independently represent a functional group of formula [II] (wherein in formula [II], Z is a single bond or a multivalent linking group, k is an integer of 1 to 4, and * is the position at which a bond is formed with a benzene ring); and Y1 and Y2 each independently represent a hydrogen atom, a halogeno group, a C1-6 alkyl group or the like, provided that when the multivalent metal ion is a trivalent metal ion, Y1 and Y2 each independently represent a halogeno group, a C1-6 alkyl group or the like], wherein the carboxylate ion and the multivalent metal ion are bound to each other.