Multiple-metal complex-containing compound and metal complex, and manufacture methods therefor, and exhaust gas purification catalyst manufacture method using the same

Abstract

A multiple-metal complex-containing compound in accordance with an embodiment has a plurality of metal complexes in each of which a ligand is coordinated to one metal atom or a plurality of metal atoms of the same kind. The plurality of metal complexes are bound to each other via a polydentate ligand that substitutes partially the ligands of the two or more metal complexes, and have 2 to 1000 metal atoms.

1 . An exhaust gas purification catalyst obtainable by a method comprising:
 providing a solution containing a metal complex in which carboxylic acid ligands and at least one dicarboxylic acid ligand are coordinated to one metal atom or a plurality of metal atoms of the same kind, wherein the at least one dicarboxylic acid ligand has an uncoordinated —COOH functional group that is not coordinated to a metal atom;   impregnating a catalyst support with the solution; and   drying and firing the solution.   
     
     
         2 . An exhaust gas purification catalyst according to  claim 1 , wherein each of the carboxylic acid ligands is of formula RCOO − , wherein R is hydrogen, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group or a monovalent alicylic group. 
     
     
         3 . An exhaust gas purification catalyst according to  claim 2 , wherein the carboxylic acid ligand is formate, acetate or propionate. 
     
     
         4 . An exhaust gas purification catalyst according to  claim 1 , wherein the at least one dicarboxylic acid ligand is of formula  − OOC—R 13 —COO −  wherein R 13  is a bond, an alkylene group, an alkenylene group, an alkynylene group, an arylene group, an aralkylene group or a divalent alicylic group. 
     
     
         5 . An exhaust gas purification catalyst according to  claim 1 , wherein the carboxylic acid ligands are acetic acid. 
     
     
         6 . An exhaust gas purification catalyst according to  claim 1 , wherein the metal is selected from iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, osmium, iridium, platinum, gold and silver. 
     
     
         7 . An exhaust gas purification catalyst according to  claim 6  wherein the metal is platinum. 
     
     
         8 . An exhaust gas purification catalyst according to  claim 1 , wherein the metal complex is an octaacetatotetraplatinum in which at least one acetic acid ligand is substituted with a dicarboxylic acid ligand as defined in  claim 1 . 
     
     
         9 . An exhaust gas purification catalyst according to  claim 1 , wherein the metal complex is an octaacetatotetraplatinum in which at least one acetic acid ligand is substituted with a dicarboxylic acid ligand as defined in  claim 4 . 
     
     
         10 . An exhaust gas purification catalyst according to  claim 1 , wherein the metal complex is represented by a formula below: 
       
         
           
           
               
               
           
         
         wherein R 14  is an alkylene group, an alkenylene group, an alkynylene group, an arylene group, an aralkylen group or a bivalent alicylic group of C 1  to C 30 . 
       
     
     
         11 . An exhaust gas purification catalyst according to  claim 1 , wherein the catalyst support is a porous metal oxide support. 
     
     
         12 . A manufacture method for an exhaust gas purification catalyst, which comprises:
 providing a solution containing the metal complex defined in  claim 1 ,   impregnating a catalyst support with the solution; and   drying and firing the solution.   
     
     
         13 . A method according to  claim 12 , wherein the catalyst support is a porous metal oxide support. 
     
     
         14 . A metal complex as defined in  claim 1 , wherein the metal is platinum.