Method for preparing metal-organic framework crystallised and porous aluminium aromatic azocarboxylates
The present invention relates to a method for preparing an MOF solid of a crystallised and porous aluminium aromatic azocarboxylate, in a non-aqueous organic medium. The invention also relates to solids made up of metal-organic frameworks (MOF) of aluminium aromatic azocarboxylates capable of being obtained by the method of the invention, as well as to the uses thereof for the storage of liquid or gaseous molecules, for selective separation of gas and for catalysis.
1. A method for preparing a MOF solid of porous and crystallized aluminum aromatic azocarboxylate, comprising:
(i) mixing in a nonaqueous organic solvent:
at least a metal inorganic precursor in the form of a metal Al, a metal salt Al 3+ or a coordination complex comprising metal ion Al 3+ ; and
at least an organic precursor of ligand L, L comprising an aromatic azodi-, azotri-, or azotetra-carboxylate ligand of formula R 0 R 1 N 2 (COO − ) q where R 0 and R 1 independently from each other represent
a mono- or poly-cyclic, fused or non fused, aryl radical, comprising 6 to 50 carbon atoms,
a mono- or poly-cyclic, fused or non fused, heteroaryl radical comprising 4 to 50 carbon atoms,
the R 0 radical being optionally substituted by one or more groups independently selected from the group consisting of C 1-10 alkyl, C 2-10 alkene, C 2-10 alkyne, C 3-10 cycloalkyl, C 1-10 heteroalkyl, C 1-10 haloalkyl, C 6-10 aryl, C 3-20 heterocyclic, C 6-10 aryl C 1-10 alkyl, C 5-10 heteroaryl C 1-10 alkyl, F, Cl, Br, I, —NO 2 , —CN, —CF 3 , —CH 2 CF 3 , —OH, —CH 2 OH, —CH 2 CH 2 OH, —NH 2 , —CH 2 NH 2 , —NHCHO, —COOH, —CONH 2 , —SO 3 H, and —PO 3 H 2 , and
q=2 to 4; and
(ii) heating the mixture obtained in (i) at a temperature of at least 50° C. so as to obtain said solid.
2. The method according to claim 1 , wherein the nonaqueous organic solvent is selected from the group consisting of DMF, DEF, dioxane, methanol, ethanol, and DMSO.
3. The method according to claim 1 , wherein in step (i) the metal inorganic precursor and the organic precursor of the ligand L are mixed in a molar ratio comprised between 1 and 5.
4. The method according to claim 1 , wherein the metal inorganic precursor is in the form of a metal salt Al 3+ .
5. The method according to claim 1 , wherein L is an aromatic azodi- or azotetra-carboxylic ligand, selected from the group consisting of:
C 12 H 8 N 2 (CO 2 − ) 2 (azobenzene-4,4′-dicarboxylate),
C 12 H 6 Cl 2 N 2 (CO 2 − ) 2 (dichloro-azobenzene-4,4′- dicarboxylate),
C 12 H 6 N 2 (CO 2 − ) 4 (azobenzene-3,3′,5,5′- tetracarboxylate), and
C 12 H 6 N 2 (OH) 2 (CO 2 − ) 2 (dihydroxy-azobenzene-4,4′-dicarboxylate).
6. The method according to claim 1 , wherein in step (ii) the mixture is heated at a temperature of 50° C. to 150° C.
7. The method according to claim 1 , wherein in step (ii) the mixture is heated for 1 to 10 days.
8. The method according to claim 1 , wherein step (ii) is carried out at an autogenous pressure higher than 10 5 Pa.
9. The method according to claim 1 , further comprising an activation step (iii) in which the solid obtained in (ii) is heated at a temperature of 100 to 300° C.
10. The method according to claim 9 , wherein the activation step (iii) is carried out in a mixture of solvents selected from the group consisting of DMF, DEF, methanol, ethanol, DMSO, and water.
11. The method according to claim 9 , wherein in activation step (iii) the solid obtained in step (ii) is heated for 1 to 48 hours.