A Hybrid Open-Framework Aluminium Phosphate-Oxalate Possessing Large Circular 12-Membered Channels

A new aluminum phosphate-oxalate, I, [N2C4H12]Al2(PO4) (HPO4)(C2O4)]H2O, has been synthesized hydrothermally in the presence of structure-directing amines. The hybrid structure comprises a vertex-linkage of AlO6 octahedra, PO4 tetrahedra, and C2O4 units leading to three-dimensional connectivity. The connectivity between AlO6 and PO4 units are such that it forms double-six rings that are connected to each other via the oxalate units, thereby leading to the formation of a large circular 12-membered channel of width ~9 Å along the c axis. The structure-directing amine along with one water molecule is situated within this channel. The connectivity also forms two different types of 8-membered channels along the a and b axes. The three-dimensional structure of I, is very similar to the naturally occurring aluminosilicate zeolite, gmelinite. Crystal data for I are: monoclinic, space group Pccm, a = 9.992(1), b = 11.644(1), c = 12.231(1) Å, V = 1423.0(2), M = 438.9, Z = 4, RF = 0.07