[H3N(CH2)4NH3]2[Al4(C2O4)(H2PO4)2(PO4)4]·4[H2O]: A new layered aluminum phosphate-oxalate

A new layered inorganic–organic hybrid aluminum phosphate-oxalate [H3N(CH2)4NH3]2[Al4(C2O4)(H2PO4)2(PO4)4]·4[H2O](AlPO-CJ25) has been synthesized hydrothermally, by using 1,4-diaminobutane (DAB) as structure-directing agent. The structure has been solved by single-crystal X-ray diffraction analysis and further characterized by IR, 31P MAS NMR, TG-DTA as well as compositional analyses. Crystal data: the triclinic space group P-1, a=8.0484(7) Å, b=8.8608(8) Å, c=13.2224(11) Å, α=80.830(6)°, β=74.965(5)°, γ=78.782(6)°, Z=2, R1[I>2σ(I)]=0.0511 and wR2(all data)=0.1423. The alternation of AlO4 tetrahedra and PO4 tetrahedra gives rise to the four-membered corner-sharing chains, which are interconnected through AlO6 octahedra to form the layered structure with 4,6-net sheet. Interestingly, oxalate ions are bis-bidentately bonded by participating in the coordination of AlO6, and bridging the adjacent AlO6 octahedra. The layers are held with each other through strong H-bondings between the terminal oxygens. The organic ammonium cations and water molecules are located in the large cavities between the interlayer regions.