Synthesis, structure and NMR characterization of a new monomeric aluminophosphate [dl-Co(en)3]2[Al(HPO4)2(H1.5PO4)2(H2PO4)2](H3PO4)4 containing four different types of monophosphates

A new zero-dimensional (0D) aluminophosphate monomer [dl-Co(en)3]2[Al(HPO4)2(H1.5PO4)2(H2PO4)2](H3PO4)4 (designated AlPO-CJ38) with Al/P ratio of 1/6 has been solvothermally prepared by using racemic cobalt complex dl-Co(en)3Cl3 as the template. The Al atom is octahedrally linked to six P atoms via bridging oxygen atoms, forming a unique [Al(HPO4)2(H1.5PO4)2(H2PO4)2]6− monomer. Notably, there exists intramolecular symmetrical O⋯H⋯O bonds, which results in pseudo-4-rings stabilized by the strong H-bonding interactions. The structure is also featured by the existence of four different types of monophosphates that have been confirmed by 31P NMR and 1H NMR spectra. The crystal data are as follows: AlPO-CJ38, [dl-Co(en)3]2[Al(HPO4)2(H1.5PO4)2(H2PO4)2](H3PO4)4, M = 1476.33, monoclinic, C2/c (No. 15), a = 36.028(7) Å, b = 8.9877(18) Å, c = 16.006(3) Å, β = 100.68(3)°, U = 5093.2(18) Å3,Z = 4, R1 = 0.0509 (I > 2σ(I)) and wR2 = 0.1074 (all data). CCDC number 689491.

Graphical abstractA new zero-dimensional aluminophosphate monomer [dl-Co(en)3]2[Al(HPO4)2(H1.5PO4)2(H2PO4)2](H3PO4)4 has been solvothermally prepared by using [dl-Co(en)3Cl3] as the template. The Al atom is octahedrally linked to six P atoms via oxygen bridges, forming a unique [Al(HPO4)2(H1.5PO4)2(H2PO4)2]6− monomer with the lowest Al/P ratio 1/6. 1H and 31P NMR characterizations confirm the existence of four different types of monophosphates and unique symmetry O⋯H⋯O bonds.Figure optionsDownload full-size imageDownload as PowerPoint slide