Amine-templated synthesis of two metal phosphonates based on 5-phosphononicotinic acid

• Synthesis two new metal phosphonates with 5-phosphononicotinic acid.
• Using multifunctional phosphonate ligand in synthesis of phosphonate based MOFs.
• Directing the MOF structures with organic amines.

Two metal phosphonates, namely [Co3(OOCC5H3NPO3)2(H2O)6]·2(H2O) (1) and [Ni5(OOCC5H3NPO3H)2(OOCC5H3NPO3)2(H2O)8]·2(H2O) (2) were hydrothermally synthesized by reacting 5-phosphononicotinic acid with corresponding metal sulfate in the presence of organic amines as templates. In compound 1, bicobaltic clusters are corner-shared with {CPO3} tetrahedrons and subsequently connected by phosphonyl and pyridyl groups into layered structures. These layers are further linked with {Co3O6} octahedrons through carboxyl groups forming a three dimensional pillared layered frameworks. In compound 2, {NiO6} and two {NiO5N} octahedrons are linked by μ-OH2 bridge of water forming a trimeric cluster of Ni3. Subsequently, Ni3 clusters are corner-shared with {CPO3} tetrahedron and link to {Ni3O5N} octahedron forming a double-chain structure. These double-chains are further connected to a three dimensional structure by three functional groups of ligands. Magnetic property of compound 2 was investigated.

DABCO directed in a pillared layered structure of compound 1 while monoamine tetrapropylammonium bromide leads to porous structure of compound 2.Figure optionsDownload as PowerPoint slide