Ionothermal synthesis, characterization of a new layered gallium phosphate with an unusual heptamer SBU

A new layered gallium phosphate Ga 3 (PO 4 ) 4 (C 2 N 2 H 8 )·(H 2 C 2 N 2 H 8 ) 2 ·Cl (compound 1 ), has been ionothermally synthesized in the presence of deep eutectic solvent (DES) comprising mixtures of choline chloride and 2-imidazolidone (IMI). Single-crystal X-ray diffraction analysis reveals that compound 1 shows 2D layered framework with 10-ring windows, which is constructed from unusual heptamer second building units (SBUs). The ethylenediamine (en) units deriving from the decomposition of IMI, play a dual role as bidentate ligands coordinated with 6-fold coordinate gallium atoms and the templates. Additionally, compound 1 shows photoluminescence property in solid state at room temperature .