A new double-Keggin-anion-templated organic–inorganic hybrid architecture: Synthesis, crystal structure and photoluminescence

Abstract A new double-Keggin-anion-templated host–guest hybrid compound, (H 4 pzdc) 5 [(H 2 pzdc) 6 (pzdc) 2 (H 2 O) 2 Na 6 ][PW 12 O 40 ] 4 ·31H 2 O ( 1 ) (H 2 pzdc = 2,3-pyrazinedicarboxylic acid), has been synthesized and characterized by elemental analysis, IR spectroscopy, TG analysis, and single crystal X-ray diffraction. Compound 1 exhibits an intriguing double-Keggin-anion-templated 2D structure, made up of [PW 12 O 40 ] 3− Keggin-type polyoxoanions covalently linked with hexanuclear [Na 6 (H 2 pzdc) 6 (pzdc) 2 ] 2+ macrocations. To our best knowledge, it represents the first example of host–guest compounds with double-Keggin anions as coordinating template. Furthermore, compound 1 displays stronger photoluminescence properties than the H 2 pzdc ligand, due to the introduction of alkali metal cations.