Two organic-inorganic hybrid 3D {P(5)W(30)}-based heteropolyoxotungstates with transition-metal/Ln-carboxylate-Ln connectors

Abstract

Two unique organic-inorganic hybrid polyoxometalates constructed from Preyssler-type [Na(H2 O)P5 W30 O110 ](14-) ({P5 W30 }) subunits and TM/Ln-carboxylate-Ln connectors (TM=transition metal, Ln=lanthanide), KNa7 [{Sm6 Mn(μ-H2 O)2 (OCH2 COO)7 (H2 O)18 }{Na(H2 O)P5 W30 O110 }]⋅22 H2 O (1) and K4 [{Sm4 Cu2 (gly)2 (ox)(H2 O)24 }{NaP5 W30 O110 }]Cl2 ⋅25 H2 O (2; gly=glycine, ox=oxalate) have been hydrothermally synthesized and characterized by elemental analyses, IR spectra, UV/Vis-NIR spectra, thermogravimetric analyses, power X-ray diffraction, and single-crystal X-ray diffraction. Compound 1 displays one interesting 3D framework built by three types of subunits, {P5 W30 }, [Sm2 Mn(μ-H2 O)2 (OCH2 COO)2 (H2 O)5 ](4+) , and [Sm4 (OCH2 COO)5 (H2 O)13 ](2+) , whereas 2 also manifests the other intriguing 3D architecture created by three types of subunits, {P5 W30 }, [SmCu(gly)(H2 O)8 ](4+) , and [Sm2 (ox)(H2 O)8 ](4+) . To our knowledge, 1 and 2 are the first 3D frameworks that contain {P5 W30 } units and TM/Ln-carboxylate-Ln connectors. The fluorescent properties of 1 and 2 have been investigated.

Keywords: carboxylic acids; luminescence; organic-inorganic hybrid composites; polyoxometalates; transition metals.