The Assembly of Phosphometalate Clusters with Copper Complex Subunits

Abstract

AbstractSix organic–inorganic hybrid compounds based on a phosphometalate cluster with copper complex subunits: {[Cu(phen)2]2Cl}(PMo12O40)·H2O (1), {[Cu(phen)2]2Cl}(PW12O40)·H2O (2), [CuI(bpy)2]2{[CuII(bpy)]2P(MoV)3(MoVI)9O40} (3), H[Cu(bpy)(H2O)]{[Cu(bpy)]4(PO4)2}(PW11CuO39)·H2O (4), [Cu(phen)(H2O)]3[(PO4)2Mo5O15]·5H2O (5), and HNa[Cu(bpy)(H2O)]2[(PO4)2Mo5O15]·6H2O (6) (phen = 1,10‐phenanthroline, bpy = 2,2′‐bipyridine) have been solvothermally synthesized. Single‐crystal X‐ray diffraction reveals that compounds 1 and 2 are composed of a Keggin polyoxoanion (PM12O40)3– (M = Mo, W) and {[Cu(phen)2]2Cl}3+ counterion. Compound 3 is built from two [CuI(bpy)2]+ cations and a reduced‐Keggin polyoxoanion [PMoV3MoVI9O40]6– which is bi‐capped by two [CuII(bpy)]2+ through four bridging oxo groups on two opposite (Mo4O4) faces. Compound 4 is based on a monovacant Keggin anion (PW11CuO39)5– linked through four Cu(bpy)2+, two PO43–, and one {H[Cu(bpy)(H2O)]}3+, generating a one‐dimensional chain. Compounds 5 and 6 exhibit a chain‐like structure constructed from [(PO4)2Mo5O15]6– clusters linked through [Cu(phen)(H2O)]2+ and [Cu(bpy)(H2O)]2+ components, respectively. The pH is crucial for the isolation of the compounds. Compounds 1 and 2 are obtained in the pH range 1–2 with the phen ligand, and 3 and 4 are isolated in the pH range 3–4 and 2–3 with the bpy ligand, respectively. Oxalic acid acting as a reductant reduces the molybdenum ion from MoVI to MoV in 3. Compounds 5 and 6 are produced in the pH range 3–4 with phen and bpy ligands, respectively. Compound 3 shows fluorescence due to the charge transfer from CuI‐to‐ligand (MLCT) [d10‐π*]. Compound 4 displays magnetic behavior based on the super‐interaction through the tri‐copper six‐membered ring [CuII–O–CuII–O–CuII–O–]. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)