Novel Hybrids Constructed from Keggin-Polyoxometalate and Mixed Copper Complex

Abstract

Two new Keggin-polyoxometalate hybrids, {[Cu2(4,4′-bpy)2][PW 10 VI W 2 V O40]}[Cu2(obpy)2]4 · 2 H2O (1) and {[Cu4(2,2′-bpy)4(4,4′-bpy)3][SiW12O40]} · 2H2O (2) (4,4′-/2,2′-bpy = 4,4′-/2,2′-bipyridyl, Hobpy = 6-hydroxy-2,2′-bipyridyl), were hydrothermally synthesized and structurally characterized. Gillard type hydration of 2,2′-bipy is observed during the synthesis of 1, resulting in a new obpy ligand in situ. X-ray structural analyses show that 1 consists of 1D hybrid chain {[Cu2(4,4′-bpy)2][PW 10 VI W 2 V O40]}∞ and [Cu2(obpy)2] dimer, whereas 2 possesses 1D hybrid structure based on Keggin-type [SiW12O40]4− anions and tetra-nuclear copper complexes [Cu4(2,2′-bpy)4(4,4′-bpy)3]4+. Both compounds present interesting supramolecular architectures based on π–π stacking and hydrogen bonds. Compounds {[Cu2(4,4′-bpy)2][PW12O40]}[Cu2(obpy)2]4 · 2H2O (1) and [Cu4(2,2′-bpy)4(4,4′-bpy)3][SiW12O40] · 2H2O (2) were hydrothermally synthesized. 1 features that the [Cu2(obpy)2] dimers based on in situ generated obpy ligands are stumped between the layers where 1D hybrid chain {[Cu2(4,4′-bpy)2][PW12O40]}∞ locates, while 2 exhibits 1D chain-like structure based on anions [SiW12O40]4− and tetra-copper complexes [Cu4(2,2′-bpy)4(4,4′-bpy)3]4+.