Hybrid Cu/V/Mo compounds with rare [α-V2Mo6O26]6– and oxides prepared by their thermal degradation were used as catalysts for water oxidation.

Two simple pathways using metallic copper or copper salts are proposed for the synthesis of hybrid compounds under mild conditions. A variety of Strandberg-and mixedmetal Keggin-based products, namely, (NH 4 ) 5n {[Cu(en) 2 ]-[PMo 8 V 4 O 40 ]} n ·9nH 2 O (1), (NH 4 ) 4n {[Cu(en)(H 2 O)][P 2 Mo 5 O 23 ]} n · 3.5nH 2 O (2), (NH 4 ) 7 [PMo 8 V 4 O 40 ]·17H 2 O (3) and (NH 4 ) 2n -{[Cu(en) 2 ][Cu(en)(H 2 O)][P 2 Mo 5 O 23 ]} n ·3nH 2 O (4), were isolated upon the variation of the composition of the reaction system. A rare four-substituted [PMo 8 V 4 O 40 ] 7-Keggin anion was obtained. The influence of the vanadium source [V 2 O 5 , NH 4 VO 3 or [a]

A one-pot reaction of a copper source (metallic powder Cu 0 or Cu 2+ salts) and bpy (bpy = 2,2′-bipyridine) in the presence of (NH 4 ) 2 HPO 4 and (NH 4 ) 6 Mo 7 O 24 •4H 2 O yields heterometallic hybrid compounds of the general type {[Cu-(bpy) n (H 2 O) m ] p [P 2 Mo x O y ]}. The structures exhibit a number of phosphomolybdate POMs including not only a common Strandberg anion [P 2 Mo 5 O 23 ] 6− but also its unprecedented biand trilacunary derivatives [P 2 Mo 3 O 18 ] 8− and [P 2 Mo 2 O 15 ] 8− . The structural determinants including the metal source (copper powder vs copper salts), counterion of the salts, and stoichiometry of the reagents were examined. An ex situ EPR study revealed the formation of different Cu II complexes in the reaction mixture depending on the copper precursor. The obtained compounds have been found to possess selectivity toward the sorption of methylene blue in a mixture of organic dyes. DC magnetic measurements of 1−3 indicate rather strong antiferromagnetic metal−metal exchange interactions. Compound 1 exhibits fieldinduced slow magnetic relaxation in AC magnetic measurements, which is a rarely observed phenomenon among Cu(II) complexes.

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