Synthesis and Properties of an Oxido‐Bridged Heptavalent Rhenium Dimer with 2‐Phenylpyridinato and Reactivity with Hydrogen Peroxide

Heptavalent rhenium compounds, [Re 2 O 4 (μ‐O) 2 (ppy) 2 ] (ppy − = 2‐phenylpyridinato), H(ppyH)[ReO 4 ] (H(ppyH) + = 2‐phenylpyridinium), and H(ppyOH)[ReO 4 ] (H(ppyOH) + = 2‐(2‐hydroxyphenyl)pyridinium)) are synthesized and characterized. The reaction of [ReIO 2 (PPh 3 ) 2 ] with [HgCl(ppy)] in a molar ratio of 1:2 in a methanol containing two molar equivalents of water affords the bis(μ‐oxido) dinuclear Re(VII) compound, [Re 2 O 4 (μ‐O) 2 (ppy) 2 ]. When the reaction is performed by the adding excess amount of water in methanol, H(ppyH)[ReO 4 ] is produced. The hydroxylation of ppy − is accomplished by the reaction of [Re 2 O 4 (μ‐O) 2 (ppy) 2 ] with excess amount of hydrogen peroxide in an acidic acetonitrile solution to give H(ppyOH)[ReO 4 ]. The structures of [Re 2 O 4 (μ‐O) 2 (ppy) 2 ], H(ppyOH)[ReO 4 ], and H(ppyOH)[ReO 4 ] are determined by single‐crystal X‐ray analysis.