Synthesis and characterization of (μ-alkoxo)bis(μ-carboxylato)diruthenium complexes, Na[Ru2(dhpta)(μ-O2CR)2] (dhptaH5 = 1,3-diamino-2-hydroxypropane tetraacetic acid). A ruthenium analogue of model systems for iron-oxo proteins

The first ruthenium analogue of hemerythrin models with μ-alkoxo bridging, Na[Ru(dhpta)(μ-O2CR)2] (1:R = CH3,2:R = C6H5,3:R = C6H4-p-OH,4:R = C6H4-p-NH2) have been prepared and characterized, and the crystal structure of 1 has been determined; these compounds undergo two one-electron reductions to the RuIIRuIII and RuIIRuII states with large separations (∼0.6 V) between the successive redox potentials, allowing the formation of stable mixed-valence species. (author)