Modulation of photoinduced energy-transfer between Ru(II) and Os(II) termini in a dinuclear complex by a conformational change induced by Ba2+ binding at a central macrocyclic site

Abstract In a dinuclear complex containing {Ru(bpy) 3 } 2+ and {Os(bpy) 3 } 2+ termini separated by a flexible diaza-18-crown-6 macrocyclic spacer, binding of a Ba 2+ ion at the central macrocycle results in an increase in the Ru⋯Os separation for electrostatic reasons, and hence a decrease in the efficiency of Ru→Os photoinduced energy-transfer.