Stabilities and reactivities of the cyano-bridged binuclear complexes of trans-isonicotinamidetetraammineruthenium and hexacyanoferrate

Abstract

The binuclear complexes, trans-(isn)(NH₃)₄RuNCFe (n = 2−, 1−, 0), were prepared both in aqueous solutions and as isolated salts. Their properties, particularly that of the mixed-valence species (M), were characterized by UV-Vis, infrared, electrochemical and kinetic studies. The results suggested that Ru(III)–Fe(II) was both thermodynamically and kinetically stable oxidation states. The extent of delocalization of M was estimated by analysis of the intervalence band on the basis of Hush's theory. The stabilization of M with respect to its oxidation state isomer (M′) was investigated and it was found that the electrostatic effect associated with the net charges of metal moieties constituted the dominant factor governing the stability of M.

Keywords:

• Mixed-valence
• Intervalence band
• Charge effect
• Electron transfer

Acknowledgement

Support of this work by the National Science Council of the Republic of China is gratefully acknowledged.