. Can. J. Chem. 68, 223 (1990). The binuclear compound trans, trans-bis(ferroceny1idene)acetone [(C5HS)Fe(C5H4CHCH)l2CO (dFca) has been synthesized in quantitative yield and characterized by FT-IR, 'H and I3c NMR, and mass spectroscopy. Cyclic voltammetry and coulometry measurements suggest that a reversible two-electron oxidative process takes place at 0.68 V vs. SSCE. FT-IR and UV-VIS spectroelectrochernical analyses show that this oxidative process occurs at the ferrocenyl centers. The compound is also found to be emissive in the solid state (A, , = 780 nrn), and charge transfer assignments for the lowest singlet and triplet excited states are made.Key words: ferrocenyl, spectroelectrochemistry, electronic charge transfer, emission spectroscopy. Introduction The cross-conjugated diarylideneacetone ligands (Ar--CH= CH-(C0)-CH=CH-Ar)are capable of forming a few stable organometallic compounds both in the solid state and in solutions (1 -9). In the non-complexed state, they generally exhibit rich photochemical (9-12), electrochemical (12-14), and photoluminescent properties (1 2). Recent resonance Raman, UV-VIS, and emission spectroscopic investigations of the binuclear Pd(0)-and Pt(0)-dibenzylideneacetone complexes reveal the metal-to-ligand charge transfer (MLCT) character of the lowest singlet and triplet excited states (15). Further studies have shown that these binuclear compounds appear photochemically inert (12). We have undertaken the synthesis and study of a series of new diarylideneacetone ligands where the aryl groups are either photo-or electroactive in order to tune photoreactivity in organo-transition binuclear Pd(0) and Pt(0) complexes (1 2).We wish to report our recent results on the newly synthesized electroactive trans, trans-bis(ferroceny1idene)acetone [(C5H5)-Fe(C5H4CHCH)I2CO (dFca) (see structure in Scheme 1). We chose the ferrocene-based substituent (Fc), because ferrocenecentered oxidations should be reversible (16). There are many examples of spectroscopic property and reactivity changes