Redox asymmetry and metal-metal coupling in pyrazine-bridged ruthenium dimers

Abstract

4229The results presented here provide not only a synthetic method of a new type of chromium(II1) porphyrin complex but also an insight into the axial coordination mode of Cr(II1)-substituted cytochrome P450 if it is prepared.Acknowledgment. Redox Asymmetry and Metal-Metal Coupling in Pyrazine-Bridged Ruthenium Dimers Sir:Elucidation of the nature and extent of electronic coupling in mixed-valenck dimers continues to present a challenging theoretical and experimental problem.'-' The pyrazine-bridged diruthenium decaammine species [ R~( N H~)~l~p y z~+ (the Creutz-Taube ion4) presents a particularly intriguing case since it does not appear to fall squarely into either the predominantly valence-localized Robin and Day class I1 category or the fully delocalized class I11 category.s-6Brown, D. M., Ed. 'Mixed-Valence Compounds"; D. Reidel: Dordrecht, Holland, 1980.

Effects of Rapid Intramolecular Electron Transfer on Vibrational Spectra

“…It is evident that the magnitude of the electronic coupling HAB can be moderated over a large range by a relatively simple ligand substitutio~~ in the series 1 through 3 . Remote ligand control of electronic coupling in mixed-valence complexes is not unusual (15)(16)(17). However, to our kno~vledge, the wide variation seen in 1 through 3 has not been reported previously.…”

“…In contrast, it seems that equatorial Kelvin waves reflect quite well i n the eastern boundary as equatorial Rossby waves (14). Third, the models that have led to this theory of the E N S 0 are based o n the doininant role of thermocline displacements o n SST in the eastern equatorial Pacific, and they underestimate or misinterpret the effects of zonal advection (15). As a result.…”

Inter- or intramolecular electron transfer between triruthenium clusters: we’ll cross that bridge when we come to it

“…While remote ligand control of electronic coupling in mixedvalence complexes is not unusual [37,41,42], the wide variation achieved here by simple substitution of bridging and ancillary ligands is remarkable. It appears that two conditions are simultaneously met: (i) very favorable overlap between the Ru 3 cluster Table 2 Electrochemical data for [Ru3(3-O)(-OAc)6(CO)(L)]2(-BL) in CH2Cl2.…”

“…The relationship between the electrochemical value of E and the electronic coupling, H AB , has been discussed [10,[37][38][39][40], and though many factors are involved, increased E tends to indicate greater electronic coupling for analogous complexes under similar conditions. An interesting aspect of these complexes is that the splitting, E, between the (0/−1) and (−1/−2) states of 4-9 depends strongly on the ancillary ligands (dmap, py, cpy) and on the bridging ligand (pz, bpy).…”

Diastereoisomers as probes for solvent reorganizational effects on IVCT in dinuclear ruthenium complexes

“…Systems of this genre have provided important experimental insights into the roles of solvent dynamics [2][3][4][5][6][7][8][9][10][11][12][13][14][15], ion-pairing [16][17][18][19][20][21], encapsulation [22,23], temperature [24][25][26][27][28], and redox asymmetry [29,30], and they have been used as model systems to verify the salient predictions of several important theoretical models that describe the activation barrier to electron transfer [31][32][33][34][35].…”