Medium Effects on Charge Transfer in Metal Complexes

Chen, Pingyun; Meyer, Thomas J.

doi:10.1021/cr941180w

Cited by 634 publications

(671 citation statements)

References 477 publications

(1,237 reference statements)

Supporting

Mentioning

613

Contrasting

Unclassified

Order By: Relevance

“…This theory has been successfully applied to [Ru(bpy) 3 ] 2+ systems to explain trends in k nr , [41][42][43] and a linear dependence of ln k nr with decreasing energy gap between the lowest-lying 3 MLCT and the 1 A 1 ground state is generally observed. 44 Time-resolved nanosecond emission data, coupled with measurements of radiative quantum yields (φ em ), provided values of k nr for this series of compounds.…”

Section: Resultsmentioning

confidence: 99%

Static and Time-Resolved Spectroscopic Studies of Low-Symmetry Ru(II) Polypyridyl Complexes

Curtright

McCusker

1999

J. Phys. Chem. A

View full text Add to dashboard Cite

The spectroscopic and electrochemical properties of a series of four Ru II polypyridyl complexes are reported. Compounds of the form [Ru(dmb) x (dea) 3-x ] 2+ (x ) 0-3), where dmb is 4,4′-dimethyl-2,2′-bipyridine and dea is 4,4′-bis(diethylamino)-2,2′-bipyridine, have been prepared and studied using static and time-resolved electronic and vibrational spectroscopies as a prelude to femtosecond spectroscopic studies of excited-state dynamics. Static electronic spectra in CH 3 CN solution reveal a systematic shift of the MLCT absorption envelope from a maximum of 458 nm in the case of [Ru(dmb) 3 ] 2+ to 518 nm for [Ru(dea) 3 ] 2+ with successive substitutions of dea for dmb, suggesting a dea-based chromophore as the lowest-energy species. However, analysis of static and time-resolved emission data indicates an energy gap ordering of [Ru(dmb) , at variance with the electronic structures inferred from the absorption spectra. Nanosecond time-resolved electronic absorption and time-resolved step-scan infrared data are used to resolve this apparent conflict and confirm localization of the long-lived 3 MLCT state on dmb in all three complexes where this ligand is present, thus making the dea-based excited state unique to [Ru-(dea) 3 ] 2+ . Electrochemical studies further reveal the origin of this result, where a strong influence of the dea ligand on the oxidative Ru II/III couple, due to π donation from the diethylamino substituent, is observed. The electronic absorption spectra are then reexamined in light of the now well-determined excited-state electronic structure. The results serve to underscore the importance of complete characterization of the electronic structures of transition metal complexes before embarking on ultrafast studies of their excited-state properties.

show abstract

Section: Resultsmentioning

confidence: 99%

Static and Time-Resolved Spectroscopic Studies of Low-Symmetry Ru(II) Polypyridyl Complexes

Curtright

McCusker

1999

J. Phys. Chem. A

View full text Add to dashboard Cite

show abstract

“…It is not known experimentally how ZFS changes on going from a solid matrix to a fluid solution and how it depends on the solvent. Nevertheless, the well-known "rigidochromic effect" [114] demonstrates that 3 MLCT states lie at lower energies in solutions than in glasses, further apart from the 3 IL states. Larger 3 MLCT-3 IL energy separation in solution results in smaller mixing and, hence, larger MLCT content in the lowest triplet.…”

Section: Experimental Observations Of Spin-orbit Phenomenamentioning

confidence: 99%

Relativistic effects in spectroscopy and photophysics of heavy-metal complexes illustrated by spin–orbit calculations of [Re(imidazole)(CO)3(phen)]+

Baková

Chergui

Daniel

et al. 2011

Coordination Chemistry Reviews

111

View full text Add to dashboard Cite

“…This is a consequence of time-scale differences in the coupling mechanisms for vibrations and solvent. Solvent is coupled by changes in local electric fields that accompany electron transfer (Ulstrup 1979;Dogonadze et al 1985;Reichardt 1988;Chen & Meyer 1998). Dynamics of solvent coupling have been measured by observing absorption band shifts following ultrafast laser excitation of charge transfer transitions (Kahlow et al 1987;Horng et al 1995;Fleming & Cho 1996).…”

Section: It Icmentioning

confidence: 99%

Probing the localized-to-delocalized transition

Concepcion

Dattelbaum

Meyer

et al. 2007

Phil. Trans. R. Soc. A.

View full text Add to dashboard Cite

Detailed understanding of the transition between localized and delocalized behaviour in mixed valence compounds has been elusive as evidenced by many interpretations of the Creutz-Taube ion, [(NH 3 ) 5 Ru(pz)Ru(NH 3 ) 5 ] 5C . In a review in 2001, experimental protocols and a systematic model to probe this region were proposed and applied to examples in the literature. The model included: (i) multiple orbital interactions in ligand-bridged transition metal complexes, (ii) inclusion of spin-orbit coupling which, for dp 5 -dp 6 complexes, leads to five low-energy bands, two from interconfigurational (dp/dp) transitions at the dp 5 site and three from intervalence transfer transitions, (iii) differences in time scale between coupled vibrations and solvent modes which can result in solvent averaging with continued electronic asymmetry defining 'class II-III', an addition to the Robin-Day classification scheme, and (iv) delineation of coupled vibrations into barrier vibrations and 'spectator' vibrations. The latter provide direct insight into localization or delocalization and time scales for electron transfer. In this paper, the earlier model is applied to a series of mixed-valence molecules.

show abstract

Medium Effects on Charge Transfer in Metal Complexes

Cited by 634 publications

References 477 publications

Static and Time-Resolved Spectroscopic Studies of Low-Symmetry Ru(II) Polypyridyl Complexes

Static and Time-Resolved Spectroscopic Studies of Low-Symmetry Ru(II) Polypyridyl Complexes

Relativistic effects in spectroscopy and photophysics of heavy-metal complexes illustrated by spin–orbit calculations of [Re(imidazole)(CO)3(phen)]+

Probing the localized-to-delocalized transition

Contact Info

Product

Resources

About