### Abstract

The spectral parameters for the optically induced intervalence charge transfer and the rates of thermal electron transfer as a function of temperature have been measured for a rigid, triply linked mixed-valence dinuclear tris(2,2'-bipyridine)iron complex. The total reorganizational energy associated with the intramolecular electron exchange in this complex is almost exclusively outer-sphere in nature and comes from thermal. fluctuations of the solvent. Thus, the system can be treated rigorously at the Classical level, where in this context classical refers to treatments of the nuclear modes. The theories developed to describe the optical electron transfer and the thermal electron. transfer are evaluated by analysis of the spectral and rate data, respectively. The quantities common to both theories are the donor-acceptor coupling matrix element, H_{12}, and the total reorganizational energy. Applying the respective theories to the appropriate corresponding sets of data yields reorganizational energies that are inexcellent agreement irrespective of the manner in which the temperature dependence is treated; however, if the reorganizational energy is assumed to be temperature independent, H_{12}(th) (from the rate data) and H_{12}(op) (from the spectral data) differ by a statistically significant factor of ~2.5. If the theoretically predicted temperature-dependent reorganizational energy composed of orientational reorganization of permanent dipoles and reorganization of solvent density is used in the calculations, the agreement between H_{12}(op) and H_{12}th improves dramatically. To our knowledge, this work constitutes the first attempt to experimentally compare these two classical theories with this level of rigor. Supplementing the experimental comparisons, we have conducted self-consistent-field (SCF) and configuration interaction (CI) calculations to obtain theoretical values of H_{12}(op) and the donor-acceptor orbital separation, r, for comparison with experimentally determined values.

Original language | English (US) |
---|---|

Pages (from-to) | 11714-11726 |

Number of pages | 13 |

Journal | Journal of the American Chemical Society |

Volume | 120 |

Issue number | 45 |

DOIs | |

State | Published - Nov 18 1998 |

Externally published | Yes |

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### ASJC Scopus subject areas

- Chemistry(all)

### Cite this

*Journal of the American Chemical Society*,

*120*(45), 11714-11726. https://doi.org/10.1021/ja981067d

**Direct experimental comparison of the theories of thermal and optical electron-transfer : Studies of a mixed-valence dinuclear iron polypyridyl complex.** / Michael Elliott, C.; Derr, Daniel L.; Matyushov, Dmitry; Newton, Marshall D.

Research output: Contribution to journal › Article

*Journal of the American Chemical Society*, vol. 120, no. 45, pp. 11714-11726. https://doi.org/10.1021/ja981067d

}

TY - JOUR

T1 - Direct experimental comparison of the theories of thermal and optical electron-transfer

T2 - Studies of a mixed-valence dinuclear iron polypyridyl complex

AU - Michael Elliott, C.

AU - Derr, Daniel L.

AU - Matyushov, Dmitry

AU - Newton, Marshall D.

PY - 1998/11/18

Y1 - 1998/11/18

N2 - The spectral parameters for the optically induced intervalence charge transfer and the rates of thermal electron transfer as a function of temperature have been measured for a rigid, triply linked mixed-valence dinuclear tris(2,2'-bipyridine)iron complex. The total reorganizational energy associated with the intramolecular electron exchange in this complex is almost exclusively outer-sphere in nature and comes from thermal. fluctuations of the solvent. Thus, the system can be treated rigorously at the Classical level, where in this context classical refers to treatments of the nuclear modes. The theories developed to describe the optical electron transfer and the thermal electron. transfer are evaluated by analysis of the spectral and rate data, respectively. The quantities common to both theories are the donor-acceptor coupling matrix element, H12, and the total reorganizational energy. Applying the respective theories to the appropriate corresponding sets of data yields reorganizational energies that are inexcellent agreement irrespective of the manner in which the temperature dependence is treated; however, if the reorganizational energy is assumed to be temperature independent, H12(th) (from the rate data) and H12(op) (from the spectral data) differ by a statistically significant factor of ~2.5. If the theoretically predicted temperature-dependent reorganizational energy composed of orientational reorganization of permanent dipoles and reorganization of solvent density is used in the calculations, the agreement between H12(op) and H12th improves dramatically. To our knowledge, this work constitutes the first attempt to experimentally compare these two classical theories with this level of rigor. Supplementing the experimental comparisons, we have conducted self-consistent-field (SCF) and configuration interaction (CI) calculations to obtain theoretical values of H12(op) and the donor-acceptor orbital separation, r, for comparison with experimentally determined values.

AB - The spectral parameters for the optically induced intervalence charge transfer and the rates of thermal electron transfer as a function of temperature have been measured for a rigid, triply linked mixed-valence dinuclear tris(2,2'-bipyridine)iron complex. The total reorganizational energy associated with the intramolecular electron exchange in this complex is almost exclusively outer-sphere in nature and comes from thermal. fluctuations of the solvent. Thus, the system can be treated rigorously at the Classical level, where in this context classical refers to treatments of the nuclear modes. The theories developed to describe the optical electron transfer and the thermal electron. transfer are evaluated by analysis of the spectral and rate data, respectively. The quantities common to both theories are the donor-acceptor coupling matrix element, H12, and the total reorganizational energy. Applying the respective theories to the appropriate corresponding sets of data yields reorganizational energies that are inexcellent agreement irrespective of the manner in which the temperature dependence is treated; however, if the reorganizational energy is assumed to be temperature independent, H12(th) (from the rate data) and H12(op) (from the spectral data) differ by a statistically significant factor of ~2.5. If the theoretically predicted temperature-dependent reorganizational energy composed of orientational reorganization of permanent dipoles and reorganization of solvent density is used in the calculations, the agreement between H12(op) and H12th improves dramatically. To our knowledge, this work constitutes the first attempt to experimentally compare these two classical theories with this level of rigor. Supplementing the experimental comparisons, we have conducted self-consistent-field (SCF) and configuration interaction (CI) calculations to obtain theoretical values of H12(op) and the donor-acceptor orbital separation, r, for comparison with experimentally determined values.

UR - http://www.scopus.com/inward/record.url?scp=17344362159&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=17344362159&partnerID=8YFLogxK

U2 - 10.1021/ja981067d

DO - 10.1021/ja981067d

M3 - Article

AN - SCOPUS:17344362159

VL - 120

SP - 11714

EP - 11726

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 45

ER -