A new class of mixed-valence systems with orbitally degenerate organic redox centers. Examples based on hexa-rhenium molecular prisms

Peter H. Dinolfo, Veaceslav Coropceanu, Jean Luc Brédas, Joseph T Hupp

Research output: Contribution to journalArticle

75 Citations (Scopus)

Abstract

The ligand-centered mixed-valence (LCMV) properties of two supramolecular complexes are reported: triangular prisms of the form ([Re(CO)3]2X)3-μ,μ′,μ″-[tPyTz]2, where X is 2,2′-bisbenzimidazolate (1) or a pair of benzylthiols (2), and tPyTz is tri-(4-pyridyl)-1,3,5-triazine. Cyclic voltammetry demonstrates that the redox-accessible bridging ligands, tPyTz, are reduced in sequential, one-electron reactions. The singly reduced prisms, which represent an unusual type of mixed-valence compound in which the tPyTz ligands themselves are the redox centers, show intense, broad intervalance transfer (IT) bands in the NIR, consistent with highly coupled MV species. Electroabsorption (Stark spectroscopy) measurements reveal small dipole moment changes associated with intervalence excitation (|Δμ12| = 0.30 ± 0.02 eÅ for 1- and 0.48 ± 0.02 eÅ for 2-), as well as noncollinear transition dipole moment (μ12) and dipole moment change vectors (ζ ≈ 45°). DFT electronic structure calculations support this unusual result, along with a through-space electronic interaction mechanism. The neutral complexes (D3h symmetry) possess doubly degenerate, but spatially distinct, LUMO and LUMO+ orbitals. The orbital degeneracy of the tPyTz ligands is lifted in the MV forms, resulting in nonsymmetrical charge redistribution within the molecules upon on optical IT.

Original languageEnglish
Pages (from-to)12592-12593
Number of pages2
JournalJournal of the American Chemical Society
Volume128
Issue number39
DOIs
Publication statusPublished - Oct 4 2006

Fingerprint

Rhenium
Prisms
Oxidation-Reduction
Dipole moment
Ligands
Triazines
Carbon Monoxide
Discrete Fourier transforms
Cyclic voltammetry
Electronic structure
Spectrum Analysis
Spectroscopy
Electrons
Molecules

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

A new class of mixed-valence systems with orbitally degenerate organic redox centers. Examples based on hexa-rhenium molecular prisms. / Dinolfo, Peter H.; Coropceanu, Veaceslav; Brédas, Jean Luc; Hupp, Joseph T.

In: Journal of the American Chemical Society, Vol. 128, No. 39, 04.10.2006, p. 12592-12593.

Research output: Contribution to journalArticle

@article{9b3798c6d09e4bf08cb80ff735df836f,
title = "A new class of mixed-valence systems with orbitally degenerate organic redox centers. Examples based on hexa-rhenium molecular prisms",
abstract = "The ligand-centered mixed-valence (LCMV) properties of two supramolecular complexes are reported: triangular prisms of the form ([Re(CO)3]2X)3-μ,μ′,μ″-[tPyTz]2, where X is 2,2′-bisbenzimidazolate (1) or a pair of benzylthiols (2), and tPyTz is tri-(4-pyridyl)-1,3,5-triazine. Cyclic voltammetry demonstrates that the redox-accessible bridging ligands, tPyTz, are reduced in sequential, one-electron reactions. The singly reduced prisms, which represent an unusual type of mixed-valence compound in which the tPyTz ligands themselves are the redox centers, show intense, broad intervalance transfer (IT) bands in the NIR, consistent with highly coupled MV species. Electroabsorption (Stark spectroscopy) measurements reveal small dipole moment changes associated with intervalence excitation (|Δμ12| = 0.30 ± 0.02 e{\AA} for 1- and 0.48 ± 0.02 e{\AA} for 2-), as well as noncollinear transition dipole moment (μ12) and dipole moment change vectors (ζ ≈ 45°). DFT electronic structure calculations support this unusual result, along with a through-space electronic interaction mechanism. The neutral complexes (D3h symmetry) possess doubly degenerate, but spatially distinct, LUMO and LUMO+ orbitals. The orbital degeneracy of the tPyTz ligands is lifted in the MV forms, resulting in nonsymmetrical charge redistribution within the molecules upon on optical IT.",
author = "Dinolfo, {Peter H.} and Veaceslav Coropceanu and Br{\'e}das, {Jean Luc} and Hupp, {Joseph T}",
year = "2006",
month = "10",
day = "4",
doi = "10.1021/ja0623764",
language = "English",
volume = "128",
pages = "12592--12593",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
publisher = "American Chemical Society",
number = "39",

}

TY - JOUR

T1 - A new class of mixed-valence systems with orbitally degenerate organic redox centers. Examples based on hexa-rhenium molecular prisms

AU - Dinolfo, Peter H.

AU - Coropceanu, Veaceslav

AU - Brédas, Jean Luc

AU - Hupp, Joseph T

PY - 2006/10/4

Y1 - 2006/10/4

N2 - The ligand-centered mixed-valence (LCMV) properties of two supramolecular complexes are reported: triangular prisms of the form ([Re(CO)3]2X)3-μ,μ′,μ″-[tPyTz]2, where X is 2,2′-bisbenzimidazolate (1) or a pair of benzylthiols (2), and tPyTz is tri-(4-pyridyl)-1,3,5-triazine. Cyclic voltammetry demonstrates that the redox-accessible bridging ligands, tPyTz, are reduced in sequential, one-electron reactions. The singly reduced prisms, which represent an unusual type of mixed-valence compound in which the tPyTz ligands themselves are the redox centers, show intense, broad intervalance transfer (IT) bands in the NIR, consistent with highly coupled MV species. Electroabsorption (Stark spectroscopy) measurements reveal small dipole moment changes associated with intervalence excitation (|Δμ12| = 0.30 ± 0.02 eÅ for 1- and 0.48 ± 0.02 eÅ for 2-), as well as noncollinear transition dipole moment (μ12) and dipole moment change vectors (ζ ≈ 45°). DFT electronic structure calculations support this unusual result, along with a through-space electronic interaction mechanism. The neutral complexes (D3h symmetry) possess doubly degenerate, but spatially distinct, LUMO and LUMO+ orbitals. The orbital degeneracy of the tPyTz ligands is lifted in the MV forms, resulting in nonsymmetrical charge redistribution within the molecules upon on optical IT.

AB - The ligand-centered mixed-valence (LCMV) properties of two supramolecular complexes are reported: triangular prisms of the form ([Re(CO)3]2X)3-μ,μ′,μ″-[tPyTz]2, where X is 2,2′-bisbenzimidazolate (1) or a pair of benzylthiols (2), and tPyTz is tri-(4-pyridyl)-1,3,5-triazine. Cyclic voltammetry demonstrates that the redox-accessible bridging ligands, tPyTz, are reduced in sequential, one-electron reactions. The singly reduced prisms, which represent an unusual type of mixed-valence compound in which the tPyTz ligands themselves are the redox centers, show intense, broad intervalance transfer (IT) bands in the NIR, consistent with highly coupled MV species. Electroabsorption (Stark spectroscopy) measurements reveal small dipole moment changes associated with intervalence excitation (|Δμ12| = 0.30 ± 0.02 eÅ for 1- and 0.48 ± 0.02 eÅ for 2-), as well as noncollinear transition dipole moment (μ12) and dipole moment change vectors (ζ ≈ 45°). DFT electronic structure calculations support this unusual result, along with a through-space electronic interaction mechanism. The neutral complexes (D3h symmetry) possess doubly degenerate, but spatially distinct, LUMO and LUMO+ orbitals. The orbital degeneracy of the tPyTz ligands is lifted in the MV forms, resulting in nonsymmetrical charge redistribution within the molecules upon on optical IT.

UR - http://www.scopus.com/inward/record.url?scp=33749526325&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33749526325&partnerID=8YFLogxK

U2 - 10.1021/ja0623764

DO - 10.1021/ja0623764

M3 - Article

VL - 128

SP - 12592

EP - 12593

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 39

ER -