Orientational Control of Electronic Coupling in Mixed-Valence, Binuclear Ruthenium(II)−Bis(2,2‘:6‘,2‘ ‘-Terpyridine) Complexes

Benniston, Andrew C.; Harriman, Anthony; Li, Peiyi; Sams, Craig A.; Ward, Michael D.

doi:10.1021/ja0451968

Cited by 54 publications

(58 citation statements)

References 21 publications

(24 reference statements)

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“…The magnitude of the electronic coupling between the terminal chromophores shows ap recise dependence on the dihedral angle around ab ridging biphenyl group, controlled by selecting the bound cations. [55][56][57] Recently,V enkataraman et al [46] and Wandlowski et al [47][48][49][50][51][52] reported the influence of f on changes in the singlemolecule conductivity in substituted biphenyls or conformationally constrained biphenyls in which the biphenyl rings are connected by a( CH 2 ) n link at the 2-and 2'-positions.O nt wisting of the biphenyl system from coplanar (f= 08)t op erpendicular (f= 908), the conductance decreased by af actor of 30. [48] However,r eports of systematics tudies on the influence of f on the electronic coupling and redox processes of bimetallic complexes [ML n (bridge)ML n ] are still scarce.…”

Section: Introductionmentioning

confidence: 99%

Conformational Tuning of the Intramolecular Electronic Coupling in Molecular‐Wire Biruthenium Complexes Bridged by Biphenyl Derivatives

Kong

Xue

Jang

et al. 2015

Chemistry A European J

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The synthesis and characterization of a series of biphenyl-derived binuclear ruthenium complexes with terminal {RuCl(CO)(PMe3)3} moieties and different structural arrangements of the phenyl rings are reported. Electrochemical studies revealed that the two metal centers of the binuclear ruthenium complexes interact with each other through the biphenyl bridge, and the redox splittings ΔE1/2 show a strong linear correlation with cos(2) ϕ, where ϕ is the torsion angle between the two phenyl rings. A combination of electrochemical, UV/Vis/NIR, and in situ IR differential spectroelectrochemical analysis clearly showed that: 1) the intramolecular electronic couplings in the binuclear ruthenium complexes could be modulated by changing ϕ; 2) the electronic ground state of the mixed-valent cations changes from delocalized to localized through the biphenyl bridge with increasing torsion angle ϕ, that is, the redox processes of these complexes change from significant involvement of the bridging ligand to an oxidation behavior with less participation of the bridge.

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Section: Introductionmentioning

confidence: 99%

Conformational Tuning of the Intramolecular Electronic Coupling in Molecular‐Wire Biruthenium Complexes Bridged by Biphenyl Derivatives

Kong

Xue

Jang

et al. 2015

Chemistry A European J

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“…[15][16][17][18] The coordination bond can be tuned by external conditions, such as pH value and temperature. Herein, we present a study of a hydrogen-bonded supramolecular network using bis(2,2':6',2"-terpyridine)-4'-oxyhexadecane (BT-O-C16), the molecular structure of which is shown in Figure 1 a.…”

Section: Introductionmentioning

confidence: 99%

Coadsorption‐Induced Reconstruction of Supramolecular Assembly Characteristics

Deng

et al. 2007

ChemPhysChem

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A host supramolecular structure consisting of bis-(2,2':6',2"-terpyridine)-4'-oxyhexadecane (BT-O-C16) is shown to respond to coadsorbed molecules in dramatic ways, as observed by scanning tunneling microscopy (STM) on a highly oriented pyrolytic graphite (HOPG) surface under ambient conditions. Interestingly, the lattice parameter of the triphenylene-filled complex differs significantly from that of the coronene-filled one, although the triphenylene and coronene molecules are nearly the same size. The STM study and density functional theory calculations reveal that intermolecular hydrogen-bond interactions play an essential role in forming the assembly structures. The different electronic properties of coronene and triphenylene molecules are responsible for the difference in lattice parameters and consequently for the difference in filling behaviors in the coronene/BT-O-C16 and triphenylene/BT-O-C16 binary systems.

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“…[9] The difference is significantly more pronounced than that found previously for hole transfer through related systems, for which the coupling element increased by a factor less than twofold on moving from orthogonal to coplanar geometries. [26] This latter finding might be suggestive of the possibility that different electronic processes have disparate sensitivities towards such angular effects. If correct, this would be a most important finding, because it would provide the opportunity to employ such angular constraints as a means by which to discriminate between rates of forward and reverse electron transfer in molecular dyads.…”

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confidence: 96%

Electron Exchange in Conformationally Restricted Donor–Spacer–Acceptor Dyads: Angle Dependence and Involvement of Upper‐Lying Excited States

Benniston

Harriman

et al. 2008

Chemistry A European J

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The rate constant for triplet energy transfer (k(TET)) has been measured in fluid solution for a series of mixed-metal Ru-Os bis(2,2':6',2''-terpyridine) complexes built around a tethered biphenyl-based spacer group. The length of the tether controls the central torsion angle for the spacer, which can be varied systematically from 37 to 130 degrees . At low temperature, but still in fluid solution, the spacer adopts the lowest-energy conformation and k(TET) shows a clear correlation with the torsion angle. A similar relationship holds for the inverse quantum yield for emission from the Ru-terpy donor. Triplet energy transfer is more strongly activated at higher temperature and the kinetic data require analysis in terms of two separate processes. The more weakly activated step involves electron exchange from the first-excited triplet state on the Ru-terpy donor and the size of the activation barrier matches well with that calculated from spectroscopic properties. The pre-exponential factor derived for this process correlates remarkably well with the torsion angle and there is a large disparity in electronic coupling through pi and sigma orbitals on the spacer. The more strongly activated step is attributed to electron exchange from an upper-lying triplet state localized on the Ru-terpy donor. Here, the pre-exponential factor is larger but shows the same dependence on the geometry of the spacer. Strangely, the difference in coupling through pi and sigma orbitals is much less pronounced. Despite internal flexibility around the spacer, k(TET) shows a marked dependence on the torsion angle computed for the lowest-energy conformation.

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Orientational Control of Electronic Coupling in Mixed-Valence, Binuclear Ruthenium(II)−Bis(2,2‘:6‘,2‘ ‘-Terpyridine) Complexes

Cited by 54 publications

References 21 publications

Conformational Tuning of the Intramolecular Electronic Coupling in Molecular‐Wire Biruthenium Complexes Bridged by Biphenyl Derivatives

Conformational Tuning of the Intramolecular Electronic Coupling in Molecular‐Wire Biruthenium Complexes Bridged by Biphenyl Derivatives

Coadsorption‐Induced Reconstruction of Supramolecular Assembly Characteristics

Electron Exchange in Conformationally Restricted Donor–Spacer–Acceptor Dyads: Angle Dependence and Involvement of Upper‐Lying Excited States

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