Nonradiative Decay in Rhenium(I) Monometallic Complexes of 2,3-Di(2-pyridyl)pyrazine and 2,3-Di(2-pyridyl)quinoxaline

Baiano, John A.; Kessler, Robert J.; Lumpkin, Richard S.; Munley, Michael J.; Murphy, W. Rorer

doi:10.1021/j100050a004

Cited by 28 publications

(15 citation statements)

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“…As expected from previous studies, [6][7][8][9][10]16] the spectra of the rhenium(I) complexes are much simpler than that of their ruthenium(II) analogs, consisting of intense absorption bands around 240 to 330 nm-assigned to ligand-centered p!p* transitions characteristic of aromatic nitrogen donor ligands-and 1 MLCT transition absorptions centered between 375 and 460 nm. Unlike their Ru II analogs 13 and 14, which contain pyridinium units, the Re I complexes display no well-defined low energy bands.…”

Section: Spectral Studiessupporting

confidence: 76%

“…[6] Studies show that this group of complexes are also able to luminesce from the triplet MLCT state with lifetimes ranging between 100 ns and 100 ms in a room temperature solution. [6][7][8][9][10] A second field that has rapidly emerged in the last two decades is the metal templated self-assembly of metallomacrocycles and other related molecular architectures. [11] Much of this work has exploited classically labile metal centers, such as Pd II , Cu I , and Co II , to produce thermodynamically favored equilibrium products.…”

Section: Introductionmentioning

confidence: 99%

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Tuning the Excited State of Photoactive Building Blocks for Metal‐Templated Self‐Assembly

Ahmad

Meijer

Thomas

2011

Chemistry An Asian Journal

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The reaction of 2,2':4,4'':4',4'''-quaterpyridyl (qtpy), with d(6) ruthenium(II) (Ru(II) ), and rhenium(I) (Re(I) ) metal centers has been investigated. The pendant pyridyl groups on the products have also been methylated to produce a second series of complexes containing coordinated Meqtpy(2+). The absorption spectra of the complexes are dominated by intraligand and charge-transfer bands. The ruthenium(II) complexes display broad unstructured luminescence consistent with emission from a Ru(d)→diimine(π*) manifold in acetonitrile solutions. In aqueous solutions, their emissions are weaker and the lifetimes are shorter. This effect is particularly acute for complexes incorporating coordinated dipyridylpyrazine, dppz, ligands. Although the emission of the ruthenium(II) complexes containing Meqtpy(2+) is generally shorter than their qtpy analogs, it is notable that solvent-dependent effects are much less intense. The rhenium(I) complexes also display broad unstructured luminescence but, compared with the ruthenium(II) systems, they have a relatively short lifetime in acetonitrile. Electrochemical studies reveal that all of the Ru(II) complexes display chemically reversible metal-based oxidations. Re(I) complexes only display irreversible metal-based oxidations. In most cases, the reduction processes were not fully chemically reversible. The electrochemical and optical studies reveal that the nature of the lowest excited state of these complexes--particularly, the systems incorporating dppz--is highly dependent on the nature of the coordinated ligands. Calculations indicate that, although the excited state of most of the complexes is centered on the qtpy or Meqtpy(2+) ligands, the excited state of the complexes containing dppz ligands is switched away from the dppz by qtpy methylation. A crystallographic study on one of the dicationic ruthenium(II) structures reveals that it forms an inclusion complex with benzene.

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Section: Spectral Studiessupporting

confidence: 76%

Section: Introductionmentioning

confidence: 99%

Tuning the Excited State of Photoactive Building Blocks for Metal‐Templated Self‐Assembly

Ahmad

Meijer

Thomas

2011

Chemistry An Asian Journal

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“…The two-band pattern is typical of this class of (NN)Re(CO) 3 L complexes, in which L coordinates to Re via a pyridyl group: the local symmetry at the Re centre is approximately C 3v , and so two bands from modes of approximate A 1 and E symmetry are observed (corresponding to A 0 (1) and A 00 /A 0 (2) modes, respectively, in C s symmetry). 16 The RR spectra of complexes 2a and 2c show one v(CO) band at ca. 2035 cm À1 (Fig.…”

Section: Vibrational Band Assignmentsmentioning

confidence: 99%

Infrared and resonance Raman studies of metal cation sensors in which an azacrown ether is linked to (bpy)Re(CO)3 via an alkenyl or alkynyl spacerElectronic supplementary information available (ESI): synthesis and characterisation of L1b, L2b, 1b and 2b; colour figure of displacement vectors calculated for selected equivalent modes of L1b and L2b. See http://www.rsc.org/suppdata/cp/b4/b408338e/

Lewis

Moore

2004

Phys. Chem. Chem. Phys.

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Infrared and resonance Raman spectra of two [(bpy)Re(CO) 3 L] 1 complexes (bpy ¼ 2,2 0 -bipyridine) in which the L ligand contains an aza-15-crown-5 ether that is attached to Re via an alkenyl-or alkynyl-pyridine spacer are reported. Vibrational assignments have been made by comparison with the spectra of model complexes and ligands, and with the results of density functional theory (DFT) calculations; they provide information on the structure and bonding within the L ligands in the complexes. The addition of alkali or alkaline-earth metal perchlorate salts to solutions of the complexes in acetonitrile results in mode-specific changes in the vibrational spectra: the magnitudes of the changes depend on the identity of the metal cation, and they are rationalised in terms of changes in structure and bonding caused by the metal cation binding to the azacrown.

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“…1,67-72 This approach relates the displacement of the potential energy curve for the MLCT excited state with respect to the curve for the ground state, expressed by S, with the extent of charge delocalization in the emissive MLCT state. [73][74][75] When the excited state undergoes extended electronic delocalization, low S m values are obtained (typically in the range 0.2-0.6), indicating that the potential energy curve for the excited state is not much displaced relative to that for the ground state. [76][77][78] On the contrary, high values for the Huang-Rys constant (S m > 0.7, as in the case of [Ru(bpy) 3 ] 2+ ) indicate that the excited state is significantly distorted along the concerned vibrational mode because of electronic localization effects.…”

Section: Photophysical Behavior Of the Cis-and Trans-[ru(dip) 2 (Meoh...mentioning

confidence: 99%

cis–trans Photoisomerization in [Ru(DIP)₂(MeOH)₂][OTf]₂: synthesis, NMR, X-ray structure of the trans-isomer and photophysical properties

et al. 2007

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The first trans-ruthenium complex trans-[Ru(DIP)2(MeOH)2][OTf]2 (1b, where DIP = 4,7-diphenyl-1,10-phenanthroline) incorporating a pi-extended ligand was prepared via two methods: either photolysis of cis-[Ru(DIP)2(OTf)2] in MeOH-Et(2)O or via crystallization from MeOH-Et(2)O in direct sunlight. The X-ray molecular structure of is reported and confirmed the trans geometry of the title compound. The cis-trans isomerization process was monitored by 1H-NMR and showed that 1b reverts back to cis-[Ru(DIP)2(MeOH)2][OTf]2 (1a) in methanol-d4 after 15 h at 55 degrees C or several days at room temperature. The absorption spectra recorded in MeOH showed a bathochromic shift of the MLCT band of the trans-isomer 1b relative to that of the cis complex 1a. Interestingly at 77 K the emission spectrum of 1b is red shifted compared to the cis analog 1a. A rational explanation in terms of the energy of the excited states in the cis- and trans-isomers is proposed to explain this behavior.

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Nonradiative Decay in Rhenium(I) Monometallic Complexes of 2,3-Di(2-pyridyl)pyrazine and 2,3-Di(2-pyridyl)quinoxaline

Cited by 28 publications

References 2 publications

Tuning the Excited State of Photoactive Building Blocks for Metal‐Templated Self‐Assembly

Tuning the Excited State of Photoactive Building Blocks for Metal‐Templated Self‐Assembly

cis–trans Photoisomerization in [Ru(DIP)₂(MeOH)₂][OTf]₂: synthesis, NMR, X-ray structure of the trans-isomer and photophysical properties

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Nonradiative Decay in Rhenium(I) Monometallic Complexes of 2,3-Di(2-pyridyl)pyrazine and 2,3-Di(2-pyridyl)quinoxaline

Cited by 28 publications

References 2 publications

Tuning the Excited State of Photoactive Building Blocks for Metal‐Templated Self‐Assembly

Tuning the Excited State of Photoactive Building Blocks for Metal‐Templated Self‐Assembly

cis–trans Photoisomerization in [Ru(DIP)2(MeOH)2][OTf]2: synthesis, NMR, X-ray structure of the trans-isomer and photophysical properties

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cis–trans Photoisomerization in [Ru(DIP)₂(MeOH)₂][OTf]₂: synthesis, NMR, X-ray structure of the trans-isomer and photophysical properties