Excited-state acid-base reactions of dicyanobis(2,2'-bipyridine)ruthenium(II) and dicyanobis(1,10-phenanthroline)ruthenium(II)

Peterson, Steven H.; Demas, J. N.

doi:10.1021/ja00516a015

“…Clearly the bipyrazine complex (II) offers a clear advantage in this respect to the bipyridine species (I) which decomposes under similar conditions. However, we note that Demas has reported some interesting protonation equilibria with the species Ru(bipy) 2 (CN) 2 , 3 to which we return below.…”

Section: +mentioning

confidence: 78%

“…The absorbance changes associated with the third set of isosbestic points, (80 to 96% sulfuric acid), also give a straight line passing through the origin for the graphical test for two species in solution. Therefore, we are observing the third protonation involving triply protonated BPZ with an estimated pKia 3 of approximately -10. From 0 to 962 sulfuric acid, protonation is consistent with…”

Section: I) Bipyrazine (Lipz)mentioning

confidence: 92%

“…Although Ru(BPZ) 3 and BPZ stock solutions in 96% H 2 SO 4 appeared stable for months at a time in dark storage, fresh stock solutions were prepared for this study. All spectra were recorded on a Perkin-Elmer Hitachi Model 340 microprocessor spectrometer.…”

Section: +mentioning

confidence: 99%

“…is not known whether the reaction rate constant between Ru(BPZ) 3 and H is influenced by the presence of oxygen in solution 8 .…”

Section: + H+mentioning

confidence: 99%

“…The six protonation steps of Ru(BPZ) 3 Each of the first three protonation steps occur at a separate ligand so that at the completion of the third protonation, each ligand is monoprotonated. where pH is taken at the inflection point in the luminescence titration curve, (see Figure 7), and ra and Tb are the excited state lifetims of protonated and unprotonated form respectively, (see Table 4).…”

Section: +mentioning

confidence: 99%

See 3 more Smart Citations

Protonation equilibria in excited-state tris(bipyrazine)ruthenium(II)

Crutchley¹,

Kress²,

Lever³

1983

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Self‐Assembly of a Light‐Harvesting Antenna Formed by a Dendrimer, a Ru^II Complex, and a Nd^III Ion

Giansante

¹

,

Ceroni

²

,

Balzani

³

et al. 2008

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Self-assembly of molecular components by weak, non-covalent interactions is widespread in natures forms and functions [1] and is attracting increasing interest in artificial systems.[2] The study of light-induced processes in artificial molecular assemblies is a very promising approach to control mechanical movements, process information, and harvest sunlight. [3] Lanthanide metal ions exhibit long-lived and line-like luminescence, but direct excitation of lanthanide metal ions is inefficient because of the forbidden nature of their electronic transitions. Therefore, coordinating organic or inorganic chromophores are usually exploited to sensitize the luminescence of the ions (antenna effect).[4] A particularly interesting class of ligands are dendrimers because they can collect excitation light and encapsulate chemical species in predetermined sites.[5] We report herein on a three-component selfassembled light-harvesting antenna formed by a dendrimer, a Ru II complex, and a luminescent Nd III ion. Dendrimer D (Scheme 1), consisting of a 1,4,8,11-tetraazacyclotetradecane (cyclam) core with appended 12 dimethoxybenzene and 16 naphthyl units [6] encapsulates Nd III ions, but, when photoexcited, it is unable to transfer energy to the metal ion.[ 2À , are particularly interesting because they are luminescent and can play the role of ligands giving rise to supercomplexes. [9,10] In particular, [Ru(bpy) 2 (CN) 2 ] has low-energy absorption bands and a luminescence band in the visible region which are related to metal-to-ligand (bpy) charge-transfer (MLCT) excited states (spin-allowed states for the absorption bands; the lowest spin-forbidden state for the emission band). [9b,c, 11] The energies of these excited states are strongly dependent on the interaction of the cyanide ligands with solvent molecules, [9,11] proton, [12] or metal ions. [13] In particular, the lowest energy band maximum shifts toward the blue when cyanide ligands are linked to a cation because of the lower electron

show abstract

Self‐Assembly of a Light‐Harvesting Antenna Formed by a Dendrimer, a Ru^II Complex, and a Nd^III Ion

Giansante

¹

,

Ceroni

²

,

Balzani

³

et al. 2008

View full text Add to dashboard Cite

Self-assembly of molecular components by weak, non-covalent interactions is widespread in natures forms and functions [1] and is attracting increasing interest in artificial systems.[2] The study of light-induced processes in artificial molecular assemblies is a very promising approach to control mechanical movements, process information, and harvest sunlight. [3] Lanthanide metal ions exhibit long-lived and line-like luminescence, but direct excitation of lanthanide metal ions is inefficient because of the forbidden nature of their electronic transitions. Therefore, coordinating organic or inorganic chromophores are usually exploited to sensitize the luminescence of the ions (antenna effect).[4] A particularly interesting class of ligands are dendrimers because they can collect excitation light and encapsulate chemical species in predetermined sites.[5] We report herein on a three-component selfassembled light-harvesting antenna formed by a dendrimer, a Ru II complex, and a luminescent Nd III ion. Dendrimer D (Scheme 1), consisting of a 1,4,8,11-tetraazacyclotetradecane (cyclam) core with appended 12 dimethoxybenzene and 16 naphthyl units [6] encapsulates Nd III ions, but, when photoexcited, it is unable to transfer energy to the metal ion.[ 2À , are particularly interesting because they are luminescent and can play the role of ligands giving rise to supercomplexes. [9,10] In particular, [Ru(bpy) 2 (CN) 2 ] has low-energy absorption bands and a luminescence band in the visible region which are related to metal-to-ligand (bpy) charge-transfer (MLCT) excited states (spin-allowed states for the absorption bands; the lowest spin-forbidden state for the emission band). [9b,c, 11] The energies of these excited states are strongly dependent on the interaction of the cyanide ligands with solvent molecules, [9,11] proton, [12] or metal ions. [13] In particular, the lowest energy band maximum shifts toward the blue when cyanide ligands are linked to a cation because of the lower electron

show abstract

Excited-state acid-base reactions of dicyanobis(2,2'-bipyridine)ruthenium(II) and dicyanobis(1,10-phenanthroline)ruthenium(II)

Cited by 55 publications

References 1 publication

Protonation equilibria in excited-state tris(bipyrazine)ruthenium(II)

Protonation equilibria in excited-state tris(bipyrazine)ruthenium(II)

Self‐Assembly of a Light‐Harvesting Antenna Formed by a Dendrimer, a Ru^II Complex, and a Nd^III Ion

Self‐Assembly of a Light‐Harvesting Antenna Formed by a Dendrimer, a Ru^II Complex, and a Nd^III Ion

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Excited-state acid-base reactions of dicyanobis(2,2'-bipyridine)ruthenium(II) and dicyanobis(1,10-phenanthroline)ruthenium(II)

Cited by 55 publications

References 1 publication

Protonation equilibria in excited-state tris(bipyrazine)ruthenium(II)

Protonation equilibria in excited-state tris(bipyrazine)ruthenium(II)

Self‐Assembly of a Light‐Harvesting Antenna Formed by a Dendrimer, a RuII Complex, and a NdIII Ion

Self‐Assembly of a Light‐Harvesting Antenna Formed by a Dendrimer, a RuII Complex, and a NdIII Ion

Contact Info

Product

Resources

About

Self‐Assembly of a Light‐Harvesting Antenna Formed by a Dendrimer, a Ru^II Complex, and a Nd^III Ion

Self‐Assembly of a Light‐Harvesting Antenna Formed by a Dendrimer, a Ru^II Complex, and a Nd^III Ion