11 research outputs found
Ring-Opening Polymerization of THF by Aryloxo-Modified (Imido)vanadium(V)-alkyl Complexes and Ring-Opening Metathesis Polymerization by Highly Active V(CHSiMe<sub>3</sub>)(NAd)(OC<sub>6</sub>F<sub>5</sub>)(PMe<sub>3</sub>)<sub>2</sub>
Ring-opening polymerizations of THF using VÂ(NR)Â(CH<sub>2</sub>SiMe<sub>3</sub>)Â(OAr)<sub>2</sub> [R = 2,6-Me<sub>2</sub>C<sub>6</sub>H<sub>3</sub>, 1-adamantyl (Ad), Ph; Ar = 2,6-Me<sub>2</sub>C<sub>6</sub>H<sub>3</sub>, C<sub>6</sub>F<sub>5</sub>] proceeded
in a living
manner in the presence of [Ph<sub>3</sub>C]Â[BÂ(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>], affording high molecular weight polymers with low
PDI (<i>M</i><sub>w</sub>/<i>M</i><sub>n</sub>) values: the observed activity (initiation efficiency) was affected
by the arylimido and aryloxo ligands employed. A new vanadiumÂ(V)-alkylidene,
VÂ(CHSiMe<sub>3</sub>)Â(NAd)Â(OC<sub>6</sub>F<sub>5</sub>)Â(PMe<sub>3</sub>)<sub>2</sub>, prepared from VÂ(NAd)Â(CH<sub>2</sub>SiMe<sub>3</sub>)<sub>2</sub>(OC<sub>6</sub>F<sub>5</sub>) by α-hydrogen elimination
in <i>n</i>-hexane in the presence of PMe<sub>3</sub> at
25 °C, exhibited remarkable catalytic activity for ring-opening
metathesis polymerization of norbornene: the activity at 25 °C
was higher than those by the reported vanadiumÂ(V)-alkylidenes and
ordinary MoÂ(CHCMe<sub>2</sub>Ph)Â(N-2,6-<sup><i>i</i></sup>Pr<sub>2</sub>-C<sub>6</sub>H<sub>3</sub>)Â(O<sup><i>t</i></sup>Bu)<sub>2</sub>
Effect of Terminal Aryloxo Ligands in Ethylene Polymerization Using Titanatranes of the Type, [Ti(OAr){(O-2,4‑R<sub>2</sub>C<sub>6</sub>H<sub>2</sub>)‑6-CH<sub>2</sub>}<sub>3</sub>N]: Synthesis and Structural Analysis of the Heterobimetallic Complexes of Titanatranes with AlMe<sub>3</sub>
Effects of aryloxo terminal ligands and AlMe<sub>3</sub> in ethylene polymerization using a series of TiÂ(OAr)Â[{(O-2,4-R<sub>2</sub>C<sub>6</sub>H<sub>2</sub>)-6-CH<sub>2</sub>}<sub>3</sub>N]
[R = Me (<b>1</b>), <sup><i>t</i></sup>Bu (<b>2</b>); Ar = 2,6-Me<sub>2</sub>C<sub>6</sub>H<sub>3</sub> (<b>a</b>), 2,6-<sup><i>i</i></sup>Pr<sub>2</sub>C<sub>6</sub>H<sub>3</sub> (<b>b</b>), 2,6-Ph<sub>2</sub>C<sub>6</sub>H<sub>3</sub> (<b>c</b>), 2,6-F<sub>2</sub>C<sub>6</sub>H<sub>3</sub> (<b>d</b>), C<sub>6</sub>F<sub>5</sub> (<b>e</b>)] (<b>1a</b>–<b>1e</b>, <b>2d</b>,<b>2e</b>) in the
presence of methylaluminoxane (MAO) have been explored. Reactions
of <b>1b</b>,<b>1d</b>,<b>1e</b>, which showed an
increase in the activity upon addition of a small amount of AlMe<sub>3</sub>, with 1.0 equiv of AlMe<sub>3</sub> afforded heterobimetallic
Ti–Al complexes, TiMeÂ(O-2,6-<sup><i>i</i></sup>Pr<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)Â[(O-2,4-Me<sub>2</sub>C<sub>6</sub>H<sub>2</sub>-6-CH<sub>2</sub>)Â(μ<sub>2</sub>-O-2,4-Me<sub>2</sub>C<sub>6</sub>H<sub>2</sub>-6-CH<sub>2</sub>)Â(Me<sub>2</sub>Al-μ<sub>2</sub>-O-2,4-Me<sub>2</sub>C<sub>6</sub>H<sub>2</sub>-6-CH<sub>2</sub>)ÂN] (<b>3b</b>) and [TiMeÂ{(O-2,4-Me<sub>2</sub>C<sub>6</sub>H<sub>2</sub>-6-CH<sub>2</sub>)<sub>2</sub>(μ<sub>2</sub>-O-2,4-Me<sub>2</sub>C<sub>6</sub>H<sub>2</sub>-6-CH<sub>2</sub>)ÂN}]Â[Me<sub>2</sub>AlÂ(μ<sub>2</sub>-OAr)] [Ar = 2,6-F<sub>2</sub>C<sub>6</sub>H<sub>3</sub> (<b>3d</b>), C<sub>6</sub>F<sub>5</sub> (<b>3e</b>)], in moderate yields, and their structures
were determined by X-ray crystallography. In contrast, the similar
reaction of <b>1a</b> (which showed a decrease in the activity
upon addition of AlMe<sub>3</sub>) yielded [AlÂ(μ<sub>2</sub>-O-2,6-C<sub>6</sub>H<sub>3</sub>)ÂMe<sub>2</sub>]<sub>2</sub> and
TiMeÂ[{(O-2,4-Me<sub>2</sub>C<sub>6</sub>H<sub>2</sub>)-6-CH<sub>2</sub>}<sub>3</sub>N] as isolated forms: [AlÂ(μ<sub>2</sub>-OC<sub>6</sub>F<sub>5</sub>)ÂMe<sub>2</sub>]<sub>2</sub> was isolated from
the mixture in the reactions of <b>1c</b>,<b>2d</b>,<b>2e</b>. The isolated heterobimetallic complexes (<b>3b</b>,<b>3d</b>,<b>3e</b>) exhibited high catalytic activities
for ethylene polymerization in the presence of MAO, suggesting that
these bimetallic species play a role in this catalysis
Effect of Terminal Aryloxo Ligands in Ethylene Polymerization Using Titanatranes of the Type, [Ti(OAr){(O-2,4‑R<sub>2</sub>C<sub>6</sub>H<sub>2</sub>)‑6-CH<sub>2</sub>}<sub>3</sub>N]: Synthesis and Structural Analysis of the Heterobimetallic Complexes of Titanatranes with AlMe<sub>3</sub>
Effects of aryloxo terminal ligands and AlMe<sub>3</sub> in ethylene polymerization using a series of TiÂ(OAr)Â[{(O-2,4-R<sub>2</sub>C<sub>6</sub>H<sub>2</sub>)-6-CH<sub>2</sub>}<sub>3</sub>N]
[R = Me (<b>1</b>), <sup><i>t</i></sup>Bu (<b>2</b>); Ar = 2,6-Me<sub>2</sub>C<sub>6</sub>H<sub>3</sub> (<b>a</b>), 2,6-<sup><i>i</i></sup>Pr<sub>2</sub>C<sub>6</sub>H<sub>3</sub> (<b>b</b>), 2,6-Ph<sub>2</sub>C<sub>6</sub>H<sub>3</sub> (<b>c</b>), 2,6-F<sub>2</sub>C<sub>6</sub>H<sub>3</sub> (<b>d</b>), C<sub>6</sub>F<sub>5</sub> (<b>e</b>)] (<b>1a</b>–<b>1e</b>, <b>2d</b>,<b>2e</b>) in the
presence of methylaluminoxane (MAO) have been explored. Reactions
of <b>1b</b>,<b>1d</b>,<b>1e</b>, which showed an
increase in the activity upon addition of a small amount of AlMe<sub>3</sub>, with 1.0 equiv of AlMe<sub>3</sub> afforded heterobimetallic
Ti–Al complexes, TiMeÂ(O-2,6-<sup><i>i</i></sup>Pr<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)Â[(O-2,4-Me<sub>2</sub>C<sub>6</sub>H<sub>2</sub>-6-CH<sub>2</sub>)Â(μ<sub>2</sub>-O-2,4-Me<sub>2</sub>C<sub>6</sub>H<sub>2</sub>-6-CH<sub>2</sub>)Â(Me<sub>2</sub>Al-μ<sub>2</sub>-O-2,4-Me<sub>2</sub>C<sub>6</sub>H<sub>2</sub>-6-CH<sub>2</sub>)ÂN] (<b>3b</b>) and [TiMeÂ{(O-2,4-Me<sub>2</sub>C<sub>6</sub>H<sub>2</sub>-6-CH<sub>2</sub>)<sub>2</sub>(μ<sub>2</sub>-O-2,4-Me<sub>2</sub>C<sub>6</sub>H<sub>2</sub>-6-CH<sub>2</sub>)ÂN}]Â[Me<sub>2</sub>AlÂ(μ<sub>2</sub>-OAr)] [Ar = 2,6-F<sub>2</sub>C<sub>6</sub>H<sub>3</sub> (<b>3d</b>), C<sub>6</sub>F<sub>5</sub> (<b>3e</b>)], in moderate yields, and their structures
were determined by X-ray crystallography. In contrast, the similar
reaction of <b>1a</b> (which showed a decrease in the activity
upon addition of AlMe<sub>3</sub>) yielded [AlÂ(μ<sub>2</sub>-O-2,6-C<sub>6</sub>H<sub>3</sub>)ÂMe<sub>2</sub>]<sub>2</sub> and
TiMeÂ[{(O-2,4-Me<sub>2</sub>C<sub>6</sub>H<sub>2</sub>)-6-CH<sub>2</sub>}<sub>3</sub>N] as isolated forms: [AlÂ(μ<sub>2</sub>-OC<sub>6</sub>F<sub>5</sub>)ÂMe<sub>2</sub>]<sub>2</sub> was isolated from
the mixture in the reactions of <b>1c</b>,<b>2d</b>,<b>2e</b>. The isolated heterobimetallic complexes (<b>3b</b>,<b>3d</b>,<b>3e</b>) exhibited high catalytic activities
for ethylene polymerization in the presence of MAO, suggesting that
these bimetallic species play a role in this catalysis
Synthesis and Structural Analysis of (Imido)Vanadium(V) Complexes Containing Chelate (Anilido)Methyl-imine Ligands: Ligand Effect in Ethylene Dimerization
A series
of (imido)vanadium dichlorido complexes containing chelate anionic
donor ligands of the type, VCl<sub>2</sub>(L)Â(NR) [R = 1-adamantyl
(Ad), L = 2-(2,6-Me<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)ÂNCH<sub>2</sub>(C<sub>9</sub>H<sub>6</sub>N) (<b>2</b>), 8-(2,6-Me<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)ÂNCH<sub>2</sub>(C<sub>9</sub>H<sub>6</sub>N) (<b>3</b>); L = 2-(2,6-R′<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)ÂNCH<sub>2</sub>(C<sub>5</sub>H<sub>4</sub>N),
R = 2-MeC<sub>6</sub>H<sub>4</sub>, R′ = Me (<b>4a</b>), <sup><i>i</i></sup>Pr (<b>4b</b>); L = 2-(2,6-Me<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)ÂNCH<sub>2</sub>(C<sub>5</sub>H<sub>4</sub>N), R = 4-MeC<sub>6</sub>H<sub>4</sub> (<b>5</b>), 3,5-Me<sub>2</sub>C<sub>6</sub>H<sub>3</sub> (<b>6</b>)], have been prepared
and identified. The reactions with ethylene by <b>2</b>,<b>3</b> in the presence of methylaluminoxane (MAO) afforded a mixture
of high molecular weight polyethylene and oligomers. Reactions with
ethylene by VCl<sub>2</sub>[2-(2,6-R′<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)ÂNCH<sub>2</sub>(C<sub>5</sub>H<sub>4</sub>N)]Â(NAd)
(<b>1a,b</b>), <b>4</b>–<b>6</b> afforded
1-butene with high selectivities (>92%), and the activities by <b>4a</b>,<b>b</b> are at the same level as those in <b>1a</b>,<b>b</b>. The activities by <b>5</b>,<b>6</b> were lower than <b>4a</b>,<b>b</b> and were
at the same level of that by VCl<sub>2</sub>[2-(2,6-Me<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)ÂNCH<sub>2</sub>(C<sub>5</sub>H<sub>4</sub>N)]Â(NPh). These results thus suggest that both the chelate anionic
donor and the imido ligands play a role for both the activity and
the selectivity
Synthesis and Structural Analysis of (Imido)Vanadium(V) Complexes Containing Chelate (Anilido)Methyl-imine Ligands: Ligand Effect in Ethylene Dimerization
A series
of (imido)vanadium dichlorido complexes containing chelate anionic
donor ligands of the type, VCl<sub>2</sub>(L)Â(NR) [R = 1-adamantyl
(Ad), L = 2-(2,6-Me<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)ÂNCH<sub>2</sub>(C<sub>9</sub>H<sub>6</sub>N) (<b>2</b>), 8-(2,6-Me<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)ÂNCH<sub>2</sub>(C<sub>9</sub>H<sub>6</sub>N) (<b>3</b>); L = 2-(2,6-R′<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)ÂNCH<sub>2</sub>(C<sub>5</sub>H<sub>4</sub>N),
R = 2-MeC<sub>6</sub>H<sub>4</sub>, R′ = Me (<b>4a</b>), <sup><i>i</i></sup>Pr (<b>4b</b>); L = 2-(2,6-Me<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)ÂNCH<sub>2</sub>(C<sub>5</sub>H<sub>4</sub>N), R = 4-MeC<sub>6</sub>H<sub>4</sub> (<b>5</b>), 3,5-Me<sub>2</sub>C<sub>6</sub>H<sub>3</sub> (<b>6</b>)], have been prepared
and identified. The reactions with ethylene by <b>2</b>,<b>3</b> in the presence of methylaluminoxane (MAO) afforded a mixture
of high molecular weight polyethylene and oligomers. Reactions with
ethylene by VCl<sub>2</sub>[2-(2,6-R′<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)ÂNCH<sub>2</sub>(C<sub>5</sub>H<sub>4</sub>N)]Â(NAd)
(<b>1a,b</b>), <b>4</b>–<b>6</b> afforded
1-butene with high selectivities (>92%), and the activities by <b>4a</b>,<b>b</b> are at the same level as those in <b>1a</b>,<b>b</b>. The activities by <b>5</b>,<b>6</b> were lower than <b>4a</b>,<b>b</b> and were
at the same level of that by VCl<sub>2</sub>[2-(2,6-Me<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)ÂNCH<sub>2</sub>(C<sub>5</sub>H<sub>4</sub>N)]Â(NPh). These results thus suggest that both the chelate anionic
donor and the imido ligands play a role for both the activity and
the selectivity
Electrochemistry, Charge Transfer Properties, and Theoretical Investigation of a Macrocyclic Boronate Dimer of 1′,1‴-Biferrocenediboronic Acid and Related Ferrocenyl Boronate Complexes
The
target compound of this study is the macrocyclic tetraferrocenyl
boronate complex <b>CP</b><sub><b>2</b></sub><b>C</b>, which has two types of metal connections (i.e., Fe<sup>II</sup>–CpCp–Fe<sup>II</sup> and Fe<sup>II</sup>–CpBO<sub>2</sub>C<sub>5</sub>H<sub>8</sub>O<sub>2</sub>BCp–Fe<sup>II</sup> (Cp = cyclopentadienyl)) in the finite structure (<b>C</b> = 1′,1‴-biferrocenediboronic acid, <b>P</b> =
pentaerythritol). The electrochemical behavior of <b>CP</b><sub><b>2</b></sub><b>C</b> in dichloromethane was compared
with that of the related boronate complexes <b>APA</b> and <b>BP</b><sub><b>2</b></sub><b>B</b>, having Fe<sup>II</sup>–CpBO<sub>2</sub>C<sub>5</sub>H<sub>8</sub>O<sub>2</sub>BCp–Fe<sup>II</sup>, and <b>Cester</b>, having Fe<sup>II</sup>–CpCp–Fe<sup>II</sup>. The effects of the counteranion of the supporting electrolyte
on potential splitting revealed that <b>CP</b><sub><b>2</b></sub><b>C</b> exhibits an intrabiferrocenyl through-bond interaction
through the CpCp ligand, as well as an interbiferrocenyl through-space
interaction across the CpBO<sub>2</sub>C<sub>5</sub>H<sub>8</sub>O<sub>2</sub>BCp ligand. Chemical oxidation of <b>CP</b><sub><b>2</b></sub><b>C</b> with AgSbF<sub>6</sub> produced the
one- and two-electron-oxidized species <b>CP</b><sub><b>2</b></sub><b>C</b><sup><b>+</b></sup> and <b>CP</b><sub><b>2</b></sub><b>C</b><sup><b>2+</b></sup>, which exhibit intervalence charge transfer transition bands through
the CpCp ligand in the near-infrared region, giving one and two valence
isomers, respectively. DFT calculations revealed the charge distribution
of <b>CP</b><sub><b>2</b></sub><b>C</b><sup><b>2+</b></sup>; the positive charges are localized on each biferrocenium
unit, especially on the longer diagonal, to minimize the electrostatic
repulsion over the CpBO<sub>2</sub>C<sub>5</sub>H<sub>8</sub>O<sub>2</sub>BCp ligand
Electrochemistry, Charge Transfer Properties, and Theoretical Investigation of a Macrocyclic Boronate Dimer of 1′,1‴-Biferrocenediboronic Acid and Related Ferrocenyl Boronate Complexes
The
target compound of this study is the macrocyclic tetraferrocenyl
boronate complex <b>CP</b><sub><b>2</b></sub><b>C</b>, which has two types of metal connections (i.e., Fe<sup>II</sup>–CpCp–Fe<sup>II</sup> and Fe<sup>II</sup>–CpBO<sub>2</sub>C<sub>5</sub>H<sub>8</sub>O<sub>2</sub>BCp–Fe<sup>II</sup> (Cp = cyclopentadienyl)) in the finite structure (<b>C</b> = 1′,1‴-biferrocenediboronic acid, <b>P</b> =
pentaerythritol). The electrochemical behavior of <b>CP</b><sub><b>2</b></sub><b>C</b> in dichloromethane was compared
with that of the related boronate complexes <b>APA</b> and <b>BP</b><sub><b>2</b></sub><b>B</b>, having Fe<sup>II</sup>–CpBO<sub>2</sub>C<sub>5</sub>H<sub>8</sub>O<sub>2</sub>BCp–Fe<sup>II</sup>, and <b>Cester</b>, having Fe<sup>II</sup>–CpCp–Fe<sup>II</sup>. The effects of the counteranion of the supporting electrolyte
on potential splitting revealed that <b>CP</b><sub><b>2</b></sub><b>C</b> exhibits an intrabiferrocenyl through-bond interaction
through the CpCp ligand, as well as an interbiferrocenyl through-space
interaction across the CpBO<sub>2</sub>C<sub>5</sub>H<sub>8</sub>O<sub>2</sub>BCp ligand. Chemical oxidation of <b>CP</b><sub><b>2</b></sub><b>C</b> with AgSbF<sub>6</sub> produced the
one- and two-electron-oxidized species <b>CP</b><sub><b>2</b></sub><b>C</b><sup><b>+</b></sup> and <b>CP</b><sub><b>2</b></sub><b>C</b><sup><b>2+</b></sup>, which exhibit intervalence charge transfer transition bands through
the CpCp ligand in the near-infrared region, giving one and two valence
isomers, respectively. DFT calculations revealed the charge distribution
of <b>CP</b><sub><b>2</b></sub><b>C</b><sup><b>2+</b></sup>; the positive charges are localized on each biferrocenium
unit, especially on the longer diagonal, to minimize the electrostatic
repulsion over the CpBO<sub>2</sub>C<sub>5</sub>H<sub>8</sub>O<sub>2</sub>BCp ligand
Electrochemistry, Charge Transfer Properties, and Theoretical Investigation of a Macrocyclic Boronate Dimer of 1′,1‴-Biferrocenediboronic Acid and Related Ferrocenyl Boronate Complexes
The
target compound of this study is the macrocyclic tetraferrocenyl
boronate complex <b>CP</b><sub><b>2</b></sub><b>C</b>, which has two types of metal connections (i.e., Fe<sup>II</sup>–CpCp–Fe<sup>II</sup> and Fe<sup>II</sup>–CpBO<sub>2</sub>C<sub>5</sub>H<sub>8</sub>O<sub>2</sub>BCp–Fe<sup>II</sup> (Cp = cyclopentadienyl)) in the finite structure (<b>C</b> = 1′,1‴-biferrocenediboronic acid, <b>P</b> =
pentaerythritol). The electrochemical behavior of <b>CP</b><sub><b>2</b></sub><b>C</b> in dichloromethane was compared
with that of the related boronate complexes <b>APA</b> and <b>BP</b><sub><b>2</b></sub><b>B</b>, having Fe<sup>II</sup>–CpBO<sub>2</sub>C<sub>5</sub>H<sub>8</sub>O<sub>2</sub>BCp–Fe<sup>II</sup>, and <b>Cester</b>, having Fe<sup>II</sup>–CpCp–Fe<sup>II</sup>. The effects of the counteranion of the supporting electrolyte
on potential splitting revealed that <b>CP</b><sub><b>2</b></sub><b>C</b> exhibits an intrabiferrocenyl through-bond interaction
through the CpCp ligand, as well as an interbiferrocenyl through-space
interaction across the CpBO<sub>2</sub>C<sub>5</sub>H<sub>8</sub>O<sub>2</sub>BCp ligand. Chemical oxidation of <b>CP</b><sub><b>2</b></sub><b>C</b> with AgSbF<sub>6</sub> produced the
one- and two-electron-oxidized species <b>CP</b><sub><b>2</b></sub><b>C</b><sup><b>+</b></sup> and <b>CP</b><sub><b>2</b></sub><b>C</b><sup><b>2+</b></sup>, which exhibit intervalence charge transfer transition bands through
the CpCp ligand in the near-infrared region, giving one and two valence
isomers, respectively. DFT calculations revealed the charge distribution
of <b>CP</b><sub><b>2</b></sub><b>C</b><sup><b>2+</b></sup>; the positive charges are localized on each biferrocenium
unit, especially on the longer diagonal, to minimize the electrostatic
repulsion over the CpBO<sub>2</sub>C<sub>5</sub>H<sub>8</sub>O<sub>2</sub>BCp ligand
Conglomerate, Racemate, and Achiral Crystals of Polymetallic Europium(III) Compounds of Bis- or Tris-β-diketonate Ligands and Circularly Polarized Luminescence Study
This work reports
(a) conglomerate and racemic crystal structures
of [(Δ,Δ,Δ,Δ,Δ,Δ)- or/and (Λ,Λ,Λ,Λ,Λ,Λ)-EuIII6(TTP)8(OH2)6Na4]n coordination polymers,
(b) racemic crystal structures of (Δ,Δ,Δ,Δ)-/(Λ,Λ,Λ,Λ)-EuIII4(TTP)4(bipy)4(MEK)2(OH2)2 tetrahedral clusters, and (c)
the achiral crystal structure of the [EuIII2(BTP)4(OH2)2Na2]n coordination polymer (where BTP = dianionic
bis-β-diketonate, TTP = trianionic tris-β-diketonate, and bipy = 2,2′-bipyridine). The screw coordination
arrangement of the TTP ligand has led to the formation of homoconfigurational
racemic EuIII products. The conglomerate crystallization
of [EuIII6(TTP)8(OH2)6Na4]n appears to be
caused by the presence of the sodium, Na+ counterions,
and interactions between oxygen atoms and the trifluoromethyl unit
of the TTP ligand and Na+ ions. All the EuIII compounds exhibit characteristic red luminescence (5D0 → 7FJ, J =
0–4) in solution or in the solid crystalline state. Circularly
polarized luminescence (CPL) was observed in the chiral EuIII6(TTP)8(OH2)6Na4]n species, displaying a |glum| value in the range of 0.15 to 0.68 at the 5D0 → 7F1 emission band. Subtle
changes of the [EuIII6(TTP)8(OH2)6Na4]n structure
which may be due to selection of twinned crystals or crystals that
do not correspond to a perfect spontaneous resolution, are considered
to be responsible for the variation in the observed CPL values
Excited State Engineering in Ag<sub>29</sub> Nanocluster through Peripheral Modification with Silver(I) Complexes for Bright Near-Infrared Photoluminescence
The optical property of an ionic metal nanocluster (NC)
is affected
by the ionic interaction with counter ions. Here, we report that the
modification of trianionic [Ag29(BDT)12(TPP)4]3– NC (BDT: 1.3-benzenedithiol; TPP: triphenylphosphine)
with silver(I) complexes led to the intense photoluminescence (PL)
in the near-infrared (NIR) region. The binding of silver(I) complexes
to the peripheral region of Ag29 NC is confirmed by the
single-crystal X-ray diffraction (SCXRD) measurement, which is further
supported by electrospray ionization mass spectrometry (ESI-MS) and
nuclear magnetic resonance (NMR) spectroscopy. The change of excited-state
dynamics by the binding of silver(I) complexes is discussed based
on the results of a transient absorption study as well as temperature-dependent
PL spectra and PL lifetime measurements. The modification of Ag29 NCs with cationic silver(I) complexes is considered to give
rise to a triplet excited state responsible for the intense NIR PL.
These findings also afford important insights into the origin of the
PL mechanism as well as the possible light-driven motion in Ag29-based NCs