“…Consistent with previous literature, the Ln ions were found to incorporate at relatively low percentages that do not correspond to the amount added to the reaction mixture. 24 For the Eu-doped samples, Bi 1.98 Eu 0.02 -1 and Bi 1.8 Eu 0.2 -1, the incorporation of Ln ions is not linear with the reaction concentration because a 10-fold increase in the Eu concentration in the reaction mixture led to only a 3.4-fold increase in Eu in the structure.…”
Section: ■ Introductionmentioning
confidence: 95%
“…Bi-based materials, in particular, are an attractive target for materials design. The global availability (i.e., low cost) and relatively low toxicity of Bi compared to other heavy elements, coupled with its unique lone-pair electron effects, flexible coordination geometries, and potential for structural regulation of the photophysical properties, are highly desirable. − Bi 3+ exhibits a closed-shell electron configuration like the d 10 metal ions, with the general electron configuration of n d 10 ( n + 1)s 2 , making it amenable for achieving ligand-based emission in hybrid systems. − Indeed, the incorporation of heavy elements into π-conjugated materials is known to enhance the probability of accessing the triplet state of organic emitters, and hence phosphorescence, by increasing the rate of intersystem crossing (ISC). − The development of stable, long-lived phosphorescent emitters utilizing Bi may thus provide new design strategies for luminescent materials, with applications in light-emitting diodes and bioimaging. , Additionally, the broadband emission of Bi-based materials, coupled with the linelike emission of metals such as the Ln ions, provides further opportunities for dual emission, the possibility of color tuning, and/or white-light emission. − …”
A new bismuth(III)−organic compound, Hphen-[Bi 2 (HPDC) 2 (PDC) 2 (NO 3 )]•4H 2 O (Bi-1; PDC = 2,6-pyridinedicarboxylate and phen = 1,10-phenanthroline), was synthesized, and the structure was determined by single-crystal X-ray diffraction. The compound was found to display bright-bluegreen phosphorescence in the solid state under UV irradiation, with a luminescent lifetime of 1.776 ms at room temperature. The room temperature and low-temperature (77 K) emission spectra exhibited the vibronic structure characteristic of Hphen phosphorescence. Time-dependent density functional theory studies showed that the excitation pathway arises from an energy transfer from the dimeric structural unit to Hphen, with participation from a ninecoordinate Bi center. The triplet state of Hphen is believed to be stabilized via supramolecular interactions, which, when coupled with the heavy-atom effect induced by Bi, leads to the observed longlived luminescence. The compound displayed a solid-state quantum yield of over 27%. To the best of our knowledge, this is the first such compound to exhibit phenanthrolinium phosphorescence with such long-lived, room temperature lifetimes in the solid state. To further elucidate the energy-transfer mechanism, Ln 3+ (Ln = Eu, Tb, Sm) ions were successfully doped into the parent compound, and the resulting materials exhibited dual emission from Hphen and Ln, promoting tunability of the emission color.
“…Consistent with previous literature, the Ln ions were found to incorporate at relatively low percentages that do not correspond to the amount added to the reaction mixture. 24 For the Eu-doped samples, Bi 1.98 Eu 0.02 -1 and Bi 1.8 Eu 0.2 -1, the incorporation of Ln ions is not linear with the reaction concentration because a 10-fold increase in the Eu concentration in the reaction mixture led to only a 3.4-fold increase in Eu in the structure.…”
Section: ■ Introductionmentioning
confidence: 95%
“…Bi-based materials, in particular, are an attractive target for materials design. The global availability (i.e., low cost) and relatively low toxicity of Bi compared to other heavy elements, coupled with its unique lone-pair electron effects, flexible coordination geometries, and potential for structural regulation of the photophysical properties, are highly desirable. − Bi 3+ exhibits a closed-shell electron configuration like the d 10 metal ions, with the general electron configuration of n d 10 ( n + 1)s 2 , making it amenable for achieving ligand-based emission in hybrid systems. − Indeed, the incorporation of heavy elements into π-conjugated materials is known to enhance the probability of accessing the triplet state of organic emitters, and hence phosphorescence, by increasing the rate of intersystem crossing (ISC). − The development of stable, long-lived phosphorescent emitters utilizing Bi may thus provide new design strategies for luminescent materials, with applications in light-emitting diodes and bioimaging. , Additionally, the broadband emission of Bi-based materials, coupled with the linelike emission of metals such as the Ln ions, provides further opportunities for dual emission, the possibility of color tuning, and/or white-light emission. − …”
A new bismuth(III)−organic compound, Hphen-[Bi 2 (HPDC) 2 (PDC) 2 (NO 3 )]•4H 2 O (Bi-1; PDC = 2,6-pyridinedicarboxylate and phen = 1,10-phenanthroline), was synthesized, and the structure was determined by single-crystal X-ray diffraction. The compound was found to display bright-bluegreen phosphorescence in the solid state under UV irradiation, with a luminescent lifetime of 1.776 ms at room temperature. The room temperature and low-temperature (77 K) emission spectra exhibited the vibronic structure characteristic of Hphen phosphorescence. Time-dependent density functional theory studies showed that the excitation pathway arises from an energy transfer from the dimeric structural unit to Hphen, with participation from a ninecoordinate Bi center. The triplet state of Hphen is believed to be stabilized via supramolecular interactions, which, when coupled with the heavy-atom effect induced by Bi, leads to the observed longlived luminescence. The compound displayed a solid-state quantum yield of over 27%. To the best of our knowledge, this is the first such compound to exhibit phenanthrolinium phosphorescence with such long-lived, room temperature lifetimes in the solid state. To further elucidate the energy-transfer mechanism, Ln 3+ (Ln = Eu, Tb, Sm) ions were successfully doped into the parent compound, and the resulting materials exhibited dual emission from Hphen and Ln, promoting tunability of the emission color.
“…Water molecules are known to quench the fluorescence due to possessing OH moieties with high-energy vibrations. 69,70 This water-assisted quenching mechanism originates in the fluorophore electronic excitation being resonantly transferred to the overtones and combination transitions of high-frequency stretching modes of the water molecules. The same effect is observed in the case of HgCl (2).…”
Eighteen organic-inorganic hybrid materials (OIHMs) with d- and p-block metal halides (chlorides and bromides) and 8-hydroxyquinoline as organic part, as well as 8-hydroxyquinoline chloride and bromide salts, have been synthesized...
“…Therein, the photolysis of BiCl 3 in benzene was studied, which resulted in the formation of chlorobenzene and bismuth metal under 290 nm irradiation . Over the years, investigations on the photochemical and photoluminescent behavior of different bismuth complexes have followed. However, it is important to note that the observed photochemical reactions were reported in the context of photodecomposition that have not been transferred to catalytic applications in organic synthesis.…”
Ligand-to-metal charge transfer (LMCT)
photocatalysis
allows the
activation and synthetic utilization of halides and other heteroatoms
in metal complexes. Many metals are known to undergo LMCT but so far
remain underutilized in the field of catalysis. A screening assay
identifying LMCT activity helped us to expand this catalysis concept
to the application of bismuth LMCT in organic radical coupling reactions.
We demonstrate its application for the generation of two different
radicals (chlorine and carboxyl) in net-oxidative as well as redox-neutral
photochemical reactions. Detailed investigation of the model Giese-type
coupling revealed BiCl4
– and BiCl5
2– as catalytically active bismuth species
under 385 nm irradiation. Combined cyclic voltammetry and UV–vis
studies gave insight into the reactivity of the highly reactive bismuth(II)
catalyst fragment.
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