مجال
التميز
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تميز دراسي وبحثي
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البحوث المنشورة
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البحث (1):
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عنوان البحث:
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Thermally-Activated, Delayed Fluorescence
in O,B,O- and N,B,O-Strapped Boron Dipyrromethene Derivatives
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رابط إلى البحث:
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Click Here
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تاريخ النشر:
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28 February
2017
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موجز عن البحث:
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A
small series of boron dipyrromethene (BODIPY) dyes has been synthesized
whereby the boron atom is constrained in a five-membered ring formed from
either o-dihydroxypyridine or o-aminophenol. In the latter case, the amino
group has been converted into the corresponding amide derivative so as to
curtail the possibility for light-induced charge transfer from strap to
BODIPY. These compounds are weakly emissive in fluid solution but cleavage of
the strap, by treatment with a photoacid generator, restores strong
fluorescence. Surprisingly, the same compounds remain weakly fluorescent in a
rigid glass at 80 K where light-induced charge transfer is most unlikely. In
fluid solution, the fluorescence quantum yield increases with increasing
temperature due to a thermally activated step but does not correlate with the
thermodynamics for intramolecular charge transfer. It is proposed that the
strap causes rupture of the potential energy surface for the excited state,
creating traps that provide new routes by which the wave packet can return to
the ground state. Access to the trap from the excited state is reversible,
leading to the delayed emission. Analysis of the temperature dependent
emission intensities allows estimation of the kinetic parameters associated
with entering and leaving the trap.
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البحث (2):
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عنوان البحث:
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Circularly
Polarised Luminescence from Helically Chiral ‘Confused’
N,N,O,C-Boron-Chelated Dipyrromethenes (BODIPYs)
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رابط إلى البحث:
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Here
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تاريخ النشر:
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19 July
2017
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موجز عن البحث:
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Chiral organic fluorophores have significant promise
in the development of efficient emitters of circularly polarized light.
Herein we describe a helically chiral BODIPY with a hitherto unreported
N,N,O,C-boron-chelation motif, synthesised via a one-pot boron metathesis,
nucleophilic aromatic substitution (SNAr), Suzuki coupling cascade reaction.
Resolution of the racemic BODIPY, by preparative chiral HPLC, allowed
examination of the chiroptical properties of the resulting enantiomers
(λmax(abs) = 593 nm, λmax(em) = 622 nm, ε = 30,000 M-1 cm-1, ΦF = 0.49, │glum│ = 3.7×10-3 (hexane)). This is the first example of
circularly polarised emission from a non-C2 symmetric helically chiral
N,N,O,C-BODIPY and as such provides a valuable benchmark for future developments
in this compound series.
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المؤتمرات العلمية:
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المؤتمر (1):
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عنوان المؤتمر:
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The 9th Saudi Students’ Conference
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تاريخ الإنعقاد:
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13 – 14 Feb
2016
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مكان
الإنعقاد:
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Birmingham, UK
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طبيعة المشاركة:
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Poster Presentation
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عنوان المشاركة:
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Synthesis
and Photophysical Properties of New BODIPY Dyes and Analogues
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ملخص المشاركة:
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In
recent years, the design of borondifluorodipyrrolemethene dyes (BODIPY,
Figure 1) has been an area of intensive research,
and has thus attracted considerable attention because of their potential
applications towards molecular devices,
such as biological markers and fluorescence probes for reporting on
intracellular environments.1-4 The important
properties of BODIPY dyes include;
1.
High molar absorption coefficient (ε)
2.
High fluorescence quantum yield (Φflu)
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Absorption and emission in visible region (>500 nm)
4.
Chemically robust, often insensitive to polarity and pH
There
is much interest in structurally modifying the molecular backbone of BODIPY
in order to adjust the photophysical
and chemical properties.
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المؤتمر (2):
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عنوان المؤتمر:
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25th
International Symposium Synthesis in Organic Chemistry
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تاريخ الإنعقاد:
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17 – 20
July 2017
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مكان
الإنعقاد:
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Oxford, UK
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طبيعة المشاركة:
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Poster Presentation
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عنوان المشاركة:
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Synthesis and Photophysical Properties of
Novel Spiroheterocyclic BODIPY dyes
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ملخص المشاركة:
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In
recent years, the design of borondifluorodipyrromethene dyes (BODIPY) has
been an area of intensive research, and has thus attracted considerable
attention because of their potential applications towards molecular devices,
such as biological markers and fluorescence probes for reporting on
intracellular environments. The important properties of BODIPY dyes include:
high molar absorption coefficient (ε); high fluorescence quantum yield
(Φflu); absorption and emission in the visible/near IR region (> 500 nm);
chemical robustness, often being insensitive to polarity and pH.
There
is much interest in structurally modifying BODIPYs in order to adjust the
photophysical and chemical properties. Replacement of the fluorine atoms by
oxygen leads to a red-shift in the absorption and emission for simple
alcohols and for the BINOL derivative but the fluorescence is quenched in
catechol derivatives, which are non-emissive.
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