New chiral atropisomeric biphenyl diols
,
and
containing additional peripheral chiral centers with different steric bulkiness and/or electronic properties were synthesized. The X-ray crystal ...structure of
shows the formation of a supramolecular structure whereas that of
, containing additional CF
substituents, shows the formation of a monomeric structure. Diols
-
were found to be active organocatalysts in oxo-Diels-Alder reactions in which
recorded a 72% ee with trimethylacetaldehyde as a substrate.
The synthesis of a new CF₃-containing stereogenic atropisomeric pair of ortho-disubstituted biphenyl scaffold is presented. The atropisomers are surprisingly conformationally stable for isolation. ...X-ray structures show that their stability comes from an intramolecular hydrogen bond formation from their two hydroxyl groups and renders the spatial arrangement of their peripheral CF₃ and CH₃ groups very different. The synthesized stereogenic scaffold proved to be effective in catalyzing the asymmetric
-nitroso aldol reaction of enamine and nitrosobenzene. Compared to similar scaffolds without CF₃ groups, one of our atropisomer exhibits an increase in enantioselectivity in this reaction.
A new direction for white organic light-emitting devices is shown, fabricated from a novel europium complex; this single component contains a double emission center of bluish-green and red, combined ...to a give a pure white emission (CIE x = 0.34 and y = 0.35).
A cyclen backbone was utilized to study the effect of backbone rigidity on Eu(
iii
) luminescence sensitization using a 1,2-HOPO derivative and 2-thenoyltrifluoroacetonate (TTA) as chromophores. The ...restriction of molecular movement of
Eu-Cy-HOPO
brought about by the increased rigidity provided a tightly packed coordination environment for the octadentate Eu(
iii
) center which resulted in the highest overall quantum yield (30.2%) and sensitization efficiency (64.6%) among 1,2-HOPO sensitized Eu(
iii
) complexes.
Eu-Cy-HOPO
is also the first 1,2-HOPO-based lanthanide complex to emit Eu(
iii
) luminescence under two-photon excitation.
Breaking the barrier of 1,2 HOPO complexes with extremely emissive
Eu-Cy-HOPO
(overall quantum yield −30.2%) that displays two photon properties.
Inhibition of the CDK4/cyclin D complex through the substrate recruitment site on the cyclin positive regulatory subunit is recognised as being a promising anti-cancer target. Specific peptide ...sequences can be used to selectively disrupt this target, but the development of peptides as anti-tumor agents in vitro/in vivo presents several obstacles. Poor cell internalization, low sensitivity towards enzymatic degradation in vivo, and ineffectiveness in monitoring via indirect screening are all issues which must be overcome. Herein, we describe the surface functionalization of lanthanide nanoparticles with cyclin D-specific peptides to prepare novel nanomaterials (UCNPs-P
) which can target the CDK4/cyclin D complex. The nanomaterials prepared (UCNPs-P
) are cell permeable and they display parallel emission spectra in vitro and in an aqueous biological environment. They can also be used in low dose concentrations under harmless NIR excitation and emission via upconversion. Uniquely, in addition to acting as a bioimaging probe, UCNPs-P
also exhibits promising cytotoxicity towards cancer cells. In light of the aforementioned properties, the prepared functionalized nanomaterials (UCNPs-P
) offer the first real dual acting system for cyclin D imaging and simultaneous inhibition of cancer cell division.
•Mechano-optics such as tribo/high-pressure luminescence is useful in stress sensing.•First to explore the possibility of lanthanide complexes as stress sensors.•A new family of halogen EuIII ...diketonate complexes with unique optics is examined.•Shows influence of crystal packing/high-pressure compression on triboluminescence.•Diamond anvil cell show material compression induces phase transition/peak shifting.
Triboluminescence and high-pressure luminescence are stress-induced phenomena with potential in stress sensing. However, the understanding of the former process and the correlation between the two processes are lacking. In this contribution, we study the influence of the crystal packing and high pressure compression on triboluminescence by using a new family of halogen-containing EuIII diketonate complexes. The size and position of halogens determine the crystal symmetry and packing due to the change in intermolecular interactions. The role of pressure is examined by a diamond anvil cell (DAC), in which the material compression induces phase transition, peak shifting and broadening in the luminescence spectrum of the complex. The experimental results show the triboluminescence of our EuIII complexes occurs at low pressure and is a fracture-induced (mechano stress) process. This work contributes to the understanding of triboluminescence and for the first time explores the possibility of applying lanthanide complexes as stress sensors.
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A responsive neodymium NIR emission (4F3/2→4I11/2, 9/2) was recorded upon binding with singlet oxygen (KB=1.79×106M−1) via the anthracene moiety. The motif ytterbium analog served as a negative ...control with no significant NIR enhancement/quenching with the addition of the same amount of singlet oxygen. Our complex was also found to react with 1O2 generated by a known photosensitizer TMPyP inside HeLa cells without inducing cell death and display no significant cytotoxicity.
•A turn-on NIR-emissive 1O2 probe has been synthesized for potential biological applications.•It has a binding constant of 1.9×106M−1 and the emission intensity has a 5-fold increase upon binding.•The probe was also found to quench singlet oxygen in vitro generated by known photosensitizer TMPyP.
Introduction of different substituents at the 7-position of a sensitising azaxanthone group in a series of emissive Eu and Tb complexes can determine the intracellular uptake and distribution profile ...and may be linked to modulation of protein affinity.
The chemistry of lanthanide supramolecular self-assembly has received much attention with many extraordinary structures discovered due to the unique photophysical properties such as the Laporte ...forbidden f-f transition, large Stokes shift and long luminescence lifetime of lanthanides. Recent investigations have demonstrated the formation of architectures that are highly sensitive towards different stimuli, such as concentration, light, solvent and counter-anions. Various stimuli have been employed extensively for the preparation of desired supramolecular topologies with specific properties. Moreover, transformation from lower order- to higher order-supramolecular systems has also been observed by various stimuli due to the labile nature of lanthanide ions. This review summarizes recent research on the factors that govern the formation of self-assembled lanthanide supramolecules and aims to provide readers with the information required for designing functional lanthanide supramolecular systems.
The structural variation of self-assembled lanthanide supramolecular complexes which can be induced by different factors such as concentration, anion and solvent, cationic radii, stoichiometric ratio and light.
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