Samarium complexes with the highest quantum yields to date have been synthesized, and their luminescence properties were studied in 12 solvents. Sensitization via a nontriplet intraligand ...charge-transfer pathway was also successfully demonstrated in solution states with good quantum yields.
Triboluminescence (TL) is a form of light emission induced upon mechanical forces on the material. However, our understanding of this phenomenon is still unclear and more examples are therefore ...needed in order to elucidate its mechanism. In this work, two types of TL complexes, Eu(
-dbm-Cl₂)₃phen and Eu(
-dbm-Cl₂)₃phen, which also displays aggregation-induced emission (AIE) were synthesized and investigated for its photo-physical and crystal structural properties. These complexes were crystallized in a centro-symmetric space group
2₁/
, and remarkably, displayed TL upon grinding that may be due to the presence of extensive π···π, C-H···π and C-H···Cl-C interactions in the close molecular packing of its structure. This rare example deviates from the widely accepted mechanism of TL, hence widening the scope of our understanding in the area.
Bioorthogonal chemistry is a rising field investigating chemical reactions in physiological environments with high specificity. However, only very few examples concern the real‐time monitoring of ...bioorthogonal reactions by luminescence or magnetic relaxivity. To fill this gap, herein, the Eu(III)‐based complex is reported as a small‐molecule optical imaging agent which shows off–on luminescence and provides quantitative analysis for the progress of the bioorthogonal reaction. The characteristic signal is achieved through efficient energy harvesting and transferring to the Eu(III) from the expansion of the conjugated system of the antenna. Moreover, the gadolinium(III) counterpart significantly enhances relaxivity in magnetic resonance imaging (MRI) after the bioorthogonal reaction since the rotational correlation time is shortened with increased molecular sizes and weights.
A novel lanthanide‐complex conjugation model incorporating different metal cores (La, Eu, and Gd) and biomolecules can serve as a rare example of achieving real‐time monitoring of bioorthogonal reactions by off–on luminescent signals from Eu(III). The Gd(III)‐analog is equally promising where much enhanced molecular relaxivity suggests the potential of our designs in multimodal diagnosis.
Shining examples: ChemPlusChem is pleased to present its Special Collection on Fluorescent Biomolecules and their Building Blocks, organized in collaboration with Guest Editors Ka‐Leung Wong, ...Chi‐Sing Lee, and Ga‐Lai Law. This collection features a top range of contributions related to the development and use of new fluorescent reporters, including lanthanide‐ and transition‐metal‐based probes, fluorescent nucleoside analogues, and fluorescent nanocelluloses.
A series of water-soluble chiral cyclen-based chelators with chemical handles for selective targeting have been synthesized (cyclen = 1,4,7,10-Tetraazacyclododecane). Optical studies, relaxivity ...measurements, and competitive titrations were performed to show the versatility of these chiral chelators. The complexations of L3, L4, and L5 with Lu3+, Y3+, Sc3+, and Cu2+ were successfully demonstrated in around 90% to 100% yields. Efficient and rapid radiolabeling of L5 with 177Lu was achieved under mild conditions with 96% yield. The chelators exhibit near quantitative labeling efficiencies with a wide range of radiometal ions, which are promising for the development of targeting specific radiopharmaceutical and molecular magnetic resonance imaging contrast agents.
The development of a europium(iii) based probe (EuL1) for the detection of Cu(ii) ions and hydrogen sulphide is presented. With the addition of Cu(ii) ions, EuL1 displayed the greatest quenching ...among the other cations examined. The binding constant was 74,026 ± 2899 M(-1). Once combined with Cu(ii) ions, EuL1Cu demonstrated high specificity for hydrogen sulfide compared to other organic and inorganic sulfur compounds. EuL1Cu exhibited an on-off-on type luminescence change with the alternate addition of Cu(ii) ions and H2S along with reversible forming-separating of the complex.
In this work, the synthesis, stability studies, and photophysical properties of a bis‐cyclometalated iridium(III) complex with a push‐pull ancillary ligand are presented. The complex was found to ...localize in mitochondria and could be excited by a two‐photon excitation process under a confocal laser scanning microscope.
In this work, the synthesis, stability studies and photophysical properties of a bis‐cyclometalated iridium(III) complex with a push‐pull ancillary ligand are presented. The complex was found to localize in mitochondria and could be excited by a two‐photon excitation process under a confocal laser scanning microscope.
We report the preparation and new insight into photophysical properties of luminescent hydroxypyridonate complexes M(III)L(-) (M = Eu or Sm) of the versatile 3,4,3-LI(1,2-HOPO) ligand (L). We report ...the crystal structure of this ligand with Eu(III) as well as insights into the coordination behavior and geometry in solution by using magnetic circular dichroism. In addition TD-DFT calculations were used to examine the excited states of the two different chromophores present in the 3,4,3-LI(1,2-HOPO) ligand. We find that the Eu(III) and Sm(III) complexes of this ligand undergo a transformation after in situ preparation to yield complexes with higher quantum yield (QY) over time. It is proposed that the lower QY in the in situ complexes is not only due to water quenching but could also be due to a lower degree of f-orbital overlap (in a kinetic isomer) as indicated by magnetic circular dichroism measurements.
Construction of lanthanide heterometallic complex is important for engineering multifunction molecular containers. However, it remains a challenge because of the similar ionic radii of lanthanides. ...Herein we attempt to prepare chiral lanthanide heterometallic tetrahedra. Upon crystallization with a mixture of Eu
L
and Ln
L
(Ln=Gd, Tb and Dy) helicates, a mixture of heterometallic Eu
Ln'
(L
) (n=0-4) tetrahedra was prepared. Selective formation of heterometallic tetrahedron was observed as MS deconvolution results deviated from statistical results. The formation of heterometallic tetrahedron was found to be sensitive to ionic radii as well as the ratio of the two helicates used in the crystallization.
Epstein-Barr virus (EBV) infects more than 90% of humans worldwide and establishes lifelong latent infection in the hosts. It is closely associated with endemic forms of a wide range of human cancers ...and directly contributes to the formation of some. Despite its critical role in cancer development, no EBV- or EBV latent protein-targeted therapy is available. The EBV-encoded latent protein, Epstein-Barr nuclear antigen 1 (EBNA1), is expressed in all EBV-associated tumors and acts as the only latent protein in some of these tumors. This versatile protein functions in the maintenance, replication, and segregation of the EBV genome and can therefore serve as an attractive therapeutic target to treat EBV-associated cancers. In the last decades, efforts have been made for designing specific EBNA1 inhibitors to decrease EBNA1 expression or interfere with EBNA1-dependent functions. In this review, we will briefly introduce the salient features of EBNA1, summarize its functional domains, and focus on the recent developments in the identification and design of EBNA1 inhibitors related to various EBNA1 domains as well as discuss their comparative merits.
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