Static and Dynamic Stereochemistry of Chiral Ln DOTA Analogues

Bari, Lorenzo Di; Salvadori, Piero

doi:10.1002/cphc.201100017

Cited by 21 publications

(20 citation statements)

References 58 publications

(94 reference statements)

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“…Chemie nonacoordinated by the four nitrogen atoms of the cyclen ring, two oxygen atoms of the carboxylate moieties, two nitrogen atoms of the indazole groups, and the bridging fluoride anion (d EuÀF = 2.27 AE 0.02 ). The coordination of the DOTA-like ligand leads to a square antiprismatic (SAP) geometry, [21] with a twisting angle of approximately 388 between the square defined by the four nitrogen atoms of the cyclen ring and the square containing the two coordinated N atoms of the indazole groups and the two coordinated O atoms of the acetate arms. In a dimer, both [EuL] monomers have the same helicity.…”

Section: Methodsmentioning

confidence: 99%

Supramolecular Luminescent Lanthanide Dimers for Fluoride Sequestering and Sensing

et al. 2014

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Lanthanide complexes (Ln = Eu, Tb, and Yb) that are based on a C 2 -symmetric cyclen scaffold were prepared and characterized. The addition of fluoride anions to aqueous solutions of the complexes resulted in the formation of dinuclear supramolecular compounds in which the anion is confined into the cavity that is formed by the two complexes. The supramolecular assembly process was monitored by UV/ Vis absorption, luminescence, and NMR spectroscopy and high-resolution mass spectrometry. The X-ray crystal structure of the europium dimer revealed that the architecture of the scaffold is stabilized by synergistic effects of the EuÀFÀEu bridging motive, p stacking interactions, and a four-component hydrogen-bonding network, which control the assembly of the two [EuL] entities around the fluoride ion. The strong association in water allowed for the luminescence sensing of fluoride down to a detection limit of 24 nm.

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Section: Methodsmentioning

confidence: 99%

Supramolecular Luminescent Lanthanide Dimers for Fluoride Sequestering and Sensing

et al. 2014

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“…[30][31][32][33] The arms can also carry a chromophore (e.g., aryl, heteroaryl, azaxanthones) able to sensitize the lanthanide ion. [30][31][32][33] The arms can also carry a chromophore (e.g., aryl, heteroaryl, azaxanthones) able to sensitize the lanthanide ion.…”

Section: Development Of Complex With High G Lum Values Macrocycles Anmentioning

confidence: 99%

“…Cyclen (L 1 ) and its smaller relative triazacyclononane (L 2 , Scheme 1) are versatile scaffolds to be functionalized at the N-atoms with arms bearing coordinating groups such as carboxylates, amides, phosphinates, and N-donors; central chirality elements can be introduced in the ring or, more frequently, on the side-arms at a carbon center. [30][31][32][33] The arms can also carry a chromophore (e.g., aryl, heteroaryl, azaxanthones) able to sensitize the lanthanide ion. These complexes have been extensively exploited as CPL probes by Parker's group (see section below).…”

Section: Development Of Complex With High G Lum Values Macrocycles Anmentioning

confidence: 99%

Lanthanide Circularly Polarized Luminescence: Bases and Applications

2014

Self Cite

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Lanthanide (III) luminescence is very characteristic: it is characterized by narrow emission bands, large Stokes shift, and a long excited state lifetime. Moreover, chiral lanthanide complexes can emit strongly circularly polarized light in a way that is almost precluded to purely organic molecules. Thanks to the sensitivity and specificity of the Ln circularly polarized luminescence (CPL) signal, CPL-active complexes are therefore employed as bioanalytical tools and other uses can be envisaged in many other fields. Here we present a brief overview of the most recently developed CPL-active lanthanide complexes and a selected few examples of their applications. We briefly discuss the main mechanisms that can rationalize the observed outstanding CPL properties of these systems, and some practical suggestions on how to measure and report data.

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“…The coordination sphere of the Yb center is completed by the presence of ac oordinated water molecule at the apical position at ad istance of 2.430 ( Figure 1). Considering the formalism used for 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-like ligands, [23] the coordination correspondst oD-llll square antiprismatic geometry,w ith average twisting angles q of 38.2 and 38.38 for Yb1 and Yb2, respectively,b etween the quadrilateral geometeries formed by the four nitrogen atoms of the macrocycle and that contain the two nitrogen atomso ft he indazolyl fragments andt he two oxygen atoms of the carboxylate functions ( Figure 3). An interesting feature of this structure is the peculiar positioning of one chloride ion in the Yb2 complex, in which the anion is located on the YbÀOH 2 pseudo-C 2 axis and interacts with four of the axial hydrogen atoms of the cyclen ring with two short (average = 2.894 )a nd two long (average = 3.296 )H ÀCl distances (see Figure S1 in the Supporting Information).…”

Section: Solid-state Structure Of the Monomeric And Dimeric Yb Complexesmentioning

confidence: 99%

Energy Transfer in Supramolecular Heteronuclear Lanthanide Dimers and Application to Fluoride Sensing in Water

Nonat

Liu

Jeannin

et al. 2018

Chemistry A European J

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In the presence of fluoride anions, [LnL(H O)] complexes, based on the coordination of a lanthanide (Ln) cation into the cavity of a C symmetrical cyclen-based ligand (L), self-assemble in water to form [(LnL) F] dimers. The crystal structures of the Yb hydrated monomer and of the fluorinated dimer are reported and analyzed to unravel the impact of the cumulative effect of weak hydrogen bonding and aromatic stacking interactions in the supramolecular assembly. The assembly is stable over a broad range of pH 3-8. A combination of equimolar amounts of Eu and Tb complexes led to a quasistatistical mixture of homo- and heterodimers, as observed by using electrospray mass spectrometry. In the heterodimers, selective excitation into the F → D absorption band of the Tb center at λ=488 nm allowed the observation of a Tb-to-Eu downshifting energy transfer, not observed in the absence of fluoride ions. Analysis of the excited-state lifetimes of the dimers within the frame of the Förster theory of energy transfer showed the transfer to have an efficiency of 34 %, with a corresponding Förster radius of 4.1 Å; thereby, unraveling the short Ln-Ln distance as a crucial parameter of the energy-transfer process. By using equimolar mixtures of the Tb and Eu complexes, the energy-transfer phenomenon was used for a ratiometric sensing of fluoride anions in water with a detection limit of 17.7 nm.

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Static and Dynamic Stereochemistry of Chiral Ln DOTA Analogues

Cited by 21 publications

References 58 publications

Supramolecular Luminescent Lanthanide Dimers for Fluoride Sequestering and Sensing

Supramolecular Luminescent Lanthanide Dimers for Fluoride Sequestering and Sensing

Lanthanide Circularly Polarized Luminescence: Bases and Applications

Energy Transfer in Supramolecular Heteronuclear Lanthanide Dimers and Application to Fluoride Sensing in Water

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