Publications by authors named "Oliver G Willis"

Article Synopsis
  • This article discusses the synthesis and structural characterization of chiral Tb(III) and Eu(III) complexes using two different ligands: an enantiopure diamine-based ligand and various hydroxycoumarin ligands.
  • Different substituents on the coumarin ligands lead to varying efficiencies in capturing light, which affects the luminescence of the Tb(III) and Eu(III) complexes.
  • The study includes theoretical calculations that explain the energy transfer processes in the complexes, alongside insights into how the coumarin ligands influence the chiroptical properties of the Tb(III) complexes.
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Here we report on the Magneto-Chiral Dichroism (MChD) detected through visible and near-infrared light absorption of two enantiomeric pairs of Er and Tm chiral complexes featuring a propeller-like molecular structure. The magnetic properties show typical features of isolated paramagnetic ions associated with I and H ground state terms. MChD spectroscopy shows high g dissymmetry factors of ca.

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We report the synthesis of chiral lanthanide complexes with extended π conjugation for efficient circularly polarized luminescence (CPL) via two-photon excitation (2PE). The pyridine bis-oxazoline (PyBox) core provides the chiral Ln environment, while the extension of the conjugated backbone through the pyridine 4-position with a phenylacetylene unit increases the two-photon absorption cross section. This work presents an important step toward the development of chiral systems displaying enhanced nonlinear optical properties, with potential applications in imaging and sensing, as well as in photodynamic therapy due to the selective excitation of molecules within a specific focal volume.

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The complexes [Eu(bpcd)(tta)], [Eu(bpcd)(Coum)], and [Tb(bpcd)(Coum)] [tta = 2-thenoyltrifluoroacetyl-acetonate, Coum = 3-acetyl-4-hydroxy-coumarin, and bpcd = ,'-bis(2-pyridylmethyl)--1,2-diaminocyclohexane-,'-diacetate] have been synthesized and characterized from photophysical and thermodynamic points of view. The optical and chiroptical properties of these complexes, such as the total luminescence, decay curves of the Ln(III) luminescence, electronic circular dichroism, and circularly polarized luminescence, have been investigated. Interestingly, the number of coordinated solvent (methanol) molecules is sensitive to the nature of the metal ion.

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In recent years, circularly polarized luminescence (CPL) has witnessed a renaissance, due to the increased popularity of CPL as a spectroscopic technique and greater accessibility to instrumentation. New efficient CPL emitters have been designed and many applications, ranging from electronic devices to microscopy have been proposed. Most examples of CPL are within the visible range, while few cases of near infrared (NIR) CPL active complexes are available.

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Novel chiral Er complexes based on both enantiomers of extended PrPyBox (2,6-Bis[4-isopropyl-4,5-dihydrooxazol-2-yl)]pyridine) show strong near-infrared circularly polarized luminescence (CPL) within the 1400 to 1600 nm spectral region under 450 nm irradiation. CPL activity in this region, despite being particularly rare, would open the way to potential applications in the domain, e.g.

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Article Synopsis
  • - The study presents a groundbreaking method for achieving highly efficient near-infrared (NIR) Circularly Polarized Luminescence (CPL) in water, utilizing a chiral Yb complex combined with PLGA nanoparticles.
  • - The complex [YbL(tta)] was effective in organic solvents due to its chiral ligand and sensitizing tta ligands, which provide the needed characteristics for good CPL.
  • - PLGA nanoparticles not only enhance the stability and biocompatibility of the Yb complex but also make it soluble in water, paving the way for innovative applications in NIR-CPL bio-assays.
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We carried out a study of absorption (CD) and emission (CPL) chiroptical properties in the NIR region of two sets of Yb, Tm and Er complexes. The two complexes include a symmetric, [TMG-H]Ln(BINOLate) (Ln = Yb, Tm, Er; TMG = 1,1,3,3-tetramethylguanidine; BINOLate = 1,1'-bi-2-naphtholate), and a tetrakis, symmetric, CsLn(hfbc) (Ln = Yb, Tm, Er; hfbc = 3-heptafluorobutylyrylcamphorate). The lanthanides studied gave access to three discrete energy domains, Yb (900-1040 nm), Tm (1180-1240 nm) and Er (1430-1600 nm) in which the chiroptical activity was assessed using (and for Yb complexes).

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Strongly electric fish use gradients of ions within their bodies to generate stunning external electrical discharges; the most powerful of these organisms, the Atlantic torpedo ray, can produce pulses of over 1 kW from its electric organs. Despite extensive study of this phenomenon in nature, the development of artificial power generation schemes based on ion gradients for portable, wearable, or implantable human use has remained out of reach. Previously, an artificial electric organ inspired by the electric eel demonstrated that electricity generated from ion gradients within stacked hydrogels can exceed 100 V.

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