labSAXS-Offline SAXS and Sample Environment Development
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Ikechukwu D.
Nwosu
,
Lujo
Matasović
,
Tárcius N.
Ramos
,
Nguyen Le
Phuoc
,
Giacomo
Londi
,
Alexander J.
Gillett
,
Daniel T. W.
Toolan
,
Charles T.
Smith
,
George F. S.
Whitehead
,
Mireille
Blanchard-Desce
,
Jonathan
Daniel
,
Mikko
Linnolahti
,
Yoann
Olivier
,
Alexander S.
Romanov
Diamond Proposal Number(s):
[40538]
Open Access
Abstract: Advanced photonic materials showing two-photon absorption (2PA) have been widely explored to develop three-dimensional imaging, micro and nanofabrication, all-optical switching, lithography on a nanoscale and many other enabling technologies. These all require nonlinear absorption chromophores with intrinsic 2PA cross-sections and long-term photo- and thermal stability. Here, we disclose the very first example of the dipolar carbene-metal-amide (CMA) material showing a enhanced 2PA cross-section up to 105 GM. Overall molecular design considerations such as extended π-conjugation (to increase polarizability), minimizing the singlet-triplet energy gap (ΔEST), and using heavy metal atoms are the first design principles to obtain bright one- and two-photon excited thermally activated delayed fluorescence (TADF) material, showing one of the highest radiative rate of 2.18·106 s-1 across CMA materials. Bright red CMA 2P-TADF material shows excellent photostability (LT50 = 3 h) to 20 mW femtosecond pulsed laser excitation at 1000 nm, encouraging further CMA exploration for future applications in advanced photonic technologies requiring third-order nonlinear optical properties.
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Feb 2026
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[31541]
Open Access
Abstract: Helical bilayer nanographenes (HBNGs) represent a promising class of materials for advanced optoelectronic and chiroptical applications, owing to their extended π-conjugation, intrinsic chirality, and tunable interlayer interactions. Here, the rational design and synthesis of bay-functionalized [7]HBNGs incorporating methoxy, diketone, and phenazine moieties is reported. These tailored modifications enable precise tuning of redox properties and significantly enhance photophysical properties, including pronounced spectral shifts, prolonged fluorescence lifetimes of up to 10 ns, and fluorescence quantum yields reaching 55%. Importantly, the resulting [7]HBNGs exhibit strong electronic circular dichroism and exceptional circularly polarized luminescence (CPL), with CPL brightness values as high as 110 M−1 cm−1. The modular, convergent strategy enables versatile late-stage modification of bay-substituted HBNGs from a single scalable precursor, streamlining access to diverse derivatives and opening new opportunities for their application in molecular electronics, chiroptical devices, and advanced optoelectronic materials.
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Jan 2026
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I10-Beamline for Advanced Dichroism - scattering
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Yuan
Huang
,
Grigore A.
Timco
,
George F. S.
Whitehead
,
Selena J.
Lockyer
,
Niklas
Geue
,
Zhibo
Qi
,
Adam
Brookfield
,
Peter
Bencok
,
Perdita E.
Barran
,
Nicholas F.
Chilton
,
Michael L.
Baker
,
Eric J. L.
Mcinnes
,
Richard E. P.
Winpenny
Diamond Proposal Number(s):
[34857, 35250]
Abstract: A rare example of a seven-membered heterometallic ring [CrIII6CeIIIF7(O2CtBu)14(THF)2] (MeCN)2 (1) and five eight-membered heterometallic rings, [nPr2NH2][CrIII6LnIII2F8(O2CtBu)17Lx] (2, Ln = Ce, L = HO2CtBu, x = 2, 3, Ln = Y, L = H2O, x = 1, 4, Ln = Gd, L = HO2CtBu, x = 1; 5, Ln = Tb, L = HO2CtBu, x = 1; 6, Ln = Yb, no L) have been synthesized and structurally characterized through X-ray diffraction. The structures consist of eight metals in an octagon, with Cr…Cr and Cr…Ln edges bridged by a fluoride and two carboxylates, while the Ln…Ln edges are bridged by a fluoride and three carboxylates. The magnetisation and susceptibility of these compounds were measured using SQUID magnetometry and electron paramagnetic resonance (EPR) spectroscopy. The magnetic data were fitted with antiferromagnetic exchange interactions between chromium(III) ions, which can be fitted in the {Cr6Y2} complex 3 and these parameters were then used to fit the magnetic properties of the {Cr6Gd2} complex 4 adding in exchange interactions between the CrIII and GdIII The magnetisation and susceptibility below 80 K of 1 and 2 were fitted on the basis of CASSCF-SO calculations at the CeIII site, and showed a weak ferromagnetic interaction between CrIII and CeIII. For 5 and 6 the magnetisation data was fitted by subtracting the data for 3 and treating the residual data as a {Tb2} and {Yb2} dimer respectively. The EPR spectra are rich, and for 3 can be modelled as due to S = 1 and S = 2 states of the {Cr6} chain. The spectra of 1 and 2 are similar, consistent with very weak interactions between the CeIII and the {Cr6} chain, while the spectra of 5 and 6 are different to that of 3, suggesting that the low temperature spectroscopy is due to a spin system in which the LnIII ions interact with the {Cr6} chain.
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Dec 2025
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labSAXS-Offline SAXS and Sample Environment Development
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Diamond Proposal Number(s):
[40538]
Open Access
Abstract: A facile, stepwise synthetic route has been developed to access symmetric double [5]helicene diimides and their planar nanographene diimide counterparts via a C-shaped asymmetric [5]helicene. The synthetic strategy employs benzannulation and Scholl reaction methodologies to achieve progressive π-extension, yielding a new class of n-type rylene diimides with reversible redox characteristics. These helical and planar diimides exhibit variable crosswise π-conjugation and structural tunability, resulting in emission wavelengths that can be tailored alongside enhanced photoluminescence quantum yields—from 12% for the S-shaped diimide, to 57% for the C-shaped intermediate, and up to 63% for the fully planar nanographene diimide. Such properties make them promising candidates for quantum photonics, particularly as single-photon emitters. Photophysical properties, including time-resolved photoluminescence and transient absorption spectroscopy, reveal correlations between molecular structure, exciton dynamics, and emission behaviour. Notably, these helical rylene diimides demonstrate high photoluminescence efficiency in the solid state, reaching up to 32%, positioning them as strong contenders for next-generation optoelectronic devices.
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Nov 2025
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I04-Macromolecular Crystallography
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Diamond Proposal Number(s):
[31850]
Abstract: The enantioselective manipulation of abundant flat (hetero)aromatic building blocks through either dearomatization, to establish new stereocenters, or cross-coupling, to construct a stereogenic axis, is an attractive means to generate three-dimensional molecular architectures. By merging the selectivity of engineered biocatalysts with the versatility of chemical synthesis, we establish a new platform for the metal-free enantioselective manipulation of sulfur-containing heteroaromatics, allowing either point or axial chirality to be set. The key to this approach is our ability to leverage the prochirality of sulfur heteroarenes; biocatalytic oxidation of benzothiophenes “switches on” reactivity and establishes a sulfur stereocenter that directs the stereochemical course of subsequent cross-couplings with non-prefunctionalized partners. Exploiting a previously unexplored mechanism, either point-to-point or point-to-axial chirality transfer from sulfur selectively delivers two different sets of chiral molecules. Enzyme evolution is used to convert a wild-type oxygenase into an efficient and selective engineered S-oxygenase capable of furnishing enantiopure benzothiophene S-oxides─little-known sulfoxides whose configurational stability we map out. Our integrated chemoenzymatic approach provides a blueprint for unlocking the potential of sulfur chirality, lying dormant in important heterocycles, to direct transformations that deliver diverse enantioenriched products.
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Nov 2025
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[31541, 39061]
Open Access
Abstract: We report a strategy for catenane synthesis that does not require persistent strong binding interactions on the components nor the addition of templates. The kinetically controlled process features the condensation of a diamine and a p-nitrophenol diester accelerated through the cavity of a crown ether. Amidation first generates a linear monoamide bearing an amine at one terminus of the chain and a p-nitrophenol ester at the other. This intermediate undergoes macrocyclization via a second amidation reaction through the crown ether cavity, resulting in interlocked macrocycles. Carrying out a similar macrocyclization reaction via ring-closing alkene metathesis (which is not accelerated through the crown ether cavity) affords macrocycle but no catenane, demonstrating that the metal-free active template synthesis enables the synthesis of catenanes despite the absence of strong intercomponent binding. A series of catenanes were synthesized in yields of up to 77%. X-Ray crystallography shows networks of weak intercomponent amide–ether hydrogen bonds in the catenanes, a rarely observed interaction adopted as a result of mechanical interlocking trapping the functional groups in close proximity.
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Jun 2025
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[31541]
Open Access
Abstract: Hydrophobic molecules lost in water systems can have significant impacts on local ecology. Notably, the discharge of unmetabolized medications, specifically hormones, and hygiene products into effluent wastewater is a pressing environmental challenge. While selective capture of these molecules has been demonstrated by metal-organic cages (MOCs), these studies typically employ an organic solvent system that does not reflect aqueous environmental conditions. In this study, we report a rare, water-soluble, tetrahedral MOC bearing hydrosolvating sulfonate moieties alongside an aromatic naphthyl spacer. The MOC encloses a large (657 Å3) cavity that can bind a range of polycyclic structures in aqueous media. Isothermal titration calorimetry measurements support guest binding being an enthalpically driven hydrophobic binding process. The synthetic strategy employed to prepare the MOC is extensible and thus serves as a promising route to a range of large, water-soluble MOCs containing hydrophobic binding cavities with exciting prospects.
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Jan 2025
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[31541]
Open Access
Abstract: We report three new polymers, based on mechanically interlocked inorganic-organic rotaxanes. They are made in very mild conditions and involve pyrimidine head groups binding to copper(II) linking units. A two-dimensional 6,3 net and a three-dimensional 10,3b net are found depending on the solvent used in the reaction.
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Aug 2024
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[23480]
Open Access
Abstract: We report the synthesis of a right-handed (Δ-stereochemistry of strand crossings) trefoil knot from a single molecular strand containing three pyrazine-2,5-dicarboxamide units adjacent to point-chiral centers and six pyridine moieties. The oligomeric ligand strand folds into an overhand (open-trefoil) knot through the assistance of coordinatively dynamic Co(II) “chaperones” that drive the formation of a three-metal-ion circular helicate. The entangled structure is kinetically locked by oxidation to Co(III) and covalently captured by ring-closing olefin metathesis to generate a trefoil knot of single topological handedness. The stereochemistry of the strand crossings in the metal-coordinated overhand knot is governed by the stereochemistry of the point-chiral carbon centers in the ligand strand. The overhand and trefoil knots were characterized by NMR spectroscopy, mass spectrometry, and X-ray crystallography. Removal of the metal ions from the knot, followed by hydrogenation of the alkene, yielded the wholly organic trefoil knot. The metal-free knot and parent ligand were investigated by circular dichroism (CD) spectroscopy. The CD spectra indicate that the topological stereochemistry of the knot has a greater effect on the asymmetry of the chromophore environment than do the point-chiral centers of the strand.
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Jul 2024
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[31541]
Abstract: Mono- and bis-salen functionalised [2]rotaxanes have been synthesised from the esterification of [2]rotaxanes containing phenol-terminated threads (salen = N,N′-bis(salicylidene)ethylenediamine). The [2]rotaxanes have general formula [RH][Cr7NiF8(O2CtBu)16], where [RH]+ is a thread with a central secondary ammonium site that templates a [Cr7NiF8(O2CtBu)16]− ring. The threads are terminated at one or both ends by carboxylic acid functionalised salen groups. The {M(salen)} groups can be free-base [M = (H+)2] or metallated [M = Cu2+, Ni2+, (VO)2+]. The [2]rotaxanes have been characterised by single crystal XRD and solid- and solution-state EPR spectroscopy. Where two paramagnetic M ions are involved [M = Cu2+ and/or (VO)2+] the [2]rotaxanes contain three electron spin S = ½ centres, since the {Cr7Ni} ring has an S = ½ ground state which is well isolated at low temperatures. These three-spin [2]rotaxanes have been characterised in solution by pulsed dipolar EPR spectroscopies (DEER, also known as PELDOR, and RIDME). The M···M and M···{Cr7Ni} interactions measured are consistent with dipolar interactions and also with the distances from single crystal XRD.
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Jun 2024
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