I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[42583]
Open Access
Abstract: Ethane-selective sorbents can enable single-step purification of ethylene but remain elusive to date. We report a Zn-based metal-organic framework (ZAI-3N) decorated with amino-based ‘molecular gates’ that exhibit highly selective adsorption of C2H6 over C2H4. Upon activation, ZAI-3N (zinc-adenine-3-aminoisonicotinic acid) features contractions of both Zn─N bonds and pores (from 2.009 to 1.914 Å and from 4.88 × 3.40 to 3.47 × 2.75 Å2, respectively). At 313 K and 1 bar, ZAI-3N exhibits an exceptional ratio of 10.6 for C2H6/C2H4 uptakes and a benchmark selectivity of 11.7, outperforming state-of-the-art porous solids. Synchrotron X-ray powder diffraction and modelling reveal that the methyl group in C2H6 can trigger amino rotation and facilitate gate opening, while π-electrons of C2H4 hinder such a process with a notably increased barrier (～5 and 11 kJ mol−1, respectively). Dynamic breakthrough experiments confirm the efficient separation of C2H6/C2H4 (v/v = 5/5 and 1/9), affording C2H4 with a high purity of 99.4% in single step with excellent recyclability and an C2H4 productivity of 10.3 mL g−1. This work demonstrates the judicious choice of ‘molecular gate’ as a promising protocol for challenging industrial gas separations.
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Apr 2026
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[35882]
Open Access
Abstract: A tetramine subcomponent featuring 1,5-naphthylene arms was designed to exhibit extensive secondary interactions when assembled around stereochemically flexible tetracoordinate CuI ions. Using 6-methyl-2-formylpyridine, a [CuI12L6]12+ pseudo-hexagonal prismatic cage formed, stabilized by 29–32 C─H···π interactions and 12 arene stacking interactions. Replacing the aldehyde component with 3-methyl-2-formylpyridine introduced steric clashes that partially prevented these interactions, leading instead to the formation of a [CuI8L4]8+ rectangular open prism. The system exhibited structural interconversion: adding 6-methyl-2-formylpyridine to the [CuI8L4]8+ cage transformed it into the [CuI12L6]12+ structure through selective displacement of 8 out of 24 aldehyde residues per cage, matching the number of sterically-hindered positions predicted from structural analysis. This work demonstrates rational control over cage architecture through fine-tuning of steric factors and intermolecular interactions, providing design principles for generating diverse structures from identical building blocks.
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Apr 2026
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I04-Macromolecular Crystallography
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Anissa
Haim
,
Sandra
Liebscher
,
Rasmus
Klintrot
,
Lorenzo
Vallino
,
Marcelo
Masman
,
Andreas H.
Simon
,
Marianne
Hahn
,
Sven
Hennig
,
Saskia
Neubacher
,
Frank
Bordusa
,
Tom N.
Grossmann
Diamond Proposal Number(s):
[34465]
Abstract: Enzymes are powerful catalysts for selective transformations but often suffer from limited stability under operational conditions such as elevated temperature or the presence of organic cosolvents. While sequence-based strategies have been widely used to improve stability, chemical protein engineering enables modifications beyond the natural amino acid repertoire thereby offering complementary routes to tailor enzyme function and robustness. Here, we apply the in situ cyclization of proteins (INCYPRO) to a D-stereospecific hydrolase with low intrinsic thermal stability. Site-specific macrocyclization substantially improved resilience to heat and cosolvent stress. Unexpectedly, we discovered a cross-linked protein dimer with enhanced activity and thermal stability. The complex structure was confirmed by x-ray crystallography. Extending the INCYPRO approach, we engineered a multicyclic enzyme dimer with a total of four cross-linking sites, which not only retained high activity under benign conditions but also outperformed the wild-type under stress. Our findings establish protein macrocyclization as a versatile strategy to stabilize both monomeric and multimeric enzymes, providing a powerful route to robust biocatalysts.
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Mar 2026
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B23-Circular Dichroism
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Diamond Proposal Number(s):
[37842]
Open Access
Abstract: Chiral materials that manipulate circularly polarised light have burgeoning applications across optoelectronics, sensing and information encoding, yet the functionality of organic molecular materials is often limited by their relatively low dissymmetry factors (gabs/lum < 10−2), including towards the near infrared (λ > 700 nm). An effective strategy to amplifying gabs/lum is to optimise the chiral arrangement of chromophores, with single crystals providing intrinsic molecular ordering. Herein, we quantify the circular dichroism and circularly polarised luminescence of single crystals of a chiral L-valinol bis-perylene diimide macrocycle by Mueller–Matrix polarimetry and circularly polarised luminescence microscopy, as required for the analysis of such anisotropic materials. Through this, we see that organic crystals are valuable for understanding how supramolecular structure can be used to modify the sign, strength and energy of the chiroptical signal. Indeed, by tuning the macrocycle's π–π stacking interactions, our materials deliver strong chiroptical properties (gabs/lum > 10−2), including circularly polarised luminescence into the near infrared (λ = 780 nm).
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Feb 2026
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B18-Core EXAFS
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Fei
Guo
,
Manxi
Gong
,
Longxiang
Liu
,
Bochen
Li
,
Ruwei
Chen
,
Mengjun
Gong
,
Wei
Zong
,
Jianuo
Chen
,
Qi
Li
,
Jing
Li
,
Yunpeng
Zhong
,
Zeyi
Zhang
,
Jianrui
Feng
,
Rhodri
Jervis
,
Guanjie
He
Diamond Proposal Number(s):
[34632]
Open Access
Abstract: Platinum–transition metal (PtM) alloys are among the most promising oxygen reduction reaction (ORR) catalysts, yet their practical deployment in proton-exchange membrane fuel cells (PEMFCs) is hindered by transition-metal dissolution, particle coarsening, and insufficient durability. Moreover, conventional alloying or intermetallic ordering strategies often aggravate these issues by inducing severe nanoparticle aggregation and instability. Here we report a controllable alloying–dealloying strategy to construct PtNi nanoparticles confined in an N-doped carbon framework (Pt1Ni1-x@Nix_NC). Ammonia-assisted dealloying produces a Pt-rich shell with an alloyed core, while the N-doped carbon anchors the released Ni atoms form Ni–N/C moieties, thereby suppressing agglomeration and strengthening metal–support interactions. This coordination–support coupling optimizes Pt 5d orbital occupation, weakens oxygen adsorption, and accelerates ORR kinetics. Consequently, Pt1Ni1-x@Nix_NC exhibits a half-wave potential of 0.932 V and an ultrahigh mass activity of 2.028 A mgPt−1, which is 8.75-fold higher than commercial Pt/C and among the best values reported to date for PtNi-based catalysts. Remarkably, it shows only a 6 mV half-wave potential loss after 30,000 cycles, demonstrating exceptional durability. In PEMFCs, the fuel cell delivers 975 mW cm−2 peak power density and retains 91.9% of initial performance, underscoring a generalizable approach for designing durable, high-performance low-PGM catalysts for next generation PEMFCs.
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Feb 2026
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I04-Macromolecular Crystallography
I24-Microfocus Macromolecular Crystallography
VMXm-Versatile Macromolecular Crystallography microfocus
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Open Access
Abstract: Structure determination by X-ray diffraction is limited by crystal size and can be compromised by radiation damage when using very intense X-ray radiation. X-ray structure determination from partial diffraction data sets combined from multiple crystals is a potential solution, but its exploitation in chemistry and materials science is largely unrealized. Here we report the use of synchrotron radiation for multi-crystal X-ray diffraction (MCXRD) adapted for structure determination of metal-organic framework (MOF) materials with crystal dimensions too small for conventional single-crystal diffraction studies. We further show that radiation-induced chemical changes and degradation of diffraction quality can be alleviated. Our approach encompasses both rotation- and stationary-MCXRD measurements for 10 to 1000s of crystals with software-optimized combination of the multiple data sets. We report the crystal structures of six MOFs: MOF-919(Sc/Cu), MET-2, MIL-88B(Cr)-1,4-NDC, PCN-260(Sc), UiO-66, and UiO-66-MoO4 with unit cell dimensions ranging from 18−114 Å and crystal sizes from 0.5−480 µm3. This approach can address the challenges of structure determination in a regime of particle size and sample radiation sensitivity that lies between existing single-crystal X-ray diffraction and the emerging field of electron diffraction. MCXRD can provide accurate atomic-resolution structure determination for some of the most challenging cases in chemistry and materials science.
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Jan 2026
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[35994]
Abstract: Gold catalysis provides access to a remarkable array of complex carbon scaffolds, but the use of silver salts to activate gold(I) chloride precatalysts can be problematic due to Ag(I) light sensitivity, hygroscopicity, redox activity, and interference with the desired catalysis. Although H-bond donors are a promising alternative to silver salts, they still suffer from much lower activity and narrower applicability, as Au–Cl cleavage remains rate limiting. To address these limitations, we have rationally designed a self-activating phosphine Au(I) chloride complex that incorporates a supramolecular chloride receptor in the form of an anthracene bisurea quintuple H-bond donor. In the absence of any additive, this complex promotes multiple intra- and intermolecular reactions, with a catalytic activity rivalling traditional inorganic chloride scavengers. Mechanistic studies for the model reaction show that the exceptional chloride binding ability of the anthracene bisurea unlocks access to a zwitterionic catalyst resting state where the Au─Cl bond has been cleaved, thus significantly reducing barriers for catalysis. The principles uncovered in this work show how supramolecular anion recognition moieties impact catalyst speciation and enhance performance, enabling for the first time H-bond donors to compete with inorganic chloride scavengers in terms of activity and generality.
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Jan 2026
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I15-1-X-ray Pair Distribution Function (XPDF)
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Jamie L.
Cleron
,
Chih-Yi
Chen
,
Feng
Pan
,
Santanu
Saha
,
Frederick P.
Marlton
,
Robert M.
Stolz
,
Jiayi
Li
,
Jennifer A.
Dionne
,
Fang
Liu
,
Marina R.
Filip
,
Hemamala I.
Karunadasa
Diamond Proposal Number(s):
[40486]
Open Access
Abstract: Self-assembly affords simpler synthetic routes to heterostructures compared with manual layer-by-layer stacking, yet controlling interlayer twist angles in a bulk solid remains an outstanding challenge. We report two new single-crystal heterostructures: (Sn2Cl2)(CYS)2SnCl4 (CYS = +NH3(CH2)2S–; Sn_CYS) and (Sn2Cl2)(SeCYS)2SnCl4 (SeCYS = +NH3(CH2)2Se–; Sn_SeCYS) synthesized in solution, with alternating perovskite and intergrowth layers. Notably, compared to the recently reported lead analog, (Pb2Cl2)(CYS)2PbCl4 (Pb_CYS), the tin heterostructures feature a twist between the perovskite and intergrowth layers. We trace this twist to local distortions at the Sn centers, which change the interfacial lattice-matching requirements compared to those of the Pb analog. Electronic band structure calculations show that the striking differences in the relative energies of perovskite- and intergrowth-derived bands in Sn_CYS and Pb_CYS arise from structural and not compositional differences. The structural anisotropy of Sn_CYS is also reflected in a large in-plane photoluminescence linear anisotropy ratio. Interfacial strain further affords differential incorporation of Pb into the perovskite and intergrowth layers of the Sn heterostructures, resulting in redshifted optical absorption onsets. Thus, we posit that local structural distortions may be exploited to manipulate the twist angle and interfacial strain in bulk heterostructures, providing a new handle for tuning the band alignments of bulk quantum-well electronic structures.
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Dec 2025
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B18-Core EXAFS
E01-JEM ARM 200CF
I09-Surface and Interface Structural Analysis
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Thomas J.
Liddy
,
Benjamin J.
Young
,
Emerson C.
Kohlrausch
,
Andreas
Weilhard
,
Gazi N.
Aliev
,
Yifan
Chen
,
Manfred E.
Schuster
,
Mohsen
Danaie
,
Luke L.
Keenan
,
Donato
Decarolis
,
Diego
Gianolio
,
Siqi
Wang
,
Mingming
Zhu
,
Graham J.
Hutchings
,
David M.
Grant
,
Wolfgang
Theis
,
Tien-Lin
Lee
,
David A.
Duncan
,
Alberto
Roldan
,
Andrei N.
Khlobystov
,
Jesum
Alves Fernandes
Diamond Proposal Number(s):
[38764]
Open Access
Abstract: Ammonia is an attractive hydrogen carrier, yet its practical use is limited by the need for efficient catalytic decomposition. We demonstrate that in-situ N-doping of Ru nanoparticles and graphitized carbon nanofiber supports during reaction produces a sharp increase in hydrogen production during the first 40 h, followed by stable activity. Spectroscopic and microscopic analyses, together with density functional theory simulations, reveal that Ru nitridation is rapid and support-independent, resulting in a mechanistic shift from the traditional Langmuir–Hinshelwood to a Mars–van Krevelen pathway, further confirmed by isotopic labelling experiments. In contrast, the progressive nitridation of the carbon support, observed via X-ray photoelectron spectroscopy, modulates the electronic environment of Ru and functions as a dynamic nitrogen reservoir that enables reversible N atoms exchange with the Ru particles, facilitating N desorption from the Ru surface and thereby governing the catalytic activity enhancement. These new findings provide new mechanistic insight into ammonia decomposition and establish progressive nitrogen doping of carbon supports as a strategy for designing efficient metal-based catalysts for hydrogen production.
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Dec 2025
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I22-Small angle scattering & Diffraction
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Open Access
Abstract: A liquid crystal (LC) polymethylsiloxane (PMS) with rod-like aromatic side-groups attached via an alkylene spacer and bearing three n-dodecyl end-tails is found to form an unusual cubic structure. In a normal LC double gyroid (DG), the two chiral subspaces, one each side of the G-surface, are occupied by one network each. Here each such network is split into two aromatic strands that wind around the central polysiloxane bundle, forming a double helix, resulting in a four-network gyroid (4NG). While in previous normal LC DGs the network twist was assumed to follow that of the subspace, in 4NG the twist sense of the double-helix is opposite to that of the subspace., i.e., while a right-handed subspace twists by +70.5° between junctions, the double-helix “supertwists” by −109.5°, and the opposite is true for the left-handed subspace. Detailed analysis by X-ray diffraction, DSC, and depolarized fluorescence (DF) shows a gradual but significant reversible change in the degree of mixing between the aromatic side groups and the polysiloxane backbones at 120 °C–130 °C in 4NG. Also, a significant increase in the system mobility starts only at ∼40 °C above the melting point, indicating persistence of local double-helical segments even in the melt.
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Dec 2025
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