Peptide glasses are an emerging class of biofunctional amorphous materials, but their atomic-level structure has remained elusive. Here, we resolve the three-dimensional (3D) organization of peptide glasses using a cyclic dipeptide model, combining molecular dynamics simulations with 2D solid-state NMR fingerprinting. Our analysis quantifies three defining hallmarks of the glassy state: (i) pronounced conformational heterogeneity that distinguishes it from the crystalline state; (ii) reorganization of diverse H-bonding types producing annealing-rate-dependent spectral fingerprints; and (iii) dominance of non-hydrogen-bonded contacts that generate annealing - temperature-dependent spectroscopic signatures. These features give rise to molecular clusters with a branched H-bonding topology that quantitatively reproduce bulk spectroscopic properties, establishing a representative structural unit analogous to the crystalline unit cell. This framework enables the identification of structural organization in amorphous peptide glasses with different thermal histories, paving the way for rational design of functional small-molecule glassy materials.
Did you know that the strongest known engineering alloy is a metallic glass? This and many other world records have emerged along the success story of amorphous metals. With their unique structural and functional properties, and arising from a vast structural design space, metallic glasses are the amorphous counterpart to the high-entropy alloys paradigm. Sixty years after their discovery, metallic glasses have matured to industrial applications, but our structural understanding remains far behind. Presently, the advent of novel structural and dynamical probing methods, combined with new theoretical and modeling approaches, allow for the first time a one-to-one mapping of structure and structural dynamics. These developments emphasize medium-range order, extended network formation, and distinct structural partitioning in long-sought depth and detail for atomically disordered solids. Such a new view on metallic-glass microstructure and dynamics bears the promise of unifying numerous macroscopically observed phenomena, including negative creep, enthalpy recovery, stress-driven rejuvenation, and many more. This issue of MRS Bulletin aims at highlighting these advances, their promise to predictively understand macroscopic behavior, and to formulate reliable descriptors for structure and dynamics and for structure–property relationships of glassy materials. Metallic glasses are outstanding metallic alloys that combine the best properties from glassy solids and crystalline engineering alloys. This article introduces the current state-of-the-art and projects the future of structure and dynamics research of metallic glasses. As an overview article, it sets the stage for a series of subsequent focused contributions in this special issue Metallic glasses are outstanding metallic alloys that combine the best properties from glassy solids and crystalline engineering alloys. This article introduces the current state-of-the-art and projects the future of structure and dynamics research of metallic glasses. As an overview article, it sets the stage for a series of subsequent focused contributions in this special issue
DNA-functionalized colloidal nanoparticles assemble through flexible, nanoscale DNA hybridization interactions that limit atomic-level structural order. Here, we report a valence-centric strategy that enables DNA-bonded, protein single crystals with unconventional mechanical properties. An octameric enzyme, glutarate L-2-hydroxylase, was site- and number-selectively conjugated with eight self-complementary single-stranded DNA, yielding octavalent molecular bonds. The resulting conjugate assembled into the designed body-centered tetragonal crystals that diffracted to 1.42- to 2.61-angstrom resolution, with contacts mediated by B-form DNA helices spanning 17 to 25 angstroms. Increasing oligonucleotide length induces anisotropic lattice expansion while preserving atomic periodicity, even with partial DNA occupancy. Mechanistic studies suggest that the dynamic motion of unhybridized DNA facilitates crystallization, analogous to fluctuating electron clouds in atomic bonding. Compared with native protein crystals, DNA-hybridized crystals are 23-fold softer. These results challenge the assumption that flexibility is incompatible with structural order and establish a programmable framework for biomolecular crystallization and nanomaterials engineering with atomic precision.
Zhenyu Han, C. Mirkin· Science Advances· 0 citations
Helical supramolecular architectures are ubiquitous in nature yet remain challenging to construct from asymmetric achiral molecules. Here, we demonstrate that structural water acts as a symmetry-breaking and frustration-generating element in artificial self-assembly. Using an asymmetric achiral naphthalene derivative (N1) as a model system, we show that trace water fundamentally redirects its assembly pathway. In the presence of structural water, N1 forms racemic P/M helical fibers, whereas only non-helical aggregates are obtained under anhydrous conditions or with control molecules lacking sufficient hydrogen-bonding capability. Single-crystal x-ray analysis reveals that each water molecule functions as a tetravalent hydrogen-bonding node, bridging four N1 molecules into a nonplanar C2-symmetric tetramer. This water-centered motif introduces geometric incompatibility with optimal π-π stacking, generating packing frustration that is relieved through hierarchical helical twisting. The hydrogen-bonding network can be reversibly modulated by acid-base stimuli, enabling interconversion between helical and non-helical morphologies. Moreover, the resulting helices can be biased into homochiral states by chiral aromatic amino acids, revealing a water-gated chirality transfer mechanism that is absent under anhydrous conditions. This work extends design principles for supramolecular helicity beyond conventional symmetric monomers and highlights the role of structural water in controlling complex self-assembly pathways.
Hao Kong, Zhen Wu, Bijun Wang et al.· Angewandte Chemie· 0 citations
Crystalline spin glasses are attractive compounds owing to their unique nature and applications. Here, we synthesised a bulk Pnma-type Mn7C3 spin glass by a high-temperature, high-pressure method. Experimental characterisation including X-ray diffraction and magnetic susceptibility measurements demonstrated that the compound has a triangular Ising-model-based structure, high freezing temperature of 37.4 K, and novel competition mechanism. Theoretical calculations and simulations revealed that the triangular Mn units are spontaneously frustrated and bridge neighbouring Mn units via polarised C atoms and messenger Mn atoms. Triangular C units each share one electron within a three-pronged electron cloud. This electron is the direct cause of frustration and competition in Mn7C3. The competition within the triangular Mn units suggests that the possible magnetic configurations are highly degenerate and that the Mn7C3 spin glass has high robustness. This work introduces a new family of spin glasses with ordered microgeometries that drive electronic structure disorder, and an application-friendly spin-glass material for use in fields like high-efficiency hardware and algorithm design in artificial intelligence.
Liquid environments can profoundly influence the formation, structural transformation, and functional response of crystalline materials, making it essential to access their genuine structures in liquids. However, atomic-level structure analysis in liquids is highly challenging, as excessive liquid thickness, strong background scattering, and severe beam damage can severely compromise diffraction data quality. Herein, we develop a liquid-cell platform based on ultrathin carbon films. This platform confines a nanoscale local liquid layer around individual crystals and, when combined with low-dose three-dimensional electron diffraction (3D ED), enables atomic-resolution structure determination under liquid conditions. Using this approach, we achieve ab initio structure determination of a flexible metal-organic framework (MOF) Al-MIL-53 in various liquids, with data resolution reaching 0.58 Å. This allows direct revealing of two previously undiscovered solvent-dependent breathing structures in ethylene glycol and DMF, which exhibit large pore structures in contrast to the narrow pore structure observed in water. This liquid-cell platform could establish liquid-phase three-dimensional electron diffraction (LP-3DED) as an effective and widely accessible method for probing atomic-level structures in liquid environments.
Xiang Rao, Xiang Zhou, Mingxing Li et al.· Journal of the American Chem...· 0 citations
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