"Dynamical Docking" of Cyclic Dinuclear Au(I) Bis-N-heterocyclic Complexes Facilitates Their Binding to G-Quadruplexes.

With the aim to improve the design of metal complexes as stabilizers of noncanonical DNA secondary structures, namely, G-quadruplexes (G4s), a series of cyclic dinuclear Au(I) N-heterocyclic carbene complexes based on xanthine and benzimidazole ligands has been synthesized and characterized by various methods, including X-ray diffraction. Fluorescence resonance energy transfer (FRET) and CD DNA melting assays unraveled the compounds' stabilization properties toward G4s of different topologies of physiological relevance. Initial structure-activity relationships have been identified and recognize the family of xanthine derivatives as those more selective toward G4s versus duplex DNA.

Layered Tin Chalcogenides SnS and SnSe: Lattice Thermal Conductivity Benchmarks and Thermoelectric Figure of Merit.

Tin sulfide (SnS) and tin selenide (SnSe) are attractive materials for thermoelectric conversion applications. Favorable small band gap, high carrier mobility, large Seebeck coefficient, and remarkably low lattice thermal conductivity are a consequence of their anisotropic crystal structure of symmetry , made of corrugated, black phosphorus-like layers. Their internal lattice dynamics combined with chemical bond softening in going from SnS to SnSe make for subtle effects on lattice thermal conductivity.

Many-Particle Li Ion Dynamics in LiMPO Olivine Phosphates (M = Mn, Fe).

LiMPO (M = Mn, Fe) olivine phosphates are important materials for battery applications due to their stability, safety, and reliable recharge cycle. Despite continuous experimental and computational investigations, several aspects of these materials remain challenging, including conductivity dimensionality and how it maps onto Li pathways. In this work, we use a refined version of our finite temperature molecular dynamics "shooting" approach, originally designed to enhance Li hopping probability.

Mechanisms of irreversible aquaporin-10 inhibition by organogold compounds studied by combined biophysical methods and atomistic simulations.

The inhibition of glycerol permeation via human aquaporin-10 (hAQP10) by organometallic gold complexes has been studied by stopped-flow fluorescence spectroscopy, and its mechanism has been described using molecular modelling and atomistic simulations. The most effective hAQP10 inhibitors are cyclometalated Au(III) C^N compounds known to efficiently react with cysteine residues leading to the formation of irreversible C-S bonds. Functional assays also demonstrate the irreversibility of the binding to hAQP10 by the organometallic complexes.

Aquaporin-driven hydrogen peroxide transport: a case of molecular mimicry?

Aquaporins (AQPs) are membrane proteins that have evolved to control cellular water uptake and efflux, and as such are amongst the most ancient biological "devices" in cellular organisms. Recently, using metadynamics, we have shown that water nanoconfinement within aquaporin channels results into bidirectional water movement along single file chains, extending previous investigations. Here, the elusive mechanisms of HO facilitated transport by the human 'peroxiporin' AQP3 has been unravelled a combination of atomistic simulations, showing that while hydrogen peroxide is able to mimic water during AQP3 permeation, this comes at a certain energy expense due to the required conformational changes within the channel.

Unveiling the Mechanisms of Aquaglyceroporin-3 Water and Glycerol Permeation by Metadynamics.

Water and glycerol permeation through human AQP3 are described by exploiting advanced metadynamics approaches, which enabled both to explore the free energies involved in pore permeation and to achieve a description of the mechanisms with an atomistic level of detail.

Molecular Basis of Aquaporin-7 Permeability Regulation by pH.

The aquaglyceroporin AQP7, a family member of aquaporin membrane channels, facilitates the permeation of water and glycerol through cell membranes and is crucial for body lipid and energy homeostasis. Regulation of glycerol permeability via AQP7 is considered a promising therapeutic strategy towards fat-related metabolic complications. Here, we used a yeast -null strain for heterologous expression and functional analysis of human AQP7 and investigated its regulation by pH.

Templated Chromophore Assembly on Peptide Scaffolds: A Structural Evolution.

The use of a template that bears pre-programmed receptor sites for selectively accommodating chromophores at given positions is an attractive approach for engineering artificial-light-harvesting systems. Indulging this line of thought, this work tackles the creation of tailored antenna architectures with yellow, red and blue chromophores, exploiting three dynamic covalent reactions simultaneously, namely disulfide exchange, acyl hydrazone, and boronic ester formations. The effect of various structural modifications, such as the chromophores as well as their spatial organization (distance, orientation, order) on the energy transfer within the antennas was studied by means of steady-state UV/Vis absorption and fluorescence spectroscopies.

Metashooting: a novel tool for free energy reconstruction from polymorphic phase transition mechanisms.

We introduce a novel scheme for the mechanistic investigation of solid-solid phase transitions, which we dub 'metashooting'. Combining transition path sampling, molecular dynamics and metadynamics, this scheme allows for both a complete mechanistic analysis and detailed mapping of the free energy surface. This is illustrated by performing metashooting calculations on the pressure-induced B4/B3 → B1 phase transition in ZnO.

On the Mechanism of Gold/NHC Compounds Binding to DNA G-Quadruplexes: Combined Metadynamics and Biophysical Methods.

The binding modes and free-energy landscape of two Au /N-heterocyclic carbene complexes interacting with G-quadruplexes, namely a human telomeric (hTelo) and a promoter sequence (C-KIT1), are studied here for the first time by metadynamics. The theoretical results are validated by FRET DNA melting assays and provide an accurate estimate of the absolute gold complex/DNA binding free energy. This advanced in silico approach is valuable to achieve rational drug design of selective G4 binders.

Microscopic description of insulator-metal transition in high-pressure oxygen.

Unusual metallic states involving breakdown of the standard Fermi-liquid picture of long-lived quasiparticles in well-defined band states emerge at low temperatures near correlation-driven Mott transitions. Prominent examples are ill-understood metallic states in d- and f-band compounds near Mott-like transitions. Finding of superconductivity in solid O on the border of an insulator-metal transition at high pressures close to 96 GPa is thus truly remarkable.

Selective orbital reconstruction in tetragonal FeS: A density functional dynamical mean-field theory study.

Transport properties of tetragonal iron monosulfide, mackinawite, show a range of complex features. Semiconductive behavior and proximity to metallic states with nodal superconductivity mark this d-band system as unconventional quantum material. Here, we use the density functional dynamical mean-field theory (DFDMFT) scheme to comprehensively explain why tetragonal FeS shows both semiconducting and metallic responses in contrast to tetragonal FeSe which is a pseudogaped metal above the superconducting transition temperature.

The mechanism of aquaporin inhibition by gold compounds elucidated by biophysical and computational methods.

The inhibition of water and glycerol permeation via human aquaglyceroporin-3 (AQP3) by gold(iii) complexes has been studied by stopped-flow spectroscopy and, for the first time, its mechanism has been described using molecular dynamics (MD), combined with density functional theory (DFT) and electrochemical studies. The obtained MD results showed that the most effective gold-based inhibitor, anchored to Cys40 in AQP3, is able to induce shrinkage of pores preventing glycerol and water permeation. Moreover, the good correlation between the affinity of the Au(iii) complex to Cys binding and AQP3 inhibition effects was highlighted, while no influence of the different oxidative character of the complexes could be observed.

Enzymatic synthesis of natural (+)-aristolochene from a non-natural substrate.

The sesquiterpene cyclase aristolochene synthase from Penicillium roquefortii (PR-AS) has evolved to catalyse with high specificity (92%) the conversion of farnesyl diphosphate (FDP) to the bicyclic hydrocarbon (+)-aristolochene, the natural precursor of several fungal toxins. Here we report that PR-AS converts the unnatural FDP isomer 7-methylene farnesyl diphosphate to (+)-aristolochene via the intermediate 7-methylene germacrene A. Within the confined space of the enzyme's active site, PR-AS stabilises the reactive conformers of germacrene A and 7-methylene germacrene A, respectively, which are protonated by the same active site acid (most likely HOPP) to yield the shared natural bicyclic intermediate eudesmane cation, from which (+)-aristolochene is then generated.

Mechanism of Germacradien-4-ol Synthase-Controlled Water Capture.

The sesquiterpene synthase germacradiene-4-ol synthase (GdolS) from Streptomyces citricolor is one of only a few known high-fidelity terpene synthases that convert farnesyl diphosphate (FDP) into a single hydroxylated product. Crystals of unliganded GdolS-E248A diffracted to 1.50 Å and revealed a typical class 1 sesquiterpene synthase fold with the active site in an open conformation.

Hierarchical thermoelectrics: crystal grain boundaries as scalable phonon scatterers.

Thermoelectric materials are strategically valuable for sustainable development, as they allow for the generation of electrical energy from wasted heat. In recent years several strategies have demonstrated some efficiency in improving thermoelectric properties. Dopants affect carrier concentration, while thermal conductivity can be influenced by alloying and nanostructuring.

Microwave-Assisted Synthesis of Defects Metal-Imidazolate-Amide-Imidate Frameworks and Improved CO2 Capture.

In this work, we report three isostructural 3D frameworks, named IFP-11 (R = Cl), IFP-12 (R = Br), and IFP-13 (R = Et) (IFP = Imidazolate Framework Potsdam) based on a cobalt(II) center and the chelating linker 2-substituted imidazolate-4-amide-5-imidate. These chelating ligands were generated in situ by partial hydrolysis of 2-substituted 4,5-dicyanoimidazoles under microwave (MW)-assisted conditions in DMF. Structure determination of these IFPs was investigated by IR spectroscopy and a combination of powder X-ray diffraction (PXRD) with structure modeling.

Magnetoresistance in the Spin-Orbit Kondo State of Elemental Bismuth.

Materials with strong spin-orbit coupling, which competes with other particle-particle interactions and external perturbations, offer a promising route to explore novel phases of quantum matter. Using LDA + DMFT we reveal the complex interplay between local, multi-orbital Coulomb and spin-orbit interaction in elemental bismuth. Our theory quantifies the role played by collective dynamical fluctuations in the spin-orbit Kondo state.

Zeolitic imidazolate framework-71 nanocrystals and a novel SOD-type polymorph: solution mediated phase transformations, phase selection via coordination modulation and a density functional theory derived energy landscape.

We report a rapid additive-free synthesis of nanocrystals (NCs) of RHO-type ZIF-71 () of composition [Zn(dcim)2] (dcim = 4,5-dichloroimidazolate) in 1-propanol as solvent at room temperature. NC- has a size of 30-60 nm and exhibits permanent microporosity with a surface area (SBET = 970 m(2) g(-1)) comparable to that of microcrystalline material. When kept under the mother solution NC- undergoes transformation into a novel SOD-type polymorph (), which in turn converts into known ZIF-72 () with lcs topology.

Theoretical investigation of the electronic structure and quantum transport in the graphene-C(111) diamond surface system.

We investigate the interaction of a graphene monolayer with the C(111) diamond surface using ab initio density functional theory. To accommodate the lattice mismatch between graphene and diamond, the overlayer deforms into a wavy structure that binds strongly to the diamond substrate. The detached ridges of the wavy graphene overlayer behave electronically as free-standing polyacetylene chains with delocalized π electrons, separated by regions containing only sp(3) carbon atoms covalently bonded to the (111) diamond surface.

Novel metastable metallic and semiconducting germaniums.

Group-IVa elements silicon and germanium are known for their semiconducting properties at room temperature, which are technologically critical. Metallicity and superconductivity are found at higher pressures only, Ge β-tin (tI4) being the first high-pressure metallic phase in the phase diagram. However, recent experiments suggest that metallicity in germanium is compatible with room conditions, calling for a rethinking of our understanding of its phase diagram.

An isoreticular family of microporous metal-organic frameworks based on zinc and 2-substituted imidazolate-4-amide-5-imidate: syntheses, structures and properties.

We report on a new series of isoreticular frameworks based on zinc and 2-substituted imidazolate-4-amide-5-imidate (IFP-1-4, IFP = imidazolate framework Potsdam) that form one-dimensional, microporous hexagonal channels. Varying R in the 2-substitued linker (R = Me (IFP-1), Cl (IFP-2), Br (IFP-3), Et (IFP-4)) allowed the channel diameter (4.0-1.

Understanding the nature of "superhard graphite".

Numerous experiments showed that on cold compression graphite transforms into a new superhard and transparent allotrope. Several structures with different topologies have been proposed for this phase. While experimental data are compatible with most of these models, the only way to solve this puzzle is to find which structure is kinetically easiest to form.

Route to a family of robust, non-interpenetrated metal-organic frameworks with pto-like topology.

A combination of topological rules and quantum chemical calculations has facilitated the development of a rational metal-organic framework (MOF) synthetic strategy using the tritopic benzene-1,3,5-tribenzoate (btb) linker and a neutral cross-linker 4,4'-bipyridine (bipy). A series of new compounds, namely [M(2)(bipy)](3)(btb)(4) (DUT-23(M), M = Zn, Co, Cu, Ni), [Cu(2)(bisqui)(0.5)](3)(btb)(4) (DUT-24, bisqui = diethyl (R,S)-4,4'-biquinoline-3,3'-dicarboxylate), [Cu(2)(py)(1.