Dissociation of HNO in water revisited: experiment and theory.

Nitric acid dissociation in water is studied as a function of concentration, employing experimental techniques (H NMR spectroscopy and calorimetry), quantum chemical methods (B3LYP and PBE functionals for molecular clusters) and molecular dynamics simulations (the PBE-D3 functional for solutions under periodic boundary conditions). The extent of dissociation, proton transfer to a neighboring water molecule, as a function of concentration is studied computationally for molecular nitric acid clusters HNO(HO) ( = 1-8), as well as periodic liquids (HNO mole fractions of 0.19 and 0.

C pNMR shifts of MOFs based on Cu(II)-paddlewheel dimers - DFT predictions for spin-1/2 defects.

We present DFT predictions (CAM-B3LYP/II level) for the paramagnetic Nuclear Magnetic Resonance (pNMR) spectra of small molecular models based on the Cu(II)-paddlewheel dimer motif that is present in metal-organic frameworks (MOFs, notably the HKUST and STAM families). We explore potential point defects with spin-1/2 discovered through electron paramagnetic resonance (EPR) experiments. We consider defects through substitution of one Cu(II) centre in the dimer with protons, or through one-electron reduction, affording a mixed-valence dimer.

Dipolar-Coupled Entangled Molecular 4f Qubits.

We demonstrate by use of continuous wave- and pulse-electron paramagnetic resonance spectroscopy on oriented single crystals of magnetically dilute Yb ions in YbLu(trensal) that molecular entangled two-qubit systems can be constructed by exploiting dipolar interactions between neighboring Yb centers. Furthermore, we show that the phase memory time and Rabi frequencies of these dipolar-interaction-coupled entangled two-qubit systems are comparable to the ones of the corresponding single qubits.

Pulse Dipolar Electron Paramagnetic Resonance Spectroscopy Reveals Buffer-Modulated Cooperativity of Metal-Templated Protein Dimerization.

Self-assembly of protein monomers directed by metal ion coordination constitutes a promising strategy for designing supramolecular architectures complicated by the noncovalent interaction between monomers. Herein, two pulse dipolar electron paramagnetic resonance spectroscopy (PDS) techniques, pulse electron-electron double resonance and relaxation-induced dipolar modulation enhancement, were simultaneously employed to study the Cu-templated dimerization behavior of a model protein ( sp. group G, protein G B1 domain) in both phosphate and Tris-HCl buffers.

Long-Range Spatial Distribution of Single Aluminum Sites in Zeolites.

How aluminum distributes during synthesis and rearranges after processing within the zeolite framework is a central question in heterogeneous catalysis, as it determines the structure and location of the catalytically active sites of the one of the most important classes of industrial catalysts. Here, exploiting the dipolar interaction between paramagnetic metal ions, we derive the spatial distribution of single aluminum sites within the ZSM-5 zeolite framework in the nanometer range, in polycrystalline samples lacking long-range order. We use a Monte Carlo approach to validate the findings on a pristine ZSM-5 sample and demonstrate that the method is sensitive enough to monitor aluminum redistribution induced in the framework by chemical stress.

Structural Features in Some Layered Hybrid Copper Chloride Perovskites: ACuCl or ACuCl.

We present three new hybrid copper(II) chloride layered perovskites of generic composition ACuCl or ACuCl, which exhibit three distinct structure types. (-PdH)CuCl (-PdH = protonated -phenylenediamine) adopts a Dion-Jacobson (DJ)-like layered perovskite structure type and exhibits a very large axial thermal contraction effect upon heating, as revealed via variable-temperature synchrotron X-ray powder diffraction (SXRD). This can be attributed to the contraction of an interlayer block, via a slight repositioning of the -PdH moiety.