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Herein, we report the synthesis and crystal structure determination of a new Cu( II ) coordination polymer (CP) with the formula [Cu( L -tryp)(azpy) 1/2 (H 2 O)(NO 3 )] ∝ ( CP1 ), which exhibits an unusual tryptophan coordination mode with copper( II ) via carboxylate monodentate binding as well as chelation via N amino and O carbonyl groups. CP1 was prepared using the ligand L -tryptophan ( L -tryp) and the co-ligand 4,4′-azopyridine (azpy), adapting the mixed-ligand approach and a solvothermal protocol. Single crystal X-ray structural analysis revealed that in CP1 , Cu( II ) sites show a distorted octahedral geometry, wherein the ligand L -tryp is coordinated through the carboxylate and amine groups, whereas the co-ligand azpy is coordinated to Cu( II ) ions through the N pyridyl atom and thus maintains a distorted octahedral geometry around the Cu( II ) ions. FT-IR and EPR spectra were also recorded to corroborate the structural analysis. Finally, CP1 was employed as a heterogeneous catalyst for the Suzuki cross-coupling reaction and afforded ～98% yield under normal reaction conditions.

A hydrothermal reaction between mixed linkers and mixed metals, alkaline earth 4MgCO 3 ·Mg(OH) 2 ·5H 2 O and 3d Ni(CH 3 COO 3 ) 2 ·4H 2 O, resulted in a unique metal–organic framework of SNNU-99 that was impressively isolated and structurally characterized. SNNU-99 was constructed from an unprecedented decanuclear Mg/Ni-based secondary building unit and represents the first (3,10)-connected 3-period net. Alternatively, SNNU-99 can be described through an unusual kgd layer pillared through 2-connected linkers. Due to its specifically structural feature, SNNU-99 has demonstrated selective CO 2 adsorption over N 2 .

Obtaining shape and size control of strongly correlated materials is imperative to obtain a fundamental understanding of the influence of finite size and surface restructuring on electronic instabilities in the proximity of the Fermi level. We present here a novel synthetic approach that takes advantage of the intrinsic octahedral symmetry of rock-salt-structured VO to facilitate the growth of six-armed nanocrystallites of related, technologically important binary vanadium oxides VO 2 and V 2 O 5 . The prepared nanostructures exhibit clear six-fold symmetry and most notably show remarkable retention of electronic structure. The latter has been evidenced through extensive X-ray absorption spectroscopy measurements.

Polymorphs of L-serine have been studied using ab initio density functional theory for pressures up to 8.1 GPa. The SIESTA code was used to perform geometry optimisations starting from the coordinates derived from high-pressure neutron powder diffraction . Between 0 and 8.1 GPa two phase transitions occur, the first of which takes place between 4.5 and 5.2 GPa and the second between 7.3 and 8.1 GPa. A change in molecular conformation occurs during the I-to-II transition, resulting in a stabilisation in intramolecular energy of 40 kJ mol ?1 . There is good agreement between the theoretical and experimental coordinates, and the largest root-mean-square deviation between experimental and optimised structures is 0.121 ?. Analysis of the effect of pressure on the intermolecular interactions using the PIXEL method showed that none becomes significantly destabilising as the phase-I structure is compressed. It is proposed that the phase transition is driven by attainment of a more stable conformation and from the reduction in the molecular volume. The second phase transition occurs with only a small change in the hydrogen bonding pattern and no substantial difference in molecular conformation. The effect on the energies of attraction between molecules suggests that this transition is driven by the bifurcation of a short OH?O interaction.

A new metal–organic framework {[Zn 2 (Htzba) 2 (dmtrz)]·(CH 3 ) 2 NH} n ( 1 ) that has already been solvothermally synthesized exhibits a high CO 2 uptake capacity based on experimental and simulation calculation results. Furthermore, the selectivities to CO 2 /CH 4 and CO 2 /N 2 are predicted by IAST to be 41.19 and 46.21 at 298 K and 100 kPa, respectively. The superior performance suggests that 1 is a promising candidate for CO 2 separation.

The cracking of KDP crystals during the growth furthermore, the cracking is mainly attributed to their high brittleness. In order to explore the mechanical parameters related to KDP crystal cracking in detail, we measured the fracture toughness of KDP crystals as a function of temperature using the single-edge notched beam (SENB) method up to 170 °C. Meanwhile, the effects of crystallographic orientation, annealing and loading rate on the fracture toughness values were investigated in detail. Strong orientation dependence was observed on the fracture toughness of KDP crystals, and the relationship was concluded as follows: x-cut type II type I z-cut. With the increase in temperature, the fracture toughness of crystals increased and reached its maximum value at 160 °C; then, it decreased, indicating that 160 °C is the temperature at which brittle-to-ductile transition occurs. Using an optical microscope, it was observed that the fractured surfaces of the samples become gradually rough with the increase in temperature. This may offer a viewpoint for understanding the dependence of fracture toughness on temperature. Furthermore, annealing and decrease in the loading rate were conducive to the significant increase in the fracture toughness of KDP crystals.

The first page of this article is displayed as the abstract.

This communication reports an unusual side-on coordination of Ag( I ) ions with C-8 substituted -N9-propyladenine. Crystal structure investigation shows the influence of C-8 substituent over silver– adenine framework, where the bulky 8-dimethylamino group restricts the ring imino nitrogens (μ-N1, N3, N7) for in-plane coordination, leading to the formation of unprecedented metallaquartets.

Existing amphoteric energetic materials (EMs) are very scarce, and their amphoteric structures are difficult to reproduce and protonate. Herein, adjacent N→O and C–NH 2 groups (O←N C–NH 2 ) were found to be a highly efficient and fairly balanced amphoteric energetic structure for EMs by crystal engineering and are the first discovered amphoteric structure caused by tautomerization to the best of our knowledge. As the O←N C–NH 2 structure has existed in many synthesized nitrogen-rich EMs, our work will greatly enrich amphoteric EMs.

The aggregation of lysozyme in crystallizing solutions prior to crystal nucleation and during crystal growth has been the subject of numerous investigations over the past two decades. Nevertheless, it remains a controversial rather than a well-recognized phenomenon. In this study, we investigate the growth of tetragonal lysozyme crystals in quiescent solutions at the early crystal growth stage using seven different protein concentrations ranging from 25 mg ml ?1 to 55 mg ml ?1 , 5% NaCl (w/v), 0.1 M sodium acetate buffer (pH 4.0), and constant temperature (22.0 °C). The growth rates of lysozyme crystals are determined by analyzing the time-lapse images of the evolving visible crystal area, recorded at relatively high magnification (600×). The calculated crystal growth rates are then analyzed according to an equilibrium distribution of lysozyme aggregates, which is based on a model two-body process (monomer ? dimer ? tetramer ? octamer ? hexadecamer) developed by M. Li et al. (1995). All types of aggregates are considered separately. We found that both octamers and tetramers are probable candidates for crystal growth units and suggested the most voluminous aggregate fraction as strongly influencing the crystal growth process. We also interpret the lysozyme crystal nucleation in the frame of the classical nucleation theory (CNT) and in accordance with the assumed two-body aggregation reaction set. Our results reveal that the tetramer appears to be the least achievable nucleus size across the whole protein concentration range, where classical nucleation could still be an observable phenomenon.