The counterintuitive phenomenon of negative linear compressibility (NLC) is a highly desirable but rare property exploitable in the development of artificial muscles, actuators and next-generation pressure sensors. In all cases, material performance is directly related to the magnitude of intrinsic NLC response. Here we show the molecular framework material zinc(II) dicyanoaurate(I), Zn[Au(CN)(2)](2), exhibits the most extreme and persistent NLC behaviour yet reported: under increasing hydrostatic pressure its crystal structure expands in one direction at a rate that is an order of magnitude greater than both the typical contraction observed for common engineering materials and also the anomalous expansion in established NLC candidates. This extreme behaviour arises from the honeycomb-like structure of Zn[Au(CN)(2)](2) coupling volume reduction to uniaxial expansion, and helical Au…Au 'aurophilic' interactions accommodating abnormally large linear strains by functioning as supramolecular springs.

This work describes the detailed structural investigation of mesophase-templated mesoporous silica films by 1D and 2D X-ray scattering techniques and transmission electron microscopy. The films are prepared by sol−gel dip coating with 2D hexagonal templating mesophases, yielding 2D mesoporous structures consisting of cylindrical pores whose axes are aligned parallel to the surface. It is shown that drying and thermal treatments induce an unidirectional shrinkage of the layers in the direction of the normal of the film. The true rectangular symmetry is only evidenced by 2D X-ray scattering in two different scattering geometries. 1D diffraction gives only an apparent hexagonal symmetry. It is furthermore shown that although the cylinder axes are randomly orientated within the plane parallel to the surface, there are large domains with well aligned 2D planar unit cells perpendicular to the surface. It is demonstrated that this preferential ordering is destroyed by nanoparticle seeding with amorphous silica or maghemite particles.

Hydrazine borane (N(2)H(4)BH(3)) is the novel boron- and nitrogen-based material appearing to be a promising candidate in chemical hydrogen storage. It stores 15.4 wt% of hydrogen in hydridic and protic forms, and the challenge is to release H(2) with maximum efficiency, if possible all hydrogen stored in the material. An important step to realize this ambitious goal is to synthesize HB with high yields and high purity, and to characterize it fully. In this work, we report a 2-step synthesis (salt metathesis and solvent extraction-drying) through which N(2)H(4)BH(3) is successfully obtained in 3 days, with a yield of about 80% and a purity of 99.6%. N(2)H(4)BH(3) was characterized by NMR, IR, XRD, TGA and DSC, its stability in dioxane and water was determined, and its thermolysis by-products were characterized. We thus present a complete data sheet that should be very useful for future studies. Furthermore, we propose a discussion on the potential of HB (with H(2) released by either thermolysis or hydrolysis) in chemical hydrogen storage.

The self-assembly of ureido crown-ether derivatives has been examined in homogeneous solution, in the solid state, and in planar bilayer membranes. The self-assembly is driven by head-to-tail hydrogen bonding between the urea functional groups. Dimers and higher oligomers are formed in CDCl3 solution as assessed by the change in the ureido NH chemical shift as a function of concentration. Single-crystal X-ray diffraction shows that an antiparallel association of the ureas produces columnar channels composed of face-to-face crown ethers. Powder X-ray diffraction studies also show the presence of a minor phase based upon a parallel urea association leading to an alternative columnar arrangement of the crown ethers. In bilayer membranes at low concentration of ureido crown ether added, membrane disruption is observed together with rare single-channel openings, but at higher concentration, a rich array of interconverting channel conductance states is observed. The channel results are interpreted as arising from discreet stacks of ureido crown ethers where the transport of cations would occur via the macrocycles, admixed with larger pores formed by association of the crown ether headgroups around a central large pore.

The reaction of manganese(III) acetate meso-tetraphenylporphyrin with phenylphosphinic acid provides the one-dimensional compound of formula [Mn(TPP)O2PHPh] x H2O, which crystallizes in the monoclinic C2/c space group. The chain structure is generated by a glide plane resulting in Jahn-Teller elongation axes of the MnIII octahedra that alternate along the chain. The phenylphosphinate anion transmits a sizable antiferromagnetic exchange interaction that, combined with the easy axis magnetic anisotropy of the MnIII sites, gives rise to a canted antiferromagnetic arrangement of the spins. The static single-crystal magnetic properties have been analyzed with a classical Monte Carlo approach, and the best fit parameters for the exchange and single ion anisotropy are J = -0.68(4) K and D = -4.7(2) K, respectively (using the -2JS(i)S(j) formalism for the exchange). Below 5 K the single-crystal dynamics susceptibility reveals a frequency-dependent out-of-phase signal typical of single-chain magnets. The extracted relaxation time follows the Arrhenius law with delta = 36.8 K. The dynamic behavior has been rationalized and correlated to geometrical parameters of the structure. The contribution of the correlation length to the energy barrier has been investigated, and it has been found that the characteristic length that dominates the dynamics strongly exceeds the correlation length estimated from magnetic susceptibility.

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Dipolar water wires stabilize quartets of ureido imidazole compounds (I‐quartets) in a manner reminiscent of stabilization of guanine (G) quartets by cation templating (see picture).

The reaction of gold nanoparticles with benzimididazol-2-ylidene ligands leads to the formation of well-defined bis-carbene gold(i) complexes, as shown by characterization techniques such as powder XRD and solid state NMR.