The title compound, {[BaPt(CN)(4)(C(12)H(26)N(2)O(4))]·0.5H(2)O}(n), is a two-dimensional coordination polymer in which the sheets are oriented approximately parallel to the (01) set of crystal planes. In the crystal structure, disordered water mol-ecules (half occupancy) connect the sheets into a three-dimensional network via inter-molecular O-H⋯O hydrogen bonds. An N-H⋯N inter-action is also present. The shortest Pt⋯Pt contacts are 7.5969 (4) Å by an inversion relationship and 7.6781 (4) Å by translation along the a axis.

The structure of the title compound, poly[triaquatetra-μ-cyanido-tetracyanidobis-(1,4,10,13-tetra-oxa-7,16-diaza-cyclo-octa-deca-ne)di-barium(II)tetra-gold(I)], [Au(4)Ba(2)(CN)(8)(C(12)H(26)N(2)O(4))(2)(H(2)O)(3)](n), displays O-H⋯N hydrogen bonding between water molecules and cyano ligands and an unusual pattern of aurophilic inter-actions that yields a monomer, dimer, and trimer of [Au(CN)(2)](-) within the same crystal structure. In two of the five Au positions, the atom resides on a center of inversion. The overall arrangement is that of a coordination polymer assisted by aurophilic and hydrogen-bonded inter-actions.

We describe the development and implementation of a compact, low power, infrared heated tube furnace for in situ powder X-ray diffraction experiments. Our silicon carbide (SiC) based furnace design exhibits outstanding thermal performance in terms of accuracy control and temperature ramping rates while simultaneously being easy to use, robust to abuse and, due to its small size and low power, producing minimal impact on surrounding equipment. Temperatures in air in excess of 1100 °C can be controlled at an accuracy of better than 1%, with temperature ramping rates up to 100 °C/s. The complete "add-in" device, minus power supply, fits in a cylindrical volume approximately 15 cm long and 6 cm in diameter and resides as close as 1 cm from other sensitive components of our experimental synchrotron endstation without adverse effects.

Crystal-to-crystal transformations have been crucial in the understanding of solid-state processes, since these may be studied in detail by means of single crystal X-ray diffraction (SCXRD) techniques. The description of the mechanisms and potential intermediates of those processes remains very challenging. In fact, solid-state transient states have rarely been observed, at least to a sufficient level of detail. We have investigated the process of guest extrusion from the non-porous molecular material [Fe(bpp)(H₂L)](ClO₄)₂·1.5C₃H₆O (bpp = 2,6-bis(pyrazol-3-yl)pyridine; H₂L = 2,6-bis(5-(2-methoxyphenyl)-pyrazol-3-yl)pyridine; C₃H₆O = acetone), which occurs through ordered diffusion of acetone in a crystal-to-crystal manner, leading to dramatic structural changes. The slow kinetics of the transition allows thermal trapping of the system at various intermediate stages. The transiting single crystal can be then examined at these points through synchrotron SCXRD, offering a window upon the mechanism of the transformation at the molecular scale. These experiments have unveiled the development of an ordered intermediate phase, distinct from the initial and the final states, coexisting as the process advances with either of these two phases or, at a certain moment with both of them. The new intermediate phase has been structurally characterized in full detail by SCXRD, providing insights into the mechanism of this diffusion triggered solid-state phenomenon. The process has been also followed by calorimetry, optical microscopy, local Raman spectroscopy and powder X-ray diffraction. The discovery and description of an intermediate ordered state in a molecular solid-state transformation is of great interest and will help to understand the mechanistic details and reaction pathways underlying these transformations.

Selective, robust and cost-effective chemical sensors for detecting small volatile-organic compounds (VOCs) have widespread applications in industry, healthcare and environmental monitoring. Here we design a Pt(II) pincer-type material with selective absorptive and emissive responses to methanol and water. The yellow anhydrous form converts reversibly on a subsecond timescale to a red hydrate in the presence of parts-per-thousand levels of atmospheric water vapour. Exposure to methanol induces a similarly-rapid and reversible colour change to a blue methanol solvate. Stable smart coatings on glass demonstrate robust switching over 10⁴ cycles, and flexible microporous polymer membranes incorporating microcrystals of the complex show identical vapochromic behaviour. The rapid vapochromic response can be rationalised from the crystal structure, and in combination with quantum-chemical modelling, we provide a complete microscopic picture of the switching mechanism. We discuss how this multiscale design approach can be used to obtain new compounds with tailored VOC selectivity and spectral responses.