Crystal structure of caesium tetramethyldithioimidodiphosphinate

In the title crystal, the salt [CsMe2P(S)NP(S)Me2] is self-assembled as an undulating supramolecular two-dimensional polymeric structure, poly[(μ4-tetramethyldithioimidodiphosphinato)caesium], [Cs(C4H12NP2S2)] n , which is parallel to the bc plane. The Cs cations are hexacoordinated, being chelated by two thioimidophosphinate groups and two sulfur atoms from neighboring ligands. The anions are linked to the Cs cations by Cs...S and Cs...N electrostatic interactions.

Novel Coordination Mode in the Potassium Mefenamate Trihydrate Polymeric Structure

As a result of the synthesis of mefenamic acid with potassium hydroxide, a salt with a polymeric structure is formed. The one-dimensional polymeric structure was studied by single crystal X-ray diffraction. The potassium cation is coordinated to one oxygen atom of the carboxylate group and six water oxygen atoms. Potassium ions are bridged by oxygen atoms of water molecules. The crystal structure was used as an input to QTAIM and NCI approaches to investigate the K-O interactions linking the cation with the water oxygen and carboxylate groups. The weak K-O interactions of the potassium cation and water oxygen atoms were strong enough to form a polymeric structure. The flexibility of the weak interactions is responsible for a novel coordination mode in the potassium mefenamate trihydrate.

Thermal Post-Buckling Strength Prediction and Improvement of SMA Bonded Carbon Nanotube-Reinforced Shallow Shell Panel: A Nonlinear FE Micromechanical Approach

This article reported first-time the post-buckling temperature load parameter values of nanotube-reinforced polymeric composite panel and their improvement by introducing the functional material (shape memory alloy, SMA) fibre. The temperature load values of nanotube composite and SMA activation are modelled using the single-layer type higher-order kinematic model in association with isoparametric finite element technique. To ensure the effective properties of SMA bonded nanotube composite under the elevated temperature, a hybrid micromechanical material modelling approach is adopted (Mori-Tanaka scheme and rule of mixture). The present structural geometry distortion under elevated temperature is modelled through the nonlinear strain kinematics (Green-Lagrange), whereas the strain reversal achieved with the help of marching technique (inclusion of material nonlinearity). Owing to the importance of geometrical distortion of the polymeric structure, the current model includes all of the nonlinear strain terms to accomplish the exact deformation. Further, to compute the post-buckling responses, the governing nonlinear eigenvalue equations are derived by Hamilton's principle. The numerical solution accuracy is verified with adequate confirmation of model consistency. The material model applicability for different structural configurations including important individual/combined parameter tested through a series of examples. Moreover, the final understanding relevant to the post-buckling characteristics of the polymeric structure and SMA influences is highlighted in details considering the prestrain, recovery stress and their volume fractions.

Copper nanoparticle anchored biguanidine-modified Zr-UiO-66 MOFs: a competent heterogeneous and reusable nanocatalyst in Buchwald–Hartwig and Ullmann type coupling reactions

We have designed a functionalized metal–organic framework (MOF) of UiO topology as a support, with an extremely high surface area, adjustable pore sizes and stable crystalline coordination polymeric structure and implanted copper (Cu) nanoparticles thereon.

Recent progress in self-healing polymers and hydrogels based on reversible dynamic B–O bonds: boronic/boronate esters, borax, and benzoxaborole

Intrinsic self-healing polymeric materials are substances that relieve external stress and restore their original mechanical properties after extreme damage via dynamic covalent bonding in the polymeric structure or the reversible...

Additive Manufacturing of Polyether Ether Ketone (PEEK) for Space Applications: A Nanosat Polymeric Structure

Recent improvements in additive layer manufacturing (ALM) have provided new designs of geometrically complex structures with lighter materials and low processing costs. The use of additive manufacturing in spacecraft production is opening up many new possibilities in both design and fabrication, allowing for the reduction of the weight of the structure subsystems. In this aim, polymeric ALM structures can become a choice, in terms of lightweight and demisability, as far as good thermomechanical properties. Moreover, provided that fused-deposition modeling (FDM) is used, nanosats and other structures could be easily produced in space. However, the choice of the material is a crucial step of the process, as the final performance of the printed parts is strongly dependent on three pillars: design, material, and printing process. As a high-performance technopolymer, polyether ether ketone (PEEK) has been adopted to fabricate parts via ALM; however, the space compatibility of 3D-printed parts remains not demonstrated. This work aimed to realize a nanosat polymeric structure via FDM, including all the phases of the development process: thermomechanical design, raw material selection, printing process tuning, and manufacturing of a proof of concept of a technological model. The design phase includes the application of topology optimization to maximize mass saving and take full advantage of the ALM capability. 3D-printed parts were characterized via thermomechanical tests, outgassing tests of 3D-printed parts are reported confirming the outstanding performance of polyether ether ketone and its potential as a material for structural space application.

Teaching chemistry with LEGO® bricks

Teachers are developing unique teaching aids to attract students to the field of chemistry. Ideal teaching aids are tools that students can enjoy utilizing, reutilizing, and which can be constructed without employing special tools. LEGO®-based teaching aids satisfy all these requirements. Chemistry teachers have employed bricks to illustrate basic chemical concepts. Moreover, LEGO-based chemistry teaching aids have been vigorously reported by Campbell and coworkers since the late 1990s and are still being persistently reported by several groups. The focus of this review is the applications of LEGO bricks in teaching chemistry. This review describes LEGO-based teaching aids that are easily constructed and may be beneficial to readers, in terms of creating new teaching aids. Since LEGO bricks possess varieties of shapes and colors, they can be employed to design various teaching aids, including periodic tables, molecular models, polymer structure models, and frameworks for handmade measuring instruments. The polymeric structure models are generally difficult to build with typical ball-and-stick type molecular models; however, they can be easily built, employing LEGO bricks. The bricks are suitable for the construction of handmade measuring instruments because of their versatility and computer interface, as well as their non-requirement of special tools.