Reversible uptake of sulfur-containing gases by single crystals of a Cr8 metallacrown.

The exposure of green crystals of the [CrF(O2CtBu)2]8Cr8 metallacrown to SO2 and H2S gases results in the binding of the gas molecules in the internal molecular cavity, despite the absence of any pores or channels in the structure. Single crystal X-ray diffraction studies show that the gas molecules bind weakly to the bridging fluoride ligands. The desorption process was followed by TGA, DSC and in situ variable temperature single crystal X-ray diffraction, obtaining the gas binding energies for the gas guest molecules. These results are supported by DFT calculations.

Binding of halogens by a Cr8 metallacrown.

A Cr8 metallacrown binds halogens X2 (Cl2, Br2 and I2) without loss of crystallinity; the binding has been studied by X-ray diffraction and thermodynamic techniques.

Binding CO2 by a Cr8 Metallacrown.

The {Cr8 } metallacrown [CrF(O2 Ct Bu)2 ]8 , containing a F-lined internal cavity, shows high selectivity for CO2 over N2 . DFT calculations and absorption studies support the multiple binding of F-groups to the C-center of CO2 (C⋅⋅⋅F 3.190(9)-3.389(9) Å), as confirmed by single-crystal X-ray diffraction.

Trends in Materials Science for Ligament Reconstruction.

The number of ligament injuries increases every year and concomitantly the need for materials or systems that can reconstruct the ligament. Limitations imposed by autografts and allografts in ligament reconstruction together with the advances in materials science and biology have attracted a lot of interest for developing systems and materials for ligament replacement or reconstruction. This review intends to synthesize the major steps taken in the development of polymer-based materials for anterior cruciate ligament, their advantages and drawbacks and the results of different in vitro and in vivo tests. Until present, there is no successful polymer system for ligament reconstruction implanted in humans. The developing field of synthetic polymers for ligament reconstruction still has a lot of potential. In addition, several nano-structured materials, made of nanofibers or in the form of ceramic/polymeric nanocomposites, are attracting the interest of several groups due to their potential use as engineered scaffolds that mimic the native environment of cells, increasing the chances for tissue regeneration. Here, we review the last 15 years of literature in order to obtain a better understanding on the state-of-the-art that includes the usage of nano- and poly-meric materials for ligament reconstruction, and to draw perspectives on the future development of the field.

Enantioanalysis of pipecolic acid with stochastic and potentiometric microsensors.

Stochastic and potentiometric microsensors based on porphyrins and polymeric surfactants such as polysodium N-undecanoyl-L-leucylvanilate and polysodium N-undecanoyl-L-vanilate were developed for enantioselective assay of pipecolic acid. The matrices used for the design of the stochastic sensors were diamond paste and graphite paste, while the matrix used for the design of potentiometric sensors was carbon paste. The response characteristics of the microsensors were determined for the enantiomers of pipecolic acid. The response characteristics, selectivity, and enantioselectivity studies proved that the proposed microsensors can be used for clinical enantioanalysis of pipecolic acid in biological fluids, e.g., urine and whole blood.