Ab-initio DFT simulation of electronic and magnetic properties of Tin+1and FeTin clusters

We report a computational investigation of the electronic and magnetic properties of neutral Tin+1and FeTin (n=1-10) clusters using ab-initio calculations based on density functional theory (DFT) within the generalized gradient approximation (GGA). The best structures for Tin+1and FeTin clusters are planar for size n<5, while from n = 5, they showed a compact three dimensional cage structure. For the best structures of the FeTin clusters, the Fe atoms favors the peripheral position with highest coordination with the neighboring Ti atoms. The evolution as a function of the size of the average binding energies (Eb/atom) and HOMO–LUMO gaps of Tin+1 and FeTin (n=1-10) clusters are studied. The stability results show that the Tin+1 clusters have relatively higher stability than the FeTin cluster with the same size. In addition, the vertical ionization potentials and electron affinities, chemical hardness and atomic magnetic moment of Tin+1and FeTin (n=1-10) clusters are also investigated.

Iron(IV) Complexes with Tetraazaadamantane-based Ligands: Synthesis, Structure, Application in Dioxygen Activation and Labeling of Biomolecules

4,6,10-Trihydroxy-1,4,6,10-tetraazaadamantane (TAAD) has been shown to form a stable Fe(IV) complex having a diamantane cage structure, in which the metal center is coordinated by three oxygen atoms of the deprotonated ligand. The complex was characterized by X-ray, HRMS, NMR, FT-IR, Mössbauer spectroscopy and DFT calculations, which supported d4 configuration of iron. The Fe(IV)-TAAD complex showed excellent performance in dioxygen activation under mild conditions serving as a mimetic of the thiol oxidase enzyme. The nucleophilicity of the bridge-head nitrogen atom in TAAD provides a straightforward way for conjugation of Fe(IV)-TAAD complexes to various functional molecules. Using this approach, steroidal and peptide molecules having an iron(IV) label have been prepared for the first time. Also, the Fe(IV)-TAAD complex was covalently bounded to a polystyrene matrix and the resulting material was shown to serve as a heterogeneous catalyst for aerobic oxidation of thiols to disulfides.

Accelerated synthesis of energetic precursor cage compounds using confined volume systems

Confined volume systems, such as microdroplets, Leidenfrost droplets, or thin films, can accelerate chemical reactions. Acceleration occurs due to the evaporation of solvent, the increase in reactant concentration, and the higher surface-to-volume ratios amongst other phenomena. Performing reactions in confined volume systems derived from mass spectrometry ionization sources or Leidenfrost droplets allows for reaction conditions to be changed quickly for rapid screening in a time efficient and cost-saving manner. Compared to solution phase reactions, confined volume systems also reduce waste by screening reaction conditions in smaller volumes prior to scaling. Herein, the condensation of glyoxal with benzylamine (BA) to form hexabenzylhexaazaisowurtzitane (HBIW), an intermediate to the highly desired energetic compound 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20), was explored. Five confined volume systems were compared to evaluate which technique was ideal for forming this complex cage structure. Substituted amines were also explored as BA replacements to screen alternative cage structure intermediates and evaluate how these accelerated techniques could apply to novel reactions, discover alternative reagents to form the cage compound, and improve synthetic routes for the preparation of CL-20. Ultimately, reaction acceleration is ideal for predicting the success of novel reactions prior to scaling up and determining if the expected products form, all while saving time and reducing costs. Acceleration factors and conversion ratios for each reaction were assessed by comparing the amount of product formed to the traditional bulk solution phase synthesis.

Design and 3D Printing of Interbody Fusion Cage Based on TPMS Porous Structure

To solve the mismatch between the comprehensive mechanical properties of the spinal fusion cage and body, a fusion cage inner hole design method based on controllable TPMS-P to characterize the inner hole structure is proposed to solve the related problems. Firstly, the method of TPMS-P parameterization was used to construct the bionic porous structure model, which was designed as the linear gradual internal porous structure model. Then, we optimized the topology of the obtained porous structure implants to achieve precise control of the overall comprehensive mechanical properties of the fusion cage structure and obtain an optimized model that matched the mechanical properties of the fusion cage. To verify whether the method met the requirements, its simulation model was established. The porous structure was fabricated by selective laser processing, and its properties were tested and analyzed. The results show that its yield strength is 79.83 MPa, which match well with spinal bone tissue.

Theoretical Investigation of the Fusion Process of Mono-Cages to Tri-Cages with CH4/C2H6 Guest Molecules in sI Hydrates

Owing to a stable and porous cage structure, natural gas hydrates can store abundant methane and serve as a potentially natural gas resource. However, the microscopic mechanism of how hydrate crystalline grows has not been fully explored, especially for the structure containing different guest molecules. Hence, we adopt density functional theory (DFT) to investigate the fusion process of structure I hydrates with CH4/C2H6 guest molecules from mono-cages to triple-cages. We find that the volume of guest molecules affects the stabilities of large (51262, L) and small (512, s) cages, which are prone to capture C2H6 and CH4, respectively. Mixed double cages (small cage and large cage) with the mixed guest molecules have the highest stability and fusion energy. The triangular triple cages exhibit superior stability because of the three shared faces, and the triangular mixed triple cages (large-small-large) structure with the mixed guest molecules shows the highest stability and fusion energy in the triple-cage fusion process. These results can provide theoretical insights into the growth mechanism of hydrates with other mono/mixed guest molecules for further development and application of these substances.

An Update Report on the Biosafety and Potential Toxicity of Fullerene-Based Nanomaterials toward Aquatic Animals

Fullerene molecules are composed of carbon in the form of a hollow sphere, tube, or ellipsoid. Since their discovery in 1985, they have gained a lot of attention in many science fields. The unique carbon cage structure of fullerene provides immense scope for derivatization, rendering potential for various industrial applications. Thus, the prospective applications of fullerenes have led to assorted fullerene derivatives. In addition, their unique chemical structure also eases them to be synthesized through various kinds of conjugating techniques, where fullerene can be located either on the backbone or the branch chain. In this review, we have compiled the toxicity and biosafety aspects of fullerene in aquatic organisms since the frequent use of fullerene is likely to come in contact and interact with the aquatic environment and aquatic organisms. According to the current understanding, waterborne exposure to fullerene-based nanomaterials indeed triggers toxicities at cellular, organic, molecular, and neurobehavioral levels.

Coherent interaction of atoms with a beam of light confined in a light cage

Controlling coherent interaction between optical fields and quantum systems in scalable, integrated platforms is essential for quantum technologies. Miniaturised, warm alkali-vapour cells integrated with on-chip photonic devices represent an attractive system, in particular for delay or storage of a single-photon quantum state. Hollow-core fibres or planar waveguides are widely used to confine light over long distances enhancing light-matter interaction in atomic-vapour cells. However, they suffer from inefficient filling times, enhanced dephasing for atoms near the surfaces, and limited light-matter overlap. We report here on the observation of modified electromagnetically induced transparency for a non-diffractive beam of light in an on-chip, laterally-accessible hollow-core light cage. Atomic layer deposition of an alumina nanofilm onto the light-cage structure was utilised to precisely tune the high-transmission spectral region of the light-cage mode to the operation wavelength of the atomic transition, while additionally protecting the polymer against the corrosive alkali vapour. The experiments show strong, coherent light-matter coupling over lengths substantially exceeding the Rayleigh range. Additionally, the stable non-degrading performance and extreme versatility of the light cage provide an excellent basis for a manifold of quantum-storage and quantum-nonlinear applications, highlighting it as a compelling candidate for all-on-chip, integrable, low-cost, vapour-based photon delay.