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9°). The results indicated that it is critical to control the extents of nitration and carbonization for maintaining the performance of the composites, especially the mechanical properties, whereas there is no strict requirement for the same objective using the mixed gas of Ar + H2 in which qualified composites could be obtained for implant applications.A nonplanar extended π-system can be found not only in compounds formed by multiple ortho-fused benzenes, such as helicenes and corannulenes, but also in compounds formed by bonding of atoms on the large π-extended rings. (1,3,5-Triazine)2n (n ≥ 3) are the latter type of compounds that are characterized by monomer units composed entirely of a 1,3,5-triazine core (general formula C3N3). The first seven polymers (C3N3)2n (n = 3-9) with a drum shape were investigated computationally. Analyses of natural bonding orbitals and atoms in molecules were applied to investigate the bonding properties. In contrast to the planar structure of the 1,3,5-triazine core, the monomer units in (C3N3)2n (n = 3-9) are transformed from their planar π-system to a warped one. Ivacaftor activator Similar to properties of the nonplanar π-system in [n]helicenes and corannulenes, the nonplanar heterocyclic aromatic configuration of the polymerization units is the determinant of the physical and chemical properties of these polymers. The discovery of nonplanar heterocyclic aromatic structures opens up a broad prospect for the study of azacyclic compounds. The results will be the supplement to the study of heterocyclic helicenes and corannulenes.HIV-1 protease is indispensable for virus propagation and an important therapeutic target for antiviral inhibitors to treat AIDS. As such inhibitors are transition-state mimics, a detailed understanding of the enzyme mechanism is crucial for the development of better anti-HIV drugs. Here, we used room-temperature joint X-ray/neutron crystallography to directly visualize hydrogen atoms and map hydrogen bonding interactions in a protease complex with peptidomimetic inhibitor KVS-1 containing a reactive nonhydrolyzable ketomethylene isostere, which, upon reacting with the catalytic water molecule, is converted into a tetrahedral intermediate state, KVS-1TI. We unambiguously determined that the resulting tetrahedral intermediate is an oxyanion, rather than the gem-diol, and both catalytic aspartic acid residues are protonated. The oxyanion tetrahedral intermediate appears to be unstable, even though the negative charge on the oxyanion is delocalized through a strong n → π* hyperconjugative interaction into the nearby peptidic carbonyl group of the inhibitor. To better understand the influence of the ketomethylene isostere as a protease inhibitor, we have also examined the protease structure and binding affinity with keto-darunavir (keto-DRV), which similar to KVS-1 includes the ketomethylene isostere. We show that keto-DRV is a significantly less potent protease inhibitor than DRV. These findings shed light on the reaction mechanism of peptide hydrolysis catalyzed by HIV-1 protease and provide valuable insights into further improvements in the design of protease inhibitors.Three-dimensional highly ordered multilayer titanium dioxide (TiO2) inverse opal (TIO) structures with two pore sizes were fabricated over a large surface using a self-convective method. The fabricated TIO multilayers were functionalized with gold nanoparticles (AuNPs) by immersing the samples in solution with gold nanoparticles. The photocatalytic activity of TiO2 was enhanced by 85% via plasmonic activation of AuNPs that increased the lifetime of photogenerated holes and electrons. The improved photocatalytic activity was characterized with both UVA and visible light irradiation using an in-house built gas-phase photoreactor.Scales of electronegativity values are used by chemists to describe numerous chemical features such as chemical mechanisms, bond polarity, band gap, atomic hardness, etc. While the many scales provide similar trends, all differ in their predictive quality. Confirmation of the quality of a new scale often uses a previous scale for comparison but does not use independent means to demonstrate the merits of the scale. Utilizing a table of binary compounds of known ionic, covalent, and metallic bonding characters, a means to evaluate electronegativity scales is developed here. By plotting the electronegativity values of the two bonded atoms in binary compounds of a known bonding character, a tripartite separation results that generally divides the three bond types. Using the results of graphs of this sort, the success of bonding separations of 14 different scales of electronegativity has been evaluated on the basis of three quantitative parameters that can provide a measure of the quality of the scales. Three scales, those of Allen, Martynov and Batsanov, and Nagle, have been shown to be superior in their ability to predict the expected separation of bond types. Since this scheme successfully demonstrates the ability to evaluate the quality of electronegativity scales, it can be applied to other scales to establish their effectiveness in predicting bond types in binary compounds and thus the quality of the scales. This scheme is applied to a recently published electronegativity scale to evaluate the ability to determine its quality.CsPbX3 (X = Cl, Br, I) perovskite nanocrystals (NCs) are promising materials due to their excellent optoelectronic properties. This work shows a successful anion exchange reaction in CsPbBr3 nanowire (NW) systems with HCl gas resulting in a blue-green light-emitting CsPbBr3@CsPbBr3-x Cl x core-shell heterojunction. By adjusting the reaction time and the reaction temperature, the structure and light emission of the NWs can be adjusted. The core-shell heterojunction NCs are stably luminescent in 24 h. The rational mechanism of anion exchange in perovskite NCs is also investigated. The work highlights the feasibility of NWs heterogeneously prepared under the HC1 gas atmosphere, which provides a new strategy for studying the two- and multicolor luminescent perovskite NCs.Substituent effects at the C2-, C8-, and N-positions of adenine and purine on the structural and π-electronic changes in their four tautomers were studied using the B97D3/aug-cc-pvdz computational level. The effect of various substituents (NO2, CN, CHO, Cl, F, H, Me, OMe, OH, and NH2) was characterized by the charge of the substituent active region (cSAR) approach and Hammett substituent constants σ. It has been found that for both adenine and purine derivatives, substituents from the C8-X position have a stronger influence on their electronic structure than from the C2-X and N-X positions. The presence of the amino group in adenine enhances the substituent effect compared to that which occurs in purine. In addition, its electronic structure is more sensitive to the effect of the substituent in 3H and 1H than in the 9H and 7H adenine tautomers. For a given substituent, a large variation in cSAR(X) values is observed, strongly dependent on the substitution position. For 7H and 9H adenine tautomers for C8-X systems, substituents reduce the aromaticity of the five-membered rings but increase the aromaticity of the six-membered rings.