Atomistic molecular dynamics simulations are performed on oligomeric polyamide-6,6 chains, composed of 10 chemical repeat units, at a carbon nanotube (CNT) interface. The effect of surface curvature on the structure and dynamics of polymer is studied by simulating systems containing CNTs of various diameters. It is shown that polymer at the CNT interface organizes into layered structures. The hydrogen bonding in the polymer is influenced by the CNT surface. In proximity to the CNT surface, the hydrogen bonds (HBs) are weaker than the corresponding unperturbed bonds and their density is lower than that of the bulk sample. On the other hand, over the region where organized layered structures are formed, stronger HBs with a higher density than that of the bulk sample are found. An analysis of chain orientation at the interface shows that the monomers (repeat units) very close to the CNT surface wrap around the tube. However, at distances corresponding to higher densities than the bulk density, the segments orient parallel to the CNT axis (along the CNT). The wrapping costs higher energies in the case of smaller diameter CNTs (more curved surfaces). It is shown that while the CNT surface perturbs the local chain properties up to a distance of ∼2 nm from the surface, perturbation in the global chain properties, such as the radius of gyration, extends to farther distances (a few times the radius of gyration of the unperturbed chain, R 0 g ). The chain translation at the interface is found to be anisotropic, depending on the surface proximity and surface curvature. This is due to the formation of extended conformations (along the CNT), facilitating smoother chain translation parallel to the CNT surface, compared to that in the radial direction. The magnitude of dynamics deceleration caused by the CNT surface depends on the surface proximity, surface curvature, and the time scale of the unperturbed dynamical property of interest. The dynamics decelerates more in the case of long-time dynamical properties (in the bulk) for chains at closer distances to flatter CNT surfaces. While the ratio of relaxation time to the corresponding bulk quantity for HB formation/rupture is increased by a factor of 3 in a cylindrical shell of thickness 0.6 nm around the flatter surface studied in this work, the above ratio for the decorrelation of chain's end-to-end vectors is increased by 3 orders of magnitude in a cylindrical shell of thickness 1.0 nm on the same surface. In this respect, the interphase thickness depends on the time scale of the dynamical property of interest. Our observations show that the surface effect on a short-time dynamical property, like the HB dynamics, extends to distances as long as 1.5 nm, while it extends to a few R 0 g (from the surface) for a long-time dynamical property, like the relaxation of the entire chain expressed in terms of chain's end-to-end vector relaxation.
The design, synthesis, antinociceptive and β-adrenoceptor blocking activities of several eugenyloxy propanol azole derivatives have been described. In this synthesis, the reaction of eugenol with epichlorohydrin provided adducts 3 and 4 which were N-alkylated by diverse azoles to obtain the eugenyloxy propanol azole analogues in good yields. Adducts 3 and 4 were also reacted with azide ion to obtain the corresponding azide 6. The 'Click' Huisgen cycloaddition reaction of 6 with diverse alkynes afforded the title compounds in good yields. The synthesized eugenyloxy propanol azole derivatives were in vivo studied for the acute antinociception on male Spargue Dawley rats using tail-flick test. Compounds 5f, 5g, 7b and 11a exhibited potent analgesic properties in comparison with eugenol as a standard drug. In addition, all compounds were ex vivo tested for β-adrenoceptor blocking properties on isolated left atrium of male rats which exhibited partial antagonist or agonist behaviour compared to the standard drugs. The molecular docking study on the binding site of transient receptor potential vanilloid subtype 1 (TRPV1) has indicated that like capsaicin, eugenyloxy propanol azole analogues exhibited the strong affinity to bind at site of TPRV1 in a "tail-up, head-down" conformation and the presence of triazolyl moieties has played undeniable role in durable binding of these ligands to TRPV1. The in silico pharmacokinetic profile, drug likeness and toxicity predictions carried out for all compounds determined that 5g can be considered as potential antinociceptive drug candidate for future research.
The design, synthesis and biological study of several novel 1,2,3-triazolyl [Formula: see text]-hydroxy alkyl/carbazole hybrid molecules as a new type of antifungal agent has been described. In this synthesis, the N-alkylation reaction of carbazol-9-ide potassium salt with 3-bromoprop-1-yne afforded 9-(prop-2-ynyl)-9H-carbazole. The 'Click' Huisgen cycloaddition reaction of 9-(prop-2-ynyl)-9H-carbazole with diverse [Formula: see text]-azido alcohols in the presence of copper-doped silica cuprous sulphate led to target molecules in excellent yields. The in vitro antifungal and antibacterial activities of title compounds were screened against various pathogenic fungal strains, Gram-positive and/or Gram-negative bacteria. In particular, 1-(4-((9H-carbazol-9-yl) methyl)-1H-1,2,3-triazol-1-yl)-3-butoxypropan-2-ol (10e) proved to have potent antifungal activity against all fungal tests compared with fluconazole and clotrimazole as studied reference drugs. Our molecular docking analysis revealed an appropriate fitting and a potential powerful interaction between compound 10e and an active site of the Mycobacterium P450DM enzyme. The strong hydrogen bondings between [Formula: see text]-hydroxyl and ether groups in 10e were found to be the main factors that drive the molecule to fit in the active site of enzyme. The in silico pharmacokinetic studies were used for a better description of 10a-10n as potential lead antifungal agents for future investigations.
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