objective: non-steroidal anti-inflammatory drugs (nsaids) are the most commonly prescribed pain control medications following periodontal surgery. this study aimed to compare the efficacy of three drug regimens namely celecoxib, celecoxib + caffeine and ibuprofen for pain relief following crown lengthening surgery.   methods: this randomized, double blind clinical trial was performed on 45 pati...

A new [2]pseudorotaxane DB24C8⊃1-H · PF6 with dibenzo[24]crown-8 (DB24C8) crown ether-dibenzylammonium (1-H · PF6) binding which was formed by slippage approach at different solvents and temperature, had been isolated and characterized by NMR spectroscopy and mass spectrometry. The [2]pseudorotaxane DB24C8⊃1-H · PF6 was stable at room temperature. The dissociation rate of [2]pseudorotaxane DB24...

The rational design of materials with tailored properties is of paramount importance for a wide variety of biological, medical, electronic and optical applications. Here we report molecular level control over the spatial distribution of functional groups on surfaces utilizing self-assembled monolayers (SAMs) of pH-switchable surface-appended pseudorotaxanes. The supramolecular systems were cons...

The reaction of 4-bromo-aniline, 18-crown-6, and perchloric acid in methanol yields the title compound, C(6)H(7)BrN(+)·ClO(4) (-)·C(12)H(24)O(6), in which the protonated -NH(3) (+) group forms three bifurcated N-H⋯O hydrogen bonds to the O atoms of the crown ether.

In the title compound, C(6)H(7)IN(+)·ClO(4) (-)·C(12)H(24)O(6), the proton-ated 4-iodo-anilinium cation inter-acts with the 18-crown-6 through three N-H⋯O hydrogen bonds, forming a rotator-stator-like structure. The cation, anion and 18-crown-6 mol-ecule all have crystallographically imposed mirror symmetry.

The 1,4-bis(3-guaiazulenylmethylium)benzene and 1,4-bis[1-(4,6,8-trimethylazulenylmethylium)]benzene dication salts were synthesized via an acid-catalyzed condensation/dehydration protocol with guaiazulene-terephthalaldehyde (2 : 1 ratio), and 4,6,8-trimethylazulene-terephthalaldehyde (2 : 1 ratio) respectively in one-pot processes. A similar condensation reaction with the parent azulene led to...

The geometric and electronic structures of cold host-guest complex ions of crown ethers (CEs) in the gas phase have been investigated by ultraviolet (UV) fragmentation spectroscopy. As host CEs, we chose 15-crown-5 (15C5), 18-crown-6 (18C6), 24-crown-8 (24C8), and dibenzo-24-crown-8 (DB24C8), and as guests protonated-aniline (aniline·H(+)) and protonated-dibenzylamine (dBAM·H(+)) were chosen. T...