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Conjugates of benzothiophene-fused azacyclononyne BT9N-NH2 with fluorescent dyes were developed to visualise azidoglycans intracellularly. The significance of the cycloalkyne core was demonstrated by comparing new reagents with DBCO- and BCN-dye conjugates. To reduce non-specificity during intracellular bioconjugation using SPAAC, less reactive BT9N-dye reagents are preferred over highly reactive DBCO- and BCN-dye conjugates.

An unprecedented silver-centered P-tetracapped [Ag@Ag 4 (μ 3 -P) 4 ] tetrahedron inscribed within a N 12 icosahedral cage has been discovered in the novel family of luminescent clusters. The latter are easily self-assembled by reacting Ag I salts with tris(2-pyridyl)phosphine (Py 3 P).

4-Aryl-1,1,1-trifluorobut-3-en-2-ones ArCH[double bond, length as m-dash]CHCOCF3 (CF3-enones) react with arenes in excess of Brønsted superacids (TfOH, FSO3H) to give, stereoselectively, trans-1,3-diaryl-1-trifluoromethyl indanes in 35-85% yields. The reaction intermediates, the O-protonated ArCH[double bond, length as m-dash]CHC(OH(+))CF3 and the O,C-diprotonated ArHC(+)CH2C(OH(+))CF3 species, have been studied by means of (1)H, (13)C, (19)F NMR, and DFT calculations. Both types of the cations may participate in the reaction, depending on their electrophilicity and electron-donating properties of the arenes. The formation of CF3-indanes is a result of cascade reaction of protonated CF3-enones to form chemo-, regio- and stereoselectively three new C-C bonds. The obtained trans-1,3-diaryl-1-trifluoromethyl indanes were investigated as potential ligands for cannabinoid receptors CB1 and CB2 types. The most potent compound showed sub-micromolar affinity for both receptor subtypes with a 6-fold selectivity toward the CB2 receptor with no appreciable cytotoxicity toward SHSY5Y cells.