Overcoming barriers with non-covalent interactions: supramolecular recognition of adamantyl cucurbit[]uril assemblies for medical applications.

Adamantane, a staple in medicinal chemistry, recently became a cornerstone of a supramolecular host-guest drug delivery system, ADA/CB[]. Owing to a good fit between the adamantane cage and the host cavity of the cucurbit[]uril macrocycle, formed strong inclusion complexes find applications in drug delivery and controlled drug release. Note that the cucurbit[]uril host is not solely a delivery vehicle of the ADA/CB[] system but rather influences the bioactivity and bioavailability of drug molecules and can tune drug properties.

Nanostructured supramolecular networks from self-assembled diamondoid molecules under ultracold conditions.

Diamondoid molecules and their derivatives have attracted attention as fascinating building blocks for advanced functional materials. Depending on the balance between hydrogen bonds and London dispersion interactions, they can self-organize in different cluster structures with functional groups tailored for various applications. Here, we present a new approach to supramolecular aggregation where self-assembly of diamondoid acids and alcohols in the ultracold environment of superfluid helium nanodroplets (HNDs) was analyzed by a combination of time-of-flight mass spectrometry and computational tools.

Ultrafast Photoelimination of Nitrogen from Upper Excited States of Diazoalkanes and the Fate of Carbenes Formed in the Reaction.

The photochemical reactivity of diphenyldiazomethane and phenyl 1- and 2-adamantyl diazomethanes and , respectively, was investigated by transient absorption spectroscopy (TA). Photoelimination of N upon UV excitation takes place in the anti-Kasha ultrafast photochemical reaction from the upper excited singlet states to deliver singlet carbenes, which were, in the case of and , detected by fs-TA. The reactivity of the carbenes differs with respect to the substituent at the carbene center.

Diamondoid ether clusters in helium nanodroplets.

Diamondoid ethers were introduced into superfluid helium nanodroplets and the resulting clusters were analyzed by time-of-flight mass spectrometry. Clusters of higher abundances (magic number clusters) were identified and the corresponding potential cluster geometries were obtained from GFN2-xTB and DFT computations. We found that the studied diamondoid ethers readily self-assemble in helium nanodroplets and that London dispersion attraction between hydrocarbon subunits acts as a driving force for cluster formation.

Photoelimination of Nitrogen from Diazoalkanes: Involvement of Higher Excited Singlet States in the Carbene Formation.

Although diazoalkanes are important carbene precursors in organic synthesis, a comprehensive mechanism of photochemical formation of carbenes from diazoalkanes has not been proposed. Synergies of experiments and computations demonstrate the involvement of higher excited singlet states in the photochemistry of diazoalkanes. In all investigated diazoalkanes, excitation to S results in nonreactive internal conversion to S.

Photoelimination of nitrogen from adamantane and pentacycloundecane (PCU) diazirines: a spectroscopic study and supramolecular control.

Photochemical reactivity of pentacycloundecane (PCU) and adamantane diazirines was investigated by preparative irradiation in different solvents, laser flash photolysis (LFP) and quantum chemical computations. In addition, formation of inclusion complexes for diazirines with cucurbit[7]uril, β- and γ-cyclodextrin (β- and γ-CD) was investigated by 1H NMR spectroscopy, isothermal microcalorimetry and circular dichroism spectroscopy, followed by the investigation of photochemical reactivity of the formed complexes. Diazirines undergo efficient photochemical elimination of nitrogen (ΦR > 0.

Photochemical deuterium exchange in phenyl-substituted pyrroles and indoles in CD3CN-D2O.

A new mechanism of photochemical deuteration of some phenylpyrroles and indoles is reported. Irradiation of 2-phenylpyrrole (8), 2-phenylindole (9), and 7-phenylindole (12) in CH(3)CN-D(2)O gives rise to deuterium exchange at the C-atoms of the heterocycle and the adjacent phenyl ring. Photolysis of indole (7), 8, 9, 12 and N-methyl-2-phenylindole (10) in CD(3)CN-D(2)O also leads to deuteration at C-atoms with significantly higher yield.