Simplification in the Acquisition and Analysis of Fluorescence Decays Acquired with Polarized Emission for Time-Resolved Fluorescence Anisotropy Measurements.

This study introduces a global fluorescence decay analysis that substantially simplifies the acquisition and analysis of time-resolved fluorescence decays acquired with a vertically polarized excitation and vertically (()) and horizontally (()) polarized emission for time-resolved fluorescence anisotropy (TRFA) measurements. TRFA measurements were conducted whereby the () and () fluorescence decays of a series of oligoquinolines labeled at one end with an oligo(phenylenevinylene) dye (OPV-Q with = 4, 7, 17, 24, 33) were acquired according to the standard protocol that is currently accepted in the scientific literature which involves toggling the emission polarizer before fitting linear combinations of the () and () decays or acquiring the () and () decays with static polarizers before fitting them globally. The rotational time (ϕ) and initial anisotropy () retrieved from these analyses were identical within experimental error regardless of whether the decays were acquired with toggling or static polarizers and fitted according to the standard protocol or globally.

Multi-dimensional charge transport in supramolecular helical foldamer assemblies.

Aromatic foldamers are bioinspired architectures whose potential use in materials remains largely unexplored. Here we report our investigation of vertical and horizontal charge transport over long distances in helical oligo-quinolinecarboxamide foldamers organized as single monolayers on Au or SiO. Conductive atomic force microscopy showed that vertical conductivity is efficient and that it displays a low attenuation with foldamer length (0.

Selenocysteine as a Latent Bioorthogonal Electrophilic Probe for Deubiquitylating Enzymes.

Deubiquitylating enzymes (DUBs) remove ubiquitin (Ub) from various cellular proteins and render eukaryotic ubiquitylation a dynamic process. The misregulation of protein ubiquitylation is associated with many human diseases, and there is an urgent need to identify specific DUBs associated with therapeutically relevant targets of Ub. We report the development of two facile selenocysteine-based strategies to generate the DUB probe dehydroalanine (Dha).

Photoinduced Electron Transfer and Hole Migration in Nanosized Helical Aromatic Oligoamide Foldamers.

A series of photoactive triads have been synthesized and investigated in order to elucidate photoinduced electron transfer and hole migration mechanism across nanosized, rigid helical foldamers. The triads are comprised of a central helical oligoamide foldamer bridge with 9, 14, 18, 19, or 34 8-amino-2-quinolinecarboxylic acid repeat units, and of two chromophores, an N-terminal oligo(para-phenylenevinylene) electron donor and a C-terminal perylene bis-imide electron acceptor. Time-resolved fluorescence and transient absorption spectroscopic studies showed that, following photoexcitation of the electron acceptor, fast electron transfer occurs initially from the oligoquinoline bridge to the acceptor chromophore on the picosecond time scale.

A one-pot azido reductive tandem mono-N-alkylation employing dialkylboron triflates: online ESI-MS mechanistic investigation.

An efficient one-pot reductive tandem mono-N-alkylation of both aromatic and aliphatic azides using dialkylboron triflates as alkylating agents has been examined under standardized reaction conditions. This methodology after optimization has been employed toward the syntheses of various secondary alkyl as well as aryl amines, including the synthesis of N10-butylated pyrrolo[2,1-c][1,4]benzodiazepine-5,11-diones via in situ azido reductive-cyclization process. This protocol is particularly attractive to provide an environmentally benign and practical method for mono-N-alkylation from organic azides without the use of toxic catalysts or corrosive alkylating agents.

Chemoselective aromatic azido reduction with concomitant aliphatic azide employing Al/Gd triflates/NaI and ESI-MS mechanistic studies.

Aluminium and gadolinium triflates catalyze the chemoselective reduction of aromatic azides to the corresponding amines in combination with sodium iodide. This mild chemoselective method has been applied to the synthesis of various aryl amines, C2-azido-substituted pyrrolo[2,1-c][1,4]benzodiazepines, and fused[2,1-b]quinazolinones by an intramolecular azido reduction tandem cyclization reaction. Interestingly, this methodology selectively reduces aryl azides with enhanced yields and proceeds in shorter reaction times than previous strategies.