Au Acyclic (Amino)(N-Pyridinium)carbenoids: Synthesis via Addition of 2-PySeCl to Au-Bound Isonitriles, Structures, and Cytotoxicity.

In this study, we report the first example of acyclic (amino)(N-pyridinium)carbenoid gold(III) complexes synthesized via a coupling reaction between 2-pyridylselenyl chloride and Au(I)-bound isonitriles. The reaction involves an initial oxidative addition of the Se-Cl moiety to Au(I), followed by the nucleophilic addition of the pyridine fragment to the isonitrile's C≡N bond, furnishing a metallacycle. Importantly, this is the first example of the pyridine acting as a nucleophile towards metal-bound isonitriles.

Diverse Cyclization Pathways Between Nitriles with Active -Methylene Group and Ambiphilic 2-Pyridylselenyl Reagents Enabled by Reversible Covalent Bonding.

Herein, we describe a novel coupling between ambiphilic 2-pyridylselenyl reagents and nitriles featuring an active α-methylene group. Depending on the solvent employed, this reaction can yield two distinct types of cationic pyridinium-fused selenium-containing heterocycles, 1,3-selenazolium or 1,2,4-selenadiazolium salts, in high yields. This is in contrast to what we observed before for other nitriles.

Fabry-Perot Effect Suppression in Gas Cells Used in THz Absorption Spectrometers. Experimental Verification.

A standard measuring gas cell used in absorption spectrometers is a cylinder enclosed by two transparent windows. The Fabry-Perot effects caused by multiple reflections of terahertz waves between these windows produce significant variations in the transmitted radiation intensity. Therefore, the Fabry-Perot effects should be taken into account to correctly measure absorption spectra in Bouguer law-based absorption spectroscopy.

Fluorescence from a single-molecule probe directly attached to a plasmonic STM tip.

The scanning tunneling microscope (STM) provides access to atomic-scale properties of a conductive sample. While single-molecule tip functionalization has become a standard procedure, fluorescent molecular probes remained absent from the available tool set. Here, the plasmonic tip of an STM is functionalized with a single fluorescent molecule and is scanned on a plasmonic substrate.