Triangulenes: From Precursor Design to On‐Surface Synthesis and Characterization

Triangulene and its higher homologues are a class of zigzag‐edged triangular graphene molecules (ZTGMs) with high‐spin ground states. These open‐shell molecules are predicted to host ferromagnetically coupled edge states with net spin values scaling with molecular size and are therefore considered promising candidates for future molecular spintronics applications. Unfortunately, the synthesis of unsubstituted [n]triangulenes and the direct observation of their edge states have been a long‐standing challenge due to a high reactivity towards oxygen. However, recent advances in precursor design enabled the on‐surface synthesis and characterization of unsubstituted [3]‐, [4]‐, and [5]triangulene. In this Minireview, we will highlight key aspects of this rapidly developing field, ranging from the principles of precursor design to synthetic strategies and characterization of a homologous series of triangulene molecules synthesized on‐surface. We will also discuss challenges and future directions.     

Electrochemiluminescent detection of labile radical intermediates of electrochemical reactions

The article considers the basic principles of electrochemiluminescent spin traps diagnostic method which consists of efficient trapping of intermediate labile radical products (free radicals of complex organic molecules) by electrogenerated radical ions of electrochemiluminescers in different liquid-phase systems including bioobjects. The method permits qualitative and quantitative identification of such particles by measurement of electrolysis radical recombination luminescence (electrogenerated chemiluminescence) intensity which is emitted by electrolyzed solutions of organic electrochemiluminescers. The unique possibilities of the method are illustrated on examples of experimental study of systems with sodium tetraphenylborate and chloride ion.     

On a nonclassical fractional boundary-value problem for the Laplace operator

In this paper we consider a boundary-value problem for the Poisson equation with a boundary condition comprising the fractional derivative in time and the right-hand sides dependent on time. We prove the one-valued solvability of this problem, and provide the coercive estimates of the solution.     

Induction of A549 Nonsmall-Cell Lung Cancer Cells Proliferation by Photoreleased Nicotine

Caged compounds comprise the group of artificially synthesized, light-sensitive molecules that enable in situ derivation of biologically active constituents capable of affecting cells, tissues and/or biological processes upon exposure to light. Ruthenium-bispyridine (RuBi) complexes are photolyzed by biologically harmless visible light. In the present study, we show that RuBi-caged nicotine can be used as a source of free nicotine to induce proliferation of A549 nonsmall-cell lung cancer (NSCLC) cells by acting on nicotinic acetylcholine receptors expressed in these cells. RuBi-nicotine was photolyzed using LED light source with the spectrum matching RuBi-absorption. Photorelease of free nicotine ([Nic]_p/r) was quantified by high-performance liquid chromatography (HPLC). 5-s-long light exposure of 10 μm of RuBi-nicotine generated 2 μm [Nic]_p/r which enhanced A549 cell proliferation similarly to the 2 μm of plain nicotine during 72 h of cell culturing. Both RuBi-nicotine per se and its photolysis byproduct exerted no effect on A549 cells. We conclude that RuBi-nicotine can be a good source of free nicotine for inducing short- and long-term biological effects. Photolysis of RuBi-nicotine is quite effective, and can produce biologically relevant concentrations of nicotine at acceptable concentrations of the source material with the use of simple, inexpensive, and easily accessible light sources.     

Halogenoarylation of allyl isothiocyanate: Synthesis of 2,5‐disubstituted 2‐thiazolines

A new approach to the synthesis of 2‐R‐5‐benzyl‐2‐thiazolines with the use of chloro‐ and bromoarylation products of allyl isothiocyanate with arenediazonium halides was elaborated. The isothiocyanates obtained were reacted with ammonia, aliphatic or aromatic amines, and sodium methoxide. The use of ammonia or weakly basic amines in this reaction allowed. Intermediate thioureas to be isolated. On the basis of ¹H NMR spectra, amino–imino tautomerism of the synthesized 2,5‐disubstituted 2‐thiazolines were analyzed. 2‐Arylamino‐5‐benzyl‐2‐thiazolines exist mainly in the Z‐configuration of the imino form. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 517–525, 1999