Andrey Lvov

A.E. Favorsky Institute of Chemistry / Irkutsk National Research Technical University

Irreversible two-photon photorearrangement of 1,2-diarylethenes is a unique process providing access to complex 2a1,5a-dihydro-5,6-dithiaacenaphthylene (DDA) heterocyclic core. This reaction was serendipitously discovered during studies on photoswitchable diarylethenes and was initially considered as a highly undesired process. However, in recent y...

A study of luminescence and photochromic properties of (E)-2,3-bis(2,5-dimethylthiophen-3-yl)-5-(4-(pyrrolidin-1-yl)benzylidene)cyclopent-2-en-1-one, which is a diarylethene with a push-pull system between carbonyl and dimethylamino groups, was performed using time-resolved methods. The intramolecular charge transfer (ICT) process as well as 6π-ele...

There is an incessant interest in transfer of common chemical processes from organic solvents to water, which is vital for the development of bioinspired and green chemical technologies. Diarylethenes feature a rich photochemistry, including both irreversible and reversible reactions that are in demand in organic synthesis, materials chemistry, and...

There is incessant interest in the transfer of common chemical processes from organic solvents to water, which is vital for the development of bioinspired and green chemical technologies. Diarylethenes feature a rich photochemistry, including both irreversible and reversible reactions that are in demand in organic synthesis, materials chemistry, an...

Photoinduced charge transfer affects the efficiency and selectivity of photochemical reactions. Incorporation of donating groups into the isoquinolinium core allowed us to overcome the photochemical inactivity of the corresponding dithienyl-substituted terarylenes, presumably by redirecting the charge transfer within the molecule, and gave access t...

The photochemical 6π‐cyclization of diarylethenes (DAE), 2‐vinylbiaryls (VBA) and their derivatives is widely used in organic synthesis. Combination of these motifs in one molecule opens the issue of selectivity of the photochemical reaction. We have found that upon UV irradiation, 3‐(1,2‐diarylvinyl)‐2‐arylimidazo[1,2‐ a ]pyridines comprising both...

A reversible interconversion of diarylethenes between two isomers became a powerful means for the development of new materials with a photoswitching function. The versatility of this phenomenon allows a wide variety of heterocyclic systems with advanced properties to be applied. In this mini-review, we analyzed the effect of incorporation of silole...

Introduction of push-pull system between carbonyl and dimethylamino groups in the ethene bridge of diarylethene provides access to multifunctional fluorescent switches, responsible for various stimuli (UV and visible light, solvent polarity, and pH change). In this work a thorough study of luminescent and photochromic properties of three cyclopente...

The azulene molecule features a unique combination of optical, luminescence, and stimuli-responsive properties. This makes the azulene motif a promising functional group to be introduced in photoswitches. Recent challenges in the field of photochromic compounds require the development of new approaches to molecules that are switched by visible ligh...

Photoswitchable diarylethenes provide a unique opportunity to optically modulate frontier molecular orbital energy levels, thereby opening an avenue for the design of electronic devices such as photocontrollable organic field-effect transistors (OFETs). In the present work, the absolute position of the frontier orbital levels of nonsymmetrical diar...

One-way photoisomerization of ligands within metal complexes is a nearly unknown phenomenon. We disclosed that a diarylethene-based ligand L-o undergoes quantitative irreversible photoisomerization to a photo- and thermostable annulated isomer...

Photoswitchable organic field-effect transistors (OFETs) with embedded photochromic materials are considered as a promising platform for development of organic optical memory devices. Unfortunately, the operational mechanism of these devices and guidelines for selection of light-sensitive materials are still poorly explored. In the present work, a...

This review analyzes the new life of a long-known reaction, the photocyclization of diarylethenes, which became a classical tool for the synthesis of phenanthrenes and their heterocyclic analogs (Mallory reaction). It has been shown in recent years that certain diarylethenes undergo photorearrangement to naphthalenes, benzannulated heterocycles or...

A novel protocol for synthesis of functionalized phenanthrenes through photocyclization of diarylethenes (DAE) under UV-irradiation is proposed. The reaction proceeds through 6π-electrocyclization with the formation of a cyclic (closed) intermediate that undergo to a rearrangement affording unsymmetrical phenanthrenes in good yields. However, in co...

Manipulating the equilibrium between a ketone and an enol by light opens up ample opportunities in material chemistry and photopharmacology. By incorporating β-ketoester into the ethene bridge of a photoactive diarylethene, we achieved reversible light-induced tautomerization to give thermally stable enol. In a pristine state, the tautomeric equili...

Early processes in photochemistry of 2,3-bis(2,5-dimethylthiophen-3-yl)cyclopent-2-enone were explored using the ultrafast pump-probe spectroscopy. The photocyclization occurs from the antiparallel conformation of an open form on a time scale of 7 ps, while the parallel conformation exhibits an intersystem crossing within 130 ps. The mechanism and...

Manipulating the equilibrium between a ketone and an enol by exposure to light opens up ample opportunities in material chemistry and photopharmacology since it allows one to reversibly control the content of the enol tautomer, which acts as a hydrogen atom donor, with high spatio-temporal and energy resolution. Although tautomerization of β-ketoes...

The photostability and antiproliferative activity of combretastatin A-4 (CA-4) analogues against human epidermoid carcinoma cells A-431 were studied. For the first time, it was shown that UV or sunlight irradiation of furanone analogues of CA-4 results in a photorearrangement giving products with relatively low antiproliferative activity. The obser...

A new family of photochromic diarylethene-based ligands bearing a 2-(imidazol-2-yl)pyridine coordination unit has been developed. Four members of the new family have been synthesized. The photoactive ligands feature non-aromatic ethene bridges (cyclopentene, cyclopentenone, and cyclohexenone), as well as closely spaced photoactive and metal coordin...

Photochemical properties of dithienylethene containing push-pull system in the cyclopentenone bridge were studied in detail. This molecule possesses notable combination of photochromic and fluorescent properties. Fluorescence was modulated between “on” and “off” via photoisomerization of the diarylethene moiety. Solvent polarity affects significant...

The efficient protocols for the synthesis of unique 1,2-bis(2,5-dimethylthiophen-3-yl)azulene and 1,2,3-tris(2,5-dimethylthiophen-3-yl)azulene as potential multi-responsive molecules have been developed. Lack of photoactivity of obtained azulenes was explained by means of DFT calculations and X-ray powder diffraction data. Protonation of the dithie...

A general strategy for the preparative benzannulation of aromatic heterocycles via photocyclization of 1,2-dihetarylethenes was proposed for the first time. The strategy includes two steps, namely, modular assembly of dihetarylethenes from widely available 3-hetarylacetic acids and 2-bromo-1-hetarylethanones, and subsequent preparative photorearran...

An unexplored ability of the long-known chemical transformation, Borsche’s cyclopentenone synthesis (the construction of a 1,4-diketone with subsequent base-induced cyclization), is reported. Double alkylation of ethyl 4-(het)aryl-3-oxobutanoates with 2-bromo-1-(het)arylethanones, with subsequent alkali treatment, provides access to cyclopentenones...

Fine‐tuning of the molecular structure of organic bistable compounds to improve their photochromic performance or to introduce additional functions remains an important issue in the development of photoresponsive materials. Diarylethenes bearing heterocyclic moieties belong to the most intensively studied class of organic photochromes due to their...

A series of photochromic diarylethenes with different bridge moieties have been investigated as light-sensitive components of photoswitchable organic field-effect transistors. It was shown that the presence of carbonyl group and its position in the bridge part of the diarylethene molecule affects strongly the electrical performance and stability of...

We have studied the photoreaction of 1,2-diarylethenes under aerobic conditions in the presence of various amines to prevent side processes promoted by singlet oxygen. It has been found that the most amines quite effectively deactivate processes associated with singlet oxygen, but primary and secondary amines unlike tertiary ones, react with substr...

A new chemoselective method for the synthesis of 2-aryl-1,3-oxazoles by deoxygenation of the corresponding N-oxides has been developed. As the deoxygenation reagent, a previously unknown complex of collidine with phosphorus trichloride in a 2:1 ratio has been used. The developed method enabled the preparation of a wide range of 2-aryl-1,3-oxazoles...

Photoinduced rearrangement of diarylethenes leading to the formation of naphthalenes or isoelectronic benzoannulated heterocycles is a novel reaction in preparative organic photochemistry. Recently it was shown that unsymmetrical diarylethenes containing benzene and oxazole derivatives efficiently undergo this transformation leading to amide deriva...

For a long time, starting from pioneering works of M. Irie in the late 80 s and early 90 s of the last century, photochromic diarylethenes were primarily associated with dithienylethenes – diarylethenes possessing thiophene groups. However, about 10 years ago, azole heterocycles (thiazole, oxazole, imidazole) started to be used as aryl moieties ins...

Six new photoactive unsymmetrical diarylethenes bearing thiazole ring with hydrogen at the reactive carbon atom have been synthesized. Their structures have been studied by DFT calculations and X-ray crystallography. All compounds undergo irreversible photochemical transformations under irradiation with ultraviolet light, proceeding through the pho...

A series of previously unreported di- and triaryl(hetaryl)cyclopentenone derivatives were prepared using a convenient synthetic method and screened preliminarily for antitumor activity in four human cell lines, i.e., T-cell leukemia (Jurkat), lung adenocarcinoma (A-549), colon cancer (HCT-116), and breast adenocarcinoma (MCF-7). The most cytotoxic...

Cyclopentenyl carbocations formed as a result of the protonation of 3,4-substituted cyclopent-3-en-1,2-diols can give either cyclopent-2-en-1-one derivatives via pinacol rearrangement or interrupted reaction products similar to the Nazarov intermediate.

A unique chemical transformation, the base-induced aerobic dimerization of ethyl 4-(2,5-dimethylthiophen-3-yl)-3-ketobutanoate leading to photochromic diarylethene with a 4-hydroxy-4-methylcyclopent-2-ene-1-one as an ethene bridge, is described. This compound is easily subjected to various chemical modifications and can be used as a new diarylethen...

In recent years, a great synthetic potential of the photorearrangement of diarylethenes leading to naphthalene derivatives via a cascade process of photocyclization/[1, n]-H shift / cycloreversion has been demonstrated. In this work first a multifaceted study of the influence of various factors on the efficiency of the photorearrangement of diaryle...

The potential of photoisomerization of β-(2-furanyl)- and β-(2-thienyl)enones in the field of optical memory was explored by synthesis and thorough studies of the cyclopentene-based series with different substituents on the aryl moiety. X-ray crystallographic analysis of the synthesized β-(2-furanyl)- and β-(2-thienyl)enones established the constan...

The effect of the size of the ethene bridge on the structural and spectral properties of photochromic diarylethenes, which remains a poorly understood phenomenon, was studied as applied to diarylethenes containing unsymmetrical (cyclohexenone and cyclopentenone) and symmetrical (cyclohexene and cyclopentene) ethene bridges. Thiophene, oxazole, and...

The acid-catalyzed cyclization of a wide range of triaryl-substituted divinyl ketones has been studied. It was found that the reaction pathway strongly depends on the nature of the aryl substituent at the α-position to the carbonyl group. An electron-rich aromatic substituent promotes the reaction to proceed through the intramolecular Friedel-Craft...

A new efficient method was developed for the synthesis of triaryl-substituted cyclohexenones and salicylates. The method is based on the Robinson annulation of readily available keto esters and chalcones, followed by the aromatization of the cyclohexenone moiety. The aromatization can be accomplished either by reaction with bromine in boiling chlor...

The photocyclization of stilbenes and their heterocyclic analogs has gained major importance in the synthesis of poly(hetero)aromatic compounds. This reaction generally leads to the formation of phenanthrene derivatives or their isosteric heterocyclic analogs. Over the last 15 years, examples of a new type of diarylethene reactions have been publis...

Unsymmetrical photoswitchable diarylethenes containing benzene, thiophene, or azoles as aromatic moieties are prepared.

A facile synthetic approach to photoactive diarylethenes comprising a cyclopentene ring as an ethene bridge was developed based on reduction of 2,3-diaryl(hetaryl)cyclopent-2-en-1-ones through ionic hydrogenation reaction. The method provides an access to unsymmetrical photoswitchable diarylethenes containing benzene, thiophene, or azoles (thiazole...

New dialkylamino groups-comprising diarylethenes of 2,3-diarylcyclopent-2-en-1-one (DCP) series have been synthesized and its photochromic, fluorescent as well as acidochromic features have been investigated. It was shown that photochromic properties of the substances depend strong on their structures; the non-symmetry of the photochromic molecule...

A two-stage preparative method is proposed for the synthesis of dithienylacetylenes – widely used intermediates in the preparation of photochromic diarylethenes.

We have proposed a promising concept of designing OFET-based organic memory elements operating via optically and electrically triggered charge separation between the semiconductor and the photochromic dielectric layers. The fi rst fabricated devices demonstrated highly promising electrical characteristics, good stability, and reliability. Further e...

A novel and efficient photochemical transformation of diarylethenes comprising five-membered heterocyclic ring and phenyl moiety is described. This reaction provides a simple method for the preparation of functionalized naphthalene derivatives via photorearrangement reaction of diarylethenes and the process is characterized by high efficiency that...

Novel photochromic diarylethenes based on a 2,3-diarylcyclopent-2-en-1-one core and containing imidazole residues as the aryl moiety were synthesized. The photochromic properties of the obtained compounds were investigated in acetonitrile and a comparative analysis with oxazole and thiophene containing diarylethenes was performed. It was found that...

An effective method is proposed for the synthesis of photochromic diarylethenes of cyclopentenone series with SnCl4-catalyzed 4π-electron cyclization of divinyl ketones by Nazarov reaction as the key step. It was shown that the introduction of an aryl group at position 4 of the cyclopentenone ring significantly improved the quantum yield of diaryle...

An alternative synthetic strategy for the preparation of 6,6a-dihydropentalene-2(1H)-one derivatives comprising the stage of the regioselective alpha-bromination of cyclopentenone system has been proposed. The method along with the bromination process includes the alkylation of ethyl 4-aryl-3-oxobutanoate with bromocyclopentenones and intramolecula...

Novel unsymmetrical photochromic diarylethenes of the cyclopentenone series are synthesized and their photospectroscopic properties are investigated in MeCN.

A novel photochemical rearrangement of diarylethenes bearing oxazole and benzene derivatives as aryl moieties that results in the formation of polyaromatic systems was investigated. The mechanism of the transformation includes photocyclization, sequential [1,9] and [1,3]-hydrogen shifts, as well as a lateral oxazole ring-opening process. It was sho...

Photochromic diarylethenes (DAEs) based on the unsymmetrical ethene "bridge" bearing heterocycles of the different nature (oxazole and thiophene) as aromatic moieties have been designed and the photoswitching properties have been studied. The comparative studies of the photochromic characteristics of unsymmetrical isomeric 2,3-diarylcyclopent-2-en-...

Oxidation of 2,3-diarylcyclopent-2-en-1-ones with m-chloroperoxybenzoic acid gave new thermally stable sulfone derivatives of photochromic diarylethenes. The spectral properties of the compounds obtained (the wavelengths of the maxima of the absorption bands of their initial and cyclic forms, the quantum yields of photocyclization and photobleachin...

Photochromic diarylethenes with an additional p system in the ethene bridge were synthesized by the condensation of 2,3-bis(2,5-di- methyl-3-thienyl)cyclopent-2-en-1-one with aromatic aldehydes. Absorption bands maxima of the initial and cyclic forms of the substances were determined and their thermal stability was studied.

The research data in the field of fluorescent photochromic di(het)arylethenes published over the last decade are summarized. The characteristics of these compounds significant for their application in the design of molecular optical memory systems and photocontrolled switches are considered. The main types of diarylethenes and methods for their syn...

A wide range of new oxime-based photochromic diarylethenes of the cyclopentenone series have been synthesized. Their spectral properties have been investigated in detail upon UV/vis light irradiation in acetonitrile solution, and distinct correlations between photochromic characteristics and substance structures are revealed. It was found that the...

New fluorescent switches with 2,3-diarylcyclopent-2-en-1-ones as the photochromic component and 6-ethoxy-3-methyl-1H-phenalen-1-one as the fluorophore have been prepared. Two approaches to develop the photoswitches have been applied. The first involves covalent binding of the fluorophore to photochromic diarylethene molecule by ether linkage. The s...

The bromination of 2,3-diarylcyclopent-2-en-1-ones under various conditions has been studied. It was found that depending on the brominating reagent and nature of solvent the bromine atom can be introduced at the 4- or 5-position of the ethene "bridge", as well as into the aryl moieties. Aryl group bromination is accomplished with such reagents as...

A simple synthesis of the analogue (VII) of Michler′s ketone and a variety of related compounds is achieved by nucleophilic substitution of aromatic fluorine with cyclic secondary aliphatic amines in refluxing water.

A novel family of photochromic diarylethenes – 2,3-diarylcyclopent-2-en-1-ones (DCPs) – having high abilities to the modification reactions of ethene “bridge” is proposed. A wide series of photochromic 2,3-diarylcyclopent-2-en-1-ones have been synthesized and switch properties of obtained compounds have been studied. The main advantage of this clas...

An environmentally friendly method for the synthesis of a series of novel, unsymmetrical Michler's ketone analogues, [4-(dialkylamino)phenyl](aryl)methanones, via nucleophilic aromatic substitution of (fluorophenyl)(aryl)methanones with various amines in water­ is described. The reaction products are formed in high yields and additional purificatio...