Synthesis, structure, ionochromic and cytotoxic properties of new 2-(indolin-2-yl)-1,3-tropolones

• Yurii A. Sayapin,
• Eugeny A. Gusakov,
• Inna O. Tupaeva,
• Alexander D. Dubonosov,
• Igor V. Dorogan,
• Valery V. Tkachev,
• Anna S. Goncharova,
• Gennady V. Shilov,
• Natalia S. Kuznetsova,
• Svetlana Y. Filippova,
• Tatyana A. Krasnikova,
• Yanis A. Boumber,
• Alexey Y. Maksimov,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2025, 21, 358–368, doi:10.3762/bjoc.21.26

• represent molecular switches of optical and fluorescent properties under sequential addition of CN− and Hg2+ ions and the transformation cycle presented in Scheme 3 can be repeated at least 5–6 times. The resulting compounds 7b and 8a,b have extremely low water solubility, which makes it impossible to

• -ray diffraction analysis. Using two-dimensional correlation NMR spectroscopy methods, it was shown that the nature of the solvent significantly affects the equilibrium of the tautomeric forms of the 1,3-tropolones. The obtained compounds represent molecular switches of optical and fluorescent

A fiber-optic spectroscopic setup for isomerization quantum yield determination

• Anouk Volker,
• Jorn D. Steen and
• Stefano Crespi

Beilstein J. Org. Chem. 2024, 20, 1684–1692, doi:10.3762/bjoc.20.150

• the positive features of the aforementioned designs, which can be used to determine the forward and backward quantum yields of molecular switches without the need for actinometry, by combining fiber-coupled LEDs with a commercially calibrated thermopile detector and following the isomerization of a

Synthesis of photo- and ionochromic N-acylated 2-(aminomethylene)benzo[b]thiophene-3(2Н)-ones with a terminal phenanthroline group

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Irina V. Dubonosova,
• Olga Yu. Karlutova,
• Oleg P. Demidov,
• Alexander D. Dubonosov and
• Vladimir A. Bren

Beilstein J. Org. Chem. 2024, 20, 552–560, doi:10.3762/bjoc.20.47

• light and H+ or sequential addition of Fe2+ and AcO− ions. Keywords: fluorescence; molecular switches; N→O acyl rearrangement; naked eye effect; photochromism; Introduction Photochromism is defined as the reversible transformation of a molecular entity between different forms, having different

• inverse photochromism), such as merocyanine forms of spiropyrans and spirooxazines, azomethine imines, thioindigoid dyes and N→O acylotropic systems [12][13][14][15]. Recently, they have been actively used to create next-generation molecular switches, materials with new properties (in particular, color

• change depending on the intensity of sunlight), photochromic tags for biological research and optical sensors [15][16][17][18][19][20][21]. To develop new dual-mode molecular switches capable of efficient modulation of optical and fluorescent properties, both upon irradiation with visible light and upon

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• Pablo Msellem Maksym Dekthiarenko Nihal Hadj Seyd Guillaume Vives Sorbonne Université, UMR CNRS 8232, Institut Parisien de Chimie Moléculaire, 4 place Jussieu, 75005, Paris, France 10.3762/bjoc.20.45 Abstract Switchable molecular tweezers are a unique class of molecular switches that, like their

• first part will be devoted to chemically responsive tweezers, including stimuli such as pH, metal coordination, and anion binding. Then, redox-active and photochemical tweezers will be presented. Keywords: coordination; molecular recognition; molecular switches; photoswitch; redox; supramolecular

• that binds to the OH groups instead of the pyrimidine nitrogen atoms. The group of Aprahamian has developed hydrazone-based molecular switches that can be controlled by photochemical or chemical stimuli such as pH [27]. They reported mesogenic tweezers-like compound 5 composed of a hydrazone switch

Synthesis, structure, and properties of switchable cross-conjugated 1,4-diaryl-1,3-butadiynes based on 1,8-bis(dimethylamino)naphthalene

• Semyon V. Tsybulin,
• Ekaterina A. Filatova,
• Alexander F. Pozharskii,
• Valery A. Ozeryanskii and
• Anna V. Gulevskaya

Beilstein J. Org. Chem. 2023, 19, 674–686, doi:10.3762/bjoc.19.49

• , electron transfer, and quantum interference [17][18][19][20], but are also considered as promising molecular switches and transistors [21][22][23][24][25], NLO materials [26][27][28][29], and suitable starting compounds for syntheses involving multiple Diels–Alder additions [30]. All these facts motivated

Comparison of crystal structure and DFT calculations of triferrocenyl trithiophosphite’s conformance

• Ruslan P. Shekurov,
• Mikhail N. Khrizanforov,
• Ilya A. Bezkishko,
• Tatiana P. Gerasimova,
• Almaz A. Zagidullin,
• Daut R. Islamov and
• Vasili A. Miluykov

Beilstein J. Org. Chem. 2022, 18, 1499–1504, doi:10.3762/bjoc.18.157

• properties. Such switchable systems with conjugated organic fragments containing an FeII/FeIII system were used in organic electronics as molecular switches, optoelectronic materials and in biochemistry as photonic or redox devices [6]. A promising approach is the coordination self-assembly of multiferrocene

Continuous flow synthesis of azobenzenes via Baeyer–Mills reaction

• Jan H. Griwatz,
• Anne Kunz and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2022, 18, 781–787, doi:10.3762/bjoc.18.78

• Azobenzene, as one of the most prominent molecular switches, is featured in many applications ranging from photopharmacology to information or energy storage. In order to easily and reproducibly synthesize non-symmetric substituted azobenzenes in an efficient way, especially on a large scale, the commonly

• . Keywords: azobenzenes; Baeyer–Mills reaction; continuous flow; molecular switches; solar fuel; Introduction Although the red-colored azobenzenes (AB) have been known for years as dyes, their applications nowadays span from energy and information storage [1][2][3][4][5], organocatalysis [6], photobiology

BINOL as a chiral element in mechanically interlocked molecules

• Matthias Krajnc and
• Jochen Niemeyer

Beilstein J. Org. Chem. 2022, 18, 508–523, doi:10.3762/bjoc.18.53

• applications as molecular switches, muscles, and motors [5][6][7][8][9][10][11], as novel materials [12], as medically active compounds [13][14], as catalysts [15][16][17][18][19], as chemosensors [20][21][22][23][24], and many more [25]. In view of their template-based synthesis and the importance of

Trichloroacetic acid fueled practical amine purifications

• Aleena Thomas,
• Baptiste Gasch,
• Enzo Olivieri and
• Adrien Quintard

Beilstein J. Org. Chem. 2022, 18, 225–231, doi:10.3762/bjoc.18.26

• operations and the associated generation of waste, discovery of alternative purification techniques is mandatory. Avoiding waste accumulation, dissipative acids have recently found interesting applications in the field of out of equilibrium molecular switches and motors [5]. They enable the temporary

• cheap and simple acid enables a temporary protonation while time-controlled decarboxylation liberates volatile CO2 and chloroform as single waste (Scheme 2a). This strategy has been applied with success by the groups of Takata, Leigh, Kim and ours to time control different molecular switches ranging

• generated can be separated from the impurities. Closely related to out of equilibrium systems applied in molecular switches and motors under temporal control, from the amine salt, isolation of the pure free amine occurs through a simple decarboxylation of TCA, releasing volatile CO2 and CHCl3. As a result

Recent advances in the asymmetric phosphoric acid-catalyzed synthesis of axially chiral compounds

• Alemayehu Gashaw Woldegiorgis and
• Xufeng Lin

Beilstein J. Org. Chem. 2021, 17, 2729–2764, doi:10.3762/bjoc.17.185

• -catalyzed enantioselective transformations [9][14][22][23]. Axial chirality is also found in chiral stationary phases for enantioselective separation, dopants in liquid-crystalline materials, chiroptical molecular switches, microporous soluble polymers, and interlocked nanotubes (Figure 3) [24]. In addition

Construction of pillar[4]arene[1]quinone–1,10-dibromodecane pseudorotaxanes in solution and in the solid state

• Xinru Sheng,
• Errui Li and
• Feihe Huang

Beilstein J. Org. Chem. 2020, 16, 2954–2959, doi:10.3762/bjoc.16.245

• , including molecular switches, molecular logic gates, molecular machines, supramolecular polymers, etc. [6][7][8][9][10][11]. Pseudorotaxanes not only are used as the supramolecular precursors for the synthesis of rotaxanes and catenanes but also play an important role in the construction of supramolecular

Thermodynamic and electrochemical study of tailor-made crown ethers for redox-switchable (pseudo)rotaxanes

• Henrik Hupatz,
• Marius Gaedke,
• Hendrik V. Schröder,
• Julia Beerhues,
• Arto Valkonen,
• Fabian Klautzsch,
• Sebastian Müller,
• Felix Witte,
• Kari Rissanen,
• Biprajit Sarkar and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2020, 16, 2576–2588, doi:10.3762/bjoc.16.209

• construction of more complex molecular structures [24][26][27]. With the introduction of stimuli-responsive units, crown ether/ammonium-based MIMs have evolved into molecular switches and motors [24][28]. Intriguing examples among them are a light-powered molecular pump [29], a chemical-fuel-driven molecular

• potential of tailor-made redox-active crown ethers for the development of new molecular switches. Yet, a careful design of tailor-made redox-active crown ethers is of great importance for tuning the crown ether binding and redox properties to achieve the desired molecular structure and switching mode, which

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• can not only be useful for enantioselective synthesis of π-bowls but also to produce novel building blocks for molecular switches, chemical machines, molecular motor, ferroelectric memories, molecular devices, and sensory materials etc. Interestingly, electronic switching, thermal transport and

Synthesis and highly efficient light-induced rearrangements of diphenylmethylene(2-benzo[b]thienyl)fulgides and fulgimides

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Valerii V. Tkachev,
• Andrey N. Utenyshev,
• Olga Yu. Karlutova,
• Alexander D. Dubonosov,
• Vladimir A. Bren,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2020, 16, 1820–1829, doi:10.3762/bjoc.16.149

• ; X-ray diffraction; Introduction Photochromic compounds are of considerable interest as molecular switches, elements of optical memory and molecular logic devices [1][2][3][4]. Fulgides and fulgimides possessing excellent thermal and photochemical stability, structurally modulated fluorescent

• heteroaromatic fulgides revealed significant advantages of the latter for applications as molecular switches and optical information storage systems [5][10]. These include higher thermal stability, longer lifetimes of the photocolored forms and higher yields of the photocoloration reactions and better

Five-component, one-pot synthesis of an electroactive rotaxane comprising a bisferrocene macrocycle

• Natalie Lagesse,
• Luca Pisciottani,
• Maxime Douarre,
• Pascale Godard,
• Brice Kauffmann,
• Vicente Martí-Centelles and
• Nathan D. McClenaghan

Beilstein J. Org. Chem. 2020, 16, 1564–1571, doi:10.3762/bjoc.16.128

• to perform several functions as artificial molecular switches [1]. The template-directed synthesis of such sophisticated catenane and rotaxane molecular architectures allowed the expansion of chemical diversity and properties. Among these architectures, electroactive rotaxanes have been described to

Synthesis and characterization of bis(4-amino-2-bromo-6-methoxy)azobenzene derivatives

• David Martínez-López,
• Amirhossein Babalhavaeji,
• Diego Sampedro and
• G. Andrew Woolley

Beilstein J. Org. Chem. 2019, 15, 3000–3008, doi:10.3762/bjoc.15.296

• ; azonium; molecular switches; ortho substitution; photoisomerization; photoswitch; visible light; Introduction The application of photoswitches to control biological targets has been a driving force for the development of photoswitches that operate at wavelengths that are compatible with cells and tissues

Design, synthesis and investigation of water-soluble hemi-indigo photoswitches for bioapplications

• Daria V. Berdnikova

Beilstein J. Org. Chem. 2019, 15, 2822–2829, doi:10.3762/bjoc.15.275

• that allowed to obtain an RNA-binding hemi-indigo derivative with photoswitchable fluorescent properties. Keywords: hemi-indigo; molecular switches; photochromism; photoswitching; visible light; water solubility; Introduction The application of organic photochromes in biological systems is fraught

A chiral self-sorting photoresponsive coordination cage based on overcrowded alkenes

• Constantin Stuckhardt,
• Diederik Roke,
• Wojciech Danowski,
• Edwin Otten,
• Sander J. Wezenberg and
• Ben L. Feringa

Beilstein J. Org. Chem. 2019, 15, 2767–2773, doi:10.3762/bjoc.15.268

• between the three isomers. Two of the isomers were able to form host–guest complexes opening up new prospects toward stimuli-controlled substrate binding and release. Keywords: coordination cages; molecular motors; molecular switches; overcrowded alkene; palladium; Introduction Supramolecular

A combinatorial approach to improving the performance of azoarene photoswitches

• Joaquin Calbo,
• Aditya R. Thawani,
• Rosina S. L. Gibson,
• Andrew J. P. White and
• Matthew J. Fuchter

Beilstein J. Org. Chem. 2019, 15, 2753–2764, doi:10.3762/bjoc.15.266

• results therefore define improved designs for high performance azo switches, which will allow for high precision optically addressable applications using such components. Keywords: arylazopyrazoles; azobenzenes; molecular switches; ortho-substitution; photoswitches; thermal half-life; Introduction

Experimental and computational electrochemistry of quinazolinespirohexadienone molecular switches – differential electrochromic vs photochromic behavior

• Eric W. Webb,
• Jonathan P. Moerdyk,
• Kyndra B. Sluiter,
• Benjamin J. Pollock,
• Amy L. Speelman,
• Eugene J. Lynch,
• William F. Polik and
• Jason G. Gillmore

Beilstein J. Org. Chem. 2019, 15, 2473–2485, doi:10.3762/bjoc.15.240

• focused on the preparation and investigation of electron-deficient analogs of the perimidinespirohexadienone (PSHD) family of photochromic molecular switches for potential application as "photochromic photooxidants" for gating sensitivity to photoinduced charge transfer. We previously reported the

• calculations of bond lengths, bond orders, and molecular orbitals allow the rationalization of this differential photochromic vs electrochromic behavior of the QSHDs. Keywords: cyclic voltammetry; density functional theory; heterocycles; molecular switches; photochromic photooxidants; spirocycles

• ; Introduction Photochromic molecular switches, in which light initiates reversible coloration of a short-wavelength isomer (SW) to a long-wavelength isomer (LW), which fades back to SW either thermally or photochemically, have become ubiquitous in a wide range of applications [1][2][3][4][5]. Typically, organic

Self-assembled coordination thioether silver(I) macrocyclic complexes for homogeneous catalysis

• Zhen Cao,
• Aline Lacoudre,
• Cybille Rossy and
• Brigitte Bibal

Beilstein J. Org. Chem. 2019, 15, 2465–2472, doi:10.3762/bjoc.15.239

• ) to 25–29 kcal/mol (ortho-CH3). A few ortho-substituted DPA atropisomers have been described as potent molecular switches [48][49], building-blocks for self-assembled capsules [50][51] or optical materials [52][53][54]. However, due to their partially frozen structure, syn-isomers of DPA are ideal

Ultrafast processes triggered by one- and two-photon excitation of a photochromic and luminescent hydrazone

• Alessandro Iagatti,
• Baihao Shao,
• Alberto Credi,
• Barbara Ventura,
• Ivan Aprahamian and
• Mariangela Di Donato

Beilstein J. Org. Chem. 2019, 15, 2438–2446, doi:10.3762/bjoc.15.236

• absorption cross-section of the molecule. Keywords: hydrazone; molecular switch; pump-probe spectroscopy; time-resolved fluorescence; Introduction Molecular switches are systems that are able to rapidly respond to an external stimulus, which can be of chemical or physical nature, through a variation of

Reversible switching of arylazopyrazole within a metal–organic cage

• Anton I. Hanopolskyi,
• Soumen De,
• Michał J. Białek,
• Yael Diskin-Posner,
• Liat Avram,
• Moran Feller and
• Rafal Klajn

Beilstein J. Org. Chem. 2019, 15, 2398–2407, doi:10.3762/bjoc.15.232

• green light and resulted in the initial 1:2 cage/E-arylazopyrazole complex. This back-isomerization reaction also proceeded in the dark, with a rate significantly higher than in the absence of the cage. Keywords: arylazopyrazoles; coordination cages; inclusion complexes; molecular switches

• , the results reported here strengthen our understanding of the behavior of molecular switches in confined spaces. Experimental Synthesis of cage 2: Cage 2 was prepared based on a modified literature known procedure [18]. Briefly, a solution of [Pd(NO3)2(tmeda)] (200 mg, 0.577 mmol) in 25 mL of water

Targeted photoswitchable imaging of intracellular glutathione by a photochromic glycosheet sensor

• Xianzhi Chai,
• Hai-Hao Han,
• Yi Zang,
• Jia Li,
• Xiao-Peng He,
• Junji Zhang and
• He Tian

Beilstein J. Org. Chem. 2019, 15, 2380–2389, doi:10.3762/bjoc.15.230

• therapy. Keywords: intracellular GSH; molecular switches; photochromic glycosheet; photoswitchable imaging; 2D MnO2 nanosheets; Introduction Cells are the basic structure and functional unit of biological organisms. Human diseases and aging are closely related to the states of cells. Thorough

Aggregation-induced emission effect on turn-off fluorescent switching of a photochromic diarylethene

• Luna Kono,
• Yuma Nakagawa,
• Ayako Fujimoto,
• Ryo Nishimura,
• Yohei Hattori,
• Toshiki Mutai,
• Nobuhiro Yasuda,
• Kenichi Koizumi,
• Satoshi Yokojima,
• Shinichiro Nakamura and
• Kingo Uchida

Beilstein J. Org. Chem. 2019, 15, 2204–2212, doi:10.3762/bjoc.15.217

• Diarylethenes are well-known photochromic molecules and are widely applied to molecular switches and systems [1][2]. Recently, the photo-switching of fluorescence signals by using diarylethene switches has attracted much attention because of the potential in various optoelectronic applications [3]. For example