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

• Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany Department of Chemistry, University of Jyvaskyla P. O. Box 35, 40014 Jyväskylä, Finland 10.3762/bjoc.16.209 Abstract Crown ethers are common building blocks in supramolecular chemistry and are frequently applied as cation sensors or as subunits in

• alkali metal ions [2]. Crown ethers and their binding properties nowadays find frequent application, e.g., as cation sensors [4][5][6][7], as phase-transfer catalysts [8][9][10], or as drug delivery systems [11][12][13]. Already at the early stages of crown ether research, considerable effort has been

• ferrocene [14][17]. Yet, switchable crown ethers are also widely applied as cation sensors, where the sensor activity can be controlled by external stimuli, e.g., light, the redox potential or chemical reagents [14][17]. Redox-switchable crown ethers have been shown to sense cations by the generation of an

Styryl-based new organic chromophores bearing free amino and azomethine groups: synthesis, photophysical, NLO, and thermal properties

• Anka Utama Putra,
• Deniz Çakmaz,
• Nurgül Seferoğlu,
• Alberto Barsella and
• Zeynel Seferoğlu

Beilstein J. Org. Chem. 2020, 16, 2282–2296, doi:10.3762/bjoc.16.189

• solutions in DMSO. Therefore, they showed potential to be utilized as colorimetric and luminescence pH sensors. The second-order nonlinear optical (NLO) responses of the dyes were measured by the electric field-induced second harmonic (EFISH) generation method. The highest μβ values were obtained for the

• pKa determination of 8 in aqueous solution The pH value of aqueous systems is important to maintain the physiological stability, both inside and outside a living organism. The hydroxide anion plays a special and critical role in the ecosystem. Therefore, the necessity to develop new pH sensors is

• vital to control pH conditions in various environments. Due to their low-cost of manufacturing and maintenance, pH sensors were developed and used for both, clinical and environmental analyses [54][55][56]. Nevertheless, fluorescent pH indicators offer higher selectivity and sensitivity than other

Design, synthesis and application of carbazole macrocycles in anion sensors

• Alo Rüütel,
• Ville Yrjänä,
• Sandip A. Kadam,
• Indrek Saar,
• Mihkel Ilisson,
• Astrid Darnell,
• Kristjan Haav,
• Tõiv Haljasorg,
• Lauri Toom,
• Johan Bobacka and
• Ivo Leito

Beilstein J. Org. Chem. 2020, 16, 1901–1914, doi:10.3762/bjoc.16.157

• electrodes showed higher selectivity towards benzoate than acetate, i.e., the selectivity patterns of the final sensors deviated from that predicted by the classic titration experiments. While the binding constants obtained by NMR titration in DMSO-d6/H2O solvent systems provided important guidance for

• sensor development, the results obtained in this work emphasize the importance of evaluating the binding behavior of receptors in real sensor membranes. Keywords: anion sensors; carboxylates; ionophores; macrocycles; sensor prototype; Introduction In 2013, Otto S. Wolfbeis asked the supramolecular

• community a question of justified critique: why do we have so few true sensors? [1]. Indeed, in the recent decades the progress towards new actual chemical sensor systems has been slow. We have seen numerous potentially very promising receptor candidates from synthetic chemistry – essential as the central

Mechanochemical green synthesis of hyper-crosslinked cyclodextrin polymers

• Alberto Rubin Pedrazzo,
• Fabrizio Caldera,
• Marco Zanetti,
• Silvia Lucia Appleton,
• Nilesh Kumar Dhakar and
• Francesco Trotta

Beilstein J. Org. Chem. 2020, 16, 1554–1563, doi:10.3762/bjoc.16.127

• instance, dye-modified cyclodextrins and CD derivatives have found wide use for the preparation of chemical sensors [24][25]. As CDs and consequently CD nanosponges can be easily coupled with fluorophores, they could find applications in the pharmacological area, for example, as biological markers, in

A smart deoxyribozyme-based fluorescent sensor for in vitro detection of androgen receptor mRNA

• Ekaterina A. Bryushkova,
• Erik R. Gandalipov and
• Julia V. Nuzhina

Beilstein J. Org. Chem. 2020, 16, 1135–1141, doi:10.3762/bjoc.16.100

• technique is more frequently used in diagnostic laboratories than the direct sequencing method [6]. A serious problem for the detection of full-sized nucleic acids is the secondary structure, which interrupts the access of sensors to the binding site. For single-stranded RNA this problem may be partially

Synthesis of novel multifunctional carbazole-based molecules and their thermal, electrochemical and optical properties

• Nuray Altinolcek,
• Ahmet Battal,
• Mustafa Tavasli,
• William J. Peveler,
• Holly A. Yu and
• Peter J. Skabara

Beilstein J. Org. Chem. 2020, 16, 1066–1074, doi:10.3762/bjoc.16.93

• synthesised solar cells (DSSCs) and sensors [1][2]. In OLEDs, carbazole derivatives are frequently used as host materials [3][4][5]. In this respect the most frequently used host materials are 1,3-bis(N-carbazolyl)benzene (mCP) [6] and polyvinylcarbazole (PVK) [7]. Carbazole derivatives, either just by

• combinations [14][15]. In sensor studies, carbazole derivatives are used as fluorophores. In this regard many different carbazole-based fluorophores are reported in the literature [16][17][18][19]. Some of the carbazole derivatives were used as colourimetric anion sensors [20], and others as biothiol sensors

A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions

• Pezhman Shiri and
• Jasem Aboonajmi

Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52

• , with a high surface area, could be employed as electronic devices, thermal or electronic insulators, catalysts, and humidity sensors [24]. Moreover, mesoporous silica nanomaterials benefit from unique properties, including a large surface area, uniform pore size and distribution, high chemical/thermal

• , superparamagnetic behavior, ease of separation, and high safety. Indeed, materials including silica, carbon, etc. were combined with MNPs to produce new compositions that illustrated unique efficiency in the areas of catalysis [89], sensors [90], water purification [91], bioimaging [92], energy storage [92], drug

The use of isoxazoline and isoxazole scaffolding in the design of novel thiourea and amide liquid-crystalline compounds

• Itamar L. Gonçalves,
• Rafaela R. da Rosa,
• Vera L. Eifler-Lima and
• Aloir A. Merlo

Beilstein J. Org. Chem. 2020, 16, 175–184, doi:10.3762/bjoc.16.20

• components, which may be substituted symmetrically or unsymmetrically [1]. Applications of this scaffold include complexing agents in anion sensors [2] organocatalysts [3], intermediates in heterocycle synthesis [1] and development of compounds with pharmacological effects [4]. Considering the importance of

Preparation of anthracene-based tetraperimidine hexafluorophosphate and selective recognition of chromium(III) ions

• Qing-Xiang Liu,
• Feng Yang,
• Zhi-Xiang Zhao,
• Shao-Cong Yu and
• Yue Ding

Beilstein J. Org. Chem. 2019, 15, 2847–2855, doi:10.3762/bjoc.15.278

• paramagnetic nature of chromium(III) can cause fluorescence quenching of the fluorophore via the enhancement of spin–orbit coupling [30][31][32][33][34][35]. So far, only a few successful examples of fluorescence enhancement sensors for Cr3+ have been reported [36][37][38][39][40]. Thus, developing new and

A new approach to silicon rhodamines by Suzuki–Miyaura coupling – scope and limitations

• Thines Kanagasundaram,
• Antje Timmermann,
• Carsten S. Kramer and
• Klaus Kopka

Beilstein J. Org. Chem. 2019, 15, 2569–2576, doi:10.3762/bjoc.15.250

• in super-resolution microscopy [1][2][3][4][5][6][7][8] and as probes for targeting various biomolecules [9][10][11][12] or sensors for metal ions [13][14][15][16][17], pH [15], voltage [18] or metabolites [19][20][21][22]. Since our group is interested in synthesizing new tumor tracers for

Probing of local polarity in poly(methyl methacrylate) with the charge transfer transition in Nile red

• Aydan Yadigarli,
• Qimeng Song,
• Sergey I. Druzhinin and
• Holger Schönherr

Beilstein J. Org. Chem. 2019, 15, 2552–2562, doi:10.3762/bjoc.15.248

• polymer films, in which the values of the glass transition temperature (Tg) and segmental mobilities were found to be altered. Likewise, this holds for transport properties, including polymer nanocapsule membrane permeability [1], enzyme-triggered bacterial sensors [2][3][4][5] and intelligent self

Formation of alkyne-bridged ferrocenophanes using ring-closing alkyne metathesis on 1,1’-diacetylenic ferrocenes

• Celine Bittner,
• Dirk Bockfeld and
• Matthias Tamm

Beilstein J. Org. Chem. 2019, 15, 2534–2543, doi:10.3762/bjoc.15.246

• ][81]. In some cases, a metal–iron interaction, e.g., as shown in complex IV [79], could be observed depending on the ring size of the ferrocenophane ligand [82][83][84][85]. Furthermore, ferrocenophanes functionalized with bridges containing various heteroatoms were utilized as ion sensors for a wide

Photochromic diarylethene ligands featuring 2-(imidazol-2-yl)pyridine coordination site and their iron(II) complexes

• Andrey G. Lvov,
• Max Mörtel,
• Anton V. Yadykov,
• Frank W. Heinemann,
• Valerii Z. Shirinian and
• Marat M. Khusniyarov

Beilstein J. Org. Chem. 2019, 15, 2428–2437, doi:10.3762/bjoc.15.235

• copper(II) ions was achieved with IV. Diarylethene V and its analogs were used as chemical sensors for a number of metal ions [27]. Despite of recent advances in this area, the scarcity of reported examples requires the search and design of novel photoswitchable ligands with advanced properties. In this

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

• , People’s Republic of China 10.3762/bjoc.15.230 Abstract The development of photochromic fluorescence sensors with dynamic and multiple-signaling is beneficial to the improvement of biosensing/imaging precision. However, elaborate designs with complicated molecular structures are always required to

• integrate these functions into one molecule. By taking advantages of both redox-active/high loading features of two-dimensional (2D) manganese dioxide (MnO2) and dynamic fluorescence photoswitching of photochromic sensors, we here design a hybrid photochromic MnO2 glycosheet (Glyco-DTE@MnO2) to achieve the

• understanding of intracellular signal transduction and metabolic processes may provide great opportunities for early disease diagnosis and treatment. To achieve this goal, cell-imaging with fluorescence sensors becomes a booming research field since it enables the high-resolution visualization of intracellular

Synthesis of a dihalogenated pyridinyl silicon rhodamine for mitochondrial imaging by a halogen dance rearrangement

• Jessica Matthias,
• Thines Kanagasundaram,
• Klaus Kopka and
• Carsten S. Kramer

Beilstein J. Org. Chem. 2019, 15, 2333–2343, doi:10.3762/bjoc.15.226

• microscopy [2][3][4][5][6][7][8][9], as direct probes for various biomolecules [10][11][12][13] or as sensors for metal ions [14][15][16][17][18], pH [16], voltage [19] or metabolites [20][21][22][23]. Several attempts were made, partially supported by DFT calculations, to correlate the dyes’ structural

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

• points of view, such as sensors, electroluminescent displays, memory devices [9]. On the other hand, molecular aggregation also affects the intensity of fluorescence [10][11]. Some material shows fluorescence by aggregation (aggregation-induced emission (AIE)), while the others decay the fluorescence by

• fluorescence, and the emission was also suppressed by forming the closed-ring isomer. The crystal shows pink fluorescence once chloroform droplets were dropped on the crystal. The system will be useful for sensors and color indicators. Experimental General: Starting materials were commercially available and

1,2,3-Triazolium macrocycles in supramolecular chemistry

• Mastaneh Safarnejad Shad,
• Pulikkal Veettil Santhini and
• Wim Dehaen

Beilstein J. Org. Chem. 2019, 15, 2142–2155, doi:10.3762/bjoc.15.211

• receptors for molecular recognition of anionic species, pH sensors, mechanically interlocked molecules, molecular machines, and molecular reactors. Keywords: anion recognition; catenane; chalcogen bonding; click reaction; molecular reactor; hydrogen bonding; pH sensor; rotaxane; supramolecular; 1,2,3

• candidates for amide bond surrogates. Interestingly, 1,2,3-triazole units can act as sensors for both anions and cations via different binding mechanisms [16][17]. The heterocyclic ring N2 and N3 atoms could realize the selective recognition of the cations whereas the C5–H···anions electrostatic interaction

• , we highlight the recent advances in the synthesis and applications of triazolium macrocycles as anion sensors, molecular reactors, and pH sensors through the description of selected examples. The macrocycles involved vary from having relatively simple structures to being part of different types of

Naphthalene diimides with improved solubility for visible light photoredox catalysis

• Barbara Reiß and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2019, 15, 2043–2051, doi:10.3762/bjoc.15.201

• self-assembly [43][44], as molecular sensors [45][46][47] and for organic electronics [48][49], but yet nearly completely unexplored for photoredox catalysis. Core-unsubstituted NDIs are colorless compounds with high extinction coefficients at the border between UV-A and visible light. Their

Attempted synthesis of a meta-metalated calix[4]arene

• Christopher D. Jurisch and
• Gareth E. Arnott

Beilstein J. Org. Chem. 2019, 15, 1996–2002, doi:10.3762/bjoc.15.195

• resulted in applications in several fields, including, amongst others, the use as ligands in transition metal catalysis [2][3], in solid-phase gas sorption [4], as molecular sensors [5][6] and as biomimetic compounds [7][8]. Our own interest has been in the synthesis of inherently chiral calix[4]arenes

Identification of optimal fluorescent probes for G-quadruplex nucleic acids through systematic exploration of mono- and distyryl dye libraries

• Xiao Xie,
• Michela Zuffo,
• Marie-Paule Teulade-Fichou and
• Anton Granzhan

Beilstein J. Org. Chem. 2019, 15, 1872–1889, doi:10.3762/bjoc.15.183

• (up to 150 nm) and, in certain cases, structural selectivity with respect to one or another G4 folding topology. These dyes can be considered as promising G4-responsive sensors for in vitro or imaging applications. As a possible application, we implemented a simple two-dye fluorimetric assay allowing

Synthesis, enantioseparation and photophysical properties of planar-chiral pillar[5]arene derivatives bearing fluorophore fragments

• Guojuan Li,
• Chunying Fan,
• Guo Cheng,
• Wanhua Wu and
• Cheng Yang

Beilstein J. Org. Chem. 2019, 15, 1601–1611, doi:10.3762/bjoc.15.164

• : aggregation; circular dichroism; chirality; click chemistry; macrocycles; pillar[5]arenes; Introduction Planar-chiral compounds are structurally appealing and potentially applicable in various functional materials such as chiral discriminators [1][2], chiral polymers, supramolecular sensors [3] and chiral

Anomeric sugar boronic acid analogues as potential agents for boron neutron capture therapy

• Daniela Imperio,
• Erika Del Grosso,
• Silvia Fallarini,
• Grazia Lombardi and
• Luigi Panza

Beilstein J. Org. Chem. 2019, 15, 1355–1359, doi:10.3762/bjoc.15.135

• . Galactose and fructose also allow tumor growth in the absence of glucose. Boronic acid derivatives have gained interest in the last years in different fields such as the development of enzyme inhibitors, drug delivery polymers, saccharide sensors and as boron carriers for BNCT, e.g., amino acid derivatives

Host–guest interactions between p-sulfonatocalix[4]arene and p-sulfonatothiacalix[4]arene and group IA, IIA and f-block metal cations: a DFT/SMD study

• Valya K. Nikolova,
• Cristina V. Kirkova,
• Silvia E. Angelova and
• Todor M. Dudev

Beilstein J. Org. Chem. 2019, 15, 1321–1330, doi:10.3762/bjoc.15.131

• ligands with novel features. They have found various applications in chemical [5], analytical [6][7][8][9], and engineering materials fields (self-assembling monolayers, surfactants, sensors [10][11]), in polymer synthesis [12][13], controlled drug-delivery systems [14], and so on, besides the biochemical

N-doped carbon dots covalently functionalized with pillar[5]arenes for Fe³⁺ sensing

• Jia Gao,
• Ming-Xue Wu,
• Dihua Dai,
• Zhi Cai,
• Yue Wang,
• Wenhui Fang,
• Yan Wang and
• Ying-Wei Yang

Beilstein J. Org. Chem. 2019, 15, 1262–1267, doi:10.3762/bjoc.15.123

• surface of CN-dots via EDC-NHS coupling reaction. Compared with unmodified CN-dots, CCDs demonstrated novel properties after the introduction of CP[5], and showed a higher selective sensing ability for Fe3+ ions. Hopefully, this strategy will inspire the design of new fluorescent chemical sensors toward

Precious metal-free molecular machines for solar thermal energy storage

• Meglena I. Kandinska,
• Snejana M. Kitova,
• Vladimira S. Videva,
• Stanimir S. Stoyanov,
• Stanislava B. Yordanova,
• Stanislav B. Baluschev,
• Silvia E. Angelova and
• Aleksey A. Vasilev

Beilstein J. Org. Chem. 2019, 15, 1096–1106, doi:10.3762/bjoc.15.106

• ]. Crown ether-containing styryl dyes are used as sensors for dications such as Ba2+, Ca2+ and Mg2+, or as materials for optical data storage [19]. Thus, to the best of our knowledge this kind of dyes has not been specified as potential MOST material yet. The aim of the present study is to reveal the