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

• images of dyes in the absence and in the presence of selected DNA samples are shown in Figure 10. All dyes display moderate to good quantum yields and brightnesses upon complexation with both G4 analytes. In more detail, distyryl dyes 1p and 1u prove more performant in this sense, displaying higher

• observed for all dyes upon complexation to G4 structures, which is more pronounced for distyryl dyes 1p and 1u (36–45 nm, cf. Table 1 and Table 3) than for mono-styryl dyes 17a and 18a (7–15 nm, cf. Table 1 and Table 3). Moreover, comparison of the absorption maxima with the corresponding emission ones

Complexation of 2,6-helic[6]arene and its derivatives with 1,1′-dimethyl-4,4′-bipyridinium salts and protonated 4,4'-bipyridinium salts: an acid–base controllable complexation

• Jing Li,
• Qiang Shi,
• Ying Han and
• Chuan-Feng Chen

Beilstein J. Org. Chem. 2019, 15, 1795–1804, doi:10.3762/bjoc.15.173

• 10.3762/bjoc.15.173 Abstract 2,6-Helic[6]arene and its derivatives were synthesized, and their complexation with 1,1′-dimethyl-4,4′-bipyridinium and protonated 4,4'-bipyridinium salts were investigated in detail. It was found that the helic[6]arene and its derivatives could all form 1:1 complexes with

• both 1,1′-dimethyl-4,4'-bipyridinium salts and protonated 4,4'-bipyridinium salts in solution and in the solid state. Especially, the helic[6]arene and its derivatives containing 2-hydroxyethoxy or 2-methoxyethoxy groups exhibited stronger complexation with the guests than the other helic[6]arene

• with larger counteranions of the guests and in less polar solvents. Furthermore, the switchable complexation between the helic[6]arene and protonated 4,4'-bipyridinium salt could be efficiently controlled by acids and bases. Keywords: 4,4'-bipyridinium salts; complexation; helic[6]arene; hydrogen bond

Functional panchromatic BODIPY dyes with near-infrared absorption: design, synthesis, characterization and use in dye-sensitized solar cells

• Quentin Huaulmé,
• Cyril Aumaitre,
• Outi Vilhelmiina Kontkanen,
• David Beljonne,
• Alexandra Sutter,
• Gilles Ulrich,
• Renaud Demadrille and
• Nicolas Leclerc

Beilstein J. Org. Chem. 2019, 15, 1758–1768, doi:10.3762/bjoc.15.169

• corresponding dipyrromethenium chloride, which was then converted into its BODIPY analogue 2 through complexation by BF3·OEt2 in basic media. Regioselective introduction of distyryl substituents is achieved via Knoevenagel-type condensation in the presence of piperidine using aldehyde derivatives 3 and 4 whose

Host–guest interactions in nor-seco-cucurbit[10]uril: novel guest-dependent molecular recognition and stereoisomerism

• Xiaodong Zhang,
• Wei Wu,
• Zhu Tao and
• Xin-Long Ni

Beilstein J. Org. Chem. 2019, 15, 1705–1711, doi:10.3762/bjoc.15.166

• ad host-2 were further studied by UV–vis spectra (Supporting Information File 1, Figure S3) and Job plot (Supporting Information File 1, Figure S4). In order to obtain detailed information on the mechanism of the complexation of G2 with host-1 and -2, 1H NMR titration experiments in acidic aqueous

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

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

• guest receptors [4][5]. Planar-chiral macrocyclic molecules are particularly interesting in the context of the host–guest complexation properties [6][7][8]. Pillararenes are typical examples of this type of compounds and have attracted considerable attention due to their facile chemical synthesis and

• symmetrical structures, as well as highly tunable functionality, the studies on pillar[5]arenes have been developed rapidly in various areas, such as artificial transmembrane channels [11][12], molecular complexation [13][14] and nonporous adaptive crystals [15][16][17]. One of the features of pillar[5]arenes

• separation of these conformational isomers is impossible. Inhibiting the rotation of the phenolic units is prerequisite to isolate the isomers. A complexation with a suitable guest molecule, such as a viologen derivative, can significantly slow down the rotation of the phenolic rings, and a conformational

Water inside β-cyclodextrin cavity: amount, stability and mechanism of binding

• Stiliyana Pereva,
• Valya Nikolova,
• Silvia Angelova,
• Tony Spassov and
• Todor Dudev

Beilstein J. Org. Chem. 2019, 15, 1592–1600, doi:10.3762/bjoc.15.163

• water and can displace (completely or partially) the hydration content of the host molecule [2]. Most of these complexation reactions take place in aqueous solutions, thus it is important to understand the mechanism and energetics of interactions between the water molecules and the components of the

• experimental) approaches are sometimes conflicting and contradictory. There is no “standard” method to investigate the complexation behavior of CDs. Thus, in our study a computational quantum mechanical modelling method, namely density functional theory (DFT) was chosen to investigate the electronic structure

Reaction of oxiranes with cyclodextrins under high-energy ball-milling conditions

• László Jicsinszky,
• Federica Calsolaro,
• Katia Martina,
• Fabio Bucciol,
• Maela Manzoli and
• Giancarlo Cravotto

Beilstein J. Org. Chem. 2019, 15, 1448–1459, doi:10.3762/bjoc.15.145

• have different complexation properties to those of their classically prepared analogues. Keywords: crosslinked cyclodextrin polymers; (2-hydroxy)propylcyclodextrin; mechanochemistry; nucleophile reaction; planetary ball mill; solventless synthesis; Introduction The derivatisation of natural

• a controlled manner, this side reaction cannot be completely eliminated. The solubilisation/complexation potential of the polymers can be increased by the application of a chemically inert guest, using the so-called molecular imprinting strategy [17][18][19]. Despite the early patents and a

• promising beginning, CDPs are poorly applied CD derivatives and a standardised quality product is still missing. Detailed studies of the complexation properties of bead polymers have demonstrated their slow and structure-dependent complexation properties [13]. The preparation of an insoluble CDP is always

Complexation of a guanidinium-modified calixarene with diverse dyes and investigation of the corresponding photophysical response

• Yu-Ying Wang,
• Yong Kong,
• Zhe Zheng,
• Wen-Chao Geng,
• Zi-Yi Zhao,
• Hongwei Sun and
• Dong-Sheng Guo

Beilstein J. Org. Chem. 2019, 15, 1394–1406, doi:10.3762/bjoc.15.139

• 300071, P. R. China Research Institute of Petroleum Engineering, Sinopec, Beijing 100101, P. R. China 10.3762/bjoc.15.139 Abstract We herein describe the comprehensive investigation of the complexation behavior of a guanidinium-modified calix[5]arene pentaisohexyl ether (GC5A) with a variety of typical

• representative candidate of luminescent transition-metal complexes. We determined the association constants of the GC5A–dye complexes by fluorescence titration and discuss the complexation-induced photophysical changes. In addition, a comparison of the complexation behavior of GC5A with that of other macrocycles

• and potential applications according to the diverse photophysical responses are provided. Keywords: calixarene; host–guest complexation; luminescent dyes; macrocycles; photophysical properties; Introduction Fluorescence sensing represents a powerful detection methodology due to its low cost, ease of

Selective detection of DABCO using a supramolecular interconversion as fluorescence reporter

• Indrajit Paul,
• Debabrata Samanta,
• Sudhakar Gaikwad and
• Michael Schmittel

Beilstein J. Org. Chem. 2019, 15, 1371–1378, doi:10.3762/bjoc.15.137

• equipped with a trimethoxyphenyl group to furnish a fourth coordination to the copper(I) center and a sterically crowded duryl group to prevent homoleptic complexation, while lutidine 9 was selected to strengthen the HETPYP-I [33] (HETeroleptic PYridine and Phenanthroline complexation) coordination. In

• quantitative interconversion is the result of a delicate double self-sorted transformation requiring orthogonality of two heteroleptic complexation motifs (HETPYP-I and hetero-sandwich complexation at DABCO). Within a selected library of binding guests, DABCO is the only one effecting the interconversion. Due

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

• cations (La3+) a supramolecular approach with explicit solvent treatment has been applied in the study of the effect of metal hydration on the complexation process. The La3+ binding to the p-sulfonatocalix[4]arene host molecule (now in the metal’s second coordination shell) is still exergonic as evidenced

• calixarenes (with the same repeating units). The sulfur functionalities are stated to provide better metal complexation [3]. Unmodified calixarenes and thiacalixarenes are sparingly soluble, have chemical and thermal stability and act as host molecules as they possess cavities, but their inclusion properties

• medicine. The binding affinities and thermodynamics of p-sulfonato-calix[4]arene upon complexation with different inorganic and organic cations in water have been investigated experimentally by Bonal et al. [30] and Morel et al. [31]. The experiments indicated 1:1 stoichiometry of the inclusion complexes

Mechanochemical Friedel–Crafts acylations

• Mateja Đud,
• Anamarija Briš,
• Iva Jušinski,
• Davor Gracin and
• Davor Margetić

Beilstein J. Org. Chem. 2019, 15, 1313–1320, doi:10.3762/bjoc.15.130

• transient reactive intermediates were predicted by density functional theory method B3LYP/6-31G* (Supporting Information File 1) [61]. The stretching of the +C≡O bond of the acylium ion was predicted to be at about 2300 cm−1. Raman spectroscopy revealed that the complexation of phthalic anhydride with AlCl3

• is rapid, and within 3 minutes of milling all anhydride is consumed (Figure 1). After 3 minutes of milling, high fluorescence prevents further following of the reaction progress. These spectra indicate that rapid complexation of anhydride with AlCl3 takes place, whereas the formation of the acylium

• ion intermediate could not be unequivocally verified. Similar conclusions could be drawn from ex situ IR spectroscopy [62] which indicates rapid complexation and disappearance of phthalic anhydride (Supporting Information File 1, Figures S43 and S44). A further study was carried on complexation of

Design of a double-decker coordination cage revisited to make new cages and exemplify ligand isomerism

• Sagarika Samantray,
• Sreenivasulu Bandi and
• Dillip K. Chand

Beilstein J. Org. Chem. 2019, 15, 1129–1140, doi:10.3762/bjoc.15.109

• Sagarika Samantray Sreenivasulu Bandi Dillip K. Chand Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India 10.3762/bjoc.15.109 Abstract The complexation study of cis-protected and bare palladium(II) components with a new tridentate ligand, i.e., pyridine-3,5

• -diylbis(methylene) dinicotinate (L1) is the focus of this work. Complexation of cis-Pd(tmeda)(NO3)2 with L1 at a 1:1 or 3:2 ratio produced [Pd(tmeda)(L1)](NO3)2 (1a). The reaction mixture obtained at 3:2 ratio upon prolonged heating, produced a small amount of [Pd3(tmeda)3(L1)2](NO3)6 (2a). Complexation

• coordination bonds enable the construction of designer targeted molecules with ease. The use of a palladium(II) component for complexation with a non-chelating bi- or polydentate ligand (usually N-donor ligands) is particularly advantageous for the construction of a variety of metallocages [1][2][3][4][5

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

• about 520 nm) and to a substantial hypsochromic shift of the maximum absorption with peak at around λmax = 440 nm. The changes in the absorption spectra of the dyes upon the addition of Ba(ClO4)2 in ACN solution are characteristic for an ion complexation by the azacrown ether group of the

• , which is true for the simplest form of complexation [18]: where A0 and A∞ are the absorptions of the chromoionophore at zero and infinite concentration of the metal ion, respectively; A is the absorption at the concentration cM of the metal ion; K is the stability constant of complex formation, and L

• constant was found to be K = 70 ± 15 M−1 which is in good correlation with the published data [22]. These results prompted us to identify the optimal Ba2+ concentration, necessary for a maximum degree of dye–Ba2+ inclusion complex formation. Obviously for a better complexation it is necessary to work with

Halogen bonding and host–guest chemistry between N-alkylammonium resorcinarene halides, diiodoperfluorobutane and neutral guests

• Fangfang Pan,
• Mohadeseh Dashti,
• Michael R. Reynolds,
• Kari Rissanen,
• John F. Trant and
• Ngong Kodiah Beyeh

Beilstein J. Org. Chem. 2019, 15, 947–954, doi:10.3762/bjoc.15.91

• evidence from 19F NMR, 1H NMR showed small changes of the –OH and –NH2 signals of 1, attributed to the formation of HB and XB in solution (Figure 5 and Figure S4 in Supporting Information File 1). In the presence of the guests (MeOH and MeCN), 1H NMR reveal significant complexation-induced shielding of the

Mechanochemistry of supramolecules

• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2019, 15, 881–900, doi:10.3762/bjoc.15.86

• by NMR as well as other spectroscopic techniques. Georghiou et al. demonstrated the mechanochemical formation of a 1:1 supramolecular complex C60–tert-butylcalix[4]azulene 41 (Figure 23). The host–guest complexation was achieved by simple grinding the individual compounds in a mortar and pestle [95

Coordination chemistry and photoswitching of dinuclear macrocyclic cadmium-, nickel-, and zinc complexes containing azobenzene carboxylato co-ligands

• Jennifer Klose,
• Tobias Severin,
• Peter Hahn,
• Alexander Jeremies,
• Jens Bergmann,
• Daniel Fuhrmann,
• Jan Griebel,
• Bernd Abel and
• Berthold Kersting

Beilstein J. Org. Chem. 2019, 15, 840–851, doi:10.3762/bjoc.15.81

• physicochemical properties of the bound guest molecules are also greatly affected. Thus, complexation of naphthalene diimide carboxylato ligands leads to a substantial (>95%) quenching of the diimide fluorescence [5], and incorporation of a Fe(CpCO2H)2 unit leads to a significant anodic shift of the metallocene’s

• , 5) were obtained directly from stoichiometric complexation reactions between H2L·6HCl, Zn(OAc)2·2H2O, and the corresponding azobenzene carboxylate ion (prepared in situ from the free acid by deprotonation with NEt3 as a base) in methanol. The green-brown nickel (2, 4, 7 and 9) and red-orange colored

Synthesis of polydicyclopentadiene using the Cp₂TiCl₂/Et₂AlCl catalytic system and thin-layer oxidation of the polymer in air

• Zhargolma B. Bazarova,
• Ludmila S. Soroka,
• Alex A. Lyapkov,
• Мekhman S. Yusubov and
• Francis Verpoort

Beilstein J. Org. Chem. 2019, 15, 733–745, doi:10.3762/bjoc.15.69

• (Figure 1) in the visible region at ambient temperature clearly demonstrate that during the first minute of the reaction an intermediate compound is formed, which gradually decomposes with formation of the blue complex [15][16]. The complexation between the organoaluminum compound and Cp2TiCl2 was further

Study on the regioselectivity of the N-ethylation reaction of N-benzyl-4-oxo-1,4-dihydroquinoline-3-carboxamide

• Pedro N. Batalha,
• Luana da S. M. Forezi,
• Maria Clara R. Freitas,
• Nathalia M. de C. Tolentino,
• Ednilsom Orestes,
• José Walkimar de M. Carneiro,
• Fernanda da C. S. Boechat and
• Maria Cecília B. V. de Souza

Beilstein J. Org. Chem. 2019, 15, 388–400, doi:10.3762/bjoc.15.35

• carboxamide group, may contribute to enhance the bioactivity. This fact could be explained by the coplanarity induced by the C-4 carbonyl hydrogen bond interactions with biological targets [3] or complexation with physiological metal cations such as magnesium and zinc [23]. Besides the derivatives 3a and 3b

First synthesis of cryptands with sucrose scaffold

• Patrycja Sokołowska,
• Michał Kowalski and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2019, 15, 210–217, doi:10.3762/bjoc.15.20

• and find many applications in, e.g., selective complexation of ionic and neutral species, medicinal chemistry (as drug carriers), and in the synthesis (as phase transfer catalysts). The complexing properties depend on several crucial parameters such as cavity size, type of heteroatoms involved in the

Fabrication of supramolecular cyclodextrin–fullerene nonwovens by electrospinning

• Hiroaki Yoshida,
• Ken Kikuta and
• Toshiyuki Kida

Beilstein J. Org. Chem. 2019, 15, 89–95, doi:10.3762/bjoc.15.10

• realizes easy handling of inclusion complexation with guest molecules as well as electrospinning due to the much lower viscosity of the CD/HFIP solution. The formation of a 2:1 inclusion complex should not affect the solution properties (e.g., viscosity and solubility), but should provide electrospinning

• –vis diffuse reflectance spectroscopy suggests that the C60 molecules are isolated in the fibers at the molecular level. We believe that inclusion complexation with various guest molecules will fabricate a wider range of functional CD fiber materials containing isolated guest molecules by

MoO₃ on zeolites MCM-22, MCM-56 and 2D-MFI as catalysts for 1-octene metathesis

• Hynek Balcar,
• Martin Kubů,
• Naděžda Žilková and
• Mariya Shamzhy

Beilstein J. Org. Chem. 2018, 14, 2931–2939, doi:10.3762/bjoc.14.272

• OES (iCAP 7000, Thermo Scientific) was used. About 50 mg of the catalyst was digested in a mixture of HF, HCl, and HNO3 (1:2:2). The samples were placed in a Berghof microwave in a closed vessel at T = 140 °C for 35 min. Saturated solution of H3BO3 was then added for complexation of the excess of HF

Calixazulenes: azulene-based calixarene analogues – an overview and recent supramolecular complexation studies

• Paris E. Georghiou,
• Shofiur Rahman,
• Abdullah Alodhayb,
• Hidetaka Nishimura,
• Jaehyun Lee,
• Atsushi Wakamiya and
• Lawrence T. Scott

Beilstein J. Org. Chem. 2018, 14, 2488–2494, doi:10.3762/bjoc.14.225

• -hydrocarbon calix[4]azulenes which have been synthesized in good yields by their method. This allowed studying their supramolecular properties. This report is of our latest work on the solution-state supramolecular complexation of one of these calix[4]azulenes, namely tetrakis(5,7-diphenyl)calix[4]azulene or

• solvents prevented a fuller examination of its potential supramolecular properties with fullerenes, a topic of particular interest to us [18]. Therefore, the solid state supramolecular complexation properties of 5 were experimentally studied using solid state NMR and XRD experiments, and also theoretically

• a chloroform solution-state complexation binding study with Lash and Colby’s calix[4]azulene 3 using a series of tetraalkylammonium halides and tetrafluoroborate salts [20]. This study was also supplemented by DFT studies to support the trends observed in the experimentally-derived binding constants

Synthesis of a water-soluble 2,2′-biphen[4]arene and its efficient complexation and sensitive fluorescence enhancement towards palmatine and berberine

• Xiayang Huang,
• Xinghua Zhang,
• Tianxin Qian,
• Junwei Ma,
• Lei Cui and
• Chunju Li

Beilstein J. Org. Chem. 2018, 14, 2236–2241, doi:10.3762/bjoc.14.198

• , Shanghai 200444, P. R. China 10.3762/bjoc.14.198 Abstract A water-soluble 2,2′-biphen[4]arene (2,2’-CBP4) containing eight carboxylato moieties was synthesized and characterized. Its complexation behavior towards two alkaloids, palmatine (P) and berberine (B), was investigated by means of fluorescence and

• exhibited dramatic fluorescence enhancement of more than 600 times upon complexation with 2,2’-CBP4. Particularly, the fluorescence intensity is strong enough to be readily distinguished by the naked eye. Although the two guests have similar structures, the association constant of B with 2,2’-CBP4 (Ka

• as bioimaging and self-assembled drug delivery systems [33][34][35][36][37][38][39][40]. For example, our group demonstrated a direct host–guest complexation-based drug delivery system for oxaliplatin by carboxylatopillar[6]arene [36]. The encapsulation could not only improve the drug‘s stability in

Dynamic light scattering studies of the effects of salts on the diffusivity of cationic and anionic cavitands

• Anthony Wishard and
• Bruce C. Gibb

Beilstein J. Org. Chem. 2018, 14, 2212–2219, doi:10.3762/bjoc.14.195

• regards to the former, we have shown how poorly solvated anions such as SCN− have an affinity for non-polar surfaces. Because of this, they can compete with the interactions between two non-polar surfaces in a host–guest complexation event and can induce an apparent weakening of the hydrophobic effect

• see no evidence of specific complexation here. More generally, despite the high charge density of 1, monovalent alkali metal ions cannot associate with it sufficiently to induce significant aggregation and a reverse Hofmeister effect. This was not, however, the case with divalent metal ions, which are