Interactions between 4-thiothymidine and water-soluble cyclodextrins: Evidence for supramolecular structures in aqueous solutions

• Vito Rizzi,
• Sergio Matera,
• Paola Semeraro,
• Paola Fini and
• Pinalysa Cosma

Beilstein J. Org. Chem. 2016, 12, 549–563, doi:10.3762/bjoc.12.54

• techniques such as, UV–visible absorption spectroscopy, FTIR–ATR and 1H NMR with the help of electrochemical analysis were utilized in order to characterize the formation of inclusion complexes between S4TdR and CDs. Among the used techniques, 1H NMR spectroscopy gave the most direct evidence for the

Interactions of cyclodextrins and their derivatives with toxic organophosphorus compounds

• Sophie Letort,
• Sébastien Balieu,
• William Erb,
• Géraldine Gouhier and
• François Estour

Beilstein J. Org. Chem. 2016, 12, 204–228, doi:10.3762/bjoc.12.23

• from external associative complexes. UV-visible and fluorescence spectroscopy often provided useful information, while IR was rarely used. Finally, NMR and X-ray crystal structures gave more details on the inclusion mode and the interactions of the pesticide into the oligosaccharide cavity. In addition

• were carried out with paraoxon to evaluate the efficiency of these scavengers as the hydrolysis of this organophosphorus pesticide releases para-nitrophenol that is easily monitored by UV–visible spectrophotometry at 400 nm [82]. It first appeared that the position of the spacer arm on the aromatic

Determination of formation constants and structural characterization of cyclodextrin inclusion complexes with two phenolic isomers: carvacrol and thymol

• Miriana Kfoury,
• David Landy,
• Steven Ruellan,
• Lizette Auezova,
• Hélène Greige-Gerges and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2016, 12, 29–42, doi:10.3762/bjoc.12.5

• phenomenon in deep. In this study, inclusion complexes were characterized in terms of formation constants (Kf), complexation efficiency (CE), CD:guest molar ratio and increase in bulk formulation by using an UV–visible competitive method, phase solubility studies as well as 1H and DOSY 1H NMR titration

• complex HP-β-CD/2 (hydroxypropylated-β-CD/2) has been reported in literature [28]. Therefore, the present study aimed to determine the ability of CDs to encapsulate and solubilize 1 and 2. The stoichiometry and Kf values of CD/1 and CD/2 inclusion complexes were determined using a competitive UV–visible

• most energetically favorable conformation of inclusion complexes. Finally, the effect of encapsulation on the antioxidant properties of 1 and 2 was evaluated using the ABTS radical cation assay. Results and Discussion UV–visible competitive studies Stoichiometries and Kf values of inclusion complexes

Physical properties and biological activities of hesperetin and naringenin in complex with methylated β-cyclodextrin

• Waratchada Sangpheak,
• Jintawee Kicuntod,
• Roswitha Schuster,
• Thanyada Rungrotmongkol,
• Peter Wolschann,
• Nawee Kungwan,
• Helmut Viernstein,
• Monika Mueller and
• Piamsook Pongsawasdi

Beilstein J. Org. Chem. 2015, 11, 2763–2773, doi:10.3762/bjoc.11.297

• RAMEB) solutions. The mixtures were shaken at 30 ± 0.5, 37 ± 0.5 and 45 ± 0.5 °C for 72 hours in a water bath shaker. After equilibrium, the samples were centrifuged at 12,000 rpm for 15 minutes; then the solubility was determined by measuring the absorbance at 256 nm using a DU650 UV visible

Inclusion complexes of 2-methoxyestradiol with dimethylated and permethylated β-cyclodextrins: models for cyclodextrin–steroid interaction

• Mino R. Caira,
• Susan A. Bourne,
• Halima Samsodien and
• Vincent J. Smith

Beilstein J. Org. Chem. 2015, 11, 2616–2630, doi:10.3762/bjoc.11.281

• reference. FTIR spectroscopy A Perkin-Elmer 100 FTIR instrument fitted with UATR and controlled with Spectrum® software for sample analysis was used to record the infrared spectra of crystalline and amorphous powders in the range 400–4000 cm−1. UV–visible spectrophotometry Spectra were recorded on a Beckman

Tetrathiafulvalene-based azine ligands for anion and metal cation coordination

• Awatef Ayadi,
• Aziz El Alamy,
• Olivier Alévêque,
• Magali Allain,
• Nabil Zouari,
• Mohammed Bouachrine and
• Abdelkrim El-Ghayoury

Beilstein J. Org. Chem. 2015, 11, 1379–1391, doi:10.3762/bjoc.11.149

• desired ligands L1 and L2 in 75% and 63% isolated yields, respectively. The structures of the new ligands were characterized by 1H and 13C NMR, UV–visible and IR spectroscopy, high resolution mass spectrometry and elemental analysis. Crystal structure description Details about data collection and

• , Supporting Information File 1) resulting in alternating stacks with a “zig zag” like manner with an angle of rotation of 135.6° (Figure 3). UV–visible absorption spectroscopy The UV–visible absorption spectra of the ligands L1 and L2 were recorded in a mixture of dichloromethane/acetonitrile solution (9/1, v

• pyridinecarboxaldehyde. In addition, E1ox of L2 is also anodically shifted when compared with E1ox of L1 because of the strong π-electron conjugation in ligand L2 and this is in agreement with the bathochromic shift observed for L2 in the UV–visible absorption spectra. Sensing properties of the azine ligands for anions

New palladium–oxazoline complexes: Synthesis and evaluation of the optical properties and the catalytic power during the oxidation of textile dyes

• Rym Hassani,
• Mahjoub Jabli,
• Yakdhane Kacem,
• Jérôme Marrot,
• Damien Prim and
• Béchir Ben Hassine

Beilstein J. Org. Chem. 2015, 11, 1175–1186, doi:10.3762/bjoc.11.132

• %). The oxazolines were prepared from enantiomerically pure α-aminoalcohols. The structures of the synthesized palladium complexes were confirmed by NMR, FTIR, TOFMS, UV–visible spectroscopic analysis and X–ray diffraction. The optical properties of the complexes were evaluated by the determination of the

• gap energy values (Eg) ranging between 2.34 and 3.21 eV. Their catalytic activities were tested for the degradation of Eriochrome Blue Black B (a model of azo dyes) in the presence of an ecological oxidant (H2O2). The efficiency of the decolorization has been confirmed via UV–visible spectroscopic

• distorted tetragonal coordination sphere. The two ligands coordinate to the palladium center in a trans geometry with respect to each other. All the complexes prepared in this work were characterized by IR, 1H, 13C, 2D NMR, X-ray diffraction (for 9 and 8) and UV–visible spectroscopy. The characterized bands

Glycoluril–tetrathiafulvalene molecular clips: on the influence of electronic and spatial properties for binding neutral accepting guests

• Yoann Cotelle,
• Marie Hardouin-Lerouge,
• Stéphanie Legoupy,
• Olivier Alévêque,
• Eric Levillain and
• Piétrick Hudhomme

Beilstein J. Org. Chem. 2015, 11, 1023–1036, doi:10.3762/bjoc.11.115

• neutral acceptor guests. Those studies are supported by electrochemical analyses (including simulation), time-resolved spectroelectrochemical experiments and UV–visible titrations. Results and Discussion Synthesis We have designed molecular clips 1–4 through three different synthetic strategies starting

• checked the influence of the redox properties towards binding ability by studying the strong electrodeficient acceptor F4-TCNQ. Interaction with 1,3-dinitrobenzene (m-DNB) The host–guest affinity was detected by UV–visible spectroscopy upon titration of clip 3 (10−3 M in o-C6H4Cl2) with addition of m-DNB

• intramolecular distance between TTF sidewalls and the strongest π-donor ability. Interaction with tetrafluoroquinodimethane (F4-TCNQ) The binding affinity of molecular clip 3 (5 × 10−4 M in CH2Cl2) was studied by a UV–visible titration with the electron acceptor F4-TCNQ (10−5 M in CH2Cl2). Addition of aliquots

Synthesis and characterization of the cyanobenzene-ethylenedithio-TTF donor

• Sandrina Oliveira,
• Dulce Belo,
• Isabel C. Santos,
• Sandra Rabaça and
• Manuel Almeida

Beilstein J. Org. Chem. 2015, 11, 951–956, doi:10.3762/bjoc.11.106

• voltammetry, NMR, UV-visible and IR spectroscopy. Keywords: cross-coupling; cyanobenzene; cyclic voltammetry; dissymmetric tetrathiafulvalene; electro-active donors; Introduction The tetrathiafulvalene molecule (TTF) and its many derivatives, due to its unique π-donor properties, have been at the basis of

Design, synthesis and photochemical properties of the first examples of iminosugar clusters based on fluorescent cores

• Mathieu L. Lepage,
• Antoine Mirloup,
• Manon Ripoll,
• Fabien Stauffert,
• Anne Bodlenner,
• Raymond Ziessel and
• Philippe Compain

Beilstein J. Org. Chem. 2015, 11, 659–667, doi:10.3762/bjoc.11.74

• , local polarity, potential quenchers, hydrophobic environment, …). Here we focus on the UV–visible characteristics of the anion of 4-methylumbelliferone, the dye commonly used for quantifying chaperoning activities (using 4-methylumbelliferyl β-D-glucopyranoside as GCase substrate) [64], to determine

Preparation and evaluation of cyclodextrin polypseudorotaxane with PEGylated liposome as a sustained release drug carrier

• Kayoko Hayashida,
• Taishi Higashi,
• Daichi Kono,
• Keiichi Motoyama,
• Koki Wada and
• Hidetoshi Arima

Beilstein J. Org. Chem. 2014, 10, 2756–2764, doi:10.3762/bjoc.10.292

• solution, and the suspension was kept at 4 °C for 12 h. The turbidity of the resulting suspension was measured with a JASCO V-630 UV–visible spectrophotometer (Tokyo, Japan) at 800 nm. To obtain the solid sample of the PPRX, the supernatant was removed after the centrifugation (12,000 rpm, 10 min). The

Solution processable diketopyrrolopyrrole (DPP) cored small molecules with BODIPY end groups as novel donors for organic solar cells

• Diego Cortizo-Lacalle,
• Calvyn T. Howells,
• Upendra K. Pandey,
• Joseph Cameron,
• Neil J. Findlay,
• Anto Regis Inigo,
• Tell Tuttle,
• Peter J. Skabara and
• Ifor D. W. Samuel

Beilstein J. Org. Chem. 2014, 10, 2683–2695, doi:10.3762/bjoc.10.283

• films from a 20 mg mL−1 solution, respectively. Film thicknesses were measured using a Dektak 150 M stylus profiler. Absorption and emission spectra of compounds 9 and 10 were obtained with a Varian Cary 300 UV–visible spectrophotometer and a Photoluminescence Quantum Yield (PLQY) measurement system

Effect of cyclodextrin complexation on phenylpropanoids’ solubility and antioxidant activity

• Miriana Kfoury,
• David Landy,
• Lizette Auezova,
• Hélène Greige-Gerges and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2014, 10, 2322–2331, doi:10.3762/bjoc.10.241

• , France ULCO, UCEIV, F-59140 Dunkerque, France 10.3762/bjoc.10.241 Abstract The complexation abilities of five cyclodextrins (CDs) with seven phenylpropanoids (PPs) were evaluated by UV–visible spectroscopy, phase solubility studies and molecular modeling. Formation constants (Kf), complexation

• UV–visible spectroscopy and phase solubility studies. The solubilizing effects of CDs was investigated by determining their complexation efficiency (CE) [18][19]. A theoretical molecular modeling study has been realized to estimate the complexation energies and illustrate the most favorable inclusion

• structural homology. Moreover, they cover a sufficiently relevant range of solubility and hydrophobicity (Table 1). Formation constant (Kf) values were calculated using a UV–visible spectral displacement method [20][21]. This method implies first the characterization of the inclusion complexes between CDs

Photo, thermal and chemical degradation of riboflavin

• Muhammad Ali Sheraz,
• Sadia Hafeez Kazi,
• Sofia Ahmed,
• Zubair Anwar and
• Iqbal Ahmad

Beilstein J. Org. Chem. 2014, 10, 1999–2012, doi:10.3762/bjoc.10.208

• studied by employing a specific UV-visible spectrometric method [27][32][100][101]. The rates of photolysis of FMF were found to be different from that of RF as non-linear curves were obtained indicating that the photolysis of FMF does not follow first-order kinetics in water and organic solvents. The

Multichromophoric sugar for fluorescence photoswitching

• Stéphane Maisonneuve,
• Rémi Métivier,
• Pei Yu,
• Keitaro Nakatani and
• Juan Xie

Beilstein J. Org. Chem. 2014, 10, 1471–1481, doi:10.3762/bjoc.10.151

• 610 nm drops back to zero and the fluorescence of the sample is fully recovered (Figure 4c and d). As shown in Figure 4e and f, several UV–visible irradiation cycles were applied to the system without any degradation of its photophysical properties, revealing its excellent fatigue resistance. 1H NMR

• spectra were recorded under increasing irradiation times at 335 nm in order to follow the photoisomerisation of compound 2 (Figure 5), and corresponding UV–visible absorption spectra were measured, in order to correlate the absorption changes with the OF → CF conversion yield. Under 335 nm illumination

• , new signals appear near 5.2 ppm (for OCH2 group) and 6.5 to 8.0 ppm which are induced by the photocyclisation of the photochromic moiety from the open to the closed form. Due to higher concentration of NMR sample, the maximum conversion reached was about 39%. Such combined 1H NMR vs UV–visible

Stereoselective synthesis of carbocyclic analogues of the nucleoside Q precursor (PreQ₀)

• Sabin Llona-Minguez and
• Simon P. Mackay

Beilstein J. Org. Chem. 2014, 10, 1333–1338, doi:10.3762/bjoc.10.135

• . We chose the benzoate protecting group to generate UV–visible intermediates and because its ease of cleavage under basic conditions would converge with the final pivalamide deprotection step. We adapted this protecting group strategy to Bond’s synthetic route since it was the most concise and

Synthesis, characterization and DNA interaction studies of new triptycene derivatives

• Sourav Chakraborty,
• Snehasish Mondal,
• Rina Kumari,
• Sourav Bhowmick,
• Prolay Das and
• Neeladri Das

Beilstein J. Org. Chem. 2014, 10, 1290–1298, doi:10.3762/bjoc.10.130

• changes in the wavelength as well as absorption maxima were observed in the UV–visible absorption spectra of the compounds 1–4 and 7, 8 in presence of ctDNA (Supporting Information File 1, Figure S3–S6). However, a slight hyperchromic shift in the absorption peak of the TPAs 5 and 6 was observed after

• addition of ctDNA (Figure 4). The observed hyperchromic effect due to the addition of DNA to 5 and 6 is indicative of the electrostatic interaction or partial destabilization of the helix structure of DNA [49][50]. Photophysical characterization Ground state properties: The UV−visible absorption spectra of

• with samples containing 30 µM DNA oligomer duplex, 5 µM EtBr and 200 µM of each of the compounds in 1 mM sodium phosphate buffer (pH 7.2), respectively. The samples along with the controls were incubated at 37 °C for 24 h before the fluorescence measurement. The electronic absorption spectra (UV

Tailoring of organic dyes with oxidoreductive compounds to obtain photocyclic radical generator systems exhibiting photocatalytic behavior

• Christian Ley,
• Julien Christmann,
• Ahmad Ibrahim,
• Luciano H. Di Stefano and
• Xavier Allonas

Beilstein J. Org. Chem. 2014, 10, 936–947, doi:10.3762/bjoc.10.92

• reaction. Thus, according to Beer–Lambert's law, the absorbance of the system decreases during the reaction: this bleaching could be followed by UV–visible absorption spectroscopy. The photolysis of an acetonitrile solution of RB/TA was done within a 1 cm width cell with a monochromatic 532 nm laser diode

Metal and metal-free photocatalysts: mechanistic approach and application as photoinitiators of photopolymerization

• Jacques Lalevée,
• Sofia Telitel,
• Pu Xiao,
• Marc Lepeltier,
• Frédéric Dumur,
• Fabrice Morlet-Savary,
• Didier Gigmes and
• Jean-Pierre Fouassier

Beilstein J. Org. Chem. 2014, 10, 863–876, doi:10.3762/bjoc.10.83

• polymerized through a photoredox catalysis approach. The new proposed PIC (Ir(piq)2(tmd)). UV–visible light absorption spectra for Ir(piq)2(tmd) (2) and Ir(ppy)3 (1); solvent: acetonitrile. (A) cyclic voltamogramm for Ir(piq)2(tmd) in acetonitrile; (B) absorption (a) and luminescence (b) spectra for Ir(piq)2

Columnar/herringbone dual crystal packing of pyrenylsumanene and its photophysical properties

• Binod Babu Shrestha,
• Shuhei Higashibayashi and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2014, 10, 841–847, doi:10.3762/bjoc.10.80

• moiety as a directing group to obtain specific crystal structures. Experimental General UV–visible absorption spectra were recorded on a JASCO V-670 spectrometer. Fluorescence spectra were recorded on a JASCO FP6500 spectrometer. Melting points were determined on a Standford Research Systems MPA 100 and

Raman spectroscopy as a tool for monitoring mesoscale continuous-flow organic synthesis: Equipment interface and assessment in four medicinally-relevant reactions

• Trevor A. Hamlin and
• Nicholas E. Leadbeater

Beilstein J. Org. Chem. 2013, 9, 1843–1852, doi:10.3762/bjoc.9.215

• taken significant strides in recent years [7][10]. Spectroscopic tools such as infrared [11][12][13][14][15], UV–visible [16][17][18], NMR [19][20], Raman [21][22][23][24][25], and mass spectrometry [26][27] have all been interfaced with success. There have been less reports when it comes to mesoflow

Superstructures of fluorescent cyclodextrin via click-reaction

• Arkadius Maciollek,
• Helmut Ritter and
• Rainer Beckert

Beilstein J. Org. Chem. 2013, 9, 827–831, doi:10.3762/bjoc.9.94

• spectrometric experiments (MS) were performed on a Thermo Finnigan Trace DSQ (Dual-Stage Quadrupole) mass spectrometer. Ionization was carried out by electron ionization (EI). The absorption spectra were measured on a Specord 210 Plus UV–visible spectrophotometer. Fluorescence spectra were recorded on a Perkin

Spin state switching in iron coordination compounds

• Philipp Gütlich,
• Ana B. Gaspar and
• Yann Garcia

Beilstein J. Org. Chem. 2013, 9, 342–391, doi:10.3762/bjoc.9.39

• in the UV–visible region distinguishes well the two spin states involved and can therefore be employed to follow the ST phenomenon qualitatively and quantitatively. From the temperature-dependent area fractions of the absorption bands one can construct the ST curve γHS(T). An example is displayed in

Cyclodextrin-induced host–guest effects of classically prepared poly(NIPAM) bearing azo-dye end groups

• Gero Maatz,
• Arkadius Maciollek and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 1929–1935, doi:10.3762/bjoc.8.224

• 210 Plus UV–visible spectrophotometer (Analytik Jena AG, Germany). SEC-MALS measurements were carried out on a combined system comprising the following elements: refractive-index detector Optilabrex (Wyatt Technologies, laser wavelength 658 nm), three-angle light-scattering detector miniDawn TREOS

Self-assembled organic–inorganic magnetic hybrid adsorbent ferrite based on cyclodextrin nanoparticles

• Ângelo M. L. Denadai,
• Frederico B. De Sousa,
• Joel J. Passos,
• Fernando C. Guatimosim,
• Kirla D. Barbosa,
• Ana E. Burgos,
• Fernando Castro de Oliveira,
• Jeann C. da Silva,
• Bernardo R. A. Neves,
• Nelcy D. S. Mohallem and
• Rubén D. Sinisterra

Beilstein J. Org. Chem. 2012, 8, 1867–1876, doi:10.3762/bjoc.8.215

• determinations as a function of time by using a FEMTO UV–visible spectrophotometer, in the wavelength of 700 nm and with a 1 cm light path quartz cell. Optical obscuration was recorded in intervals of 4 min over 120 min. Suspensions containing 4.6 mg L–1 of solid ferrite and 5.1 mg L–1 of solid MHM were analyzed