The interaction between cucurbit[8]uril and baicalein and the effect on baicalein properties

• Xiaodong Zhang,
• Jun Xie,
• Zhiling Xu,
• Zhu Tao and
• Qianjun Zhang

Beilstein J. Org. Chem. 2020, 16, 71–77, doi:10.3762/bjoc.16.9

• ] inclusion complex had an obvious melting point at 448.7 °C and the melting point and endothermic peaks of BALE and Q[8] disappeared. The results showed that a new material appeared, which improved the thermal stability of BALE (Figure 6d). The effect of cucurbit[8]uril on baicalein properties Stability

Photocontrolled DNA minor groove interactions of imidazole/pyrrole polyamides

• Sabrina Müller,
• Jannik Paulus,
• Jochen Mattay,
• Heiko Ihmels,
• Veronica I. Dodero and
• Norbert Sewald

Beilstein J. Org. Chem. 2020, 16, 60–70, doi:10.3762/bjoc.16.8

• ]. According to molecular dynamics calculations, the 3,3'-substituted azobenzenes are more suitable as photoswitchable building blocks to induce a hairpin motif than the 4,4'-substituted correlates [35]. For 3,3'-substituted azobenzenes, the Z-form is expected to display higher thermal stability than for the

• azobenzene compounds proceeds substantially slower than for 4,4’-substituted azobenzene analogs [36]. Moreover, the solutions were kept in the dark to evaluate the thermal stability of the Z-isomer, and it was noted that after one or two days, the percentage of Z-isomer was slightly reduced (after 2 d: 62

• % P1; 67% P2; after 1 d: 76% P3). Analysis of polyamide–DNA interaction by induced circular dichroism CD spectroscopic analysis is suitable for the characterization of DNA minor groove binders, providing semiquantitative information about binding affinity and thermal stability of the target dsDNA [47

Starazo triple switches – synthesis of unsymmetrical 1,3,5-tris(arylazo)benzenes

• Andreas H. Heindl and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2020, 16, 22–31, doi:10.3762/bjoc.16.4

• substitution prolongs the thermal stability up to years [4], while electron-donating groups attached to the different phenyl rings decrease the thermal half-lives below the time scale of seconds. Even subtle interactions, such as London dispersion in alkyl-substituted ABs, can have a significant influence on

Palladium-catalyzed Sonogashira coupling reactions in γ-valerolactone-based ionic liquids

• László Orha,
• József M. Tukacs,
• László Kollár and
• László T. Mika

Beilstein J. Org. Chem. 2019, 15, 2907–2913, doi:10.3762/bjoc.15.284

• recently γ-valerolactone [19]. The series of these alternative media can implicitly be continued by ionic liquids (ILs) [20], which have attracted considerable attention, due to their extremely low vapor pressure, good solvating properties, reasonable thermal stability, and easily tuneable physical

Carbazole-functionalized hyper-cross-linked polymers for CO₂ uptake based on Friedel–Crafts polymerization on 9-phenylcarbazole

• Dandan Fang,
• Xiaodong Li,
• Meishuai Zou,
• Xiaoyan Guo and
• Aijuan Zhang

Beilstein J. Org. Chem. 2019, 15, 2856–2863, doi:10.3762/bjoc.15.279

• structure of the obtained polymers. The TG analysis of the HCPs showed good thermal stability. More importantly, a comparative study on the porosity revealed that: the molar ratio of cross-linker to monomer was the main influence factor of the BET specific surface area. Increasing the reaction temperature

• carbon. Based on the above peaks in the solid state NMR, the Friedel–Crafts polymerization product was confirmed. TGA analysis The thermal stability of HCPs was investigated by TGA tests (Figure 3 and Supporting Information File 1, Figure S3). A slight weight loss at 100 °C was observed for P2, P4, P5

• the temperature raised up to 800 °C (Supporting Information File 1, Table S1), demonstrated the splendid thermal stability of P1–P11 as reported for microporous polymers [34]. Morphology analysis The morphology of P1–P11 was investigated by SEM images (Figure 4), which showed that HCPs were composed

Chemical tuning of photoswitchable azobenzenes: a photopharmacological case study using nicotinic transmission

• Lorenzo Sansalone,
• Jun Zhao,
• Matthew T. Richers and
• Graham C. R. Ellis-Davies

Beilstein J. Org. Chem. 2019, 15, 2812–2821, doi:10.3762/bjoc.15.274

• shorter thermal half-life of about 75 min at rt [16], a value that would be much lower at physiological temperatures Next we tested the chemical reactivity and stability of 1 in physiological buffer. First, we tested the thermal stability of 1 in physiological buffer (HEPES, pH 7.4). We found that in

• acetylcholine seems impossible to derivatize with a photochemical protecting group, a biologically inert photo-activatable agonist such 2 could be useful for neurophysiological studies. The long-term thermal stability of the 4FAB core allows a "stock" of the biologically inert cis PSS to be made. Since thermal

• ) in HEPES (pH 7.4) at rt. c) Time course of thermal decay of cis-2 PSS in HEPES (pH 7.4) at 37 °C. Reaction of t-4FABTA (1) with thiols, and thermal stability of initial conjugate. a) Chemical reaction of 1 with glutathione in HEPES (pH 7.4) at 37 °C to coupled conjugate 12, and hydrolysis to 13. b

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

• thermal stability of the Z-isomer. Despite the huge body of structure–property relationship studies known for substituted azobenzenes [8][9], it is still common to observe azo photoswitches that undergo incomplete photoswitching and/or possess low Z-isomer thermal stability. Perhaps the most important

• that in order to improve the photochemical addressability of the Z-isomer of these molecules (as is observed in 4pzMe and 3pzH) we needed to sacrifice thermal stability (4pzH vs 4pzMe and 3pzH), (Figure 1b) [17][18]. One parameter that was not explored in our previous structure–property relationship

• ). Electron-poor (F and Cl) and electron-rich moieties (methoxy and pyrrolidine abbreviated as OMe and Pyr, respectively) were considered to analyze the effect of these ortho-groups on the thermal stability of Z-arylazopyrazoles (Table 1). Such substitution has proved useful in the improvement of azobenzene

Fluorinated maleimide-substituted porphyrins and chlorins: synthesis and characterization

• Valentina A. Ol’shevskaya,
• Elena G. Kononova and
• Andrei V. Zaitsev

Beilstein J. Org. Chem. 2019, 15, 2704–2709, doi:10.3762/bjoc.15.263

• the generation of active oxygen forms (1O2, HO−, НО2−˙and O2−˙) upon excitation with monochromatic light which causes the death of the tumor [10][11][12][13][14]. Some other important features, that photosensitizers should have for such applications are their photo and thermal stability, and an

In search of visible-light photoresponsive peptide nucleic acids (PNAs) for reversible control of DNA hybridization

• Lei Zhang,
• Greta Linden and
• Olalla Vázquez

Beilstein J. Org. Chem. 2019, 15, 2500–2508, doi:10.3762/bjoc.15.243

• tetra-ortho-fluoroazobenzene–PNA conjugates have promising properties (fast reversible isomerization, exceptional thermal stability, high isomer conversions and sensitivity to visible-light irradiation) as reversible modulators to control oligonucleotide hybridization in biological contexts. Furthermore

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

• cyclohexenone bridges show good cycloreversion quantum yields of 0.20–0.32. The thermal stability of closed-ring isomers reveals half-lives of up to 20 days in solution at room temperature. The ligands were used to explore coordination chemistry with iron(II) targeting photoswitchable spin-crossover complexes

• ], ligands 3, 6, and 7 possess high cycloreversion quantum yields. Note, that the photostationary state for the cyclization with λ = 313 nm is characterized by a high conversion to the close-ring isomers at 0.70–0.93. Finally, thermal stability of closed-ring isomers was determined. Previously, it was

• demonstrated that imidazole as a heteroaryl moiety decreases thermal stability [42]. In particular, a close analogue of 3 with a phenyl instead of a pyridyl group showed a half-live of the ring-closed isomer as low as 7.3 days. In accordance to this data, diarylethene 3 showed a half-life of 8.6 days. However

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

• ]. Among them, arylazopyrazoles have attracted considerable interest because of their synthetic availability and desirable photochemical properties, such as the high thermal stability of the Z isomer and a large band separation between the E and Z isomers, allowing each to be addressed with a high

• diffusion to an aqueous solution of 1 (290 mg; yield = 95%). Cage 2 has an excellent solubility in water and is stable in the pH range of 4–9. It also exhibits high thermal stability, remaining stable for prolonged periods at 80 °C. Synthesis of inclusion complex (E-1)22: E-1 was encapsulated by stirring

Thermal stability of N-heterocycle-stabilized iodanes – a systematic investigation

• Andreas Boelke,
• Yulia A. Vlasenko,
• Mekhman S. Yusubov,
• Boris J. Nachtsheim and
• Pavel S. Postnikov

Beilstein J. Org. Chem. 2019, 15, 2311–2318, doi:10.3762/bjoc.15.223

• Federation Department of Solid State Engineering, University of Chemistry and Technology, 16628 Prague, Czech Republic 10.3762/bjoc.15.223 Abstract The thermal stability of pseudocyclic and cyclic N-heterocycle-stabilized (hydroxy)aryl- and mesityl(aryl)-λ3-iodanes (NHIs) through thermogravimetric analysis

• explosive properties of Togni’s reagent and very recently, Williams and co-workers analyzed the sensitivity of common oxidants including 2-iodoxybenzoic acid (IBX) and Dess–Martin periodinane (DMP) [19][20]. Waser and co-workers examined the thermal stability of the Zhdankin reagent ABX and compared it with

• the amide-stabilized derivative ABZ (azidobenziodazolone). They found a remarkable higher thermal stability of the latter compound by DSC analysis indicated by a higher onset temperature and a lower heat release during decomposition [21]. ABZ is a rare example of a nitrogen-stabilized iodane, showing

Fluorinated azobenzenes as supramolecular halogen-bonding building blocks

• Esther Nieland,
• Oliver Weingart and
• Bernd M. Schmidt

Beilstein J. Org. Chem. 2019, 15, 2013–2019, doi:10.3762/bjoc.15.197

• thermal stability of the Z-isomer, now exhibiting thermal half-lives up to two years at room temperature [36]. Most important for application in supramolecular systems, it should be possible to study both states of the system on a laboratory timescale, a key aspect in the design of our halogen bonded

• the, also broadened, n→π* band of Z-A3. Apart from the photoisomerisation using light, azobenzenes A1–3 also undergo thermal back reaction, which we studied experimentally and theoretically. To gain insight into the effect of the iodine atoms on the thermal stability we investigated A1, A2 and A3 in

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

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

• 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

Mechanochemical synthesis of hyper-crosslinked polymers: influences on their pore structure and adsorption behaviour for organic vapors

• Sven Grätz,
• Sebastian Zink,
• Hanna Kraffczyk,
• Marcus Rose and
• Lars Borchardt

Beilstein J. Org. Chem. 2019, 15, 1154–1161, doi:10.3762/bjoc.15.112

• protocol the polymer obtained through this mechanochemical route is also amorphous as visualized by the XRD (X-ray diffraction) patters recorded (Supporting Information File 1, Figure S1) [43]. Furthermore, NG-HCP similarly shows a high thermal stability with a decomposition onset in air (Supporting

Fabrication, characterization and adsorption properties of cucurbit[7]uril-functionalized polycaprolactone electrospun nanofibrous membranes

• Changzhong Chen,
• Fengbo Liu,
• Xiongzhi Zhang,
• Zhiyong Zhao and
• Simin Liu

Beilstein J. Org. Chem. 2019, 15, 992–999, doi:10.3762/bjoc.15.97

• temperature range of 25–650 °C are depicted in Figure S7 (Supporting Information File 1). From the TG/DTG curves, the thermal decomposition temperatures of the PCL/CB[7] nanofibers are higher than that of CB[7] alone, demonstrating a better thermal stability of the PCL/CB[7] nanofiber composites. Methylene

Application of olefin metathesis in the synthesis of functionalized polyhedral oligomeric silsesquioxanes (POSS) and POSS-containing polymeric materials

• Patrycja Żak and
• Cezary Pietraszuk

Beilstein J. Org. Chem. 2019, 15, 310–332, doi:10.3762/bjoc.15.28

• minor amount of homometathesis. Fortunately, the product of homocoupling could be easily separated from the desired CM products. The presence of the carborane clusters was shown to enhance the thermal stability of the materials. Absorption and emission data of carborane–POSS hybrids indicate a large red

• heptacyclopentylnorbornenylethyloctasilsesquioxane and its copolymerization with cyclooctene [43]. The obtained copolymer was subsequently hydrogenated to afford polyethylene–POSS random copolymer (Scheme 21). Thermogravimetric analysis of the polyethylene–POSS copolymers under air showed a significant improvement of the thermal stability relative

• of polymers and copolymers with 3-(trifluoromethyl)phenyl-7-oxanorbornene-5,6-dicarboximide (Scheme 25) [48]. It was found that the increase in the content of POSS units in the copolymer results in a decrease in thermal stability and Tg values. TEM and AFM microimages show spherical POSS aggregates

Catalysis of linear alkene metathesis by Grubbs-type ruthenium alkylidene complexes containing hemilabile α,α-diphenyl-(monosubstituted-pyridin-2-yl)methanolato ligands

• Tegene T. Tole,
• Johan H. L. Jordaan and
• Hermanus C. M. Vosloo

Beilstein J. Org. Chem. 2019, 15, 194–209, doi:10.3762/bjoc.15.19

• Grubbs 2-type (5) metal carbenes with pyridinyl alcoholato ligands for the 1-octene metathesis reaction (Figure 3) [10][11][12][13][14]. The incorporation of pyridinyl-alcoholato ligands in the Grubbs-type precatalysts has shown an increase in the thermal stability, activity and lifetime of the

Ruthenium-based olefin metathesis catalysts with monodentate unsymmetrical NHC ligands

• Veronica Paradiso,
• Chiara Costabile and
• Fabia Grisi

Beilstein J. Org. Chem. 2018, 14, 3122–3149, doi:10.3762/bjoc.14.292

• other N-alkyl (neopentyl and neophyl) and N-aryl (mesityl) substituents, was published later [61]. Among these novel Hoveyda-type catalysts 193–198 (Figure 35), 198 was of particular interest due to its excellent thermal stability in solution and to the high efficiency in the ethenolysis of ethyl oleate

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• handling, and even reusability [34]. Ionic liquids (ILs) have been extensively reported as green solvents in organic transformations, owing to their considerable properties such as the ability to dissolve a wide range of substances, very low vapor pressure, high thermal stability, recyclability, non

Some mechanistic aspects regarding the Suzuki–Miyaura reaction between selected ortho-substituted phenylboronic acids and 3,4,5-tribromo-2,6-dimethylpyridine

• Piotr Pomarański,
• Piotr Roszkowski,
• Jan K. Maurin,
• Armand Budzianowski and
• Zbigniew Czarnocki

Beilstein J. Org. Chem. 2018, 14, 2384–2393, doi:10.3762/bjoc.14.214

• ). Considering further applications of atropisomeric arylated pyridines in the design of new materials like molecular switches [4], it would be desirable to estimate their thermal stability. We therefore performed kinetic experiments in order to establish the value of the barrier to rotation in the

Practical tetrafluoroethylene fragment installation through a coupling reaction of (1,1,2,2-tetrafluorobut-3-en-1-yl)zinc bromide with various electrophiles

• Ken Tamamoto,
• Shigeyuki Yamada and
• Tsutomu Konno

Beilstein J. Org. Chem. 2018, 14, 2375–2383, doi:10.3762/bjoc.14.213

• the CF2CF2 unit between two cyclohexane rings caused significant enhancement in thermal stability in a liquid crystalline phase (Figure 1c) [11]. In addition to the development of a convenient access to CF2CF2-containing pyranoses [12], our group also showed that tricyclic mesogens with a CF2CF2

• that possesses higher thermal stability than the corresponding organolithium or -magnesium species due to the almost covalent C–Zn bond [29][30]. Moreover, organozinc reagents can be easily transformed to the “reactive” species, through a transmetallation process with a transition metal (e.g., Pd or Cu

• 1.5 years in the refrigerator [35]. In order to examine the stability of 2-Zn in more detail, we quantitatively evaluated the thermal stability of 2-Zn under various temperature conditions (Figure 2). After a given duration, the recovery yield of 2-Zn was determined by 19F NMR analysis using an

A general and atom-efficient continuous-flow approach to prepare amines, amides and imines via reactive N-chloramines

• Katherine E. Jolley,
• Michael R. Chapman and
• A. John Blacker

Beilstein J. Org. Chem. 2018, 14, 2220–2228, doi:10.3762/bjoc.14.196

• -toluenesulfonamide (11) was investigated as substrate. Differential scanning calorimetry (DSC) was used to assess the thermal stability of 11, which melts at 78 °C and decomposes between 160–200 °C. This profile peaks at 188 °C, corresponding to an enthalpy of decomposition of −84.7 kJ mol−1 (see Supporting

Functionalization of graphene: does the organic chemistry matter?

• Artur Kasprzak,
• Agnieszka Zuchowska and
• Magdalena Poplawska

Beilstein J. Org. Chem. 2018, 14, 2018–2026, doi:10.3762/bjoc.14.177

• and hydrogen bonding-dependent adsorption of glucose on the RGO surface results in a shift of the absorption bands coming from the C=O of RGO (from 1724 cm−1 to 1735 cm−1). Another consideration is that this process further influences the obtained material’s morphology, properties and thermal

• stability [41][42]. Additionally, some researchers have used the acid catalysis [39] or grinding-induced process [40] for the esterification reaction, and the changes in the spectra (e.g., IR, XPS) were not prominent enough to imply the formation of covalent ester-type linkages. In the grinding-induced case