Mechanochemistry II

• José G. Hernández

Beilstein J. Org. Chem. 2019, 15, 1521–1522, doi:10.3762/bjoc.15.154

• find contributions from renowned global experts in the field of mechanochemistry spanning areas from organic mechanochemistry, supramolecular mechanochemistry to polymer mechanochemistry. Moreover, findings reported in this current thematic issue also contribute to the expansion of synthetic chemistry

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

• only those based on epichlorohydrin, have been reported, their accessibility even on a kg-scale is very limited. The spread of insoluble polymer use can be easily improved by the existence of a readily transferable and engineered method, which would eliminate the main limiting factors of solution

• ratio of CDs/epichlorohydrin was set to 1:10, which was based on the preparation of a soluble polymer [44]. Surprisingly, insoluble CDPs were almost exclusively formed at this molar ratio, unlike in the solution method. This result suggests that, in accordance with the practice, the soluble polymer

• considered negligible. Salt formation in the 10-fold scaled-up synthesis of the β-CD polymer resulted in some materials that became stuck on the jar wall. However, these were considerably easier to remove than the salts of hydrated CDs. The scale-up experiment (20 mmol scale) did not give a significantly

Reversible end-to-end assembly of selectively functionalized gold nanorods by light-responsive arylazopyrazole–cyclodextrin interaction

• Maximilian Niehues,
• Patricia Tegeder and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2019, 15, 1407–1415, doi:10.3762/bjoc.15.140

• 20-fold higher binding constant to β-CD (6.5 × 104 M−1) [32] than unmodified azobenzenes (2.5 × 103 M−1) [33]. Therefore, the competitive binding of CTAB to β-CD has been applied previously, e.g., in sensing applications [34] or to enhance the water solubility of a cyclodextrin polymer [35]. On

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

• Yu-Ying Wang Yong Kong Zhe Zheng Wen-Chao Geng Zi-Yi Zhao Hongwei Sun Dong-Sheng Guo College of Chemistry, Key Laboratory of Functional Polymer Materials, State Key Laboratory of Elemento-Organic Chemistry, Tianjin Key Laboratory of Biosensing and Molecular Recognition, Nankai University, Tianjin

Selenophene-containing heterotriacenes by a C–Se coupling/cyclization reaction

• Pierre-Olivier Schwartz,
• Sebastian Förtsch,
• Astrid Vogt,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2019, 15, 1379–1393, doi:10.3762/bjoc.15.138

• properties provides interesting structure–property relationships and gives valuable insights into the role of heteroatoms within the series of the heterotriacenes. Electrooxidative polymerization led to the corresponding poly(heterotriacene)s P2–P4. Keywords: conducting polymer; C–S coupling; C–Se coupling

• subsequent electrochemical characterization of polymer P(DTS) P2 at various scan rates in a monomer-free electrolyte is shown (right). The other examples for P1, P3, and P4 are shown in Supporting Information File 1, Figure S14. After the oxidation of the monomer in the first scan, polymerization starts by

• the steady growth of polymer film. After 20 sweeps, homogeneous films of polymers P1–P4 were obtained (observed by optical microscopy) which were then electrochemically and spectroelectrochemically characterized (Table 5 and Table S7 in Supporting Information File 1). Cyclic voltammograms of polymers

Formation of an unexpected 3,3-diphenyl-3H-indazole through a facile intramolecular [2 + 3] cycloaddition of the diazo intermediate

• Andrew T. King,
• Hugh G. Hiscocks,
• Lidia Matesic,
• Mohan Bhadbhade,
• Roger Bishop and
• Alison T. Ung

Beilstein J. Org. Chem. 2019, 15, 1347–1354, doi:10.3762/bjoc.15.134

• with dimensions of 0.11 × 0.19 × 0.22 mm, selected under the polarising microscope (Leica M165Z), was mounted on a MicroMount (MiTeGen, USA) consisting of a thin polymer tip with a wicking aperture. The X-ray diffraction measurements were carried out on a Bruker kappa-II CCD diffractometer at 150 K

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

Enantioselective Diels–Alder reaction of anthracene by chiral tritylium catalysis

• Qichao Zhang,
• Jian Lv and
• Sanzhong Luo

Beilstein J. Org. Chem. 2019, 15, 1304–1312, doi:10.3762/bjoc.15.129

• widely used in inorganic and organic chemistry [24][25][26][27] as well as in polymer chemistry [28][29][30][31][32][33]. Although tritylium salts with various types of these counter anions based on B(III), Al(III), Ga(III), Fe(III), Nb(III), Ta(III), Y(III) and La(III) centers and ligands have been

Mechanochemical amorphization of chitin: impact of apparatus material on performance and contamination

• Thomas Di Nardo and
• Audrey Moores

Beilstein J. Org. Chem. 2019, 15, 1217–1225, doi:10.3762/bjoc.15.119

• combination of balls, size and apparatus materials can help to optimize the energy input while allowing the desired loss of crystallinity for hard milling or maintaining crystallinity for soft milling techniques. In order to better understand the role of the milling medium on polymer reactivity, we launched a

Ugi reaction-derived prolyl peptide catalysts grafted on the renewable polymer polyfurfuryl alcohol for applications in heterogeneous enamine catalysis

• Alexander F. de la Torre,
• Gabriel S. Scatena,
• Oscar Valdés,
• Daniel G. Rivera and
• Márcio W. Paixão

Beilstein J. Org. Chem. 2019, 15, 1210–1216, doi:10.3762/bjoc.15.118

• polyfurfuryl alcohol-supported catalysts for applications in heterogeneous enamine catalysis. The utilization of the polymer-supported catalysts in both batch and continuous-flow organocatalytic procedures proved moderate catalytic efficacy and enantioselectivity, but excellent diastereoselectivity in the

• ; multicomponent reactions; organocatalysis; polyfurfuryl alcohol; Introduction The immobilization of secondary amine-based catalysts onto organic polymers and silica gel has emerged as an effective strategy that combines the power of heterogeneous and organocatalysis [1][2][3]. Asymmetric catalysis using polymer

• ., polystyrene) [1][2][3]. When aiming at implementing large-scale catalytic processes with supported organocatalysts, a relevant “green” premise is the use of renewable and readily available solid supports [1][2][3][4][5]. Accordingly, we envisioned the utilization of the polymer polyfurfuryl alcohol (PFA

Insertion of [1.1.1]propellane into aromatic disulfides

• Robin M. Bär,
• Gregor Heinrich,
• Martin Nieger,
• Olaf Fuhr and
• Stefan Bräse

Beilstein J. Org. Chem. 2019, 15, 1172–1180, doi:10.3762/bjoc.15.114

• peroxide, DTBP) led to increased amounts of insoluble polymer. Molecular structure of 6a (displacement parameters are drawn at 50% probability level), distance C1–C3 1.844(3) Å. NMR spectra of pure 6a (green) and 6d (red) and the obtained mixture with the new compound 15 (blue). Summary of the most recent

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

• Universität Darmstadt, Darmstadt, Germany 10.3762/bjoc.15.112 Abstract This study elucidates a mechanochemical polymerization reaction towards a hyper-crosslinked polymer as an alternative to conventional solvent-based procedures. The swift and solvent-free Friedel–Crafts alkylation reaction yields a porous

• polymer with surface areas of up to 1720 m2g−1 and pore volumes of up to 1.55 cm3g−1. The application of LAG (liquid-assisted grinding) revealed a profound impact of the liquid´s boiling point on the textural properties of the obtained polymer materials. Finally, the materials are characterized by vapour

• trifluoromethanesulfonic acid or sulfuric acid was developed yielding basically the same polymer but avoiding residual traces of the metal [11]. These synthetic pathways often afford a gel from the dissolved monomers upon the crosslinking that is subsequently washed and dried with a significant volume loss. Still, a high

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

• Technologies “Acad. J. Malinowski”, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany, Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria 10.3762/bjoc.15.106

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

• isotherm model. Keywords: adsorption; cucurbit[7]uril; electrospinning; macrocycles; methylene blue; nanofiber; Introduction Electrospinning is recognized as the most simple and versatile method to fabricate multifunctional nanofibers from the solution or melt of polymers, polymer/nanoparticle mixtures

• series of CD-functionalized electrospun nanofibers in the forms of CD-pseudopolyrotaxane [11][12], CDs/polymer [13][14][15], CD-ICs/polymer [16][17], and polymer-free CDs [5][18] or CD-ICs [19] have been fabricated. In addition, calix[8]arene (C[8])/polyacrylonitrile (PAN) composite nanofiber membranes

• [20] and supramolecular polymer nanofibers based on pillar[5]arene [21] also were prepared by the electrospinning technique. Cucurbit[n]urils (CB[n]s, n = 5–8, 10) are a family of pumpkin-shaped cyclic host molecules containing a hydrophobic cavity surrounded by two identical hydrophilic portals [22

Mechanochemical synthesis of poly(trimethylene carbonate)s: an example of rate acceleration

• Sora Park and
• Jeung Gon Kim

Beilstein J. Org. Chem. 2019, 15, 963–970, doi:10.3762/bjoc.15.93

• important for chain-length control. Liquid-assisted grinding was applied for the synthesis of high molecular weight polymers, but it failed to protect the polymer chain from mechanical degradation. Keywords: aliphatic polycarbonate; green polymerization; mechanochemistry; organocatalyst; poly(trimethylene

• achieved by solution synthesis occur, which makes mechanochemistry a topic of rigorous research [6]. In the area of polymer chemistry, the use of mechanical forces has a long history. Strong mechanical forces can break covalent bonds, including strong C–C bonds, thus their utilization has generally focused

• brief ball milling of monomer and base [10]. The remarkable reactivity exemplified that the general concepts of mechanochemical synthesis are applicable to polymerization reactions. Other examples of polymer syntheses have followed. The Borchardt research team reported the efficient mechanochemical

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

• yellow cloud. (a) The halogen bonding (blue broken lines), hydrogen bonding (red broken lines) and the host–guest effect (water molecules in CPK, and the cavity space in transparent yellow cloud) in Water@2&DIOFB; (b) The halogen bonded polymer. Water molecules in CPK mode and all the other in ball-and

Mechanochemistry of supramolecules

• Anima Bose and
• Prasenjit Mal

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

• -benzenetricarbonyl chloride and 1,4-phenylenediamine in a ball mill afforded 75% of the desired 2D polymer 24 within 15 min (Figure 13). When using 4,4'-diaminobiphenyl in place of 1,4-phenylenediamine the analogous 2D structure comprising biphenylene units was obtained within the same time albeit with a lower yield

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

• through the layers. Consequently, this leads to the transition of the oxidation from a kinetic mode into a diffusive mode. Such structural changes do not occur in a polymer that was stabilized by adding an antioxidant. Keywords: bis(cyclopentadienyl)titanium dichloride; cationic polymerization; oxidation

• obtain a polymer with particular properties – polydicyclopentadiene (PDCPD) [8][9]. Cationic polymerization of DCPD takes place with metal-halide-based catalyst systems and organometallic compounds. A number of scientific reports were dedicated to the investigation of DCPD polymerization based on these

• cationic polymerization, are characterized by certain disadvantages. They have a low molecular weight, a fairly rigid structure of the polymer chains due to crosslinking processes occurring during polymerization. In addition, DCPD polymers obtained from "hard" catalytic systems, such as TiCl4, SnCl4, etc

Synthesis of functionalized diazocines for application as building blocks in photo- and mechanoresponsive materials

• Widukind Moormann,
• Daniel Langbehn and
• Rainer Herges

Beilstein J. Org. Chem. 2019, 15, 727–732, doi:10.3762/bjoc.15.68

• , amine and vinyl groups, which are suitable for polymer synthesis. Upon irradiation at 385 and 530 nm the diazocines perform a reversible, pincer-type movement switching the 3,3’-distance between 6.1 Å (cis, stable isomer) and 8.2 Å (trans, metastable isomer). Key reactions in the synthesis are an

Polyaminoazide mixtures for the synthesis of pH-responsive calixarene nanosponges

• Antonella Di Vincenzo,
• Antonio Palumbo Piccionello,
• Alberto Spinella,
• Delia Chillura Martino,
• Marco Russo and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2019, 15, 633–641, doi:10.3762/bjoc.15.59

• with CyCaNSs. This fact was explained assuming that a diazidoalkane is a less effective reticulating agent than a heptakisazido-β-cyclodextrin, simply because of the lesser number of reactive azide groups present. Hence, we reasoned that the polymer network formation process could have been improved by

• decreases on increasing the pH, clearly indicating that inclusion is favorably affected by the presence of positive charges on the polymer network due to protonation of amine basic sites. Consistently, the behavior of the diamine derivative 10 is reversed (inclusion decreases on decreasing the pH). A

• -sensitive functionalities in the highly hydrophobic nanoporous environment provided by the fully synthetic calixarene-based polymer, might open interesting perspectives for applicative purposes, in particular in the fields of organocatalysis and of hybrid organic-inorganic materials, such as in the emerging

Design and synthesis of multivalent α-1,2-trimannose-linked bioerodible microparticles for applications in immune response studies of Leishmania major infection

• Chelsea L. Rintelmann,
• Tara Grinnage-Pulley,
• Kathleen Ross,
• Daniel E. K. Kabotso,
• Angela Toepp,
• Anne Cowell,
• Christine Petersen,
• Balaji Narasimhan and
• Nicola Pohl

Beilstein J. Org. Chem. 2019, 15, 623–632, doi:10.3762/bjoc.15.58

• microparticles 2 to allow a single delivery of trimannose from a total of 5 × 107 particles, a four-fold lower level than what was used for the latex bead study [42], as studies by Huntimer and co-workers showed in 2013 that the CPH:SA polymer provided inherent adjuvant properties and dose sparing effects [57

Low-budget 3D-printed equipment for continuous flow reactions

• Jochen M. Neumaier,
• Amiera Madani,
• Thomas Klein and
• Thomas Ziegler

Beilstein J. Org. Chem. 2019, 15, 558–566, doi:10.3762/bjoc.15.50

• resolution for our printing method, we designed test reactors with a very small channel width down to 0.1 mm. Here, the smallest possible resolution appeared to be a profile area of 0.3 mm × 0.3 mm in the CAD drawing which resulted in channel width of around 0.2 mm (Figure 3). Due to polymer spreading during

Selectivity in multiple multicomponent reactions: types and synthetic applications

• Ouldouz Ghashghaei,
• Francesca Seghetti and
• Rodolfo Lavilla

Beilstein J. Org. Chem. 2019, 15, 521–534, doi:10.3762/bjoc.15.46

• interesting case, where this principle does not apply, is introduced by Wessjohann [5][18], who introduced a family of MMCRs leading to complex macrocyclic structures instead of linear polymer chains. In these examples, a low concentration together with the use of specific substrates tune the reactivity

• ; V) generation of new functional groups; VI) polymerization; VII) macrocyclization; FG = functional group. Indiscriminate double Ugi MCR upon pyridine-2,6-dicarboxylic acid. Representative examples of MCR-polymer synthesis. A) Biginelli HTS of polymers; B) Passerini;- C) Ugi-; D) metal-catalyzed MCR

Aqueous olefin metathesis: recent developments and applications

• Valerio Sabatino and
• Thomas R. Ward

Beilstein J. Org. Chem. 2019, 15, 445–468, doi:10.3762/bjoc.15.39

• tremendous impact in organic synthesis, enabling a variety of applications in polymer chemistry, drug discovery and chemical biology. Although challenging, the possibility to perform aqueous metatheses has become an attractive alternative, not only because water is a more sustainable medium, but also to

• different research fields spanning polymer chemistry [11][12] to drug discovery [13][14][15]. Scheme 1 displays the most common metathesis reactions. The metathesis reaction mechanism, proposed by Chauvin in 1971, suggests that the reaction proceeds via the reversible formation of a metallacyclobutane

• polymer is currently being investigated for possible biomedical applications. Table 4 summarizes the activities of the different ammonium-tagged catalysts discussed above with several water-soluble substrates. Catalysts 3 and 4 showed modest to excellent activities in the RCM of N,N-diallylated substrate

LCST phase behavior of benzo-21-crown-7 with different alkyl chains

• Yan Deng,
• Xing Li,
• Qiao Zhang,
• Zheng Luo,
• Chengyou Han and
• Shengyi Dong

Beilstein J. Org. Chem. 2019, 15, 437–444, doi:10.3762/bjoc.15.38

• molecule [40][41] or introducing hydrophobic units into B21C7 structures. For the first method, though the incorporation of B21C7s to polymeric backbones/cores can effectively lower the critical transition temperature, an accurate control of polymer/core structures is necessary but challenging. Because the