In-depth characterization of self-healing polymers based on π–π interactions

• Josefine Meurer,
• Julian Hniopek,
• Johannes Ahner,
• Michael Schmitt,
• Jürgen Popp,
• Stefan Zechel,
• Kalina Peneva and
• Martin D. Hager

Beilstein J. Org. Chem. 2021, 17, 2496–2504, doi:10.3762/bjoc.17.166

• ]. Besides the examples of self-healing/regeneration that exist in Nature, the general concept could also be transferred to different synthetic materials. Hereby, two concepts can be distinguished. In extrinsic self-healing materials, a material flow is achieved by the encapsulation of microcapsules [7] or

An initiator- and catalyst-free hydrogel coating process for 3D printed medical-grade poly(ε-caprolactone)

• Jochen Löblein,
• Thomas Lorson,
• Miriam Komma,
• Tobias Kielholz,
• Maike Windbergs,
• Paul D. Dalton and
• Robert Luxenhofer

Beilstein J. Org. Chem. 2021, 17, 2095–2101, doi:10.3762/bjoc.17.136

• on the hydrophobic surface can lead to fibrous encapsulation of medical implants [17][18]. Accordingly, it would be beneficial for PCL implants to have a hydrophilic, non-fouling surface while avoiding factors that complicate the regulatory path to the clinic. So far, the wettability could be

Co-crystallization of an organic solid and a tetraaryladamantane at room temperature

• Fabian Rami,
• Jan Nowak,
• Felix Krupp,
• Wolfgang Frey and
• Clemens Richert

Beilstein J. Org. Chem. 2021, 17, 1476–1480, doi:10.3762/bjoc.17.103

• . The encapsulation occurs even though the host compound assembling into the crystal lattice is able to also crystallize in solvate-free form [12]. Three tetraaryladamantanes (TAAs) were found to show this behavior as hosts, namely 1,3,5,7-tetrakis(2,4-dimethoxyphenyl)adamantane (TDA), 1,3,5,7-tetrakis

• that the encapsulation of the guest molecules in the crystals occurs as a kinetic phenomenon [17]. The TAA finds a crystalline arrangement quickly, without full desolvation, and once the crystal lattice has formed, the guest molecule is unable to escape from it, blocking the path to solvent-free

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Enhanced target cell specificity and uptake of lipid nanoparticles using RNA aptamers and peptides

• Roslyn M. Ray,
• Anders Højgaard Hansen,
• Maria Taskova,
• Bernhard Jandl,
• Jonas Hansen,
• Citra Soemardy,
• Kevin V. Morris and
• Kira Astakhova

Beilstein J. Org. Chem. 2021, 17, 891–907, doi:10.3762/bjoc.17.75

• ]. Clinical trial safety assessments of this formulation showed no liver toxicity and no immune stimulation, with ≈10% of trial participants experiencing mild to moderate adverse events upon administration [38]. It includes encapsulation of siRNA by a mixture of lipid components, such as an ionizable cationic

Synthesis of trifluoromethyl ketones by nucleophilic trifluoromethylation of esters under a fluoroform/KHMDS/triglyme system

• Yamato Fujihira,
• Yumeng Liang,
• Makoto Ono,
• Kazuki Hirano,
• Takumi Kagawa and
• Norio Shibata

Beilstein J. Org. Chem. 2021, 17, 431–438, doi:10.3762/bjoc.17.39

• success of our DMF-free systems lies in the generation of sterically demanding cationic species, [P4-t-Bu]H+ or glyme capsulized K+, resulting in the stabilization of CF3− from HCF3 by ion separation. The sterically demanding [P4-t-Bu]H+ or encapsulation of K+ by glymes effectively inhibits the contact of

• ) Formation of the [P4-t-Bu]H+ CF3 anion salt. d) Encapsulation of K+ by glymes. Transformation of esters to trifluoromethyl ketones. Trifluoromethylation of esters by HCF3 by a) Russell and Roques (1998), b) Prakash and co-workers (2012), c) Szymczak and co-workers (2018), d) Han, Lian and co-workers (2019

Using multiple self-sorting for switching functions in discrete multicomponent systems

• Amit Ghosh and
• Michael Schmittel

Beilstein J. Org. Chem. 2020, 16, 2831–2853, doi:10.3762/bjoc.16.233

• . e) A solvent change from CDCl3 to [d8]-toluene leads to a 2-fold completive self-sorting upon treatment with C60. (a) Two new Zn4L6-type cages. (b) The encapsulation of C70 induced distinct reconstitutions within a dynamic library of mixed ligand Zn4L6 cages. The formation of octahedral cages (a

• (2019) American Chemical Society. Cyclic metallosupramolecular transformations. Fully reversible multiple-state rearrangement of metallosupramolecular architectures depending upon copper(I) stoichiometry. Reproduced from [65]. The selective encapsulation and sequential release of guests in a self-sorted

Water-soluble host–guest complexes between fullerenes and a sugar-functionalized tribenzotriquinacene assembling to microspheres

• Si-Yuan Liu,
• Xin-Rui Wang,
• Man-Ping Li,
• Wen-Rong Xu and
• Dietmar Kuck

Beilstein J. Org. Chem. 2020, 16, 2551–2561, doi:10.3762/bjoc.16.207

• : fullerenes; host–guest systems; microspheres; supramolecular chemistry; tribenzotriquinacene; Introduction In the field of supramolecular chemistry, host–guest association through noncovalent interactions is an interesting and exciting topic, especially for the encapsulation of various fullerenes, such as

The B & B approach: Ball-milling conjugation of dextran with phenylboronic acid (PBA)-functionalized BODIPY

• Patrizia Andreozzi,
• Lorenza Tamberi,
• Elisamaria Tasca,
• Gina Elena Giacomazzo,
• Marta Martinez,
• Mirko Severi,
• Marco Marradi,
• Stefano Cicchi,
• Sergio Moya,
• Giacomo Biagiotti and
• Barbara Richichi

Beilstein J. Org. Chem. 2020, 16, 2272–2281, doi:10.3762/bjoc.16.188

• solution-based synthetic route. PBA-BODIPY dextran assembles into nanoparticles of around 200 nm by hydrophobic interactions. The resulting PBA-BODIPY dextran nanoparticles retain an apolar interior as proved by pyrene fluorescence, suitable for the encapsulation of hydrophobic drugs with high

• assemblies had an apolar interior that makes them appealing for encapsulation of organic molecules. Since the assemblies retained the superior biocompatibility of dextran we envisage their use in drug delivery, also profiting from the fluorescence properties of the nanoparticles that could be used to trace

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

The charge-assisted hydrogen-bonded organic framework (CAHOF) self-assembled from the conjugated acid of tetrakis(4-aminophenyl)methane and 2,6-naphthalenedisulfonate as a new class of recyclable Brønsted acid catalysts

• Svetlana A. Kuznetsova,
• Alexander S. Gak,
• Yulia V. Nelyubina,
• Vladimir A. Larionov,
• Han Li,
• Michael North,
• Vladimir P. Zhereb,
• Alexander F. Smol'yakov,
• Artem O. Dmitrienko,
• Michael G. Medvedev,
• Igor S. Gerasimov,
• Ashot S. Saghyan and
• Yuri N. Belokon

Beilstein J. Org. Chem. 2020, 16, 1124–1134, doi:10.3762/bjoc.16.99

• ][31], gas separation and absorption [28][29], enzyme encapsulation [36], and even asymmetric synthesis (albeit with a framework that contained a transition metal ion) [37]. However, for the HOF and CAHOF catalysts to have a similar appeal to other regular active site distribution materials, such as

Anion-driven encapsulation of cationic guests inside pyridine[4]arene dimers

• Anniina Kiesilä,
• Jani O. Moilanen,
• Anneli Kruve,
• Christoph A. Schalley,
• Perdita Barran and
• Elina Kalenius

Beilstein J. Org. Chem. 2019, 15, 2486–2492, doi:10.3762/bjoc.15.241

• to the electron-poor nature of the pyridine ring. Herein, we demonstrate the encapsulation of Me4N+ cations inside a dimeric hydrogen-bonded pyridine[4]arene capsule, which contradicts with earlier assumptions. The complexation of a cationic guest inside the pyridine[4]arene dimer has been detected

• and studied by multiple gas-phase techniques, ESI-QTOF-MS, IRMPD, and DT-IMMS experiments, as well as DFT calculations. The comparison of classical resorcinarenes with pyridinearenes by MS and NMR experiments reveals clear differences in their host–guest chemistry and implies that cation encapsulation

• been previously detected by ESI-MS [7]. Very recently, with the help of ion mobility mass spectrometry (IM-MS), we showed that pyridine[4]arenes favor encapsulation of neutral molecules over anionic species and anions are in fact complexed in an exo-position (exclusion complexation) between the lower

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

• arylazopyrazoles, that 2 would similarly encapsulate E-1. Results and Discussion Arylazopyrazole E-1 has a very low solubility in water and its encapsulation in cage 2 was attempted from the solid state. Encouragingly, when a colorless aqueous solution of 2 was stirred with an excess of solid E-1, it turned to

• encapsulated two molecules of E-1 (in agreement with the NMR spectra), arranged in an antiparallel fashion (Figure 3). The binding of E-1 within 2 is driven by a combination of π–π stacking, van der Waals forces, and C–H···π interactions (vide infra); in addition, the encapsulation is likely facilitated by the

• ), the signal due to H1 shifted upfield by 0.20 ppm. This behavior is analogous to our previous findings, which showed that shifts of H1 protons are indicative of switching of the bound guest and/or (de)encapsulation [18][49]. Integrating the signals due to E-1’s Hc protons (cyan in Figure 6) allowed us

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

• capable of binding to specifically targeted substrates by imitating various chemical processes is one of the most substantial objectives in chemistry. Encapsulation of two or more substrates within the inner space of the host speeds up and controls the reaction because of a significant increase of the

• ·TCNQ]2+ complex by pre-reduction to a [TCNQ]−· anion radical in situ, and encapsulation in the host, photochemical excitation of the porphyrin unit in the reactor, photoinduced electron transfer from the excited porphyrin unit to a neutral TCNQ, giving rise to a porphyrin radical cation and a second

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

• encapsulation of this moiety. Pyrene group, that are too large for the individual CB[6]–CB[7] sized cavities of ns-CB[10] [23], it is thus believed that the upfield shift of the pyrene protons is attributed the intermolecular π–π stacking between the two pyrenyl moieties as proposed in the plausible inclusion

A heteroditopic macrocycle as organocatalytic nanoreactor for pyrroloacridinone synthesis in water

• Piyali Sarkar,
• Sayan Sarkar and
• Pradyut Ghosh

Beilstein J. Org. Chem. 2019, 15, 1505–1514, doi:10.3762/bjoc.15.152

• reactants. In fact, encapsulation can result in the stabilization of a specific transition state by stripping it out from solvent molecules [13][14]. Hence, in aqueous medium, the syntheses of nanoreactors with a covalent organic framework is important, which is indeed a difficult task due to their large

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

• fluorophores through supramolecular encapsulation using artificial macrocyclic hosts has always been an active research area [10][11][12]. The complexes of macrocycles with luminescent dyes not only act as reporter pairs for sensing [13][14][15], but also offer various applications in bioimaging [16][17

• calculated in aqueous solution [35]. The fluorescence intensity of TPPS was slightly enhanced upon PMCD encapsulation, accompanied by a sharpening of the fluorescence band [36]. The 2:1 PMCD–TPPS complex has been applied in photodynamic therapy with improved photoactivity due to the inhibition of TPPS

Efficient resolution of racemic crown-shaped cyclotriveratrylene derivatives and isolation and characterization of the intermediate saddle isomer

• Sven Götz,
• Andreas Schneider and
• Arne Lützen

Beilstein J. Org. Chem. 2019, 15, 1339–1346, doi:10.3762/bjoc.15.133

• highest binding constant for Xe encapsulation in organic solvents known today [25]. However, unless fixed like in a cryptophane CTVs are usually flexible enough to undergo ring inversion which is synonymous to a racemization in case of chiral CTVs. This intramolecular process presumably proceeds via less

Steroid diversification by multicomponent reactions

• Leslie Reguera,
• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Daniel G. Rivera

Beilstein J. Org. Chem. 2019, 15, 1236–1256, doi:10.3762/bjoc.15.121

• serving as diamino component – to render macrobicycle 72 in moderate yield over three steps. Despite the process was not conducted in one pot, this simple synthetic setup was employed to produce a set of very complex steroidal macrobicycles suitable for molecular and ion pair encapsulation [75]. Aiming at

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

• utilised [5][6]. The Pd2L4-type cages are well explored for the encapsulation of guests that are anionic [7][8][9][10][11], neutral [12][13][14][15][16], radical initiators [17], and drug molecules [18][19]. It is necessary to emphasize here that Pd2L4-type cages contain a cavity. McMorran and Steel

• complexes; rather the corresponding mononuclear complexes were formed and the uncomplexed palladium(II) remained in solution (Scheme 3(ii)). Each of the two cavities of cage 4a is loaded with one NO3–. This phenomenon of NO3– encapsulation by a related isomeric cage was established by us earlier [22][23

• change observable except a slight broadening of the signals for Hb and Hc. Further addition of TBAF led to the formation of [(F)2@Pd3(L1)4](NO3)4 (5a) along with minor impurities. However, the addition of TBAI to 4a showed no changes and hence iodide encapsulation did not happen. The 1H NMR spectra for

Molecular recognition using tetralactam macrocycles with parallel aromatic sidewalls

• Dong-Hao Li and
• Bradley D. Smith

Beilstein J. Org. Chem. 2019, 15, 1086–1095, doi:10.3762/bjoc.15.105

• the central cavity. In organic solvents, hydrogen bonding with the four tetralactam NH residues is the dominant interaction that drives encapsulation of complementary guests, with aromatic stacking as a secondary contributor [23][24][25]. In water, the thermodynamic importance of these non-covalent

• dicarboxamide bridges are in the range of 6.61–6.78 Å, which is shorter than the range of 6.91–7.18 Å for analogous macrocycles with 1,3-benzene dicarboxamide bridges [31]. In some cases, it has been shown that the narrower cavity leads to slower rates of guest encapsulation but no significant changes in

Mechanochemistry of supramolecules

• Anima Bose and
• Prasenjit Mal

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

• capsule 40 formed through hydrogen-bonding and the cavity was found to be able to encapsulate different organic molecules such as alkanes, acids, amines, etc. The encapsulation of a [2.2]paracyclophane in the cage was achieved by ball milling at 30 Hz (Figure 22) and the host–guest product 40 was verified

• reaction through solid-state grinding. Hydrogen-bond donors are a) resorcinol and b) 1,8-dipyridylnaphthalene, respectively. Formation of the cage and encapsulation of [2.2]paracyclophane guest molecule in the cage was done simultaneously under mechanochemical conditions. Formation of the 1:1 complex C60

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

• of mixed ligand complexes of the type [M2L(μ-O2CR)]+ [1], where M is a divalent or trivalent metal ion (M = Mn2+, Fe2+, Co2+, Co3+, Ni2+, Zn2+ and Cd2+) and μ-O2CR is a μ1,3-bridging carboxylato ligand (Figure 1). The encapsulation of a functional carboxylate ion by the bowl-shaped [M2L] fragment can

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

• studies evaluating altered particle degradation rate(s) and encapsulation of trimannose within the particle could also be performed to provide sustained release of the trimannose. Conclusion Herein we described our newly designed pathogen-associated bioerodible microparticle 2 for investigation into the

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

• by Lipshutz and co-workers for RCM and for CM reactions [40][41]. Scheme 6 displays the RCM of selected substrates with G-II as catalyst in the presence of PTS as surfactant. The work of Lipshutz and co-workers is extensively reported elsewhere [21][33][42][43]. Catalyst encapsulation is a recent

• substrates through the beads. However, the reaction rates are very low compared to the non-encapsulated catalyst G-II. The main advantage of the catalyst encapsulation is the catalyst recycling, as the alginate beads can be reused up to 10 times, retaining about 80% of activity. Catalysts bearing quaternary