N-doped carbon dots covalently functionalized with pillar[5]arenes for Fe³⁺ sensing

• Jia Gao,
• Ming-Xue Wu,
• Dihua Dai,
• Zhi Cai,
• Yue Wang,
• Wenhui Fang,
• Yan Wang and
• Ying-Wei Yang

Beilstein J. Org. Chem. 2019, 15, 1262–1267, doi:10.3762/bjoc.15.123

• units, the newly constructed fluorescent CCDs could recognize Fe3+ with high selectivity. Therefore, such CCDs can potentially serve as a promising chemical sensor for Fe3+ ions. Keywords: chemical sensor; CN-dots; fluorescence; ion recognition; supramolecular chemistry; Findings Carbon dots (C-dots

• macrocyclic compounds, especially new macrocyclic arenes, have become one of the research hotspots in supramolecular chemistry [11][12][13][14]. Among them pillarenes as a relatively new family of pillar-shaped members discovered a decade ago have played a key role due to their unique conformations

• , symmetrical structures, superior host–guest properties, supramolecular assembly characteristics, and versatile functionalities [11][15][16]. Carboxylatopillar[5]arene (CP[5]) is one of the most popular functional pillarenes that has been exploited in many research areas, especially in sensing and detection

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

• supramolecular chemistry applications. Keywords: conjugation; heterocycles; macrocycles; multicomponent reactions; steroids; Review 1 Introduction The utilization of multicomponent reactions (MCRs) [1] for the derivatization of biomolecules has continuously grown over the last years. These diversity-oriented

• in the pursuit of medicinal and supramolecular chemistry applications. Despite some review articles have described selected examples of MCRs used to modify and to macrocyclize steroidal compounds [12][13], to our knowledge there is no review exclusively dedicated to covering the applications of MCRs

• synthetic program towards steroid-based supramolecular receptors [28]. There, steroidal diamines and diisocyanides derived from bile acids were employed in a procedure known as MiBs, i.e., multiple multicomponent macrocyclization including bifunctional building blocks. In a series of subsequent reports

Understanding the unexpected effect of frequency on the kinetics of a covalent reaction under ball-milling conditions

• Ana M. Belenguer,
• Adam A. L. Michalchuk,
• Giulio I. Lampronti and
• Jeremy K. M. Sanders

Beilstein J. Org. Chem. 2019, 15, 1226–1235, doi:10.3762/bjoc.15.120

• for a wide range of different syntheses and chemical reactions of inorganic [8][9] and organic [10][11] compounds. Even supramolecular architectures such as co-crystals and metal-organic frameworks [4][12][13][14], cages [15] and rotaxanes [16] could be formed mechanochemically. Crucially, the

• mechanisms and driving forces which underpin mechanochemical transformations and supramolecular reactions remain poorly understood and are subject to considerable debate [2][4][7][8][14][17][18][19][20][21][22][23][24][25]. The future successful academic and industrial application of these methods depends on

• their dependence on the milling frequency. Furthermore, they each exhibit sizeable induction periods, far greater than most reported kinetic profiles of multi-phase mechanochemical non-covalent supramolecular chemical reactions [28][45]. The notable exceptions are similar synthetic reactions, which

Self-assembly behaviors of perylene- and naphthalene-crown macrocycle conjugates in aqueous medium

• Xin Shen,
• Bo Li,
• Tiezheng Pan,
• Jianfeng Wu,
• Yangxin Wang,
• Jie Shang,
• Yan Ge,
• Lin Jin and
• Zhenhui Qi

Beilstein J. Org. Chem. 2019, 15, 1203–1209, doi:10.3762/bjoc.15.117

• -assemblies have been recognized as a type of exciting nanomaterials with tremendous potential for research and commercial applications [1][2][3][4][5][6]. Thanks to the development of supramolecular chemistry, the ordered structures could be obtained through programmed self-assembly coupled with covalent

• chemical synthesis [7]. In fact, supramolecular technology has shown great importance in various kinds of functional materials, including natural protein complexes [8][9][10], hydrogels [11][12][13], carbon-based materials [14][15][16][17], self-healing materials [18][19][20][21][22][23], and composite

• materials [24][25][26]. Moreover, several new proof-of-concept applications of supramolecular assemblies are also of increasing interest, specifically in the fields of energy generation and storage [27], water treatment and environmental remediation [28][29], and healthcare and biomedical engineering [30

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

• : anion binding; double-decker cage; ligand isomerism; macrocycles; palladium; self-assembly; supramolecular; Introduction Coordination-driven self-assembly is a convenient strategy for the construction of supramolecules of desired dimensions via simple synthetic procedures. Well-defined metal–ligand

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

• Dong-Hao Li Bradley D. Smith Department of Chemistry and Biochemistry, University of Notre Dame, 236 Nieuwland Science Hall, Notre Dame, Indiana 46556, United States 10.3762/bjoc.15.105 Abstract This review summarizes the supramolecular properties of tetralactam macrocycles that have parallel

• aromatic sidewalls and four NH residues directed into the macrocyclic cavity. These macrocycles are versatile hosts for a large number of different guest structures in water and organic solvents, and they are well-suited for a range of supramolecular applications. The macrocyclic cavity contains a mixture

• selectivity. In organic solvents, the supramolecular factors are reversed; the polar NH groups drive high affinity and the aromatic surfaces provide the secondary interactions. In addition to an amphiphilic cavity, macrocyclic tetralactams exhibit conformational flexibility, and the combination of properties

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

• engineering [6], energy storage [7], biosensors [8], catalysis [9], and environmental engineering [10]. Various supramolecular host molecules such as cyclodextrins (CDs), calix[n]arenes, and pillar[n]arenes can form host–guest inclusion complexes (ICs) with numerous compounds due to their unique cavity

• present in the molecular structure. Combined with merits of host molecules and electrospun nanofibers, the supramolecular host functionalized nanofibers have been widely reported in recent years as efficient molecular filters and absorbent for the removal of hazardous chemicals or polluting substances. A

• [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

Catalytic asymmetric oxo-Diels–Alder reactions with chiral atropisomeric biphenyl diols

• Chi-Tung Yeung,
• Wesley Ting Kwok Chan,
• Wai-Sum Lo,
• Ga-Lai Law and
• Wing-Tak Wong

Beilstein J. Org. Chem. 2019, 15, 955–962, doi:10.3762/bjoc.15.92

• formation of a supramolecular structure whereas that of 6, containing additional CF3 substituents, shows the formation of a monomeric structure. Diols 1–6 were found to be active organocatalysts in oxo-Diels–Alder reactions in which 2 recorded a 72% ee with trimethylacetaldehyde as a substrate. Keywords

• supramolecular helices or dimers through intermolecular hydrogen bonding of two axially chiral biphenyl hybrid diols (1 and 2 in Scheme 1) which contain point chirality at the side arms and axial chirality at the biphenyl backbone [37]. We envisage the structural similarity and the ability of our scaffold to

• ; inter- D(OH···O): 1.822(3) Å] led to an enantiomerically pure infinite helical supramolecular structure. In contrast, only a dimeric structure was observed for the corresponding racemic mixture [39]. In our case, atropisomerization from (M)-(S,S) to (P)-(S,S) was not observed in solution. For catalyst 4

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

• guest inclusion in solution. Keywords: capsule; dimeric assemblies; halogen bonding; host–guest chemistry; resorcinarene salts; X-ray crystallography; Introduction The construction of specific supramolecular assemblies based on the directional non-covalent bonding has been a central goal of

• supramolecular chemistry and materials science [1][2][3]. New systems both help us to better understand the nature and impetus behind the self-assembly of these fascinating systems, while also providing new materials that can provide the basis for a wide number of applications [4][5]. Halogen bonding (XB), as a

Towards the preparation of synthetic outer membrane vesicle models with micromolar affinity to wheat germ agglutinin using a dialkyl thioglycoside

• Dimitri Fayolle,
• Nathalie Berthet,
• Bastien Doumeche,
• Olivier Renaudet,
• Peter Strazewski and
• Michele Fiore

Beilstein J. Org. Chem. 2019, 15, 937–946, doi:10.3762/bjoc.15.90

• ). Moreover, a thin layer of compounds 5 or 8 without POPC, hydrated in the same conditions, gave similar giant vesicles (Figure 3, images f,g and i). Microscopic observation suggested that those supramolecular assemblies microscopically resemble the well-known outer membrane vesicles (OMV) [1]. The tentative

• solution inevitably cause the disruption of the supramolecular assembly [23]. Analyses under saline stress were not performed as the ultimate aim is to use of those OMV models under physiological conditions. Biological evaluation of the synthesized compounds Competitive enzyme-linked lectin assays (ELLA

• ] or using natural glycolipids from Gram-negative bacteria such as lipid A [4]. This work represents the first step towards the formulation of an heterogeneous, stable systems (under biological conditions) that can be used for several biological purposes including synthetic vaccines, supramolecular

Synthesis of (macro)heterocycles by consecutive/repetitive isocyanide-based multicomponent reactions

• Angélica de Fátima S. Barreto and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2019, 15, 906–930, doi:10.3762/bjoc.15.88

• study using this same protocol. Using this same combined approach, Wessjohann and Rivera developed a very efficient strategy for the synthesis of supramolecular compounds via Ugi-type multiple multicomponent macrocyclizations of polyfunctional building blocks (Scheme 29) [46]. An initial double Ugi-4CR

Mechanochemistry of supramolecules

• Anima Bose and
• Prasenjit Mal

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

• . Contrastingly, achieving syntheses through mechanochemical methods are generally time-saving, environmentally friendly and more economical. This review is written to shed some light on supramolecular chemistry and the synthesis of various supramolecules through mechanochemistry. Keywords: ball milling

• ; mechanochemistry; self-assembly; solvent-free; supramolecular; Introduction In living systems an important aspect is to create complex functional molecules from simpler units by following biomolecular mechanisms [1]. The biological assemblies for living beings are developed from processes of spontaneous self

• conditions through covalent approaches. By using common synthetic methodologies chemists are able to proficiently synthesize a variety of both natural and unnatural molecular scaffolds [4][5][6]. The era of supramolecular chemistry began with the introduction of coordination theory by Alfred Werner in 1893

New α- and β-cyclodextrin derivatives with cinchona alkaloids used in asymmetric organocatalytic reactions

• Iveta Chena Tichá,
• Simona Hybelbauerová and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2019, 15, 830–839, doi:10.3762/bjoc.15.80

• ; cinchona alkaloids; CuAAC click reaction; cyclodextrin; organocatalysts; Introduction Cyclodextrins (CDs) [1], cyclic oligosaccharides consisting of α-D-glucopyranoside units, and their derivatives are widely used in many industrial and research areas for their ability to form supramolecular inclusion

Homo- and hetero-difunctionalized β-cyclodextrins: Short direct synthesis in gram scale and analysis of regiochemistry

• Gábor Benkovics,
• Mihály Bálint,
• Éva Fenyvesi,
• Erzsébet Varga,
• Szabolcs Béni,
• Konstantina Yannakopoulou and
• Milo Malanga

Beilstein J. Org. Chem. 2019, 15, 710–720, doi:10.3762/bjoc.15.66

• -difunctionalization; regioselectivity; Introduction Cyclodextrins (CDs) are cyclic oligomers of α-D-glucopyranose (Figure 1 illustrates the heptamer, β-CD) that have attracted worldwide interest in various fields of applied supramolecular chemistry due to their ability to form host–guest inclusion complexes [1]. A

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

• nanosponge materials with tunable properties. Nanosponges (NSs) [7][8][9][10][11][12][13][14] are hyper-cross-linked polymers or copolymers obtained by reacting supramolecular host species as the monomer units with suitable reticulating agents. Of course, the structural, physical and chemical features of the

• classes of supramolecular hosts such as calixresorcinarenes and cyclodextrins [31][32][33][34][35][36][37][38]. The results obtained (percent of guest absorbed under the operational conditions chosen, see Experimental) are summarized in Table 1. As expected, both materials may show remarkable variations

Design, synthesis and spectroscopic properties of crown ether-capped dibenzotetraaza[14]annulenes

• Krzysztof M. Zwoliński and
• Julita Eilmes

Beilstein J. Org. Chem. 2019, 15, 617–622, doi:10.3762/bjoc.15.57

• emerged as non-pyrrolic surrogates of porphyrins, and have become a versatile platform for supramolecular [15], biomimetic [16][17], biological [18][19] and material chemistry [20][21]. Although much effort has been directed towards the study of crown ether-capped porphyrins [22] and sapphyrines [23

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

• [21], supramolecular structures (cryptands, cages, cryptophanes, podands, etc.) [22][23][24], cyclic/macrocyclic peptides [25] and other complex structures in a straightforward manner (Scheme 5). The diversity in these systems arises not only from combining a variety of building blocks (from simple

• polymerizations; E) alkyne-sulfonylazide-alcohol interactions; F) sulfur-amine-isocyanide combination. Concept of multicomponent macrocyclization. Supramolecular structures out of MMCR macrocyclizations. Macrocyclization by MMCRs. A) Staudinger MCR; B) boronic-imine MCR. Selective Sequential MMCRs. A and B) MCRs

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

• supramolecular, dative, as well as covalent anchoring. Ward and co-workers reported the first artificial metathase based on the biotin–(strept)avidin technology in 2011 [65], thus expanding the set of reported reactions with this class of ArMs [66]. It is well known that the biotin–(strept)avidin couple

• possesses one of the highest non-covalent binding affinities (Kd = 10−12–10−15 M). This exceptional affinity warrants the ArM remaining assembled throughout catalysis. Biotinylated HG-type catalysts anchored within (strept)avidin through supramolecular interactions were tested in the RCM of N,N

• [70]. α-Chymotrypsin is a serine protease that recognizes hydrophobic residues in one of its clefts. A modified HG-type catalyst (66) contains an L-phenyl chloromethyl ketone moiety that acts as inhibitor and is first recognized by supramolecular anchoring and then covalently attaches upon

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

• -crown-7, B21C7s) can effectively control the thermo-responsive properties. Keywords: crown ethers; hydrophobic units; lower critical solution temperature; LCST; thermo-responsiveness; supramolecular chemistry; Introduction The introduction of stimuli-responsiveness into artificial materials is vital

• to design advanced functional materials [1][2][3][4][5][6][7]. An external thermal stimulus is often applied to supramolecular systems to realize reversible control over supramolecular self-assemblies [8][9][10][11][12][13]. In this context, lower critical solution temperature behavior, known as LCST

• behavior, is a type of thermo-responsiveness [14][15][16], which has gained much attention in supramolecular chemistry, because of its profound impact on the development of stimuli-sensitive supramolecular materials with controllable and/or programmable phase separation properties [17][18][19]. Though LCST

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

• processes was tested. The X-ray crystal structures of the octaester showed an interpenetrated compact packing of the molecular building blocks without any specific supramolecular interaction. The structure of the octaacid was found to contain hydrogen-bonded ribbons, thanks to the two-dimensional character

Olefin metathesis in multiblock copolymer synthesis

• Maria L. Gringolts,
• Yulia I. Denisova,
• Eugene Sh. Finkelshtein and
• Yaroslav V. Kudryavtsev

Beilstein J. Org. Chem. 2019, 15, 218–235, doi:10.3762/bjoc.15.21

• the initiator efficiency. The sacrificial approach also helps to describe the multiblock copolymer structure: owing to the acid-labile acetal group, polymer scission takes place at the point of the dioxepin insertion thus providing an indirect way to detect the monomer location [73]. Supramolecular

• to obtain pincer-functionalized telechelic polymer 1 or a pyridine-containing end-terminator to yield pyridine-functionalized telechelic polymers 2. On this basis, supramolecular copolymers with alternating blocks were constructed using AgBF4 to remove Cl from the pincer complex and generate a

• reactions, replotted from [63][64]. Synthesis of multiblock bottle-brush copolymers by ROMP, replotted from [68]. Sacrificial synthesis of multiblock copolymers, replotted from [70]. Synthesis of supramolecular multiblock copolymers, replotted from [74]. Macromolecular cross metathesis. Elementary reactions

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

• ’,4,4’-penta-O-benzylsucrose and 1’,2,3,3’,4,4’-hexa-O-benzylsucrose. Keywords: cryptands; macrocyclization; sucrose; Introduction The design and synthesis of macrocyclic receptors is one of the main challenges of supramolecular chemistry [1][2]. These artificial systems exhibit interesting properties

Ammonium-tagged ruthenium-based catalysts for olefin metathesis in aqueous media under ultrasound and microwave irradiation

• Łukasz Gułajski,
• Andrzej Tracz,
• Katarzyna Urbaniak,
• Stefan J. Czarnocki,
• Michał Bieniek and
• Tomasz K. Olszewski

Beilstein J. Org. Chem. 2019, 15, 160–166, doi:10.3762/bjoc.15.16

• surface area involved or on the electrostatic nature of the surface itself [81]. Additionally, the packing density of supramolecular clusters of water created by strong intermolecular hydrogen bonds may also play a key role. Indeed, various effects may be depending on the solubility of the reactants in

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

• supramolecular fiber materials composed of cyclodextrin (CD)–fullerene inclusion complexes by electrospinning. Similar to the molecular state of fullerenes in solution, the resulting fibers include molecularly-dispersed fullerenes. We believe such a concept could be expanded to diverse host–guest complexes

• , opening up supramolecular solid materials science and engineering. Keywords: cyclodextrin; electrospinning; fullerene; nanofiber; supramolecular complex; Introduction Fiber is a fundamental material that constitutes a variety of everyday items and supports the maintenance of life [1][2][3]. In the field

• paper, we report the successful electrospinning of native CD–fullerene inclusion complexes in a HFIP solution to produce a new type of supramolecular fiber material. An advantage of our system compared with the previous technique [10] is that only 12.5–20 w/v % CD/HFIP solution is required. This

Olefin metathesis catalysts embedded in β-barrel proteins: creating artificial metalloproteins for olefin metathesis

• Daniel F. Sauer,
• Johannes Schiffels,
• Takashi Hayashi,
• Ulrich Schwaneberg and
• Jun Okuda

Beilstein J. Org. Chem. 2018, 14, 2861–2871, doi:10.3762/bjoc.14.265

• are supramolecular, dative and covalent anchoring. Supramolecular anchoring was pioneered by Wilson and Whitesides in 1978 [27]. They made use of the high affinity of (strept)avidin (Sav) to biotin that represents one of the strongest supramolecular interactions found in nature with a dissociation

• active site from the protein easier as compared to supramolecular anchoring. However, the design of catalysts capable of undergoing dative anchoring is usually based on interactions of inhibitors with the active site of the protein. This makes the catalyst design challenging and the application is

• , because it is not necessary to have or to design interactions that are required for non-covalent anchoring, e.g., supramolecular or dative anchoring. All three anchoring approaches – supramolecular, dative and covalent – have been utilized to construct artificial metalloproteins capable of catalyzing