Multiswitchable photoacid–hydroxyflavylium–polyelectrolyte nano-assemblies

• Alexander Zika and
• Franziska Gröhn

Beilstein J. Org. Chem. 2021, 17, 166–185, doi:10.3762/bjoc.17.17

• molecular recognition processes have been established based on different non-covalent interactions such as hydrogen bonding [9][10][11][12], π–π interaction [13][14][15][16][17], hydrophobic effects, and amphiphilicity [18][19][20][21]. It has been highly desirable to establish concepts that could be

Tuning the solid-state emission of liquid crystalline nitro-cyanostilbene by halogen bonding

• Subrata Nath,
• Alexander Kappelt,
• Matthias Spengler,
• Bibhisan Roy,
• Jens Voskuhl and
• Michael Giese

Beilstein J. Org. Chem. 2021, 17, 124–131, doi:10.3762/bjoc.17.13

• tuning of the fluorescence behaviour and mesomorphic properties of the assemblies. Keywords: fluorescence; halogen bonding; liquid crystal; Introduction Supramolecular chemistry has proven to be an efficient approach for the development of novel smart materials, since it relies on non-covalent

• interactions, which allow for dynamic responses to external stimuli [1]. In addition, the self-assembly of the complementary molecular entities provides an easy access to functional systems and enables recyclability and self-healing properties of the materials [2]. With respect to the formation of

UV resonance Raman spectroscopy of the supramolecular ligand guanidiniocarbonyl indole (GCI) with 244 nm laser excitation

• Tim Holtum,
• Vikas Kumar,
• Daniel Sebena,
• Jens Voskuhl and
• Sebastian Schlücker

Beilstein J. Org. Chem. 2020, 16, 2911–2919, doi:10.3762/bjoc.16.240

• vibrational modes of the molecule. Especially for non-covalent interactions such as hydrogen bonding, vibrational spectroscopy has been shown to be very sensitive [10][11]. In the context of supramolecular recognition, for example, IR spectroscopy has been applied to monitor the binding of tetrapeptides by

• -covalent interactions namely hydrogen bonds, van der Waals, and/or hydrophobic interactions [1][2][3][4][5]. In this context, Schmuck and co-workers have introduced a class of synthetic receptors based on the guanidiniocarbonyl pyrrole (GCP) moiety (cf. Figure 1 top right) as a carboxylate binding site

• the results from density functional theory (DFT) calculations. Keywords: GCI; GCP; guanidiniocarbonyl indole; guanidiniocarbonyl pyrrole; UVRR; Raman spectroscopy; resonance Raman; Introduction Supramolecular ligands are capable to selectively bind to peptides and proteins via reversible non

NMR Spectroscopy of supramolecular chemistry on protein surfaces

• Peter Bayer,
• Anja Matena and
• Christine Beuck

Beilstein J. Org. Chem. 2020, 16, 2505–2522, doi:10.3762/bjoc.16.203

• steric accessibility is an important determining factor for calixarene binding, the overall local electrostatic potential of the protein surface as well as other non-covalent interactions such as hydrophobic interactions or aromatic ring stacking contribute to a certain selectivity for some lysine

• in the crystal structures, which enable a greater diversity of non-covalent interactions with the protein and even different binding modes on the same lysine side chain. With increasing ring size, the calixarenes promote ligand-induced ordered multimerization of proteins. Cyt c for example is

Naphthalene diimide bis-guanidinio-carbonyl-pyrrole as a pH-switchable threading DNA intercalator

• Poulami Jana,
• Filip Šupljika,
• Carsten Schmuck and
• Ivo Piantanida

Beilstein J. Org. Chem. 2020, 16, 2201–2211, doi:10.3762/bjoc.16.185

• energetically favourable non-covalent interactions, hydrogen bonds, and van der Waals interactions formed between the DNA/RNA and solvent, and between the compound 4 and solvent. The large positive entropy changes suggest solvent release upon binding, which makes a favourable contribution to the reaction Gibbs

Naphthalene diimide–amino acid conjugates as novel fluorimetric and CD probes for differentiation between ds-DNA and ds-RNA

• Annike Weißenstein,
• Myroslav O. Vysotsky,
• Ivo Piantanida and
• Frank Würthner

Beilstein J. Org. Chem. 2020, 16, 2032–2045, doi:10.3762/bjoc.16.170

• ; Introduction The interplay of non-covalent interactions between nucleic acids and proteins or peptides is the basis of life and is also often used for the design of artificial small molecules, aiming for sensing or control of biorelevant processes. Many naturally occurring bioactive molecules contain a short

Models of necessity

• Timothy Clark and
• Martin G. Hicks

Beilstein J. Org. Chem. 2020, 16, 1649–1661, doi:10.3762/bjoc.16.137

• ideas about chemical structures and reactions. This early extension of the Lewis model and the introduction of two-center three-electron bonding [44] serve as prototypes for what will become necessary improvements to handle in particular non-covalent interactions but in general any structures or

• ] or quantitative VB calculations. If we delve deeper, we find MO interpretations of, for instance, non-covalent interactions [82] coexisting with more fundamentally physical electrostatic pictures [83]. Indeed, the polarization/charge transfer shown in Figure 4 is often interpreted as donation into an

• reactions. There is, however, a need to add non-covalent interactions to the model in order to take the importance of complexation and aggregation via non-covalent interactions into account. This could be done in a purely ad hoc fashion for each type of interaction. This is how force-field developers have

Fluorohydration of alkynes via I(I)/I(III) catalysis

• Jessica Neufeld,
• Constantin G. Daniliuc and
• Ryan Gilmour

Beilstein J. Org. Chem. 2020, 16, 1627–1635, doi:10.3762/bjoc.16.135

• non-covalent interactions [8][9][10]. These collective attributes render fluorination a valuable strategy in drug discovery [11] and agrochemical development [12]. In the conception of enabling fluorination technologies, the α-fluorocarbonyl motif has emerged as a prominent target scaffold [13

Highly selective Diels–Alder and Heck arylation reactions in a divergent synthesis of isoindolo- and pyrrolo-fused polycyclic indoles from 2-formylpyrrole

• Carlos H. Escalante,
• Eder I. Martínez-Mora,
• Carlos Espinoza-Hicks,
• Alejandro A. Camacho-Dávila,
• Fernando R. Ramos-Morales,
• Francisco Delgado and
• Joaquín Tamariz

Beilstein J. Org. Chem. 2020, 16, 1320–1334, doi:10.3762/bjoc.16.113

• aromatization of the polycyclic intermediates provides the corresponding polycyclic pyrrolo-isoindoles and isoindolo-pyrrolo-indoles. A theoretical study on the stereoselective Diels–Alder reactions, carried out by calculating the endo/exo transition states, revealed the assistance of non-covalent interactions

• in governing the endo stereocontrol. Keywords: endo-Diels–Alder stereocontrol; 2-formylpyrrole; intramolecular Heck arylation reaction; non-covalent interactions; pyrroloindoles; pyrroloisoindoles; Introduction Pyrrolizines [1][2] and pyrrolizidines [3][4], abundant in nature [4][5], are among the

Small anion-assisted electrochemical potential splitting in a new series of bistriarylamine derivatives: organic mixed valency across a urea bridge and zwitterionization

• Keishiro Tahara,
• Tetsufumi Nakakita,
• Alyona A. Starikova,
• Takashi Ikeda,
• Masaaki Abe and
• Jun-ichi Kikuchi

Beilstein J. Org. Chem. 2019, 15, 2277–2286, doi:10.3762/bjoc.15.220

• promising trigger to directly change the charge distributions of molecules and assemblies, potentially allowing tuning of the strength of non-covalent interactions, including hydrogen bonds (H-bonds) [23][24][25][26]. In this context, a number of redox-active compounds bearing H-bond donors and acceptors

Complexation of 2,6-helic[6]arene and its derivatives with 1,1′-dimethyl-4,4′-bipyridinium salts and protonated 4,4'-bipyridinium salts: an acid–base controllable complexation

• Jing Li,
• Qiang Shi,
• Ying Han and
• Chuan-Feng Chen

Beilstein J. Org. Chem. 2019, 15, 1795–1804, doi:10.3762/bjoc.15.173

• -polar solvent, acetone hampers or competes the intermolecular non-covalent interactions between the hosts and the guests, and thus resulted in a decrease of the host–guest complexation. ESIMS studies of the formation of host–guest complexes The electrospray ionization (ESI) mass spectra also confirmed

• multiple intermolecular non-covalent interactions with distances ranging from 1.651 to 2.575 Å. Compared with hosts H2 and H3, helic[6]arene H1 and its derivatives H4 and H5 all show multiple hydrogen-bonding interactions with the examined guests, which were confirmed by not only X-ray crystal structures

• ) Top view, (b) side view, and (c) packing viewed along c-axis. Blue lines denote the non-covalent interactions between H1 and G1. Solvent molecules and hydrogen atoms not involved in the non-covalent interactions were omitted for clarity. Crystal structure of complex H5·G1. (a) Top view, (b) side view

2,3-Dibutoxynaphthalene-based tetralactam macrocycles for recognizing precious metal chloride complexes

• Li-Li Wang,
• Yi-Kuan Tu,
• Huan Yao and
• Wei Jiang

Beilstein J. Org. Chem. 2019, 15, 1460–1467, doi:10.3762/bjoc.15.146

• smaller than that in the presence of one equivalent of TBA[AuCl4] (Figure 3), although they have rather similar binding affinities. This may be due to a different extent hydrogen bonding is involved in diverse complexes and other non-covalent interactions may contribute more in the cases of (TBA)2[PtCl4

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

• with their linear glycol chain counterparts, B21C7 shows great potential to be an easy-to-accessed building block to probe the non-covalent interactions and chemical transformations influenced by water molecules. Perylene diimide (PDI) and naphthalene diimide (NDI) are polycyclic aromatic chromophores

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

• preorganized structures that favor high affinity and shape-selective association of guest molecules or ions. Usually, it is the solvent that determines which non-covalent interactions are the most important for strong association. Polar interactions are often dominant in weakly polar organic solvents, and thus

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

• are working in tandem and concertedly to form networks of non-covalent interactions stabilizing the dimeric and capsular structures in the solid state. The inclusion guests affect the geometry of the cavity of the hex-NARBr and cy-NARCl, thus affecting the halogen bonding connection in the final

Mechanochemistry of supramolecules

• Anima Bose and
• Prasenjit Mal

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

• [7] followed by the lock-and-key concept of Emil Fischer in 1894 [8]. Weak or non-covalent interactions had been used systematically in the early 1960s by Lehn, Cram and Pederson to create targeted supramolecular architectures [9]. Small molecules, anions or cations could be assembled spontaneously

• to form supramolecular structures through self-assembly processes by exploiting the weak or non-covalent interactions [10]. Self-assembly is a kinetically reversible process which is more efficient than traditional stepwise synthesis concerning large molecules. Some recent developments in

• (≈65%). Subcomponent self-assembly and mechano-milling Nature displays innumerable and beautiful creations [67][68] which include highly complex self-assembled structures made from smaller building blocks by using weak or non-covalent interactions [69][70]. Therefore, the supramolecular approach [71

Tetrathiafulvalene – a redox-switchable building block to control motion in mechanically interlocked molecules

• Hendrik V. Schröder and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2018, 14, 2163–2185, doi:10.3762/bjoc.14.190

• to rotaxanes is that the axle does not have bulky stopper groups that prevent the deslipping of the wheel. Thus, a pseudorotaxane forms by non-covalent interactions between host and guest without a mechanical bond. Pseudorotaxanes are important precursors of MIMs from which the construction of

• the [3]rotaxane 23 which bears two cofacially oriented TTF crown ethers on a divalent ammonium axle. The distance between the wheels is convenient for TTF-dimer interactions. In the non-switched neutral state of both TTFs, the wheels adopt a syn co-conformation caused by weak non-covalent interactions

Synthesis and supramolecular self-assembly of glutamic acid-based squaramides

• Juan V. Alegre-Requena,
• Marleen Häring,
• Isaac G. Sonsona,
• Alex Abramov,
• Eugenia Marqués-López,
• Raquel P. Herrera and
• David Díaz Díaz

Beilstein J. Org. Chem. 2018, 14, 2065–2073, doi:10.3762/bjoc.14.180

• gels are typically made of low-molecular-weight (LMW) compounds self-assembled in different solvents via non-covalent interactions. In most cases, this feature enables reversible stimuli-responsive gel-to-sol transitions [31]. Usually, the entanglement of 1D nanofibers of gelator molecules generates a

A pyridinium/anilinium [2]catenane that operates as an acid–base driven optical switch

• Sarah J. Vella and
• Stephen J. Loeb

Beilstein J. Org. Chem. 2018, 14, 1908–1916, doi:10.3762/bjoc.14.165

• easily understood as the neutral benzylaniline site does not allow for appreciable non-covalent interactions and cannot compete for the DB24C8 ring with the dicationic bis(pyridinium)ethane site. However, the addition of one equivalent of triflic acid (CF3SO3H) to a solution of [8DB24C8]6+ results in

Efficient catenane synthesis by cucurbit[6]uril-mediated azide–alkyne cycloaddition

• Antony Wing Hung Ng,
• Chi-Chung Yee,
• Kai Wang and
• Ho Yu Au-Yeung

Beilstein J. Org. Chem. 2018, 14, 1846–1853, doi:10.3762/bjoc.14.158

• yields of the [3]catenanes can serve as an entry point to other high-order [n]catenanes by introducing additional macrocycles through other non-covalent interactions. Results and Discussion Building block design The bis(aminoalkyne) and bis(aminoazide) building blocks used in this study are summarized in

• other topological isomers. The building blocks contain either a central hexaethylene glycol (HEG) unit or are derived from 1,5-dioxynaphthalene (DN), naphthalenediimide (NDI), 2,9-phenanthroline (Phen) or 4,4’-biphenyl (BP) cores which can engage in additional non-covalent interactions, such as metal

• ). Together with our previous demonstration of the compatibility of CBAAC with Cu+-phenanthroline coordination in a [6]catenane assembly, the successful synthesis of Cat-11 shows the feasibility of using CBAAC with a versatile selection of building blocks and non-covalent interactions to construct complex

Host–guest complexes of conformationally flexible C-hexyl-2-bromoresorcinarene and aromatic N-oxides: solid-state, solution and computational studies

• Rakesh Puttreddy,
• Ngong Kodiah Beyeh,
• S. Maryamdokht Taimoory,
• Daniel Meister,
• John F. Trant and
• Kari Rissanen

Beilstein J. Org. Chem. 2018, 14, 1723–1733, doi:10.3762/bjoc.14.146

• understanding of the particular interactions is required. The N-oxide oxygen atoms potential to act as a HB acceptor for multiple simultaneous N–O···(O–H)host interactions raises the molecular complexity. These are the dominant non-covalent interactions, in both the solid and solution state, compared to endo

• , one resides in the upper-rim endo cavity, held in position by C–H···π interactions. The second sits in the lower rim between the hexyl chains and is stabilised through N–O···(H–C)Ar(host) and other weak non-covalent interactions. The remaining final two guests are exo cavity hydrogen bonded to the

• potential regions of the N-oxide oxygen atom in guest 3 (red region in Figure 4a) to establish several intermolecular (C–H)Ar···O–N H-bond interactions at the lower-rim host pocket. In addition, we used Bader’s quantum theory of atoms in molecules (QTAIM) [49] to analyse multiple non-covalent interactions

A conformationally adaptive macrocycle: conformational complexity and host–guest chemistry of zorb[4]arene

• Liu-Pan Yang,
• Song-Bo Lu,
• Arto Valkonen,
• Fangfang Pan,
• Kari Rissanen and
• Wei Jiang

Beilstein J. Org. Chem. 2018, 14, 1570–1577, doi:10.3762/bjoc.14.134

• structures may provide an explanation for their surprising binding behaviors. Multiple non-covalent interactions, including C–H···O hydrogen bonds, cation···π, C–H···π and π···π interactions, are involved in all the cases. Undoubtedly, cation···π interactions between the core quaternary ammonium ions of the

• complexes 16+@ZB4-III and 18+@ZB4-III may be better suited than those of 14+@ZB4-III and 21+@ZB4-III to host the quaternary ammonium and maximize all the non-covalent interactions. Any deviation from these cavity sizes weakens the binding. That is, the secondary C–H···O hydrogen bonds can be tuned through

Cobalt-catalyzed C–H cyanations: Insights into the reaction mechanism and the role of London dispersion

• Eric Detmar,
• Valentin Müller,
• Daniel Zell,
• Lutz Ackermann and
• Martin Breugst

Beilstein J. Org. Chem. 2018, 14, 1537–1545, doi:10.3762/bjoc.14.130

• ORCA 4 [65]. All DFT calculations were performed with Turbomole 7.1 [66][67] and the NCIPLOT code was employed for the visualization non-covalent interactions [48][49]. Experimental Details General remarks: Catalytic reactions were carried out in Schlenk flasks under nitrogen atmosphere using predried

Steric “attraction”: not by dispersion alone

• Ganna Gryn’ova and
• Clémence Corminboeuf

Beilstein J. Org. Chem. 2018, 14, 1482–1490, doi:10.3762/bjoc.14.125

• Ganna Gryn'ova Clemence Corminboeuf Institut des Sciences et Ingénierie Chimiques, École polytechnique fédérale de Lausanne, CH-1015 Lausanne, Switzerland 10.3762/bjoc.14.125 Abstract Non-covalent interactions between neutral, sterically hindered organic molecules generally involve a strong

• recognized in aliphatic systems compared to London dispersion, and are therefore likely to have implications for the development of force fields and methods for crystal structure prediction. Keywords: charge penetration; dispersion; hydrocarbon; non-covalent interactions; steric attraction; Introduction In

• of non-covalent interactions for a range of hydrocarbon dimers featuring both aromatic and aliphatic skeletons and bearing substituents, from methyl all the way to bulky adamantyl (Figure 2). First, we consider the dimers, constructed from the optimized monomers that are kept fixed (frozen) in terms

Spectroelectrochemical studies on the effect of cations in the alkaline glycerol oxidation reaction over carbon nanotube-supported Pd nanoparticles

• Dennis Hiltrop,
• Steffen Cychy,
• Karina Elumeeva,
• Wolfgang Schuhmann and
• Martin Muhler

Beilstein J. Org. Chem. 2018, 14, 1428–1435, doi:10.3762/bjoc.14.120

• voltammetry revealing a lower overpotential of glycerol oxidation for nitrogen-functionalized Pd/NCNTs compared with oxygen-functionalized Pd/OCNTs. Whereas significantly lower current densities were observed for Pd/OCNT in NaOH than in KOH in agreement with stronger non-covalent interactions on the Pd

• observed higher current densities for Pd/NCNT in NaOH compared with KOH considering the non-covalent interactions proposed by Strmcnik et al. [24]. In situ FTIR spectroscopy The reaction products in NaOH and KOH solutions formed over Pd/NCNT were identified by IR spectroscopy (Figure 3, Table 2) using a

• current densities were higher in KOH than in NaOH solution for Pd/OCNT in agreement with the theory of weaker non-covalent interactions on the Pd surface in KOH. Pd/NCNT was electrocatalytically more active as shown by the lower anodic onset potential achieving slightly higher current densities in KOH