Facile access to pyridinium-based bent aromatic amphiphiles: nonionic surface modification of nanocarbons in water

• Lorenzo Catti,
• Shinji Aoyama and
• Michito Yoshizawa

Beilstein J. Org. Chem. 2024, 20, 32–40, doi:10.3762/bjoc.20.5

• tighter and more adaptable aromatic–aromatic stacking interactions. The aliphatic amphiphile sodium dodecyl sulfate (SDS) showed a 10-times lower efficiency compared to PA-Im under the same conditions (Figure S38 in Supporting Information File 1). The concentration of C60 in the solution of (PA-Im)n·(C60

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

• many reasons, the most common ones being solvatochromic effects or aromatic stacking interactions. In this particular case, the NDI chromophore in threading intercalation has to be stacked with two base pairs, causing typical hypochromic and bathochromic effects. However, the positioning of the NDI

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

• : for instance, binding of a large aromatic dye by aromatic stacking on the terminal base pairs [35], as a competitive binding mode to expected intercalation. Further, the chosen DNA/RNA polynucleotides are characterised by different secondary structures [36][37]: poly(dA-dT)2 representing the B-helical

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

• where the guest benzyl group engages in aromatic stacking with the host anthracene sidewalls. Furthermore, the affinities followed a rough linear free energy relationship with electron density on the benzyl group, with highest affinity achieved when the benzylammonium contained a withdrawing p-CN group

• macrocycle. Supramolecular picture of the amide-bond-formation step that clips tetralactam A around a biscarbonyl template to form a [2]rotaxane. Complex stabilization due to guest back folding and aromatic stacking with the surrounding tetralactam macrocycle. Acknowledgements We are grateful for funding by

Organic chemistry meets polymers, nanoscience, therapeutics and diagnostics

• Vincent M. Rotello

Beilstein J. Org. Chem. 2016, 12, 1638–1646, doi:10.3762/bjoc.12.161

• ], aromatic stacking (Figure 1) [10] and donor atom–π interactions [11] influence the energetics of redox processes. We also used integrated experimental and computational techniques to actually establish what hydrogen bonding does to the electrons in hydrogen-bonded complexes [12]. Finally, we put this all

• with our rather neurotic Weimaraner Trudy, allowing us to get double duty from our toil. Flavoenzyme model system for determining the role of aromatic stacking in flavin redox processes. Reprinted with permission from [10]. Copyright (1997) American Chemical Society. Recognition element-functionalized

A journey in bioinspired supramolecular chemistry: from molecular tweezers to small molecules that target myotonic dystrophy

• Steven C. Zimmerman

Beilstein J. Org. Chem. 2016, 12, 125–138, doi:10.3762/bjoc.12.14

• report [8] of compound 2 containing two caffeine units linked by a rigid diyne spacer (Figure 2e). Whitlock noted that conventional bisintercalators such as 1 would have their affinity for oligonucleotides significantly reduced as a result of intramolecular π–π aromatic stacking. Whereas the diyne spacer

• hydrogen bonding functionality into the molecular tweezer was appealing because it meant that aromatic stacking and hydrogen bonding might cooperate to give higher binding constants and guest selectivity. However, the preparation of a rigid aromatic spacer with a functional group converging on the binding

• bind 9-propyladenine in chloroform with a very high association constant of Kassoc = 120,000 M−1 [17][18][19]. What role do the hydrogen bonding and aromatic stacking play? As seen in Figure 4, this system provides an excellent example of what Jencks called “complex additivity of binding energies” [20

Supramolecular chemistry: from aromatic foldamers to solution-phase supramolecular organic frameworks

• Zhan-Ting Li

Beilstein J. Org. Chem. 2015, 11, 2057–2071, doi:10.3762/bjoc.11.222

• secondary structures from aromatic backbones driven by different noncovalent forces (including hydrogen bonding, donor–acceptor, solvophobicity, and dimerization of conjugated radical cations) and solution-phase supramolecular organic frameworks driven by hydrophobically initiated aromatic stacking in the

• and aliphatic ammonium and, at high concentrations in chloroform, a chiral aliphatic ammonium induced 23 to produce helicity bias. One important difference between fluorine and alkoxy groups is that fluorine does not cause a steric effect on aromatic stacking. Zeng and co-workers demonstrated this

Come-back of phenanthridine and phenanthridinium derivatives in the 21st century

• Lidija-Marija Tumir,
• Marijana Radić Stojković and
• Ivo Piantanida

Beilstein J. Org. Chem. 2014, 10, 2930–2954, doi:10.3762/bjoc.10.312

• aromatic stacking and hydrogen-bonding interactions [73][74]. At variance to phenanthridinium–nucleobase conjugates (Scheme 23), which were not able to differentiate among mononucleotides, some bis-phenanthridinium–nucleobase conjugates provided a more convenient binding site for the nucleobase. For

• . The obtained results [92][93][94] stress the importance of DNA-basepair dynamics for the electronic transfer processes in DNA-stacks. The efficiency of transfer is rather more controlled by motions of chromophores involved in aromatic stacking of DNA-reporter complex than with rigid aryl-stacking

• with the aromatic stacking interactions between phenanthridine and nucleobase as dominant binding interaction (most likely intercalation), while differences between permanent (EB, PHEN-Me) and reversible (PHEN-H+) positive charge do not play a significant role. Intriguingly, EB revealed an order of

Molecular recognition of AT-DNA sequences by the induced CD pattern of dibenzotetraaza[14]annulene (DBTAA)–adenine derivatives

• Marijana Radić Stojković,
• Marko Škugor,
• Łukasz Dudek,
• Jarosław Grolik,
• Julita Eilmes and
• Ivo Piantanida

Beilstein J. Org. Chem. 2014, 10, 2175–2185, doi:10.3762/bjoc.10.225

• intramolecular aromatic stacking between DBTAA and adenine. The observed AT-DNA-ICD pattern differs from previously reported ss-DNA (poly dT) ICD recognition by a strong negative ICD band at 350 nm, which allows for the dynamic differentiation between ss-DNA (poly dT) and coupled ds-AT-DNA. Keywords: AT-DNA

• determining the importance of aromatic stacking interactions. The results were compared with the reference APH (lacking adenine) and previously studied DP77 [12] (Scheme 1), which, having pyridinium instead of adenine, can also be regarded as a reference structure. Double-stranded DNA/RNA targets chosen for

• denaturation resulting in the increase of DNA/RNA-Tm. In particular, thermal stabilization is characteristic for the intercalative binding mode due to the strong aromatic stacking interactions between studied condensed aromatic molecule and adjacent base pairs [1][16]. None of the AP compounds showed any

Crystal design using multipolar electrostatic interactions: A concept study for organic electronics

• Peer Kirsch,
• Qiong Tong and
• Harald Untenecker

Beilstein J. Org. Chem. 2013, 9, 2367–2373, doi:10.3762/bjoc.9.272

• isotropic charge transport compared to the “herring bone” stacking observed for other acenes. Keywords: aromatic stacking; charge carrier transport; crystal design; electrostatic control; organic semiconductor; organo-fluorine; Introduction Within a very few years the first organic semiconductors have

Molecular assembly of amino acid interlinked, topologically symmetric, π-complementary donor–acceptor–donor triads

• M. B. Avinash,
• K. V. Sandeepa and
• T. Govindaraju

Beilstein J. Org. Chem. 2013, 9, 1565–1571, doi:10.3762/bjoc.9.178

• [18], catenane [19], rotaxane [20], self-healable supramolecular polymer [21], aromatic stacking within a coordination cage [22], superamphiphile [23] and thermochromic [24] materials. Notably, Wilson et al. have reported preferential π-stacking of pyrene and NDI amongst a pool of π-electron D-A

• strong aromatic stacking (see Supporting Information File 1). Remarkably 1, 2 and 3 form free floating aggregates within a couple of hours in aqueous DMSO and aqueous NMP (Figure 2). These free floating aggregates were subjected to morphological studies using field emission scanning electron microscopy

Dependency of the regio- and stereoselectivity of intramolecular, ring-closing glycosylations upon the ring size

• Patrick Claude,
• Christian Lehmann and
• Thomas Ziegler

Beilstein J. Org. Chem. 2011, 7, 1609–1619, doi:10.3762/bjoc.7.189

• in ratios depending upon the ring size formed during glycosylation. No β(1→2) linked disaccharides were formed. Molecular modeling of saccharides 6–8 revealed that a strong aromatic stacking interaction between the aromatic parts of the benzyl and benzylidene protecting groups in the galactosyl and

• ? Figure 11 illustrates what we intuitively anticipated at the beginning of the discussion, namely that the aromatic stacking interactions have a remarkable influence on the course of an intramolecular cyclization reaction: If the precyclized (seco) cyclic oxonium ion is modeled as an approximation for its

• aromatic-stacking interactions (ASI). Stereo view of the superposition of β(1→3)-linked disaccharide models of 6a–d in stable triad-ASI conformations. 6a (n = 5) orange, 6b (n = 4) green, 6c (n = 3) pink, 6d (n = 2) magenta. Most-stable product conformations for the cyclo-glycosidation reaction with ring

Development of the titanium–TADDOLate-catalyzed asymmetric fluorination of β-ketoesters

• Lukas Hintermann,
• Mauro Perseghini and
• Antonio Togni

Beilstein J. Org. Chem. 2011, 7, 1421–1435, doi:10.3762/bjoc.7.166

• steric requirement and aromatic stacking area was realized with 9-phenanthrenyl-TADDOL T4; this gave a maximal enantioselectivity with benzyl ester 10, rather than with the bulky ester 11. Presumably, the combined steric effects of substrate and ligand cannot exceed certain optimal limits. In the series

Self-association of an indole based guanidinium-carboxylate-zwitterion: formation of stable dimers in solution and the solid state

• Carolin Rether,
• Wilhelm Sicking,
• Roland Boese and
• Carsten Schmuck

Beilstein J. Org. Chem. 2010, 6, No. 3, doi:10.3762/bjoc.6.3

• within the dimer (164.78° for the outer and 148.97° for the inner guanidinium NH-bonds and 141.37° for the indole NH-bond). Within the crystal lattice the molecules of 2 are arranged in parallel planes held together most likely by aromatic stacking interactions: The centroid-centroid distance of two

Inversion symmetry and local vs. dispersive interactions in the nucleation of hydrogen bonded cyclic n-mer and tape of imidazolecarboxamidines

• Sihui Long,
• Venkatraj Muthusamy,
• Peter G. Willis,
• Sean Parkin and
• Arthur Cammers

Beilstein J. Org. Chem. 2008, 4, No. 23, doi:10.3762/bjoc.4.23

• process of C1 dimer, 8b perturbed hydrogen bonding away from optimum. Aromatic stacking is quoted anywhere between 2 and 0.5 kcal/mol so a scenario in which the eight aromatic-interactions in dimer 8b perturbed the energies of the hydrogen bonds is very reasonable. The red circles in Figure 10 represent