Rotaxanes with integrated photoswitches: design principles, functional behavior, and emerging applications

• Jullyane Emi Matsushima,
• Khushbu,
• Zuliah Abdulsalam,
• Udyogi Navodya Kulathilaka Conthagamage and
• Víctor García-López

Beilstein J. Org. Chem. 2025, 21, 2345–2366, doi:10.3762/bjoc.21.179

• methoxide anion (Figure 2). The neutral acridane is restored through the thermal nucleophilic attack of the alkoxide on the acridinium ion. Abraham and co-workers exploited this dramatic change in the electronic nature and geometric shape of acridane to modulate the translation of cyclobis(paraquat-4,4

Research progress on calixarene/pillararene-based controlled drug release systems

• Liu-Huan Yi,
• Jian Qin,
• Si-Ran Lu,
• Liu-Pan Yang,
• Li-Li Wang and
• Huan Yao

Beilstein J. Org. Chem. 2025, 21, 1757–1785, doi:10.3762/bjoc.21.139

• further utilized this feature to achieve reversible transformation of amphiphilic guest molecules between micellar and vesicular states and have successfully applied it to the controlled release of dye molecules. Notably, the system can also effectively neutralize the toxicity of paraquat through host

• ]arene (WP7) by adding 14 anionic carboxylic acid groups to both sides [102]. They explored the pH-dependent complexation of WP7 with paraquat derivative G1 in water. The host WP7 and guest G1 form a 1:1 pseudorotaxane, with an association constant of (2.96 ± 0.31) × 105 M−1. Furthermore, they leveraged

• this new molecular recognition motif to create a supramolecular amphiphilic reagent using WP7 and an amphiphilic paraquat derivative G2. This pH-responsive drug delivery system has considerable potential for future medical applications. Hydrophilic supramolecular polymers that respond to stimuli

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

• first TTF-based pseudorotaxane was reported by Stoddart and Williams in 1991 (Figure 5) [33]. At this time, they investigated the host–guest properties of the π-electron-poor cyclophane cyclobis(paraquat-p-phenylene) (3) in form of the tetrakis(hexafluorophosphate) salt [58]. The square-shaped host

• -called “rotacatenane” (Figure 22) [99]. The rotacatenane 24 consists of their previously used rotaxane framework except that the enlarged cyclophane cyclobis(paraquat-4,4′-biphenylene) is used as wheel component. The cavity of this macrocycle is large enough to host two planar molecules in a cofacial

• (Figure 25) [106]. The catenane 27 is made of a macrocycle with a TTF, a 4,4′-bipyridinium and a dihydroxynaphthalene recognition site which is encircled by a cyclobis(paraquat-p-phenylene) wheel. In the resting state, the wheel is located at the TTF unit forming a donor–acceptor complex with a green

Complexation of molecular clips containing fragments of diphenylglycoluril and benzocrown ethers with paraquat and its derivatives

• Leonid S. Kikot',
• Catherine Yu. Kulygina,
• Alexander Yu. Lyapunov,
• Svetlana V. Shishkina,
• Roman I. Zubatyuk,
• Tatiana Yu. Bogaschenko and
• Tatiana I. Kirichenko

Beilstein J. Org. Chem. 2017, 13, 2056–2067, doi:10.3762/bjoc.13.203

• , Kharkiv, Ukraine 10.3762/bjoc.13.203 Abstract The complexation of molecular clips containing fragments of diphenylglycoluril and benzocrown ethers with paraquat and its derivatives has been studied both in solution and in the solid state. In this paper we studied the influence of the crown ether ring

• size and the nature of the substituents at the nitrogen atoms of the paraquat derivatives on the composition and stability of these complexes. Keywords: complexation; crown ethers; "host–guest chemistry"; molecular clips; paraquat; Introduction After the first report on the synthesis of crown ethers

• and co-workers in 1987 [2] reported the complexation of crown ethers with paraquat and diquat for the first time, these compounds have become the most commonly used models in the design of various systems such as host–guest and supramolecular assemblies based on crown ethers [3]. The development of

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

• and nanomaterials is a challenging task. Huang and co-workers [165] have reported a taco complex template method to synthesize a cryptand/paraquat [2]rotaxane and [2]catenane (e.g., 207) by using RCM as a key step. Structural features and interesting bioactivity of the hirsutellones have grabbed the

Recent progress in the discovery of small molecules for the treatment of amyotrophic lateral sclerosis (ALS)

• Allison S. Limpert,
• Margrith E. Mattmann and
• Nicholas D. P. Cosford

Beilstein J. Org. Chem. 2013, 9, 717–732, doi:10.3762/bjoc.9.82

• development and validation of this series of small molecules may prove valuable for future therapeutic development. Another mechanism to attenuate the toxicity of TDP-43 is to prevent its aggregation into intercellular inclusions. In a study by Parker et al. [38], treatment of SH-SY5Y cells with paraquat to

Control over molecular motion using the cis–trans photoisomerization of the azo group

• Estíbaliz Merino and
• María Ribagorda

Beilstein J. Org. Chem. 2012, 8, 1071–1090, doi:10.3762/bjoc.8.119

• thermodynamically stable conformations [138]. The energy barriers between these conformations can be controlled kinetically by photochemical modulation. The ring component of the [2]rotaxane is cyclobis(paraquat-p-phenylene) and the dumbbell is comprised of a tetrathiafulvalene unit and a 1,5-dioxynaphthalene as π

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32