17340-32-8Relevant academic research and scientific papers
Room-temperature thermotropic ionic liquid crystals: Viologen bis(triflimide) salts
Bhowmik, Pradip K.,Han, Haesook,Nedeltchev, Ivan K.,Cebe, James J.
, p. 27 - 46 (2004)
Several dicationic salts with bis(triflimide) as counterions - otherwise known as viologens - were prepared by metathesis reaction of the corresponding viologen dibromides (diiodides) with lithium triflimide in a polar solvent. They were characterized for
Synergistic effect of hydrophobic and hydrogen bonding interaction-driven viologen-pyranine charge-transfer aggregates: adenosine monophosphate recognition
Narendran, Redhills L.,Patnaik, Archita
, p. 903 - 914 (2021)
Understanding the role of non-covalent interactions that dictate and fine-tune the direction of self-assembly of functional molecules is crucial for developing stimuli responsive materials. Herein, we systematically designed and synthesized viologen derivatives with hydrophobic dodecyl chains and alkyl carboxylic acid functionalities. The complementary electronic and electrostatic counterpart of viologens was chosen as pyranine. Viologens comprising of a hydrophobic dodecyl chain on one terminal and hydrogen bonding alkyl carboxylic acid on the other (V1andV2) underwent aggregation to a varying extent upon interaction with pyranine. The length of the alkyl carboxylic acid had a greater impact on the nature and morphology of the aggregates. Control molecules (V3andV4) in which 4,4′-bipyridine was symmetrically quaternized with alkyl carboxylic acids did not aggregate upon interaction with pyranine. The delicate balance existing between the hydrophobicity of the dodecyl chains and the intermolecular hydrogen bonding interaction between the alkyl carboxylic acid groups inV1orV2of the corresponding charge transfer (CT) complexes was instrumental in driving the aggregation. The CT aggregates of [V1-Pyr] and [V2-Pyr] exhibited excellent stability in water which disaggregated at physiological pH. We emphasize on the importance of synergy between hydrophobic and hydrogen bonding interactions in reinforcing each other to drive the supramolecular aggregation of the CT complexes. Such pH dependent CT aggregates are of importance as scaffolds in pH controlled drug release. In the present study, the CT aggregates were evaluated for adenosine nucleotide recognition in water; [V1-Pyr] and [V2-Pyr] exhibited selective response towards adenosine monophosphateviadeprotonation induced dissolution of aggregates in water leading to emission enhancement.
Influence of Constitution and Charge on Radical Pairing Interactions in Tris-radical Tricationic Complexes
Cheng, Chuyang,Cheng, Tao,Xiao, Hai,Krzyaniak, Matthew D.,Wang, Yuping,McGonigal, Paul R.,Frasconi, Marco,Barnes, Jonathan C.,Fahrenbach, Albert C.,Wasielewski, Michael R.,Goddard, William A.,Stoddart, J. Fraser
, p. 8288 - 8300 (2016)
The results of a systematic investigation of trisradical tricationic complexes formed between cyclobis(paraquat-p-phenylene) bisradical dicationic (CBPQT2(?+)) rings and a series of 18 dumbbells, containing centrally located 4,4′-bipyridinium radical cationic (BIPY?+) units within oligomethylene chains terminated for the most part by charged 3,5-dimethylpyridinium (PY+) and/or neutral 3,5-dimethylphenyl (PH) groups, are reported. The complexes were obtained by treating equimolar amounts of the CBPQT4+ ring and the dumbbells containing BIPY2+ units with zinc dust in acetonitrile solutions. Whereas UV-Vis-NIR spectra revealed absorption bands centered on ca. 1100 nm with quite different intensities for the 1:1 complexes depending on the constitutions and charges on the dumbbells, titration experiments showed that the association constants (Ka) for complex formation vary over a wide range, from 800 M-1 for the weakest to 180 000 M-1 for the strongest. While Coulombic repulsions emanating from PY+ groups located at the ends of some of the dumbbells undoubtedly contribute to the destabilization of the trisradical tricationic complexes, solid-state superstructures support the contention that those dumbbells with neutral PH groups at the ends of flexible and appropriately constituted links to the BIPY?+ units stand to gain some additional stabilization from C-H?π interactions between the CBPQT2(?+) rings and the PH termini on the dumbbells. The findings reported in this Article demonstrate how structural changes implemented remotely from the BIPY?+ units influence their non-covalent bonding interactions with CBPQT2(?+) rings. Different secondary effects (Coulombic repulsions versus C-H?π interactions) are uncovered, and their contributions to both binding strengths associated with trisradical interactions and the kinetics of associations and dissociations are discussed at some length, supported by extensive DFT calculations at the M06-D3 level. A fundamental understanding of molecular recognition in radical complexes has relevance when it comes to the design and synthesis of non-equilibrium systems.
The antitumor activity of 4,4′-bipyridinium amphiphiles
Wang, Senlin,Wu, Hongshuai,Chen, Fanghui,Zhang, Yu,Zhang, Yuchen,Sun, Baiwang
, p. 33023 - 33028 (2019)
A series of 4,4′-bipyridinium amphiphiles were synthesized and their anticancer activities were further evaluated. MTT assay showed that the cytotoxicity first increased and then decreased with the growth of carbon chains (8-16 C) at both ends of bipyridy
The antibacterial activity of 4,4′-bipyridinium amphiphiles with conventional, bicephalic and gemini architectures
Grenier, Melissa C.,Davis, Robert W.,Wilson-Henjum, Kelsey L.,Ladow, Jade E.,Black, Jacob W.,Caran, Kevin L.,Seifert, Kyle,Minbiole, Kevin P.C.
, p. 4055 - 4058 (2012)
Dialkyl 4,4′-bipyridinium compounds are widely employed for their useful redox properties, and are commonly known as viologens due to their intense coloration upon reduction. Despite their prevalence and amphiphilic nature, the antibacterial activity of these compounds remains largely unreported. We have thus prepared a series of mono- and bis-alkylated analogs of 4,4′-bipyridine to investigate structure-activity relationships in their inhibition of a battery of Gram positive and Gram negative bacteria. The prepared cationic compounds were conventional (one cationic head, one non-polar tail), bicephalic (two heads, one tail), or gemini (two heads, two tails) in their amphiphilic structure. Additionally, an isomeric series of six bis-alkylated compounds ranging from symmetric (PQ-11,11) to highly asymmetric (PQ-20,2) were prepared. Four themes of bioactivity emerged: (1) the most bioactive compounds were gemini in structure; (2) 22 carbons in the alkyl chains, with little to modest asymmetry, led to optimal activity; (3) bicephalic compounds were generally comparable to conventional amphiphiles, though only about 12 carbons in the alkyl chains were solubilized in water by each cationic nitrogen; (4) the effects of counterion identity were not evident between chlorides and bromides; however, the presence of the iodide counterion inhibited dissolution in all compounds tested. Three isomeric compounds with little to no asymmetry in tail length, PQ-11,11, PQ-12,10, and PQ-14,8, prepared as the bromide salts, showed comparable and highly potent activity, with MIC levels around 2 μM against 3 of 4 bacteria tested. The simple (one- to two-step) syntheses of potent antimicrobials portend well for future optimization.
Band-Gap Opening in Metallic Single-Walled Carbon Nanotubes by Encapsulation of an Organic Salt
Nieto-Ortega, Belén,Villalva, Julia,Vera-Hidalgo, Mariano,Ruiz-González, Luisa,Burzurí, Enrique,Pérez, Emilio M.
, p. 12240 - 12244 (2017)
The encapsulation of viologen derivatives into metallic single-walled carbon nanotubes (SWNTs) results in the opening of a band gap, making the SWNTs semiconducting. Raman spectroscopy, thermogravimetric analysis, and aberration-corrected high-resolution transmission electron microscopy confirm the encapsulation process. Through the fabrication of field-effect transistor devices, the change of the electronic structure of the tubes from metallic to semiconducting upon the encapsulation is confirmed. The opening of a gap in the band structure of the tubes was not detected in supramolecular controls.
Fulleropillar[4]arene: The Synthesis and Complexation Properties
Dai, Ling,Ma, Jingyu,Mi, Yan,Wu, Wanhua,Xiao, Chao,Yang, Cheng,Yao, Jiabin
supporting information, (2020/02/15)
A multihydroquinone ether dialdehyde derivative 2 was incidentally obtained through an unexpected ring opening of pillar[4]arene[1]quinone 1. And the Prato reaction of 2 with [60]fullerene led to [60]fullerene bisadducts, from which trans-4 cyclic regioisomer 3 was isolated and characterized. The fulleropillar[4]arene 3 showed a larger cavity and can accommodate a viologen derivative C12V2+with a much stronger affinity than permethyl pillar[5]arene (MP5) and pillar[4]arene[1]quinone 1.
