Spectral and DFT studies of anion bound organic receptors: Time dependent studies and logic gate applications

• Srikala Pangannaya,
• Neethu Padinchare Purayil,
• Shweta Dabhi,
• Venu Mankad,
• Prafulla K. Jha,
• Satyam Shinde and
• Darshak R. Trivedi

Beilstein J. Org. Chem. 2017, 13, 222–238, doi:10.3762/bjoc.13.25

• for F− and AcO– ions allowing the real time analysis of these ions in aqueous media. The formation of the receptor–anion complexes has been supported by UV–vis titration studies and confirmed through binding constant calculations. The anion binding process follows a first order rate equation and the

• ][24][25][26]. The choice of the appropriate detection technique is highly essential as it directly dictates the efficacy of the sensor. Anion binding through colorimetric probes comprising of a binding site and a signaling unit works in a coordinative way yielding an optical output visible to the

• response of the anion detection process. The anion binding properties of receptors R1 and R2 (4.5 × 10−5 M in DMSO), have been studied through the addition of 2 equiv of a series of anions as their tetrabutylammonium salts (F−, Cl−, Br−, I−, NO3−, HSO4−, H2PO4− and AcO− at concentrations of 1 × 10−2 M in

New approaches to organocatalysis based on C–H and C–X bonding for electrophilic substrate activation

• Pavel Nagorny and
• Zhankui Sun

Beilstein J. Org. Chem. 2016, 12, 2834–2848, doi:10.3762/bjoc.12.283

• through chloride anion binding by Mancheno and co-workers [35]. Examples of chiral triazole-based catalysts for anion activation designed by Mancheno and co-workers [36][37][38][39]. Application of chiral triazole-based catalysts L3 and L4 for counterion activation of pyridinium, quinolinium and

• isoquinolinium salts by Mancheno and co-workers [36][37][38][39]. Ammonium salt anion binding via C–H hydrogen bonds in solid state [40][41][42][43][44][45][50][51]. Early examples of ammonium salts being used for electrophilic activation of imines in aza-Diels–Alder reactions [52]. Ammonium salts as hydrogen

From steroids to aqueous supramolecular chemistry: an autobiographical career review

• Bruce C. Gibb

Beilstein J. Org. Chem. 2016, 12, 684–701, doi:10.3762/bjoc.12.69

Creating molecular macrocycles for anion recognition

• Amar H. Flood

Beilstein J. Org. Chem. 2016, 12, 611–627, doi:10.3762/bjoc.12.60

• preparation of the macrocycle (Figure 5e). To this day, the stepwise procedure [6] we currently use to make triazolophanes still largely follows the path he set for it. Anion binding to triazolophane macrocycles. At the time when the triazolophane was drawn on the notepad, the central cavity clearly beckoned

• self-assembly and anion binding (Figure 17a) using STM and were surprised by what we saw. Clear in the imaging (Figure 17b) were their shapes, looking like lumpy donuts; a shape similar to the one offered by Japan’s Mister Donut. Interestingly, these macrocycles displayed a reliable propensity for

• from naphthalimides (20) [39], and investigated the transfer of function to polymeric constructs (21) [40]. The most recent crescents (22) provided a basis to investigate surface self-assembly [41], anion binding and switching at interfaces [42]. They also provide a base for foldamers; a series of

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

• -triazole foldamers. In 2008, several groups independently described that the intermolecular C–H····Cl− hydrogen bonding could induce benzene-linked 1,2,3-triazole oligomers to form folded or helical conformations [61][62][63]. Currently, this family of foldamers have found wide applications in anion

• binding and design of photo-active molecular devices [64][65][66]. We were interested in developing inherently folded structural patterns for aromatic oligotriazole backbones. In 2009, Yuanyuan Zhu established that 1,5-diphenyl-1,2,3-triazole formed an intramolecular six-membered C–H····OMe hydrogen bonds

Fluoride-driven ‘turn on’ ESPT in the binding with a novel benzimidazole-based sensor

• Kai Liu,
• Xiaojun Zhao,
• Qingxiang Liu,
• Jianzhong Huo,
• Bolin Zhu and
• Shihua Diao

Beilstein J. Org. Chem. 2015, 11, 563–567, doi:10.3762/bjoc.11.61

• )imino)methyl)-5-(dimethylamino)phenol (BIP) made up of benzimidazole and phenol units with a C=N linker. Although BIP is weakly fluorescent, its anion-binding adduct is expected to be highly fluorescent by opening up ESPT channel [2][14][15][19]. In this paper, we demonstrated that BIP displayed

• to the literature [28][29] with little modification, as displayed in Scheme 1. It was well characterized by 1H NMR, mass spectrometry and elemental analysis before its practical application. The anion binding and sensing properties of BIP were first evaluated by UV–vis studies. There were three

• indicated the occurrence of hydrogen-bonding interaction between BIP and F−. Moreover, the acidity of the OH group of BIP was expected to be enhanced by anion binding, and the ESPT channel would be open [8][9][10][15]. The subsequent spectral behavior proved our assumption. The new peak at 376 nm occurred

Macrocyclic bis(ureas) as ligands for anion complexation

• Claudia Kretschmer,
• Gertrud Dittmann and
• Johannes Beck

Beilstein J. Org. Chem. 2014, 10, 1834–1839, doi:10.3762/bjoc.10.193

• rather weak complexing agent, the large ring of 2 binds anions with association constants up to log K = 7.93 for chloride ions. Keywords: anion binding; macrocyclic compounds; NMR spectra; supramolecular chemistry; template; urea; Introduction Supramolecular chemistry – the “chemistry beyond the

Similarity analysis, synthesis, and bioassay of antibacterial cyclic peptidomimetics

• Workalemahu M. Berhanu,
• Mohamed A. Ibrahim,
• Girinath G. Pillai,
• Alexander A. Oliferenko,
• Levan Khelashvili,
• Farukh Jabeen,
• Bushra Mirza,
• Farzana Latif Ansari,
• Ihsan ul-Haq,
• Said A. El-Feky and
• Alan R. Katritzky

Beilstein J. Org. Chem. 2012, 8, 1146–1160, doi:10.3762/bjoc.8.128

• enantiomeric recognition [22][23]. Incorporation of amino acids in abiotic anion receptors can lead to systems that mimic the anion coordination properties of anion-binding proteins [24]. Introduction of cysteine subunits into a macrocycle facilitates receptor synthesis and allows control of the relative

A ferrocene redox-active triazolium macrocycle that binds and senses chloride

• Nicholas G. White and
• Paul D. Beer

Beilstein J. Org. Chem. 2012, 8, 246–252, doi:10.3762/bjoc.8.25

• that the redox-active macrocycle is capable of sensing chloride in CH3CN solution. Keywords: anion binding; C–H···anion interactions; electrochemistry; ferrocene; triazolium; Introduction The copper(I)-catalysed cycloaddition of alkynes and azides (CuAAC) [1][2] to give the 1,2,3-triazole group is

• ][7]. More recently, we [8], and others [9][10], have shown that alkylating the triazole group to give the triazolium group increases the strength of anion binding significantly by further polarising the C–H bond of the heterocycle. With one notable recent exception of an acyclic ferrocene-appended

• investigate its anion binding and electrochemical-sensing properties. Results and Discussion Synthesis The CuAAC reaction of ferrocene bis(azide) 1 [12], with a large excess of 1,6-heptadiyne afforded 2 in 50% yield. An intramolecular Eglinton cyclisation reaction was used to prepare the ferrocene bis

Binding of group 15 and group 16 oxides by a concave host containing an isophthalamide unit

• Jens Eckelmann,
• Vittorio Saggiomo,
• Svenja Fischmann and
• Ulrich Lüning

Beilstein J. Org. Chem. 2012, 8, 11–17, doi:10.3762/bjoc.8.2

• halide anions. A general method for a quick estimation of the strength of binding derived from only a few data points is presented and gives an estimated Kass of pyridine-N-oxide of ca. 40 M−1, NMR titration confirms 25 M−1. Keywords: anion binding; association constant; estimation of binding constants

• ][5] or bi-macrocycles for ion-pair and ion-triplet recognition [6][7][8][9]. During the last few years, it was also shown that the orientation of the amide bonds of the isophthalamides plays an important role in the effectiveness of anion binding and subsequently in applications such as transmembrane

• there is almost no CIS observed for the endo-CH of model compound 2, a small shift for the NH protons is observed. However, for DMSO, the CIS of the NH is larger for the concave host 1 than for model compound 2 (0.57 ppm for 1 and 0.25 ppm for 2), in contrast to the results of the anion-binding

(How) does 1,3,5-triethylbenzene scaffolding work? Analyzing the abilities of 1,3,5-triethylbenzene- and 1,3,5-trimethylbenzene-based scaffolds to preorganize the binding elements of supramolecular hosts and to improve binding of targets

• Xing Wang and
• Fraser Hof

Beilstein J. Org. Chem. 2012, 8, 1–10, doi:10.3762/bjoc.8.1

• imidazolium-based hosts 5 (used for anion binding) [18][19] as instructive systems for computational analysis (Figure 2). These hosts were chosen because (1) they are typical of the kinds of heterocycles often used as recognition elements in this family of hosts; (2) we wished to examine the effects of charge

NMR studies of anion-induced conformational changes in diindolylureas and diindolylthioureas

• Damjan Makuc,
• Jennifer R. Hiscock,
• Mark E. Light,
• Philip A. Gale and
• Janez Plavec

Beilstein J. Org. Chem. 2011, 7, 1205–1214, doi:10.3762/bjoc.7.140

• along the C7–N7α bonds and the syn–syn conformer was preferred for anion–receptor complexes. The conformational changes upon anion binding are in good agreement with energetic preferences established by ab initio calculations. Keywords: anion recognition; conformation analysis; host–guest systems; NMR

• anion binding relative to thiourea 2 (the data were supported by the stability constant determinations performed previously and shown in Table 1). The larger sulfur atom can prevent the receptor 2 from adopting a planar conformation, which may reduce the affinity of this receptor for anionic guests

Effects of anion complexation on the photoreactivity of bisureido- and bisthioureido-substituted dibenzobarrelene derivatives

• Heiko Ihmels and
• Jia Luo

Beilstein J. Org. Chem. 2011, 7, 278–289, doi:10.3762/bjoc.7.37

• stereoselectivity of the DPM rearrangement of the thioureido-substituted dibenzobarrelene 1i upon complexation of chiral anions is not clear. Nevertheless, it has been shown that neighboring aryl substituents decrease the anion-binding ability of thiourea derivatives because of the steric repulsion between the

A new fluorescent chemosensor for fluoride anion based on a pyrrole–isoxazole derivative

• Zhipei Yang,
• Kai Zhang,
• Fangbin Gong,
• Shayu Li,
• Jun Chen,
• Jin Shi Ma,
• Lyubov N. Sobenina,
• Albina I. Mikhaleva,
• Guoqiang Yang and
• Boris A. Trofimov

Beilstein J. Org. Chem. 2011, 7, 46–52, doi:10.3762/bjoc.7.8

• , China A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1 Favorsky Str., Irkutsk, 664033, Russian Federation 10.3762/bjoc.7.8 Abstract Molecules containing polarized NH fragments that behave as anion-binding motifs are widely used as receptors for

• reported in recent years, those employing polarized NH groups as anion-binding motifs have attracted considerable attention. Typical examples are charge neutral receptors containing pyrrole, amide, indolocarbazole, guanidium, imidazolium and urea/thiourea moieties. Usually, the anions are recognized via H

Anion receptors containing thiazine-1,1-dioxide heterocycles as hydrogen bond donors

• Hong-Bo Wang,
• James A. Wisner and
• Michael C. Jennings

Beilstein J. Org. Chem. 2010, 6, No. 50, doi:10.3762/bjoc.6.50

• change in the 1H NMR spectrum of 3 is observed upon the addition of iodide. We believe that the differences in anion binding between these two receptors can be satisfactorily explained by the differences in their cleft geometries. The central three atoms (NH and CHa) that define the binding cleft in both

Synthesis of indolo[3,2-b]carbazole-based new colorimetric receptor for anions: A unique color change for fluoride ions

• Ajit Kumar Mahapatra,
• Giridhari Hazra and
• Prithidipa Sahoo

Beilstein J. Org. Chem. 2010, 6, No. 12, doi:10.3762/bjoc.6.12

• orange) observed. Keywords: anion binding; colorimetry; fluorescence quenching; fluoride binding; indolocarbazole; Introduction The design and synthesis of chromogenic receptors for biologically important and environmentally harmful anion pollutants has attracted considerable attention in

• same plane as the carbazole unit. Interaction studies UV–vis study The anion-binding properties of receptor 1 were investigated by UV–vis, fluorescence and 1H NMR spectroscopic methods. The sensing ability of chemosensor 1 with a series of tetrabutylammonium salts ([Bu4N]+X−, X = F−, Cl−, Br−, I−, AcO

Variations in product in reactions of naphthoquinone with primary amines

• Marjit W. Singh,
• Anirban Karmakar,
• Nilotpal Barooah and
• Jubaraj B. Baruah

Beilstein J. Org. Chem. 2007, 3, No. 10, doi:10.1186/1860-5397-3-10

• have anion binding ability on protonation or have complex forming ability with metals. The incorporation of pyridine ring to a quinone has also another facet as we have recently observed that in picolyl derivative of 1,8-naphthalimides the π-π interactions are governed by the position of the nitrogen