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1.
Francesca Tancini Dr. Thomas Gottschalk Dr. W. Bernd Schweizer Dr. François Diederich Prof. Dr. Enrico Dalcanale Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(26):7813-7819
The capability of resorcinarenes to bind anions within the alkyl feet at the lower rim has been exploited as the starting point for developing a new cavitand able to engulf contact ion pairs of primary ammonium salts in chlorinated solvents with association constants (Kass) in the range of 103–104 M ?1. Methylene bridges were introduced into the upper rim to freeze the resorcinarene in the cone conformation with the four Hdown protons converging in the lower pocket, thereby maximizing the CH–anion interactions responsible for the anion binding. Four additional phosphate moieties were introduced into the lower rim in close proximity to the anionic site to provide hydrogen‐bonding‐acceptor P?O groups and promote cation complexation at the bottom of the cavitand. The binding ability of the synthesized ligands was analyzed by 1H NMR spectroscopy and, when possible, by isothermal titration calorimetry (ITC); the data were in agreement when complementary techniques were used. 相似文献
2.
Chloride‐Anion‐Templated Synthesis of a Strapped‐Porphyrin‐Containing Catenane Host System
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Dr. Asha Brown Dr. Matthew J. Langton Dr. Nathan L. Kilah Dr. Amber L. Thompson Prof. Paul D. Beer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(49):17664-17675
The synthesis, structure and anion‐recognition properties of a new strapped‐porphyrin‐containing [2]catenane anion host system are described. The assembly of the catenane is directed by discrete chloride anion templation acting in synergy with secondary aromatic donor–acceptor and coordinative pyridine–zinc interactions. The [2]catenane incorporates a three‐dimensional, hydrogen‐bond‐donating anion‐binding pocket; solid‐state structural analysis of the catenane?chloride complex reveals that the chloride anion is encapsulated within the catenane’s interlocked binding cavity through six convergent CH????Cl and NH???Cl hydrogen‐bonding interactions and solution‐phase 1H NMR titration experiments demonstrate that this complementary hydrogen‐bonding arrangement facilitates the selective recognition of chloride over larger halide anions in DMSO solution. 相似文献
3.
Introduction Interest in the selective recognition and sensing of anionic species continues to attract the attention of su-pramolecular chemistry community.1 The importance of anions in chemical and biological process can not be underestimated. It is well known that in nature neutral proteins bind anions only via hydrogen bonding interac-tions.2 Several anion receptors have been constructed from five-membered heterocycle,3 amide,4 (thio) urea,5 since these groups form relatively strong NHanio… 相似文献
4.
Simon C. Picot Benjamin R. Mullaney Prof. Paul D. Beer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(20):6230-6237
A new heteroditopic calix[4]diquinone triazole containing receptor capable of recognising both cations and anions through Lewis base and C? H hydrogen‐bonding modes, respectively, of the triazole motif has been prepared. This ion‐pair receptor cooperatively binds halide/monovalent‐cation combinations in an aqueous mixture, with selectivity trends being established by 1H NMR and UV/Vis spectroscopy. Cation binding by the calix[4]diquinone oxygen and triazole nitrogen donors enhances the strength of the halide complexation at the isophthalamide recognition site of the receptor. Conversely, anions bound in the receptor’s isophthalamide cavity enhance cation recognition. 1H NMR investigations in solution suggest that the receptor’s triazole motifs are capable of coordinating simultaneously to both cation and anion guest species. Solid‐state X‐ray crystallographic structural analysis of a variety of receptor ion‐pair adducts further demonstrates the dual cation–anion binding role of the triazole group. 相似文献
5.
Anne Bretschneider Dr. Diego M. Andrada Dr. Sebastian Dechert Steffen Meyer Prof. Dr. Ricardo A. Mata Prof. Dr. Franc Meyer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(50):16988-17000
1,3‐Bis(pentafluorophenyl‐imino)isoindoline (AF) and 3,6‐di‐tert‐butyl‐1,8‐bis(pentafluorophenyl)‐9H‐carbazole (BF) have been designed as preorganized anion receptors that exploit anion–π interactions, and their ability to bind chloride and bromide in various solvents has been evaluated. Both receptors AF and BF are neutral but provide a central NH hydrogen bond that directs the halide anion into a preorganized clamp of the two electron‐deficient appended arenes. Crystal structures of host–guest complexes of AF with DMSO, Cl?, or Br? (AF:DMSO, AF:Cl?, and ${{\rm A}{{{\rm F}\hfill \atop 2\hfill}}}$ :Br?) reveal that in all cases the guest is located in the cleft between the perfluorinated flaps, but NMR spectroscopy shows a more complex situation in solution because of E,Z/Z,Z isomerism of the host. In the case of the more rigid receptor BF, Job plots evidence 1:1 complex formation with Cl? and Br?, and association constants up to 960 M ?1 have been determined depending on the solvent. Crystal structures of BF and BF:DMSO visualize the distinct preorganization of the host for anion–π interactions. The reference compounds 1,3‐bis(2‐pyrimidylimino)isoindoline (AN) and 3,6‐di‐tert‐butyl‐1,8‐diphenyl‐9H‐carbazole (BH), which lack the perfluorinated flaps, do not show any indication of anion binding under the same conditions. A detailed computational analysis of the receptors AF and BF and their host–guest complexes with Cl? or Br? was carried out to quantify the interactions in play. Local correlation methods were applied, allowing for a decomposition of the ring–anion interactions. The latter were found to contribute significantly to the stabilization of these complexes (about half of the total energy). Compounds AF and BF represent rare examples of neutral receptors that are well preorganized for exploiting anion–π interactions, and rare examples of receptors for which the individual contributions to the binding energy have been quantified. 相似文献
6.
Thermodynamic Study of Dihydrogen Phosphate Dimerisation and Complexation with Novel Urea‐ and Thiourea‐Based Receptors
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Nikola Bregović Nikola Cindro Dr. Leo Frkanec Dr. Krunoslav Užarević Prof. Vladislav Tomišić 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(48):15863-15871
Complexation of dihydrogen phosphate by novel thiourea and urea receptors in acetonitrile and dimethyl sulfoxide was studied in detail by an integrated approach by using several methods (isothermal titration calorimetry, ESI‐MS, and 1H NMR and UV spectroscopy). Thermodynamic investigations into H2PO4? dimerisation, which is a process that has been frequently recognised, but rarely quantitatively described, were carried out as well. The corresponding equilibrium was taken into account in the anion‐binding studies, which enabled reliable determination of the complexation thermodynamic quantities. In both solvents the thiourea derivatives exhibited considerably higher binding affinities with respect to those containing the urea moiety. In acetonitrile, 1:1 and 2:1 (anion/receptor) complexes formed, whereas in dimethyl sulfoxide only the significantly less stable complexes of 1:1 stoichiometry were detected. The solvent effects on the thermodynamic parameters of dihydrogen phosphate dimerisation and complexation reactions are discussed. 相似文献
7.
Graham Smith Marcus S. Cotton Urs D. Wermuth Sue E. Boyd 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(5):o252-o255
The 1:1 proton‐transfer compound of the potent substituted amphetamine hallucinogen (R)‐2‐amino‐1‐(8‐bromobenzo[1,2‐b;5,4‐b′]difuran‐4‐yl)propane (common trivial name `bromodragonfly') with 3,5‐dinitrosalicylic acid, namely 1‐(8‐bromobenzo[1,2‐b;5,4‐b′]difuran‐4‐yl)propan‐2‐aminium 2‐carboxy‐4,6‐dinitrophenolate, C13H13BrNO2+·C7H3N2O7−, forms hydrogen‐bonded cation–anion chain substructures comprising undulating head‐to‐tail anion chains formed through C(8) carboxyl–nitro O—H...O associations and incorporating the aminium groups of the cations. The intrachain cation–anion hydrogen‐bonding associations feature proximal cyclic R33(8) interactions involving both an N+—H...Ophenolate and the carboxyl–nitro O—H...O associations and aromatic π–π ring interactions [minimum ring centroid separation = 3.566 (2) Å]. A lateral hydrogen‐bonding interaction between the third aminium H atom and a carboxyl O‐atom acceptor links the chain substructures, giving a two‐dimensional sheet structure. This determination represents the first of any form of this compound and is in the (R) absolute configuration. The atypical crystal stability is attributed both to the hydrogen‐bonded chain substructures provided by the anions, which accommodate the aminium proton‐donor groups of the cations and give crosslinking, and to the presence of the cation–anion aromatic ring π–π interactions. 相似文献
8.
Dr. M. Laura Soriano Dr. Joseph T. Lenthall Dr. Kirsty M. Anderson Dr. Stephen J. Smith Prof. Jonathan W. Steed 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(35):10818-10831
Treatment of a range of bis(thiourea) ligands with inert organometallic transition‐metal ions gives a number of novel complexes that exhibit unusual ligand binding modes and significantly enhanced anion binding ability. The ruthenium(II) complex [Ru(η6‐p‐cymene)(κS,S′,N‐ L3 ?H)]+ ( 2 b ) possesses juxtaposed four‐ and seven‐membered chelate rings and binds anions as both 1:1 and 2:1 host guest complexes. The pyridyl bis(thiourea) complex [Ru(η6‐p‐cymeme)(κS,S′,Npy‐ L4 )]2+ ( 4 ) binds anions in both 1:1 and 1:2 species, whereas the free ligand is ineffective because of intramolecular NH???N hydrogen bonding. Novel palladium(II) complexes with nine‐ and ten‐membered chelate rings are also reported. 相似文献
9.
A m-xylene bridged imidazolium receptor 1 has been designed and synthesized. The receptor 1 utilizes two imidazole (C–H)+—anion hydrogen bonds and one aromatic hydrogen—anion hydrogen bond. The major driving force of complexation between the receptor 1 and anions comes from two imidazole (C–H)+—anion hydrogen bonding. However, some hydrogen bonding energy between aromatic hydrogen and anion exists, although it is expected to be much smaller than that of imidazole (C–H)+—anion hydrogen bonds. 相似文献
10.
Using basis‐set extrapolation schemes for a given data set, we evaluated the binding energies and geometries at the complete basis set (CBS) limit at the levels of the second order Møller–Plesset perturbation theory (MP2) and the coupled cluster theory with singles, doubles, and perturbative triples excitations [CCSD(T)]. The systems include the hydrogen bonding (water dimer), aromatic interaction (benzene dimer), π–H interaction (benzene–water), cation–water, anion–water, π–cation interaction (cation–benzene), and π–anion interaction (anion–triazine). One extrapolation method is to exploit both BSSE‐corrected and BSSE‐uncorrected binding energies for the aug‐cc‐pVNZ (N = 2, 3, 4, …) basis set in consideration that both binding energies give the same CBS limit (CBSB). Another CBS limit (CBSC) is to use the commonly known extrapolation approach to exploit that the electron correlation energy is proportional to N?3. Since both methods are complementary, they are useful for estimating the errors and trend of the asymptotic values. There is no significant difference between both methods. Overall, the values of CBSC are found to be robust because of their consistency. However, for small N (in particular, for N = 2, 3), CBS is found to be slightly better for water–water interactions and cation–water and cation–benzene interactions, whereas CBS is found to be more reliable for bezene–water and anion–water interactions. We also note that the MP2 CBS limit value based on N = 2 and 3 combined with the difference between CCSD(T) and MP2 at N = 2 would be exploited to obtain a CCSD(T)/CBS value for aromatic–aromatic interactions and anion–π interactions, but not for cationic complexes. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008 相似文献
11.
Dual Role of the 1,2,3‐Triazolium Ring as a Hydrogen‐Bond Donor and Anion–π Receptor in Anion‐Recognition Processes
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Dr. Fabiola Zapata Lidia Gonzalez Dr. Antonio Caballero Prof. Ibón Alkorta Prof. Jose Elguero Prof. Pedro Molina 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(27):9797-9808
Several bis(triazolium)‐based receptors have been synthesized as chemosensors for anion recognition. The central naphthalene core features two aryltriazolium side‐arms. NMR experiments revealed differences between the binding modes of the two triazolium rings: one triazolium ring acts as a hydrogen‐bond donor, the other as an anion–π receptor. Receptors 92+?2BF4 ? (C6H5), 112+?2BF4 ? (4‐NO2?C6H4), and 132+?2BF4? (ferrocenyl) bind HP2O73? anions in a mixed‐binding mode that features a combination of hydrogen‐bonding and anion–π interactions and results in strong binding. On the other hand, receptor 102+?2 BF4 ? (4‐CH3O?C6H4) only displays combined Csp2?H/anion–π interactions between the two arms of the receptors and the bound anion rather than triazolium (CH)+???anion hydrogen bonding. All receptors undergo a downfield shift of the triazolium protons, as well as the inner naphthalene protons, in the presence of H2PO4? anions. That suggests that only hydrogen‐bonding interactions exist between the binding site and the bound anion, and involve a combination of cationic (triazolium) and neutral (naphthalene) C?H donor interactions. Theoretical calculations relate the electronic structure of the substituent on the aromatic group with the interaction energies and provide a minimum‐energy conformation for all the complexes that explains their measured properties. 相似文献
12.
Raatikainen K Beyeh NK Rissanen K 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(48):14554-14564
A series of symmetrical tri‐ and tetrameric N‐ethyl‐ and N‐phenylurea‐functionalized cyclophanes have been prepared in nearly quantitative yields (86–99 %) from the corresponding tri‐ and tetraamino‐functionalized piperazine cyclophanes and ethyl or phenyl isocyanates. Their conformational and complexation properties have been studied by single‐crystal X‐ray diffraction, variable‐temperature NMR spectroscopy, and ESI‐MS analysis. The rigid 27‐membered trimeric cyclophane skeleton assisted by a seam of intramolecular hydrogen bonds results in a preorganized ditopic recognition site with an all‐syn conformation of the urea moieties that, complemented by a lipophilic cavity of the cyclophane, binds molecular and ionic guests as well as ion pairs. The all‐syn conformation persists in acidic conditions and the triprotonated triurea cyclophane binds an unprecedented anion pair, H2PO4????HPO42?, in the solid state. The tetra‐N‐ethylurea cyclophane is less rigid and demonstrates an induced‐fit recognition of diisopropyl ether in the solid state. The guest was encapsulated within the lipophilic interior of a quasicapsule, formed by intramolecular hydrogen‐bond‐driven folding of the 36‐membered cyclophane skeleton. In the gas phase, the essential role of the urea moieties in the binding was demonstrated by the formation of monomeric 1:1 complexes with K+, TMA+, and TMP+ as well as the ion‐pair complexes [KI+K]+, [TMABr+TMA]+ and [TMPBr+TMP]+. In the positive‐mode ESI‐MS analysis, ion‐pair binding was found to be more pronounced with the larger tetraurea cyclophanes. In the negative mode, owing to the large size of the binding site, a general binding preference towards larger anions, such as the iodide, over smaller anions, such as the fluoride, was observed. 相似文献
13.
S. Shylaja K. N. Mahendra K. B. R. Varma T. Narasimhamurthy R. S. Rathore 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(7):o361-o363
The title salt, C13H12N3+·H2PO4−, contains a nonplanar 2‐(2‐aminophenyl)‐1H‐benzimidazol‐3‐ium cation and two different dihydrogen phosphate anions, both situated on twofold rotation axes in the space group C2. The anions are linked by O—H...O hydrogen bonds into chains of R22(8) rings. The anion chains are linked by the cations, via hydrogen‐bonding complementarities and electrostatic interactions, giving rise to a sheet structure with alternating rows of organic cations and inorganic anions. Comparison of this structure with that of the pure amine reveals that the two compounds generate characteristically different sheet structures. The anion–anion chain serves as a template for the assembly of the cations, suggesting a possible application in the design of solid‐state materials. 相似文献
14.
Despite their ready availability, O?H groups have received relatively little attention as anion recognition motifs. Here, we report two simple hydroxy‐containing anion receptors that are prepared in two facile steps followed by anion exchange, without the need for chromatographic purification at any stage. These receptors contain a pyridinium bis(amide) motif as well as hydroxyphenyl groups, and bind mono‐ and divalent anions in 9:1 CD3CN:D2O, showing a selectivity preference for sulfate. Notably, a “model” receptor that does not contain hydroxy groups shows only very weak sulfate binding in this competitive solvent mixture. In the solid state, X‐ray crystallographic studies show that the receptors tend to form extended assemblies with anions; however, 1H and DOSY NMR studies as well as molecular dynamics simulations show that only 1:1 complexes are present in solution. Molecular dynamics simulations suggest that one of the receptors suffers from competing intramolecular hydrogen bonding, while another binds partially‐hydrated anions, with the receptor's O?H groups forming hydrogen bonds to water molecules within the anion's coordination sphere. 相似文献
15.
Dr. Brice Kauffmann Dr. Gilles Guichard 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(44):15684-15692
Anion binding properties of neutral helical foldamers consisting of urea type units in their backbone have been investigated. 1H NMR titration studies in various organic solvents including DMSO suggest that the interaction between aliphatic oligoureas and anions (CH3COO?, H2PO4?, Cl?) is site‐specific, as it largely involves the urea NHs located at the terminal end of the helix (positive pole of the helix), which do not participate to the helical intramolecular hydrogen‐bonding network. This mode of binding parallels that found in proteins in which anion‐binding sites are frequently found at the N‐terminus of an α‐helix. 1H NMR studies suggest that the helix of oligoureas remains largely folded upon anion binding, even in the presence of a large excess of the anion. This study points to potentially useful applications of oligourea helices for the selective recognition of small guest molecules. 相似文献
16.
Li M Wu B Jia C Huang X Zhao Q Shao S Yang XJ 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(7):2272-2280
A neutral tripodal tris(ferrocenylurea) anion receptor has been designed that can electrochemically and optically recognize sulfate and phosphate anions. The binding of the tetrahedral anion induced distinct cathodic shifts of the ferrocene/ferrocenium redox couple in chloroform, whereas the UV/Vis spectrum of the receptor showed an increase in the d–d transition band upon addition of sulfate ions. Furthermore, the anion complexes (TBA)2 ? [SO4?L] ? H2O ( 1 ) and TBA[F?L] ( 2 ; TBA=tetrabutylammonium ion) were isolated. Crystal structural analyses showed that the receptor in the two 1:1 (host/guest) complexes encapsulated sulfate or fluoride ions in the tripodal cavity through multiple hydrogen bonds. 1H NMR spectroscopic and ESI mass‐spectrometric analysis revealed strong sulfate and fluoride binding in solution. 相似文献
17.
S. Byrne 《Supramolecular chemistry》2018,30(3):196-205
Herein we report the development of a new series of surface bound anion sensors exploiting the urea or thiourea motif capable of binding anions through hydrogen bonding interactions. The use of high resolution magic angle spinning 1H NMR allows the direct comparison of the anion binding properties of these receptors in solution versus those tethered to polymer resins. Some intramolecular hydrogen bonding and solvent effects were observed at the solution:surface interface however in general the anion binding properties of the polymer bound urea and thiourea receptors were maintained. 相似文献
18.
Batoul Makiabadi Mohammad Zakarianejad Sotoodeh Bagheri Hamid Reza Masoodi Raziyeh Sadaat Aghaie 《International journal of quantum chemistry》2013,113(21):2361-2371
Molecular interactions between uracil and nitrous acid (U–NA) [C4N2O2H4? NO2H] have been studied using B3LYP, B3PW91, and MP2 methods with different basis sets. The optimized geometries, harmonic vibrational frequencies, charge transfer, topological properties of electron density, nucleus‐independent chemical shift (NICS), and nuclear magnetic resonance one‐ and two‐bonds spin–spin coupling constants were calculated for U–NA complexes. In interaction between U and NA, eight cyclic complexes were obtained with two intermolecular hydrogen bonds N(C)HU…N(O) and OHNA…OU. In these complexes, uracil (U) simultaneously acts as proton acceptor and proton donor. The most stable complexes labeled, UNA1 and UNA2, are formed via NH bond of U with highest acidity and CO group of U with lowest proton affinity. There is a relationship between hydrogen bond distances and the corresponding frequency shifts. The solvent effect on complexes stability was examined using B3LYP method with the aug‐cc‐pVDZ basis set by applying the polarizable continuum model (PCM). The binding energies in the gas phase have also been compared with solvation energies computed using the PCM. Natural bond orbital analysis shows that in all complexes, the charge transfer takes place from U to NA. The results predict that the Lone Pair (LP)(O)U → σ*(O? H) and LP(N(O)NA → σ*(N(C)? H)U donor–acceptor interactions are most important interactions in these complexes. Atom in molecule analysis confirms that hydrogen bond contacts are electrostatic in nature and covalent nature of proton donor groups decreases upon complexation. The relationship between spin–spin coupling constant (1hJH…Y and 2hJH…Y) with interaction energy and electronic density at corresponding hydrogen bond critical points and H‐bonds distances are investigated. NICS used for indicating of aromaticity of U ring upon complexation. © 2013 Wiley Periodicals, Inc. 相似文献
19.
Alessandro Casnati Laura Pirondini Nicola Pelizzi Rocco Ungaro 《Supramolecular chemistry》2013,25(1):53-65
Abstract The synthesis and anion binding properties of several new cone calix[4]arenes having different flexibility and tetrafunctionalized at the upper rim with various type of hydrogen bonding donor groups such as thioureas (1–3), trifluoroacetamides (4, 5) and perfluorinated alcohols (6) are reported. The results obtained show that thiourea receptors are the most effective in the complexation of all anions and that the rigid cone compound 2 is more efficient than the mobile cone analog 1 in the binding of spherical anions, whereas the reverse is true for the complexation of tetrahedral H2PO4 ? anion. 相似文献
20.
The conformational analysis of four C2-amido and C7-ureido functionalised indole anion receptors was performed by a combination of heteronuclear NMR spectroscopy and ab initio quantum mechanical calculations. NOE experiments showed that anti–anti conformation across C2–C2α and C7–N7α bonds is predominant in acetone solution in the absence of anions. Upon anion binding to receptors, syn–syn conformation becomes predominant. The conformational changes upon anion binding are in good agreement with energetic preferences established by ab initio calculations. Chemical shift changes induced by interaction of anions suggest that binding of chloride and bromide anions occurs primarily to H1 and H7α protons. Nitrate anions favour interaction with H7α and H7γ ureido protons, whereas acetate anions interact strongly with all four available hydrogen bond donor groups. 相似文献