Protonation of electroneutral p-tert-butylcalix[4]arenetetraacetic acid

Křı́ž, Jaroslav; Dybal, Jiřı́; Makrlík, Emanuel; Budka, Jan; Vaňura, Petr

doi:10.1007/s00706-009-0218-3

Cited by 33 publications

(35 citation statements)

References 28 publications

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“…They established relatively high affinity of this receptor for the oxonium cation (lg K = 5.1) in nitrobenzene. The results of DFT calculations were analogous to those obtained by Křiž et al [22][23][24] The binding of oxonium ion with a cali [4]arene secondary-amide derivative, namely p-tert-butylcalix [4]arene tetrakis(N,N-dimethylacetamide), was investigated by Makrlík et al 26 The stability of the complex formed in nitrobenzene was found to be quite high (lg K = 10.9). The computational DFT based investigations revealed a preference of H 3 O + for the hydrogen bonding with amide carbonyl with respect to the ether oxygen atoms.…”

Section: Introductionsupporting

confidence: 64%

“…H 3 O + and NH 4 + , which are similar in size to K + and Rb + , has been rarely explored. Křiž et al [22][23][24] studied the binding of oxonium ion with calix [4]arene esters, ketones and tetraacids by means of 1 H and 13 C NMR spectroscopy in acetonitrile and nitrobenzene, as well as by quantum chemical DFT in vacuo calculations. The experimentally obtained results indicated that complexation occurred through hydrogen bonding between the cation and both ether and carbonyl oxygen atoms of the ligand.…”

Section: Introductionmentioning

confidence: 99%

“…The mentioned authors established that the p-tert-butylcalix [4]arene tetraacetic acid exhibited moderate affinity towards the oxonium ion in nitrobenzene (lg K = 2.1). 22 On the other hand, the stability constant of the complex of H 3 O + cation with ptert-butylcalix [4]arene tetraacetate in acetonitrile was estimated to be much higher. 23 The DFT in vacuo calculations were in accord with the experimental results.…”

Section: Introductionmentioning

confidence: 99%

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Complexation of Oxonium and Ammonium Ions by Lower-rim Calix[4]arene Amino Acid Derivatives

Požar¹,

Horvat²,

Čalogović³

et al. 2012

Croat. Chem. Acta

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Section: Introductionsupporting

confidence: 64%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Complexation of Oxonium and Ammonium Ions by Lower-rim Calix[4]arene Amino Acid Derivatives

Požar¹,

Horvat²,

Čalogović³

et al. 2012

Croat. Chem. Acta

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“…Calculations also indicated that binding almost exclusively to the phenoxy-oxygen atoms could be even preferred in some cases. In a recent study, [18] we were able to show that H 3 O + binds to a calix [4]arene containing only Ar-O-R groups (R is an alkyl such as n-propyl). All calixarenes investigated in these studies had the characteristic structure with the four aromatic groups arranged in an almost rigid four-member cup, which also determined a regular configuration of four aryl-oxygen atoms offering the binding sites for H 3 O + .…”

Section: Introductionmentioning

confidence: 98%

Cooperative interaction of H₃O⁺ with 1,3‐alternate tetrapropoxycalix[4]arene: NMR and theoretical study

Křı́ž

Dybal

Makrlík

et al. 2008

Magnetic Reson in Chemistry

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Interaction of H3O+ or H5O2+ with 1,3-alternate tetrapropoxycalix[4]arene (1) was studied in nitrobenzene and dichloromethane using 1H and 13C NMR including transverse and rotating-frame relaxations and density functional level of theory (DFT) quantum calculations. According to NMR, the ion forms an equimolecular complex with 1 with the equilibrium constant K being 3.97 x 10(3) L.mol(-1) at 296 K. The ions are bound by strong hydrogen bonds to the phenoxy-oxygen atoms of one half of 1 and by a medium-strong hydrogen bond to the pi system of the aromatic rings of the other half. The complex appears to have C(4h) symmetry in NMR even when cooling its solution down to 213 K, which could be due either to a genuine symmetry of the complex (if the ion is H5O2+) or to fast structure averaging by ion exchange processes (if the ion is H3O+). Therefore, the dynamics of the system was studied. Using two independent NMR methods (transverse and rotating-frame relaxation), two different exchange processes were discerned with correlation times 25 x 10(-6) and 5 x 10(-6) s, the first being clearly intermolecular and the other being apparently intramolecular. The energetic aspects of the possible exchange processes were examined by DFT quantum calculations. Rotation of H3O+ ion within one binding site with the energy barrier 8.13 kcal/mol is easily possible. Intermolecular exchange by freeing the ion from the complex has too high a barrier but cooperative interaction of the ion with additional water molecules makes it viable. The intramolecular exchange (or hopping) of the H3O+ ion between the two sites of the molecule is not viable in the classical manner, the barrier being 25.6 kcal/mol. Quantum tunneling of the ion is highly improbable, too. Alternative mechanisms including concerted two-ion intermolecular exchange and cooperative interaction with another bound water molecule including complexation with proton dihydrate H5O2+ are discussed.

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“…This applies also to a calix [4]arene containing only Ar-O-R groups (R is an alkyl such as n-propyl) where H 3 O + binds to phenoxy oxygen atoms. [18] Somewhat surprisingly, metal ions are also effectively bound by 1,3-alternate calix [4]arenes [19] possessing two opposite cavities, each with only two phenoxy groups. [20,21] This is also true [22] for H 3 O + , where the ion binds by two strong hydrogen bonds to the phenoxy groups of one half of the molecule and by a medium-strong bond to one of the π -systems of the other half (a possibility generally predicted [23,24] for aromatic systems).…”

Section: Introductionmentioning

confidence: 98%

Cooperative interaction of n‐butylammonium ion with 1,3‐alternate tetrapropoxycalix [4]arene: NMR and theoretical study

Křı́ž

Dybal

Budka

et al. 2008

Magnetic Reson in Chemistry

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The interaction of 1,3-alternate tetrapropoxycalix[4]arene (1) with n-butylammonium ion (2) in CD(2)Cl(2) was examined using (1)H, (13)C and (14)N NMR spectroscopy and DFT (density functional theory) calculations. NMR shows that 1 forms with 2 an equimolecular hydrogen-bonded complex with the equilibrium constant 5.91 x 10(3) l/mol at 296 K. The structure of the complex can be shown to be asymmetric at 203 K, with 2 interacting by hydrogen bonds with the two ethereal oxygen atoms of one half of 1 and with the pi system of the other half, but is rapidly averaged to an apparent C(4h) symmetry by chemical exchange at higher temperatures. Using two related but independent techniques based on transverse and rotating-frame proton relaxation, it is shown that only an intermolecular exchange of 2 between the bound and free states takes place, in contrast to previously studied interaction of 1 with H(3)O(+). Its correlation time is 0.169 ms. It is shown by DFT calculations that such swift exchange is not possible without a cooperative interaction of both 2 and 1 with several molecules of water present. Similarities and contrasts between the exchange processes of 2 and H(3)O(+) bound to 1 are discussed, in particular with respect to the apparent quantum tunneling of the latter inside the molecule of the complex.

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Protonation of electroneutral p-tert-butylcalix[4]arenetetraacetic acid

Cited by 33 publications

References 28 publications

Complexation of Oxonium and Ammonium Ions by Lower-rim Calix[4]arene Amino Acid Derivatives

Complexation of Oxonium and Ammonium Ions by Lower-rim Calix[4]arene Amino Acid Derivatives

Cooperative interaction of H₃O⁺ with 1,3‐alternate tetrapropoxycalix[4]arene: NMR and theoretical study

Cooperative interaction of n‐butylammonium ion with 1,3‐alternate tetrapropoxycalix [4]arene: NMR and theoretical study

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Protonation of electroneutral p-tert-butylcalix[4]arenetetraacetic acid

Cited by 33 publications

References 28 publications

Complexation of Oxonium and Ammonium Ions by Lower-rim Calix[4]arene Amino Acid Derivatives

Complexation of Oxonium and Ammonium Ions by Lower-rim Calix[4]arene Amino Acid Derivatives

Cooperative interaction of H3O+ with 1,3‐alternate tetrapropoxycalix[4]arene: NMR and theoretical study

Cooperative interaction of n‐butylammonium ion with 1,3‐alternate tetrapropoxycalix [4]arene: NMR and theoretical study

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Cooperative interaction of H₃O⁺ with 1,3‐alternate tetrapropoxycalix[4]arene: NMR and theoretical study