An unprecedentedly reactive iron species (2) has been generated by reaction of excess peracetic acid with a mononuclear complex [FeII(CF3SO3)2(PyNMe3)] (1) at cryogenic temperatures, and characterized spectroscopically. Compound 2 is kinetically competent for breaking strong C—H bonds alkanes (BDE ≈ 100 kcal·mol–1) through hydrogen-atom transfer mechanism, the transformations proceed stereoretention regioselectively, responding to bond strength, as well steric polar effects. Bimolecular...

The incorporation of four carboxylic acids or amino groups to the upper rim an aryl extended calix[4]pyrrole produces water-soluble receptors which are able effectively bind aromatic N-oxides in water by a combination hydrogen bonding, π−π, CH−π, and hydrophobic interactions.

DNA interaction with scorpiand azamacrocycles has been achieved through modulation of their binding affinities. Studies performed different experimental techniques provided evidence that pH or metal-driven molecular reorganizations these ligands regulate ability to interact calf thymus (ctDNA) an intercalative mode. Interestingly enough, serve increase decrease the biological activities compounds significantly.

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTCO2 Fixation by Copper(II) Complexes of a Terpyridinophane Aza ReceptorEnrique García-España, Pablo Gaviña, Julio Latorre, Conxa Soriano, and Begoña VerdejoView Author Information Instituto de Ciencia Molecular, Departamentos Química Inorgánica y Orgánica, Materiales la Universidad Valencia, Departamento Inorgánica, C/ Dr. Moliner 50, 46100, Burjassot (Valencia), Spain Cite this: J. Am. Chem. Soc. 2004, 126, 16, 5082–5083Publication Date...

We report and rationalize the formation of gels, responsive to sodium cations or pH changes, in aqueous media by a supramolecular system constituted an aryl extended calix[4]pyrrole receptor tetramethylammonium guest.

Two aza scorpionand-like macrocycles (L2 and L3) have been prepared. L2 consists of a tren amine with two its arms cyclizized 2,6-bis(bromomethyl)pyridine. In L3, the remaining pendant arm has further functionalized fluorophoric naphthalene group. X-ray data on compounds [H(L3)]ClO4·H2O (1) [H3(L3)](H2PO4)3·H2O (2) as well solution studies (pH-metry, UV−vis, fluorescence data) show movement result protonation degree formation intramolecular hydrogen bonds. complexes [Cu(L2)](ClO4)2]2·H2O (3)...

The synthesis of the terpyridinophane-type polyamine 2,6,9,12,16-pentaaza[17]-(5,5' ')-cyclo-(2,2':6',2' ')-terpyridinophane heptahydrobromide tetrahydrate (L·7HBr·4H2O) is described. L presents six protonation constants with values in range 9.21−3.27 logarithmic units. interacts Cu2+ and Zn2+ forming both cases, neutral, protonated, hydroxylated mono- binuclear complexes whose have been calculated by potentiometry 0.15 M NaClO4 at 298.1 K. crystal structures compounds...

MnII complexes of scorpiand-type azamacrocycles constituted by a tretrazapyridinophane core appended with an ethylamino tail including 2- or 4-quinoline functionalities show very appealing in vitro SOD activity. The observed behaviour is related to structural and electrochemical parameters.

We describe the use of two series aryl-extended calix[4]pyrrole receptors bearing and four electronically tunable phenyl groups, respectively, in their meso-positions as model systems for quantification CH-π interactions solution. The “four-wall” “two-wall” formed thermodynamically stable 1:1 complexes acetonitrile solution with both trimethylamine N-oxide trimethylphosphine P-oxide guests. were mainly stabilized by formation convergent hydrogen bonds between oxygen atom guests pyrrole NHs...

L-glutamate and L-aspartate selectivity is achieved by the action of two Cu2+ metal ions rightly disposed in a cyclophane-type macrocyclic framework; electrochemical sensing glutamate has been adsorption copper complexes on graphite electrodes.

The dinuclear Cu2+ and Zn2+ as well the mixed Cu2+–Zn2+ complexes of a 5,5″-pentaazaterpyridinophane ligand (L) are able to incorporate imidazolate (Im−) bridging ligand. crystal structure [Cu2L(Im)(Br)(H2O)](CF3SO3)2·3H2O (1) shows one copper coordinated by three pyridine nitrogens terpyridine unit, nitrogen bridge bromide anion occupying axial position distorted square pyramid. second atom is remaining nitrogen, secondary at centre polyamine water molecule that occupies position. Magnetic...

The new receptor 3,7,11,15,19,23-hexaaza-1(2,6)-pyridinacyclotetracosaphane (L1) containing a complete sequence of propylenic chains has been synthesised. acid–base behaviour and Cu2+ Zn2+ coordination have analysed by potentiometric measurements in 0.15 M NaClO4 for L1 the related compounds 3,7,11,14,18,22-hexaaza-1(2,6)-pyridinacyclotricosaphane (L2), 3,7,10,13,16,20-hexaaza-1(2,6)-pyridinacycloheneicosaphane (L3) 3,7,10,12,15,19-hexaaza-1(2,6)-pyridinacycloicosaphane (L4). crystal...

Two polytopic aza-scorpiand-like ligands, 6-[7-(diaminoethyl)-3,7-diazaheptyl]-3,6,9-triaza-1-(2,6-pyridina)cyclodecaphane (L1) and 6-[6'-[3,6,9-triaza-1-(2,6-pyridina)cyclodecaphan-6-yl]-3-azahexyl]-3,6,9-triaza-1-(2,6-pyridina)cyclodecaphane (L2), have been synthesized. The acid-base behavior Cu2+, Zn2+, Cu2+/Zn2+ mixed coordination analyzed by potentiometry, cyclic voltammetry, UV-vis spectroscopy. resolution of the crystal structures [Cu2L2Cl2](ClO4)2·1.67H2O (1),...

Polyiodide chemistry is among the first historically reported examples of supramolecular forces at work. To date, owing to increasingly recognized role halogen bonding and incorporation iodine-based components in several devices, it remains an active field theoretical applied research. Herein we re-examine azacyclophanes as a class ligands for stabilization iodine-dense three-dimensional networks, showing how devised novel possible strategies starting from literature material. The new set...

Enzymatic browning in fruits and vegetables can produce undesirable colour changes adversely affect the taste, flavour, nutritional value. This fact poses a challenge to food industry apply appropriate inhibitors control enzymatic maintain quality. Accordingly, this study aims evaluate effect of small mazamacrocyclic compounds modified with hydroxypyridinone similar kojic acid on browning, total polyphenols antioxidant activity apple juice. The results showed how these interact tyrosinase...

The sodium salt of the diethyl 1H-pyrazole-3,5-dicarboxylate (2) amphiphilic character is able to interact with (+)-amphetamine, (+)-methamphetamine, and dopamine, yielding stable complexes. Crystal structure 2 (+)-amphetamine leads a very nice double helical supramolecular structure.

The synthesis of two new tritopic double-scorpiand receptors in which equivalent 5-(2-aminoethyl)-2,5,8-triaza[9]-(2,6)-pyridinophane moieties have been linked with 2,6-dimethylpyridine (L1) or 2,9-dimethylphenanthroline (L2) units is reported for the first time. Their acid-base behaviour and Zn(2+) coordination chemistry studied by pH-metric titrations, molecular dynamic calculations, NMR, UV-Vis steady-state fluorescence techniques. L1 L2 behave, respectively, as hexaprotic heptaprotic...

The synthesis of two new ligands constituted a tris(2-aminoethyl)amine moiety linked to the 2,6 positions pyridine spacer through methylene groups in which hanging arm is further functionalized with 2-pycolyl (L1) or 3-pycolyl (L2) group presented. protonation L1 and L2 formation Cu2+ complexes have been studied using potentiometric, NMR, X-ray, kinetic experiments. results provide information about relevance molecular movements chemistry this kind so-called scorpiand ligand. comparison...

The affinities of polyamines consisting ethylenediamine units equipped with either one or two terminal naphthyl-, anthryl-, acridyl towards PolyA.PolyU as an RNA model, and Poly(dA).Poly(dT) a DNA model are screened by measuring the melting point changes (ΔTm) double strands, also partially fluorimetric binding assay using ethidium bromide. larger aromatic moieties long spacers between them allow bisintercalation; this leads to increased preference for in comparison RNA, where ion pairing...

The synthesis, characterization, Cu2+ coordination and interaction with AMP of three tripodal polyamines are reported. based on the structure tetraamine (tren) which has been enlarged propylamino functionalities (TAL), a further anthrylmethyl fragment at one its terminal primary nitrogens (ATAL) or naphthylmethyl fragments ends (N3TAL). protonation constants all show that pH 6, six secondary nitrogen atoms in arms protonated. (adenosine-5′-monophosphate) studied by potentiometric, UV-Vis,...

Abstract An aza‐terpyridinophane receptor containing the polyamine 4,7,10,13‐tetraazahexadecane‐1,16‐diamine linked through methylene groups to 5,5″ positions of a terpyridine unit has been prepared and characterized (L). The acid‐base behaviour, Cu II speciation ability form ternary complexes (Cu ‐L‐carbonate) have explored by potentiometric titrations in 0.15 M NaClO 4 UV/Vis paramagnetic NMR spectroscopy. Comparisons are made with previously reported terpyridinophane...

Modulation of hydrogen bonds and iodine–iodine interactions, both covalent supramolecular, unlocks novel possibilities for the construction transition metal-polyiodide hybrid networks.