Extra large macrocycle: 40-membered macrocycle via 2:2 cyclization and its dimercury(II) complex

A large 40-membered N(4)O(4)S(4) macrocycle (L(2)) was obtained through a 2:2 cyclization of the corresponding dithiol and dichloride as a minor product during the preparation of a 20-membered N(2)O(2)S(2) macrocycle (L(1), 1:1 cyclization product). Each macrocycle was successfully separated from the mixed products and identified. The larger macrocycle L(2) allowed the preparation of its dimercury(II) complex, adopting a one-dimensional (1D) stairway-like polymeric chain linked with the anion. A monomercury(II) complex of the smaller macrocycle L(1) was also prepared. Both complexes and the larger macrocycle L(2) were structurally characterized by the single crystal X-ray analysis.     

Synthesis, spectral and oxidase studies of a new diamide copper(II) complex with pendant benzimidazolyl groups

A new benzimidazole-based diamide ligand-N,N'-bis(alanine-2-benzimidazolyl) hexanediamide (ABHA) has been synthesized and utilized to prepare Cu(II) complexes of general composition [Cu(ABHA)X2].nH2O,where X is an exogenous anionic ligand (X=Cl-,NO3-). Low temperature EPR spectra has been obtained that shows gparallel>gperpendicular>2.0024, indicating a tetragonal geometry in the solution state. The complexes display a quasi-reversible redox wave due to the Cu(II)/Cu(I) reduction process. E1/2 values shift anodically as NO3-相似文献   

Chelating behaviour of new 12-membered Schiff base macrocycles containing pendant groups

Summary The free Schiff base macrocycles 1,4,7,10-tetraazacyclo-dodeca-5,6,11,12-tetraaminoacetic acid-4,6,10,12-tetraene (L¹), 1,4,7,10-tetraazacyclododeca-5,6,11,12-tetraamino-phenyl-4,6,10,12-tetraene (L²) and 1,4,7,10-tetraazacyclo-dodeca-5,6,11,12-tetraaminopyridyl-4,6,10,12-tetraene (L³) have been prepared by the reaction of oxamidediacetic acid, oxamidediphenyl and oxamidedipyridyl, respectively, with ethylenediamine. Their complexes with first row transition metal ions, of types [MLCl₂] and [MLCl₂]Cl, have also been prepared and characterized by physico-chemical and spectroscopic methods. The complexes of divalent metal ions are non-ionic while those of trivalent metal ions appear to be 11 electrolytes. An octahedral geometry is proposed for all the complexes.     

Acid dissociation kinetics of the copper(II) complex of a 15-membered mixed N3O2 donor macrocycle

Summary The kinetics of the acid dissociation of the copper(II) complex of the 15-membered N₃O₂ donor macrocycle [prepared by reaction of 2,6-bis(2-aminophenoxymethyl)-pyridine with glyoxal in the presence of a manganese(II) template followed by reduction of the two imine linkages with NaBH₄] was studied over an acidity range (0.01–0.5 mol dm^-3 [H⁺]) at 25 °C and I = 1.0 mol dm^-3 by stopped-flow methods. A biphasic reaction was observed at 752 nm, the first reaction being complete within 20 ms at 25 °C and too rapid to study in detail. The second reaction shows a good first order dependence on the hydrogen ion concentration over the whole acidity range and k _obs=k0+k _H[H⁺], where k ₀ = 0.52 s^-1 and k _H = 40.2 dm³ mol^-1 s^-1 at 25 °C. The k ₀ term represents a small but significant solvolytic reaction. The mechanism of the acid-catalysed dissociation is discussed.     

Protonation and coordination properties towards Zn(II), Cd(II) and Hg(II) of a phenanthroline-containing macrocycle with an ethylamino pendant arm

Protonation and Zn(II), Cd(II) and Hg(II) coordination with the ligand 5-aminoethyl-2,5,8-triaza-[9]-10,23-phenanthrolinophane (L2), which contains an aminoethyl pendant attached to a phenanthroline-containing macrocycle, have been investigated by means of potentiometric, 1H NMR and spectrofluorimetric titrations in aqueous solutions. The coordination properties of L2 are compared with those of the ligand 2,5,8-triaza-[9]-10,23-phenanthrolinophane (L1). Ligand protonation occurs on the aliphatic amine groups and does not involve directly the heteroaromatic nitrogens. The fluorescence emission properties of L2 are controlled by the protonation state of the benzylic nitrogens: when not protonated, their lone pairs are available for an electron transfer process to the excited phenanthroline, quenching the emission. As a consequence, the ligand is emissive only in the highly charged [H3L2]3+ and [H4L2]4+ species, where the benzylic nitrogens are protonated. Considering metal complexation, both [ML1]2+ and [ML2]2+ complexes (M = Zn(II) and Cd(II)) are not emissive, since the benzylic nitrogens are weakly involved in metal coordination, and, once again, they are available for quenching the fluorescence emission. Protonation of the L2 complexes to give [MHL2]3+ species, instead, leads to a recovery of the fluorescence emission. Complex protonation, in fact, occurs on the ethylamino group and gives a marked change of the coordination sphere of the metals, with a stronger involvement in metal coordination of the benzylic nitrogens; consequently, their lone pairs are not available for the process of emission quenching.     

Structural and magnetic properties of a complete halide series of Ni(II) complexes with a pyridine-containing 14-membered macrocycle

The complete halide series of Ni(II) complexes containing the tetradentate macrocyclic ligand 3,11-dithia-7,17-diazabicyclo[11.3.1]heptadeca-1(17),13,15-triene (L), was fully characterized by X-ray diffraction. The fluoro, chloro, and bromo complexes are dinuclear species with formula [{Ni(L)}2(mu-X)2]2+ (X = halide), whereas only mononuclear species with formula [Ni(Y)(solv)(L)]n+ (Y = halide or solvent molecule), were obtained with I. To date, the fluoro derivative is the first nonorganometallic coordination compound containing the Ni(mu-F)2Ni core. The magnetic properties of these halo complexes have been studied. Intramolecular interactions were observed in the three dinuclear complexes, being antiferromagnetic in the fluoro derivative and ferromagnetic in both the chloro and bromo ones. The two iodo derivatives are paramagnetic species, as would be expected for mononuclear octahedral Ni(II) complexes. Density functional theory calculations led us to relate the magnetic behaviors of these compounds to the values of the corresponding Ni-X-Ni(i) angle. The analysis of the singly occupied molecular orbitals gave a clear comprehension of the different magnetic exchange interactions found in these Ni(II) complexes.     

Carboxyester hydrolysis catalyzed by a novel dicopper(II) complex with an alcohol-pendant macrocycle

A novel hexaaza macrocycle bearing two hydroxyethyl pendants (L), 3,6,9,16,19,22-hexaaza-6,19-bis(2-hydroxyethyl)tricyclo[22,2,2,2(11,14)]triaconta-1,11,13,24,27,29-hexaene, was synthesized as a potential binucleating ligand. The corresponding Cu(II) complex [Cu(2)LCl(2)]Cl(2) small middle dot5.5H(2)O was isolated as a blue crystal, triclinic, space group P with a= 9.4920(19) A, b = 4.783(3) A, c = 16.553(3) A, alpha = 63.87(3) degrees, beta = 86.10(3) degrees, gamma = 83.8(3) degrees, V = 2072.8(7) A(-3), Z = 2, R1 = 0.0658, and wR2 = 0.1839. Both Cu ions adopt the geometry of a distorted trigonal bipyramid in a pentacoordinated environment. A complexation study on the novel title complex has revealed that the alcoholic OH groups of the complex Cu(2)L exhibit an obvious acidity with rather low pK(a) values at 25 degrees C. The Cu(II)-bound alkoxides, which act as reactive nucleophiles toward the hydrolysis of 4-nitrophenyl acetate in 10% (v/v) CH(3)CN at 25 degrees C, with I = 0.10 (NaNO(3)) and pH 9.3, have shown a second-order rate constant, 0.41 +/- 0.02 M(-1) s(-1), a value that is approximately 10 times greater than the corresponding value for the mononuclear Cu(II) complex formed by a relatively simple tripodal ligand (L1). The pH-rate profile gave a sigmoidal curve. The possible catalytic mechanism has been proposed, and the reason for the high catalytic activity of the title complex has been discussed.     

Structure of a new trinuclear nickel(II) complex with a salen-type bisoxime ligand

A new trinuclear Ni(II) complex {[NiL(DMF)]₂(OAc)₂Ni}·2DMF (H₂L = 4,4′-dichloro-2,2′-[(1,3-propylene)dioxybis(nitrilomethylidyne)]diphenol) is synthesized and characterized by elemental analyses, IR spectra, UV-Vis spectra and X-ray crystallography. The results show that the Ni(II) complex consists of three Ni(II) ions, two tetradentate (μ-L)^2? units, two coordinated μ-acetate ions, two coordinated DMF molecules, and two crystallization DMF molecules. All hexacoordinated Ni(II) ions of the complex have a slightly distorted octahedral geometry. The crystal packing of the Ni(II) complex reveals a notable feature of this structure: the formation of an infinite supramolecular 2D layered structure by virtue of intermolecular C-H…O hydrogen bonding.     

Polyazamacrocycles VI. Homo-trimetallic copper(II) and nickel(II) complexes with a new tri-cavity macrocycle

Summary A new tri-cavity decaaza macrocycle (TCM) has been synthesised by the condensation of tetra(aminopropyl)-cyclam with diethanolamine. The new macrocyclic ligand forms tri-nuclear complexes, [Cu₃(TCM)(H₂O)₂]-(ClO₄)₆ and [Ni₃(TCM)(H₂O)₂](ClO₄)₆.     

一种含有咔唑功能基团的有机聚磷腈的合成与表征

采用传统的亲核取代反应的方法合成了一种新有含有咔唑侧基的有机磷腈高分子，并用红外、＾１Ｈ核磁、紫外、热失重、差热分析了其结构，它的玻璃化转变温度为９１．６℃，大大低于聚乙烯咔唑的玻璃化转变温度。     

Synthesis and characterization of Cd(II) macrocyclic schiff base complex with two 2-Aminoethyl pendant arms

A new pendant armed Schiff base macrocyclic complex of [CdL]²⁺, was prepared via cyclocondensation of 2,6-bis(2- formylphenoxymethyl)pyridine with branched hexaamine in the presence of Cd(II) ion. The ligand was 23-membered oxaazamacrocycle having two 2-aminoethyl pendant arms [L: 3,28-dioxa-14,17-bis(aminoethyl)-11,14,17,20,34- pentaazatetracyclo[34.3.1] tetratriacontane-1(34), 4, 6, 8, 10, 20, 22, 24, 26, 30, 32-undecaene]. The complex was investigated by IR, ¹H NMR, microanalysis and MALDI mass spectroscopy. The structure of the complex was verified by ab initio HF-MO calculations using a standard 3-21G* basis set. This article introduces an unusual seven-membered chelate ring and shows that by its using, the Cd-N bonds lengths within the macrocycle would be longer and also Cd(II)-pendant amine bonds lengths would be shorter.     

DNA-binding and cleavage studies of a dinuclear copper(II) complex with a 26-membered hexaazamacrocycle

The complex, [Cu₂LCl₂]Cl₂ · 3H₂O, where L = the macrocyclic ligand bis-p-xylylBISDIEN Schiff base, has been prepared and characterized by elemental analysis, i.r. and mass spectra. The binding of the complex with calf thymus DNA has been investigated using absorption spectroscopy, cyclic voltammetry, fluorescence spectroscopy and viscosity measurements. The results suggest that the complex can bind to CT DNA by intercalation via the aromatic ring on the macrocycle into the base pairs of DNA. The complex exhibits efficient nuclease activity.     

A new pyridine-based 12-membered macrocycle functionalised with different fluorescent subunits; coordination chemistry towards Cu(II), Zn(II), Cd(II), Hg(II), and Pb(II)

The coordination chemistry of the new pyridine-based, N2S2-donating 12-membered macrocycle 2,8-dithia-5-aza-2,6-pyridinophane (L1) towards Cu(II), Zn(II), Cd(II), Hg(II), and Pb(II) has been investigated both in aqueous solution and in the solid state. The protonation constants for L1 and stability constants with the aforementioned metal ions have been determined potentiometrically and compared with those of ligand L2, which contains a N-aminopropyl side arm. The measured values show that Hg(II) in water has the highest affinity for both ligands followed by Cu(II), Cd(II), Pb(II), and Zn(II). For each metal ion considered, 1:1 complexes with L1 have also been isolated in the solid state, those of Cu(II) and Zn(II) having also been characterised by X-ray crystallography. In both complexes L1 adopts a folded conformation and the coordination environments around the two metal centres are very similar: four positions of a distorted octahedral coordination sphere are occupied by the donor atoms of the macrocyclic ligand, and the two mutually cis-positions unoccupied by L1 accommodate monodentate NO3- ligands. The macrocycle L1 has then been functionalised with different fluorogenic subunits. In particular, the N-dansylamidopropyl (L3), N-(9-anthracenyl)methyl (L4), and N-(8-hydroxy-2-quinolinyl)methyl (L5) pendant arm derivatives of L1 have been synthesised and their optical response to the above mentioned metal ions investigated in MeCN/H2O (4:1 v/v) solutions.     

Synthesis of a new 24-membered tetramide macrocycle and X-ray crystal structure determination

The synthesis and characterization of a new 24-membered tetramide macrocycle (6) related to Leigh's macrocycles and catenanes is reported. The replacement of p-xylylenediamine (Leigh) by m-xylylenediamine (this work) strongly modifies the geometry and properties of the new macrocycle. NMR spectroscopy (in DMSO?d₆ solution) and X-ray crystallography have been used to characterize compound 6. The structural features in the crystal (conformational aspects and H-bonding) have been discussed comparatively to two similar macrocycles NEWHIJ and UJUNOC.