Accelerated Hydrolysis of p-Nitrophenyl Picolinate Catalyzed by Metallomicelle Made from a Novel Macrocyclic Polyamine Copper（Ⅱ） Complex

A copper（Ⅱ） complex 1 of a novel macrocyclic polyamine ligand with hydroxylethyl pendant groups, 4,11-bis（hydroxylethyl）-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane （L） has been synthesized and characterized. Rate enhancement for hydrolysis of p-nitrophenyl picolinate （PNPP） catalyzed by 1 was studied kinetically under Brij35 micellar condition. For comparision, the catalytic activity of corresponding copper（Ⅱ） complex 2 of non-substituted macrocyclic polyamine ligand, 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraaza-cyclotetradecane （L＇） toward the hydrolysis of PNPP was also investigated. The results indicate that the macrocyclic polyamine copper（Ⅱ） complex 1 effectively catalyzed the hydrolysis of PNPP, and the pendant ligand hydroxyl group or deprotonated pendant ligand hydroxyl group can act as catalytically active species in the reaction. A ternary Complex kinetic model involving metal ion, ligand and substrate has been proposed, and the results confirmed the reasonability of such kinetic model.     

Synthesis, Characterization and Inclusion Properties of an Iron(II) Polyimine Complex Derived from 2,6-Diacetylpyridine and an Aliphatic Polyamine

A novel multibinding species has been obtained by attaching four aliphatic polyamine chains to an iron(II)-polyimine centre, derived from 2,6-diacetylpyridine. Molecular simulations for the complex corroborate the evidence from 1H NMR spectroscopy of a symmetric structure, with the four polyamines displaying a tetrahedral arrangement around the metal centre. The protonated polyamine complex interacts with hexacyanoferrate(II) ions, leading to an inclusion compound which has been characterized based on vibrational and Mössbauer spectroscopy, and on cyclic voltammetry.     

Interaction between Bifunctional Dioxo Macrocyclic Polyamine Co(II) Complex and DNA in Metallomicellar System

Artificial enzymes are non-protein molecules that are more simple than natural enzymes, but they also possess high efficiency and specificity. In recent years, the study of enzyme models is one of the most active fields1-2, especially chemical nuclease. Micelles, dynamic colloidal aggregates formed by amphipathic surfactant molecules, can mimic the hydrophobic structure of active site of enzymes because they offer a hydrophobic microenviornment which is similar to the important part located …     

含吡啶环大环多胺的合成及其与Cu(Ⅱ)的络合行为

本文以2,6-二溴甲基吡啶和对甲苯磺酰胺钠盐合成含吡啶环大环多胺,得到了尚未见文献报道的含四个吡啶环的三十二环胺. 2,6-二溴甲基-吡啶与甲苯磺酰胺钠盐在无水乙醇回流温度下得到1,9,17,25-四甲苯磺酰基大环多胺.用浓硫酸脱去N-甲苯磺酰基化合物的甲苯磺酰基, 生成标题大环多胺化合物. 配体与Cu(Ⅱ)的络合由紫外吸收光谱测定. 实验结果表明配体确与Cu^2^+以1:2络合成为双核络合物.     

Interactions of cadmium(II) ions with adenosine as well as adenosine-5′-monophosphate and diamine or triamines in the ternary systems

The mode of coordination in complexes formed in the systems Cd(II)/Ado/di- or triamine and Cd(II)/AMP/di- or triamine has been established on the basis of the equilibrium and spectral investigation. The overall stability constants (log?β) and equilibrium constants of formation (log?K _e) of the complexes formed in the above systems have been determined. In the species, the main interaction centres are the nitrogen atoms N(1) or N(7) of the purine ring of Ado and AMP, while in the nucleotide also the oxygen atoms of the phosphate group and donor nitrogen atoms of the polyamine (PA) molecule. The effect of polyamine on the coordination dichotomy has been ascertained. For example, the presence of polyamine in the ternary system is responsible for involvement of only N(7) of the nucleoside in the metallation in Cd(Ado)H(Put), while in the binary system Cd(II)/Ado, the N(1)/N(7) dichotomy occurs in the whole pH range studied. Polyamine can also affect the character of the phosphate group of the nucleotide. The phosphate group, inactive in the binary system Cd(II)/AMP, after introduction of the polyamine becomes engaged in the interactions, e.g. in the complex Cd(AMP)H(dien). In Cd(AMP)H(en) and Cd(AMP)H(Put) no participation of the oxygen atom of the phosphate group has been found. This group is involved in weak interactions with a protonated amine group PA located in the outer coordination sphere. On the other hand, in the Cd(AMP)H(3,3-tri) complex the phosphate group is the only site of Cd(II) bonding. In this species the donor nitrogen atoms N(1) and N(7) of the nucleotide are outside the inner coordination sphere and involved in noncovalent interactions with protonated amine group from 3,3-tri.     

Photoremovable NPEC group compatible with Ns protecting group in polyamine synthesis

Herein, we disclose an efficient combination of NPEC and Ns protecting groups in the synthesis of polyamine, by showing the orthogonal reactivity using N-NPEC-N-Ns alkylamines prepared from NPEC-NHNs. Selective photodeprotection of NPEC group in 12-mer polyamine and the complex conjugate has been further demonstrated toward the synthesis of novel polyamine natural product protoaculeine B.     

Cadmium(II) and Mercury(II) Complexes in Ternary Systems with Cytidine and Diamines or Triamines

The mode of coordination of complexes formed in the systems Cd(II) or Hg(II)/cytidine/di- or triamine is proposed on the basis of equilibrium and spectroscopic studies. Mercury(II) binds much more strongly to cytidine and polyamine (PA) than cadmium. It was found from equilibrium and 13 C NMR studies that in the Hg(II) and Cd(II)/ Cyd /di- or triamine complexes, metallation mainly involves the N(3) atom of the pyrimidine base of the nucleoside and m NH x + groups from PA. In MLL' complexes of both metals with diamines, all available donor nitrogen atoms of the polyamine are involved in coordination. In analogous systems with triamines, interaction of all nitrogen atoms is observed for Cd(II) systems as well as in the Hg( Cyd )(2,3- tri ) species. Only two nitrogen atoms of the polyamine coordinate in ternary Hg(II) complexes with dien, 3,3-tri and Spd .     

Application of emulsion liquid membranes to recover cobalt ions from a dual-component sulphate solution containing nickel ions

Emulsion liquid membranes (ELMs) containing 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC-88A) have been applied to recover cobalt II ions from a dilute sulphate solution containing equal amounts of nickel II ions (0.16 g/l). We focused on the study to develop an effective technique to recover cobalt as a target metal. It is found that polyamine (PX 100) membranes allow better permeation rates of cobalt ions than sorbitan monooleate (Span 80) membranes. The separation factor (β_Co/Ni) in polyamine membranes averaged 70 at a carrier concentration of 12 mol/m³ and feed solution pH 5.5. The permeation rate of Co II was found to increase proportionately with feed pH while for Ni II it decreased substantially at pH above 5.5 indicative of slower interfacial reaction rate. We found that short contact time (4–6 min) of feed solution and emulsion improved separation factor (β_Co/Ni) at feed pH above 5.5 and also minimized chances of emulsion break up. We have also observed that Span 80 membranes are hydrolyzed readily in a moderate acidic sulphate solution (pH 4.0–5.5) to form viscous gels. Results have shown that excess carrier [(HR)₂] affects the stability of emulsion and thus the separation factor. The critical ratio of carrier to emulsifier [(HR)₂]/[C_sf] was found to be approximately 0.5. This paper concludes with a discussion on the prospects of ELM system in practical use.     

Equilibrium and spectroscopic studies of ternary cadmium(II) and mercury(II) complexes with CMP and triamines

Formation of ternary Cd(II) and Hg(II) complexes with cytidine 5′-monophosphate (CMP) and triamines has been studied. Complexes M(CMP)(H _x PA) and M(CMP)(PA) (M?=?Cd, Hg; PA?=?polyamine) were detected and overall stability constants and equilibrium constants for their formation determined. The mode of coordination in the complexes has been proposed on the basis of the equilibrium and ¹³C, ³¹P NMR and IR studies. In the Hg(II) systems, metalation involves the donor endocyclic N(3) atom, the CMP phosphate group and nitrogen donor atoms of PA. Relative to the Hg/CMP binary systems, the presence of a polyamine in ternary systems does not change the metal–nucleotide mode of coordination. In ternary systems including Hg(II) ions, the occurrence of noncovalent interactions has not been detected. Cd(II) ions form molecular complexes as well as protonated species. Introduction of a polyamine to the Cd/CMP system changes the coordination mode of the nucleotide. The phosphate group of CMP is inactive in binary complexes (metalation by the N(3) atom) but is involved in coordination in heteroligand species. In contrast to other polyamines studied, in the system including 1,7-diamino-4-azaheptane (3,3-tri), the phosphate group of CMP in Cd(CMP)(H3,3-tri) does not participate in metalation but is engaged in intramolecular noncovalent interactions that stabilize the complex.     

Binuclear schiff base complex of cobalt(II) linked by m-phthaloyl as a bridging group

A binuclear cobalt(II) complex with an unsymmetrical quadridentate Schiff base linked by m-phthaloyl was prepared and characterized. The complex formed both 1:1- and 2:1-type oxygenated species in a benzene solution containing 1% of pyridine at room temperature. Although the mononuclear cobalt(II) complex did not significantly catalyze the auto-oxidation of N,N,N′,N′-tetramethyl-p-phenylenediamine, the reaction was catalyzed by the binuclear cobalt(II) complex.     

Metal complexes of mercaptoamines—II: New assignment of the structure of bis(β-mercaptoethylamine)nickel(II) and related compounds

A cis-geometry was proposed for the green complex bis(β-mercaptoethylamine) nickel(II) on the basis of its reactivity, IR spectroscopy and orbital geometry considerations. The crystal and molecular structure of this complex has been determined by X-ray diffraction and shows that the complex has a trans geometry. The crystal structure consists of trans-NiL₂ molecules strongly linked through NH-S hydrogen bonds. Electronic and IR spectroscopy, and powder X-ray analysis are in agreement with the same trans geometry for the complexes bis(β-mercaptoethylamine)palladium(II) and bis-(γ-mercaptopropylamine)nickel(II). As a result of the new assignment of the structure of these complexes some concepts, such as its reactivity with nickel(II), are reconsidered.     

Competitive Complexation by Ligand and Solvent: Polarographic Characterization of ATRP Catalyst Polyamine–Copper Complexes in Acetonitrile + Water Mixed Solvents

In the Atom Transfer Radical Polymerization (ATRP) technique, the suggested polymerization scheme is pivoted by a metal complex acting as a redox catalyst able to coordinate with the incipient radicals. The development of an a priori criterion of choice of the best (complex + solvent) combination is one of the current topics in this field. In this context we performed polarographic investigations on copper complexes with multidentate amino ligands (TMEDA and Me₆TREN, plus acetonitrile as a reference) in water and in water + acetonitrile mixed solvents. In the latter case we took into account the competition between the co-solvent acetonitrile [a weaker ligand, but concentrated, selectively stabilizing Cu(I)], and the polyamine [a stronger ligand, but diluted, preferentially stabilizing Cu(II)], achieving further stabilization of the complexed copper, with a narrow potential range of stability as Cu(I), which is modulated through the acetonitrile/polyamine ratio. An interpretative scheme is presented.     

Synthesis, Crystal Structure and Properties of Polyamine Copper(II) Complexes

Two polyamine copper(II) complexes were synthesized by the reaction between N,N,N′,N′-tetrakis(2′-aminoethyl)propane-1,2-diamine hexahydrochloride and copper(II) perchlorate under almost the same conditions except for reaction temperature. The crystal structures of two complexes were determined by X-ray diffraction techniques, which shows that one of the complexes is unexpected and is a double chlorine or chloride-bridged dinuclear copper(II) complex formed by two diethylenetriamines, and another is a pentadentate mononuclear copper(II) complex composed of homo-protonated N,N,N′,N′-tetrakis(2′-aminoethyl)propane-1,2-diamine. The mechanism of the reaction leading to form the unexpected complex was discussed. The UV-visible spectra and cyclic voltammogram of the complexes were measured.     

Tailoring of new Ni(II), Hg(II) and UO2(II)–hydrazide complexes: characterization,studies in-vitro and in-silico as well as the Hartree-Fock modeling

A new hydrazide ligand was prepared to synthesize Ni(II), Hg(II) and UO₂(II) complexes, which elucidated by all possible tools. Accordingly, 1M:2L molar ratio was suggested for Ni(II) and Hg(II) complexes, while UO₂(II) complex close to 1:1 ratio. The ligand binds as a bidentate or tridentate mode either as a monobasic via deprotonation of azomethine group or as a neutral with Hg(II) complex. A square-planer geometry was suggested for [Ni(L)₂], while the other complexes reveal octahedral geometry. The antimicrobial screening was performed as well as the antioxidant and cytotoxic activity test towards Ehrlich ascites cells. The ligand and its Ni(II) complex produce a notable inhibition for microorganisms, while their antioxidant and cytotoxicity are up to the standards themselves. The DFT/B3LYP and Hartree-Fock (HF) methods were used to optimize the structures under suitable basis sets to obtain essential parameters and 3D-maps. Utilizing Swiss-ADME link reveals the positive response of the ligand to blood brain barrier and human intestinal absorption. Moreover, other silico tests were performed via Pharmacophore and Molecular Operating Environmental module (MOE) against different proteins. Finally, the agreement between vitro and silico results was noticed with the ligand and its Ni(II)complex.     

A dizinc complex for selective fluorescence sensing of uridine and uridine-containing dinucleotides

A dizinc complex with a polyamine macrocycle is able to selectively bind and sense uridine (U) as well as the uridine-containing ribodinucleotides U(3'-5')pU and U(3'-5')pA, thanks to an exciplex emission arising from a pi-stacked complex involving the dipyridine unit and Zn(II)-bound uridine moieties.     

Spectroscopy of Ni(II) and Zn(II) tetra(p-vinylphenyl) porphyrin: Aggregation characteristics and luminescence properties

Concentration effects on the absorption and emission properties of Ni(II) and Zn(II) tetra(p-vinylphenyl) porphyrins have been studied in benzene solutions. Whereas exciton splitting of the Soret band is observed for the Ni(II) complex, only a hypochromic effect is observed for the Zn(II) complex. The exciton parameters calculated for the Ni(II) complex are: U = 710 ± 40 cm⁻¹, θ = 78 ± 2° and R = 4.5 ± 0.3 Å. Fluorescence is observed only for the Zn(II) complex. The 77 K spectrum is red shifted compared with the room temperature spectrum.     

Crystal Structure and Thermal Property of a Binuclear Manganese(II) Sulfate Complex with Carbohydrazide

The binuclear manganese(II) complex of formula [Mn₂(CHZ)₂(H₂O)₂(SO₄)₂] (CHZ = carbohydrazide) (1) has synthesized in aqueous solution and characterized by elemental analysis, IR, and single crystal X-ray diffraction. The compound 1 crystallizes in monoclinic system, space group P2(1)/n, a = 7.083(1) Å, b = 7.985(1) Å, c = 14.045(2) Å, β = 90.46(1)^°, V = 794.42(16) ų, Z = 2, R = 0.0308 with 1481 reflections. In the title complex, two Mn(II) cations are bonded via the bridging oxygen atoms into a centrosymmetric dimeric unit. The Mn(II) dimers are further extended into layers by means of the bridging sulfate groups. Each Mn atom in the complex is in bivalent state with a distorted pentagonal bipyramid configuration and has a N₂O₅ donor set which consists of two nitrogen atoms and five oxygen atoms provided by the ligands of two CHZ molecules, one water molecule, and two sulfate ions. The CHZ tridentate ligands are coordinated with adjacent Mn(II) cation via two terminal N atoms and the carbonyl O atom and sulfate anions act as bidentate bridge ligand. Four kinds of Mn(II) CHZ complex structures are compared. The thermal property of title complex was studied by using DSC and TG-DTG techniques. The results exhibit the title complex is highly stable.     

Synthesis,characterization, crystal structure and catalytic property of [Cu(SalAHE)2] (SalAHE = salicylaldehydeimine-1-hydroxyethane) complex for the oxidation of 3,5-di-tert-butylcatechol

The crystal structure, spectroscopic properties and catalytic property of the copper(II) complex, prepared by the reaction between copper(II) diacetate with the bidentate Schiff base, SalAHE (SalAHE = salicylaldehydeimine-1-hydroxyethane), are reported. This complex is able to oxidize 3,5-di-tert-butylcatechol to the respective o-quinone. The oxidation reaction was studied in CH₃CN with molecular oxygen at 0, 5, 15 and 25 °C. The progress of the catalytic reaction was followed by gas chromatographic analyses (GC).     

Electrochemistry of microparticles of tris (2,2′-bipyridine) ruthenium(II) hexafluorophosphate

The electrochemical behaviour of tris(2,2′-bipyridine)ruthenium(II) hexafluorophosphate (Ru(II)) microparticles, immobilised on a graphite electrode and adjacent to an aqueous electrolyte solution, has been studied by cyclic voltammetry and an in situ spectroelectrochemical technique. The solid Ru(II) complex exhibits one reversible redox couple with a formal potential (E_f) of 1.1 V versus Ag¦AgCl. The continuous cyclic voltammetric experiments showed that the Ru(II) microparticles are stable during the electrochemical conversions. The in situ spectroelectrochemical study showed that the absorbance at 463 nm decreased due to the oxidation of Ru(II) to Ru(III). Upon reduction, the growth of absorbance at 463 nm was observed due to the formation of Ru(II) complex and this process was reversible.     

Catalytic hydrolysis of phosphate diester （BNPP） and plasmid DNA by mononuclear macrocyclic polyamine metal complexes

The activities of the catalytic hydrolysis of phosphate diester(BNPP)[bis(p-nitrophenyl)phosphate diester]and plasmid DNA (pUC18)by mononuclear macrocyclic polyamine metal complexes have been investigated in this paper.The results showed that the highest activity in hydrolysis of BNPP was obtained with 1e-Zn(Ⅱ)complex(composed of lipophilic group)as catalyst.The hydrolysis rate enhancement is up to 3.64×10~4 fold.These metal complexes could effectively promote the cleavage of plasmid DNA(pUC18)at physiol...