Kinetics of the interaction of ninhydrin with the [Ni(II)–histidine]+ complex in water and surfactant micelles

Kinetics of the condensation reaction of ninhydrin and the [Ni(II)–histidine]⁺ complex has been studied spectrophotometrically at pH 5.0, both in aqueous and aqueous–cationic micelles of cetyltrimethylammonium bromide (CTAB). The same product was obtained in both the media. The results obtained in the micellar medium are treated quantitatively in terms of the kinetic pseudo‐phase and Piszkiewicz models. The rate constants, binding constants with the micelles, and the index of cooperativity have been evaluated. On the basis of observed data a possible mechanism has been proposed. The same product was obtained in nonionic micelles of TX‐100, but the studies were hampered due to the appearance of turbidity, whereas anionic micelles of sodium dodecyl sulphate did not catalyze the reaction. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 47–54, 1999     

Micellar effects on the rates of the condensation reaction between copper(II)‐histidine complex and ninhydrin

The kinetics of formation of N‐diketohydrindylidenehistidinatocopper(II) complex has been investigated in the presence of cationic cetyltrimethylammonium bromide (CTAB) surfactant in aqueous medium (pH = 5.0). Similarly in aqueous solution, the reaction followed irreversible first‐order kinetics with respect to [Ninhydrin]. Although the reaction mechanism remained unaltered by micelles, a typical k_ψ‐[CTAB] profile was observed, that is, with a progressive increase in [CTAB], the reaction rate increased, reached a maximum value, and then decreased. The results are treated quantitatively in terms of the kinetic pseudo‐phase model. Activation parameters were also evaluated and a large decrease in ΔS^# shows the formation of a well‐structured activated complex. It was found that anionic sodium dodecyl sulphate (SDS) and non‐ionic Triton X‐100 (TX‐100) surfactants have no effect on the reaction. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 729–736, 1999     

Synthesis and Crystal Structure of Dissymmetrical Double Schiff Base Cu（Ⅱ） Homobinuclear and Cu（Ⅱ）-Mg（Ⅱ）-Cu（Ⅱ） Heterotrinuclear Complexes

Homobinuclear complex （HCuL）2 （1） （H3L： N-3-carboxylsalicylidene-N＇-salicylaldehyde-1,2-diaminoethane） was obtained from self-organization of the reported complex HCuL, and its crystal structure was determined through X-ray diffraction at room temperature. The crystal of complex 1 belongs to monolinic system, the space group Cc, a=2.5326（5） nm, b=0.88861（18） nm, c=1.3738（3） nm, β=96.95（3）°, Z=4, R1=0.0520, wR2=0.1185. （HCuL）2 is a dimeric molecule and has extended phenolic oxygen-bridged structure. In addition, using mononuclear complex HCuL as building blocks, Cu（Ⅱ）-Mg（Ⅱ）-Cu（Ⅱ） heterotrinuclear complex 2 was synthesized, and its crystal structure also has been determined by X-ray analysis. The crystal of complex 2 is of monoclinic system, space group Pc, a=1.1816（2） nm, b=1.5599（3） nm, c=1.9642 （4） nm, β=98.22°, Z=2, R1=0.0701, wR2=0.1498. Each dissymmetricai cell unit of complex 2 contains two heterotrinucler neutral molecules： {[CuL（H2O）]Mg[CuL（CH3OH）]} and {[CuL]Mg[CuL（H2O）]}.     

Synthesis,crystal structure and infrared spectra of Cu(II) and Co(II) complexes with 4,4′‐dichloro‐2,2′‐[ethylene dioxybis(nitrilomethylidyne)]diphenol

Novel 4,4′‐dichloro‐2,2′‐[ethylenedioxybis(nitrilomethylidyne)]diphenol (H₂L) and its complexes [CuL] and {[CoL(THF)]₂(OAc)₂Co} have been synthesized and characterized by elemental analyses, IR, ¹H‐NMR and X‐ray crystallography. [CuL] forms a mononuclear structure which may be stabilized by the intermolecular contacts between copper atom (Cu) and oxygen atom (O3) to form a head‐to‐tail dimer. In {[CoL(THF)]₂(OAc)₂Co}, two acetates coordinate to three cobalt ions through Co? O? C? O? Co bridges and four µ‐phenoxo oxygen atoms from two [CoL(THF)] units also coordinate to cobalt ions. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthese und Strukturen von [Cu8As3(AsSiMe3)2(dppb)4]+‐[Cu{As2(SiMe3)2}{As4(SiMe3)4}]‐, [Cu8As3(AsSiMe3)2(dppb)4]+‐[Cu{As(SiMe3)2}2]‐ und [Cu10(Sb3)2(SbSiMe3)2(dppm)6]

The reaction of CuCl, LiAs(SiMe₃)₂ and dppb (Bis(diphenylphosphino)butane) leads to the formation of ionic cluster complexes. Depending on the reaction conditions one can isolate [Cu₈As₃(AsSiMe₃)₂(dppb)₄]⁺[Cu{As₂(SiMe₃)₂}{As₄(SiMe₃)₄}]^‐ ( 1 ) and [Cu₈As₃(AsSiMe₃)₂(dppb)₄]⁺[Cu{As(SiMe₃)₂}₂]^‐ ( 2 ). The same reaction of CuCl, dppm (Bis(diphenylphosphino)methane) and LiSb(SiMe₃)₂ leads to the neutral cluster complex [Cu₁₀(Sb₃)₂(SbSiMe₃)₂(dppm)₆] ( 3 ). The structures of 1‐3 have been solved by X‐ray single crystal analyses.     

catena‐Poly[hexaaquamagnesium(II) [bis(μ3‐5‐nitro‐2‐oxidoisophthalato)dicopper(II)] dihydrate]

In the centrosymmetric dinuclear anions of the title bimetallic complex, {[Mg(H₂O)₆][Cu₂(C₈H₂NO₇)₂]·2H₂O}_n, each Cu^II ion is strongly coordinated by four O atoms in a distorted square‐planar geometry. Two of these O atoms belong to phenolate groups and the other two to carboxylate groups from 5‐nitro‐2‐oxidoisophthalate (L1) trianions, derived from 5‐nitrobenzene‐1,2,3‐tricarboxylic acid (O₂N–H₃L). The phenolate O atoms bridge the two Cu^II ions in the anion. In addition, each Cu^II cation interacts weakly with a symmetry‐related carboxylate O atom of an adjacent L1 ligand, giving a square‐pyramidal coordination geometry. The copper residue forms a ladder‐like linear coordination polymer via L1 ligands. The [Mg(H₂O)₆]²⁺ cations sit on centres of inversion. The polymeric anions, cations and free water molecules are self‐assembled into a three‐dimensional supramolecular network via O—H...O hydrogen bonds.     

Cu(II)‐promoted cyclization of hydrazonophthalazine to triazolophthalazine; Synthesis and structure diversity of six novel Cu(II)‐triazolophthalazine complexes

A novel route for the synthesis of Cu(II)‐triazolophthalazine complexes using the Cu(II)‐promoted cyclization dehydrogenation reactions of hydrazonophthalazines under reflux was presented. Two hydrazonophthalazines were cyclized to the corresponding triazolophthalazine ligands, 3‐pyridin‐2‐yl‐3,10b‐dihydro‐[1,2,4]triazolo[3,4‐a]phthalazine ( TPP ) and 3‐(3,10b‐dihydro‐[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐benzoic acid ( TP3COOH ), followed by in situ complexation with Cu(II) yielding six novel Cu(II)‐triazolophthalazine complexes depending on the reaction conditions. The molecular and supramolecular structures of the Cu(II)‐triazolophthalazine complexes were discussed. The metal sites have rectangular pyramidal geometry in the [Cu(TPP)Cl₂]₂; 1 and [Cu(TP3COOEt)Cl₂(H₂O)]₂; 4 dinuclear complexes, distorted square planar in [Cu(TP3COOMe)₂Cl₂]; 3 , [Cu(TP3COOH)₂Cl₂]; 5 and [Cu(TP3COOH)₂Cl₂]·H₂O; 6 and a distorted octahedral in [Cu(TPP)(H₂O)₂(NO₃)₂]; 2 . Hirshfeld analysis showed that the O…H, C…H, Cl…H (except TP3COOH and 2 ), N…H and π‐π stacking interactions are the most important intermolecular contacts. The π‐π stacking interactions are the maximum for TP3COOH and complex 6 with net C…C/C…N contacts of 19.4% and 15.4%, respectively. The orbital–orbital interaction energies of the Cu‐N/Cu‐Cl bonds correlated inversely with the corresponding Cu‐N/Cu‐Cl distances, respectively. The charge transfer processes between Cu(II) and ligand groups were also discussed. The charge densities of the Cu(II) centers are reduced to 0.663–0.995 e due to the interactions with the ligand groups coordinating it.     

The [B3(NN)3]+ and [B3(CO)3]+ Complexes Featuring the Smallest π‐Aromatic Species B3+

We report the spectroscopic identification of the [B₃(NN)₃]⁺ and [B₃(CO)₃]⁺ complexes, which feature the smallest π‐aromatic system B₃⁺. A quantum chemical bonding analysis shows that the adducts are mainly stabilized by L→[B₃L₂]⁺ σ‐donation.     

Synthesis,Spectral, Thermal and Biological Studies of Mn(II), Co(II), Ni(II) and Cu(II) Complexes with 1‐(((5‐Mercapto‐1H‐1,2,4‐triazol‐3‐yl)imino)‐methyl)naphthalene‐2‐ol

Mn(II), Co(II), Ni(II) and Cu(II) complexes of 5‐mercapto‐1,2,4‐triazol‐3‐imine‐2′‐hydroxynaphthaline have been synthesized and characterized by elemental analysis, IR, ¹H NMR, EI‐mass, UV‐Vis, and ESR (electron spin resonance) spectra, molar conductance, magnetic moment measurements, DC conductivity and thermogravimetric analysis. IR spectra confirm that the ligand molecule existed in both thione and thiole forms. The molar conductance values indicate the complexes are nonelectrolyte. The magnetic moment values of the complexes display paramagnetic behavior. All studies confirm the formation of an octahedral geometry for complex 1 and the other complexes have tetrahedral geometrical structures. The structures of the complexes have also been theoretically studied by using the molecular mechanic calculations by the hyperchem. 8.03 molecular modeling program which confirm the proposed structures. The Schiff‐base ligand and its metal complexes have also been screened for their antimicrobial activities.     

The σ‐Aromatic Clusters [Zn3]+ and [Zn2Cu]: Embryonic Brass

The triangular clusters [Zn₃Cp*₃]⁺ and [Zn₂CuCp*₃] were obtained by addition of the in situ generated, electrophilic, and isolobal species [ZnCp*]⁺ and [CuCp*] to Carmona’s compound, [Cp*Zn? ZnCp*], without splitting the Zn? Zn bond. The choice of non‐coordinating fluoroaromatic solvents was crucial. The bonding situations of the all‐hydrocarbon‐ligand‐protected clusters were investigated by quantum chemical calculations revealing a high degree of σ‐aromaticity similar to the triatomic hydrogen ion [H₃]⁺. The new species serve as molecular building units of Cu_nZn_m nanobrass clusters as indicated by LIFDI mass spectrometry.     

原位水热合成的二(2,4-二(对硝基苯)-1,3,5-环戊二烯铜配合物的实验和理论研究

以4-硝基对苯腈,氨水和铜盐反应于在原位水热条件下合成了二（2,4-二（对硝基苯）-1,3,5-环戊二烯铜配合物,通过单晶X射线衍射,元素分析,红外,核磁光谱和热重分析等手段对其进行了表征。结构分析表明,铜与四个源自原位合成的配体上的氮原子配位形成平面四边形构型。基于密度泛函的理论计算对配合物的热力学稳定性进行了阐释。     

Synthesis,characterization, DNA interaction,apoptosis and molecular docking of Cu(II) and Mn(II) complexes with endo‐norbornene‐cis‐5,6‐dicarboxylic acid

Two new novel complexes, [Cu₄(Endc)₄(phen)₄]⋅7(H₂O)⋅2(O) and [Mn₂(Endc)₂(phen)₂(H₂O)₂]⋅(H₂O) (phen =1,10‐phenanthroline, H₂Endc = endo ‐norbornene‐cis ‐5,6‐dicarboxylic acid), were synthesized and structurally characterized using IR and ¹H NMR spectroscopies, elemental analysis and single‐crystal X‐ray diffractometry. Their reactivity with calf thymus DNA and HeLa cell DNA was measured using UV absorption and fluorescence spectroscopies. The results indicated that these complexes can bind to DNA with different binding affinity. Gel electrophoresis assay demonstrated the ability of the complexes to cleave pBR322 plasmid DNA. Apoptotic study showed that the complexes exhibit significant cancer cell inhibitory rates. Eventually, the complexes can suitably dock with a special DNA (PDB ID: 1AIO).     

catena‐Poly[copper(II)‐di‐μ‐acetylacetonato‐copper(II)‐bis(μ‐4‐hydroxy‐3‐methoxybenzaldehyde picoloylhydrazonato)] and (acetylacetonato)(4‐methoxybenzaldehyde picoloylhydrazonato)copper(II)

In the two title copper(II) complexes, [CuL(C₅H₇O₂)]_n, (I), and [CuL′(C₅H₇O₂)], (II), respectively, where HL is 4‐hydroxy‐3‐methoxybenzaldehyde picoloylhydrazone, C₁₄H₁₂N₃O₃, and HL′ is 4‐methoxybenzaldehyde picoloylhydrazone, C₁₄H₁₂N₃O₂, the Cu^II ions display a highly Jahn–Teller‐distorted octahedral and a square‐planar coordination geometry, respectively. In complex (I), two neighbouring Cu^II atoms are bridged by L⁻ and acetylacetonate, alternately, giving rise to a one‐dimensional chain of CuN₂O₄ octahedra interconnected by these two ligands along the a axis. In addition, the hydroxy H atom of the vanillin group connects to the carboxyl O atom of the adjacent chain via an O—H...O hydrogen bond, giving rise to a three‐dimensional supramolecular assembly. Complex (II) displays a discrete structure.     

Poly[diaquabis(μ3‐2,2‐dimethylpropanedioato)calcium(II)copper(II)]

The title complex, [CaCu(C₅H₆O₄)₂(H₂O)₂]_n, is the first heterobimetallic complex based on a substituted malonate dianion. The Cu^II cation and two independent 2,2‐dimethylmalonate (or 2,2‐dimethylpropanedioate) dianions build up a robust dianionic [Cu(C₅H₆O₄)₂]²⁻ complex, which acts as a building block to coordinate to four Ca²⁺ cations. Each Cu^II centre is in a four‐coordinate square plane of dimethylmalonate O atoms, while each Ca^II atom is in an eight‐coordinate distorted bicapped trigonal–prismatic environment of six O atoms from four different dimethylmalonate groups and two water molecules. This arrangement creates a two‐dimensional layer connectivity of the structure. The dianionic [Cu(C₅H₆O₄)₂]²⁻ units are involved in different intermolecular hydrogen‐bonding interactions with water molecules via the formation of hydrogen‐bonded rings of graph sets R₁²(8) and R(6) within this layer. The crystal was nonmerohedrally twinned by rotation about [011] with a major twin volume fraction of 0.513 (3).     

Anti‐proliferative activity of newly synthesized Cd(II), Cu(II), Zn(II),Ni(II), Co(II), VO(II), and Mn(II) complexes of 2‐((4,9‐dimethoxy‐5‐oxo‐5H‐furo[3,2‐g]chromen‐6‐yl)methylene) hydrazinecarbothioamide on three human cancer cells

Thiosemicarbazone ligand, 2‐((4,9‐dimethoxy‐5‐oxo‐5H‐furo[3,2‐g]chromen‐6‐yl)methylene) hydrazinecarbothioamide and its Cd(II), Cu(II), Zn(II), Ni(II), Co(II), VO(II), and Mn(II) complexes have been prepared and characterized by various spectroscopic and analytical techniques. Complexes molar conductance measurements displayed that all complexes (2–8) are non‐electrolyte. With general composition [M(H₃L)(CH₃COO)₂H₂O].nH₂O, where M = Cd(II), Cu(II), Zn(II), Ni(II), Co(II) and Mn(II) while complex (8) has [VO(H₃L)(SO₄)H₂O].2H₂O formula. Based on analytical and spectral measurements, the octahedral or distorted octahedral geometries suggested for complexes. Ligand and complexes anti‐proliferative activities were assessed against three various human tumor cell lines including breast cancer (MCF‐7), liver cancer (HepG2) and lung cancer (A549) using SRB fluorometric assay and cis‐platin as positive control. The anti‐proliferative activity result indicated that the ligand and its complexes have considerable anti‐proliferative activity analogous to that of ordinarily utilized anti‐cancer drug (cis‐platin). They do their anti‐cancer activities by modifying free radical's generation via raising the superoxide dismutase activity and depletion of intracellular reduced glutathione level, catalase, glutathione peroxidase activities, escorted by highly generation of hydrogen peroxide, nitric oxide and other free radicals leading to tumor cells death, as monitoring by decreasing the protein and nucleic acids synthesis.     

Poly[tetraaquadi‐μ4‐malonato‐barium(II)zinc(II)]

The title complex, [BaZn(C₃H₂O₄)₂(H₂O)₄]_n, is polymeric, due to the connectivity brought about by each malonate dianion bonding to two different Zn^II cations and two different Ba^II cations. The Ba^II cations, on crystallographic twofold axes, have slightly distorted square‐anti­prismic coordination, with Ba—O distances ranging from 2.795 (2) to 2.848 (2) Å. The Zn^II cations, which lie on crystallographic centres of symmetry, have distorted octa­hedral coordination, with Zn—O bonds in the range 2.0364 (19)–2.3248 (18) Å. The water mol­ecules participate in extensive O—H⋯O hydrogen bonding. The structure comprises alternating layers along [100], with one type containing Zn^II cations and malonate dianions, while the other is primarily composed of Ba^II cations and water mol­ecules.     

Cu(II) and Ni(II)‐1,10‐phenanthroline‐ 5,6‐dione‐amino acid ternary complexes exhibiting pH‐sensitive redox properties

Syntheses, and electrochemical properties of two novel complexes, [Cu(phendio)(L ‐Phe)(H₂O)](ClO₄) ·H₂O (1) and [Ni(phendio)(Gly)(H₂O)](ClO₄)·H₂O (2) (where phendio = 1,10‐phenanthroline‐5,6‐dione, L ‐Phe = L ‐phenylalanine, Gly = glycine), are reported. Single‐crystal X‐ray diffraction results of (1) suggest that this complex structure belongs to the orthorhombic crystal system. The electrochemical properties of free phendio and these complexes in phosphate buffer solutions in a pH range between 2 and 9 have been investigated using cyclic voltammetry. The redox potential of these compounds is strongly dependent on the proton concentration in the range of ? 0.3–0.4 V vs SCE (saturated calomel reference electrode). Phendiol reacts by the reduction of the quinone species to the semiquinone anion followed by reduction to the fully reduced dianion. At pH lower than 4 and higher than 4, reduction of phendio proceeds via 2e^?/3H⁺ and 2e^?/2H⁺ processes. For complexes (1) and (2), being modulated by the coordinated amino acid, the reduction of the phendio ligand proceeds via 2e^?/2H⁺ and 2e^?/H⁺ processes, respectively. Copyright © 2006 John Wiley & Sons, Ltd.