DNA-binding and photocleavage studies of metallofluorescein–porphyrin complexes of zinc(II) and copper(II)

The DNA-binding behaviors of the fluorescein?Cporphyrinatozinc(II) complex Zn(Fl-PPTPP) (Fl-PPTPP?=?5-(4-fluoresceinpropyloxy)phenyl-10,15,20-triphenylporphyrin) and fluorescein?Cporphyrinatocopper(II) complex Cu(Fl-PPTPP) with calf thymus DNA (CT-DNA) were investigated by UV?CVis absorption titrations, fluorescence spectra, viscosity measurements, thermal denaturation and circular dichroism. The results suggest that both complexes interact with CT-DNA by intercalation. In addition, their photocleavage reactions with pBR322 supercoiled plasmid DNA were investigated. Both complexes exhibit significant DNA cleavage activity, and singlet oxygen may play an important role in these reactions.     

Soft template synthesis in copper(II)–dithiooxamide–methanal,copper(II)–dithiooxamide–ethanal and copper(II)–dithiooxamide–propanone triple systems in a copper(II)hexacyanoferrate(II) gelatin-immobilized matrix

Novel complexing processes in the Cu^II–dithiooxamide–methanal, Cu^II–dithiooxamide–ethanal and Cu^II–dithiooxamide–propanone triple systems proceeding under specific conditions, to copper(II)hexacyanoferrate(II) gelatin-immobilized matrix systems in contact with aqueous-alkaline (pH 12) solutions containing dithiooxamide and methanal, ethanal or propanone, have been studied. It has been shown that template synthesis leading to the formation of macrocyclic coordination compounds (2,8-dithio-3,7-diaza-5-oxanonandithioamide-1,9)copper(II), (2,8-dithio-3,7-diaza-4,6-dimethyl-5-oxanonandithio-amide-1,9)copper(II) and (4,4,6-trimethyl-2,8-dithio-3,7-diazanonen-6-dithioamide-1,9)copper(II), respectively, takes place under such conditions. Dithiooxamide, methanal, ethanal and propanone act as ligand synthons in these processes.     

Copper(II)–8-mercaptoquinoline,copper(II)–5,8-dimercaptoquinoline and copper(II)–5-thiomethyl-8-mercaptoquinoline complexing in a copper(II)hexacyanoferrate(II) gelatin-immobilized matrix

Novel complexing processes in the Cu^II–8-mercaptoquinoline, Cu^II–5,8-dimercaptoquinoline and Cu^II–5-thiomethyl-8-mercaptoquinoline systems proceeding in the copper(II)hexacyanoferrate(II) gelatin-immobilized matrix in contact with aqueous solutions of the ligands indicated, have been studied. Under the conditions specified for complexing in the Cu^II–8-mercaptoquinoline system, only a monomeric water-insoluble coordination compound was formed. In the Cu^II–5,8-dimercaptoquinoline system, three coordination compounds were formed and, in the Cu^II–5-thiomethyl-8-mercaptoquinoline system, two such compounds were formed. Conversely, complexing in solution or solid phase results in the formation only coordination compounds in each of the system studied.     

Ferromagnetic copper(II)–copper(II) interaction in a single chlorido and dicyanamido bridged mixed–valence copper(I/II) 2-D polymer generated by in situ partial reduction of copper(II)

A mixed-valence 2-D Cu(I/II) complex, [{Cu(II)(dmen)(μ-Cl)(μ_1,5-dca)}{Cu(I)(μ_1,5-dca)}]_n (1) (dmen = N,N-dimethylethylenediamine, dca = dicyanamide = [N(CN)₂]^?), has been synthesized by in situ partial reduction of Cu(II) to Cu(I) using benzoin (2-hydroxy-1,2-di(phenyl)ethanone) as reductant. Complex 1 was characterized by spectroscopic techniques, single crystal X-ray diffraction, and low temperature magnetic measurements. Structural investigation reveals that 1 represents a mixed-valence 2-D coordination polymer formed by parallel 1-D [Cu(II)(dmen)(Cl)Cu(I)(μ_1,5-dca)₂]_n chains running along the b axis, where chloride bridges Cu(II) ions of adjacent polymers through long connections (2.8401(1) Å) to form a 2-D network. The metal centers have two different geometrical environments (distorted square pyramidal and distorted trigonal planar geometries for Cu(II) and Cu(I), respectively). The Cu(II) ions in [Cu(II)(dmen)(μ-Cl)(dca)]_n are interconnected through single chloride bridges while within the [Cu(I)(μ_1,5-dca)]_n units, the dca connects adjacent Cu(I) ions through μ_1,5-dca bridges. Magnetic susceptibility measurements reveal weak ferromagnetic interactions (J = +0.3 cm^?1) within the chlorido-bridged Cu(II) regular chain present in 1. Simultaneous presence of μ_1,5-dca and single chlorido bridges with ferromagnetic coupling is believed to be unique in mixed-valence Cu(I)/Cu(II) complexes.     

Synthesis and properties of double copper(I)–nickel(II) sulfite

Pourbaix diagrams of Cu–H₂SO4–H₂O and Ni–H₂SO₄–H₂O systems have been refined, and stability regions of the sulfite phases have been determined. State diagrams of double copper(I)–copper(II) and copper(I)–nickel(II) sulfites have been constructed. Double copper(I)–nickel(II) sulfite has been isolated from aqueous solutions saturated with sulfur dioxide. The solutions at different ratios of the metals have been studied by spectrophotometry; the isolated double sulfite has been studied by X-ray diffraction, IR spectroscopy, dispersion analysis, and thermal analysis. Fundamentals of thermodynamic prognostication of the Cu₂SO₃·MSO₃ double sulfites synthesis have been elaborated.     

Syntheses and crystal structures of mixed-ligand copper(II)–imidazole–carboxylate complexes

The syntheses, characterization, and crystal structures of the reaction products of Cu²⁺ with imidazole (Himz) and different aromatic carboxylates, viz.: [Cu(Himz)₂(cinn)₂(H₂O)] (1), [Cu(Himz)₂(paba)₂] (2) and [Cu(Himz)₂(clba)₂] (3) (cinn^– = C₉H₇O₂^–, paba^– = C₇H₆NO₂^–, clba^– = C₇H₄ClO₂^–) are described and studied by spectroscopic (UV–visible, FTIR) measurements. Single-crystal X-ray diffraction analyses indicate that each complex is monomeric. The metal ion in 1 adopts square-pyramidal coordination geometry arising from two imidazole nitrogens, two cinnamate oxygens, and an apical aqua. The metal ions of 2 and 3, however, assume a square planar configuration, which is realized by coordination of two nitrogens of two imidazoles and two oxygens; in both complexes, the imidazole moieties are trans to each other. TGA results indicate that upon heating, these complexes lose their carboxylate anions first, followed by removal of the imidazole molecules.     

Interconversion of copper(II) to copper(I): synthesis,characterization of copper(II) and copper(I) 2,2′-biquinoline complexes and their microbiological activity

The complexes [Cu(biq)₂]Cl₂ and [Cu(biq)₂]BF₄·biq (biq?=?2,2′-biquinoline) have been prepared and characterized. The interconversion to copper(I) complex [Cu(biq)₂]BF₄·biq, from [Cu(biq)₂]Cl₂ has been established. The new complexes have been characterized by elemental analysis, conductivity and magnetic measurements, IR, UV-vis and ¹H- and ¹³C-NMR spectroscopy. The X-ray analysis of the complex [Cu(biq)₂]BF₄·biq supports the assumption of the interconversion of copper(II) to copper(I) in this case. The crystal structure shows that geometry around the metal is severely distorted from T_d, and displays many supramolecular motifs incorporating both hydrophobic (aryl···aryl) and hydrophilic (C–H···F) intermolecular interactions. The microbiological activity of the complexes against bacteria and fungi was found to be high against Candida albicans, and slight to moderate against bacteria. The antimicrobial activity of [Cu(biq)₂]BF₄·biq was slightly better than that observed for [Cu(biq)₂]Cl₂ against both bacteria and fungi.     

Palladium(II)–copper(I) mediated homotrimerization and homotetramerization of terminal alkynes

Alkyne homocoupling is commonly observed in cross coupling reactions; however, self trimerization and homotetramerization of alkynes to form branched products through cross-coupling reactions are rarely reported. We describe herein homotrimerization and homotetramerization of terminal alkynes under the Sonogashira reaction conditions that gave the corresponding modified enediynes. Substrate scope for this reaction was explored.     

Syntheses,crystal structures and magnetic properties of two cyano-bridged copper(I)–copper(II) mixed-valence complexes

Two cyano-bridged copper(II)–copper(I) mixed-valence assemblies, Cu(EAM)₂[Cu(CN)₂]₂ 1 (EAM?=?ethanolamine) and Cu(DETA)[Cu(CN)₂]₂·0.5H₂O 2 (DETA?=?diethylenetriamine), have been prepared and structurally and magnetically characterized. IR spectra indicate the presence of bridging cyano groups in both 1 and 2, confirmed by structure analyses; Cu(I)–CN–Cu(II), Cu(I)–CN–Cu(I) and Cu(I)–Cu(I) metal bond linkages are evident. In the lattice, a 3D network is formed by two [Cu(CN)₂]?^? units and one [Cu(EAM)₂]²⁺unit for 1. Variable temperature magnetic susceptibilities, measured in the 5–300?K range, indicate weak antiferromagnetic exchange interactions in complex 1.     

Copper(II)–1,2-bis(thiocarbamoyl)hydrazine and copper(II)–(1-carbamoyl-2-thiocarbamoyl)hydrazine complexing in copper(II)hexacyanoferrate(II) gelatin-immobilized matrix systems

The complex formation that occurs in gelatin-immobilized copper(II)hexacyanoferrate(II) matrices upon contact with aqueous alkaline (pH 12.0) solutions of 1,2-bis(thiocarbamoyl)hydrazine, H₂NC(S)NHNHC(S)NH₂ and 1-carbamoyl-2-(thiocarbamoyl)hydrazine, H₂NC(O)NHNHC(S)NH₂ has been studied. The reaction of each of these ligands with copper(II) is preceded by the destruction of copper(II)hexacyanoferrate(II) in an alkaline medium to form a polymeric copper(II) hydroxide, which is involved in the subsequent copper(II)–ligand complex formation. In both Cu^II–N ligand systems, two complex compounds are formed; the water-insoluble Cu₂B₂(H₂O)₂ dimer and a water-soluble product of tentative composition [CuB(HB)]^– (H₂B=ligand).     

Features of сhitosan interaction with copper(II) and cobalt(II) tetrasulfophthalocyanines

The interaction of chitosan with copper(II) and cobalt(II) tetrasulfophthalocyanines is studied by spectral methods. The main parameters of binding of chitosan to anionic metal phthalocyanines are determined by Scatchard analysis. It is found that the formation of the polymer complex is considerably contributed by donor?acceptor interactions between the coordinately unsaturated metal phthalocyanine and chitosan amino groups. Сhitosan reacts with a monomeric cobalt(II) tetrasulfophthalocyanine, whereas copper(II) tetrasulfophthalocyanine in its complex with chitosan remains in the dimeric state. The reaction centers responsible for the Cu(SO₃H)₄Pc)₂–chitosan and Co(SO₃H)₄Pc–chitosan complexes are revealed by means of IR spectroscopy.     

Complexes of copper(II) with the β-blocker atenolol

Mono- and binuclear copper(II) complexes with atenolol (HAt) can be obtained, depending on the reaction conditions. The mononuclear violet complex cation has the general formula Cu(HAt)₄ ²⁺ with an elongated octahedral geometry. The two ligands in the equatorial plane are bound in a bidentate fashion through the hydroxyl oxygen and amino nitrogen, while the other two atenolol molecules in axial position are coordinated in a monodentate way. The binuclear green complex Cu₂At₂Cl₂, is neutral, where atenolol acts as a bidentate (O^–, NH) bridging ligand. The bridge between the two Cu atoms is realized by the deprotonated oxygen of the alcohol group.     

Kinetics and mechanism of the oxidation of DL-methionine bybis(2,2′-bipyridyl)copper(II) permanganate

Summary The oxidation ofDL-methionine (MT) bybis(2,2-bipyridyl)copper(II) permanganate (BBCP) to the corresponding sulphoxide is first order in BBCP. Michaelis-Menten-type kinetics were observed with respect to MT. The formation constant of the intermediate complex and the rate constant for its decomposition were evaluated. The thermodynamic and activation parameters were also evaluated. The reaction is catalysed by H⁺ but 2,2-bipyridine does not affect the reaction rate. A mechanism is proposed.     

Synthesis and characterization of β-diketonato- and phenoxoderivatives of mono(dizirconium-ennea-isopropoxy)copper(II)

Summary -Diketonato- and phenoxo-derivatives of mono(dizirconium-ennea-isopropoxy) copper(II), [Cu{Zr₂(OPr-i)₉}-(RCOCHCOR)] and [Cu{Zr₂(OPr-i)₉}(-OAr)], have been prepared by the interaction of K(RCOCHCOR) or KOAr (1 mol) [R = R = Me (1a); R = R = CF₃ (1b); R = Me, R = CF₃ (1c); OAr = 2,6-Me₂C₆H₃O (2a), 3,5-Me₂C₆H₃O (2b), p-ClC₆H₄O (2c)] with [Cu{Zr₂-(OPr-i) ₉}(-Cl)] (1 mol) in PhH. Alcohol interchanges of the derivative [Cu{Zr₂(OPr-i)₉}(-Cl)] have also been studied. These new compounds have been characterized by elemental analyses, i.r., electronic and e.s.r. spectra, and magnetic susceptibility measurements. The studies indicate a distorted octahedral geometry around Cu^II.     

Synthesis,spectral, magnetic,electrochemical and catalytic studies of cyclam-based copper(II) and nickel(II) complexes–effect of N-substitution

New N-substituted cyclam ligands 1,8-[bis(3-formyl-2-hydroxy-5-methyl)benzyl]-1,4,8,11-tetraazacyclotetradecane, 1,8-[bis(3-formyl-2-hydroxy-5-methyl)benzyl]-4,11-dimethyl-1,4,8,11-tetraazacyclotetradecane, 1,8-[bis(3-formyl-2-hydroxy-5-bromo)benzyl]-1,4,8,11-tetraazacyclotetradecane, and 1,8-[bis(3-formyl-2-hydroxy-5-bromo)benzyl]-4,11-dimethyl-1,4,8,11-tetraazacyclotetradecane (L¹–L⁴) were synthesized and mononuclear copper(II) and nickel(II) complexes prepared. The ligands and complexes were characterized by elemental analysis, electronic, IR, ¹H NMR and ¹³C NMR spectral studies. N-alkylation causes red shifts in the λ_max values of the complexes. Copper(II) complexes show one-electron, quasi-reversible reduction waves in the range ?1.04 to ?1.00 V. The nickel(II) complexes show one-electron, quasi-reversible reduction waves in the range ?1.18 to ?1.30 V and one-electron, quasi-reversible oxidation waves in the range +1.20 to +1.40 V. The reduction potential of the copper(II) and nickel(II) complexes of the ligands L¹ to L² and L³ to L⁴ shift anodically on N-alkylation. The ESR spectra of the mononuclear copper(II) complexes show four lines, characteristic of square-planar geometry with nuclear hyperfine spin 3/2. All copper(II) complexes show a normal room temperature magnetic moment value μ_eff?=?1.70–1.74 BM which is close to the spin only value of 1.73 BM. Kinetic studies on the oxidation of pyrocatechol to o-quinone using the copper(II) complexes as catalysts and on the hydrolysis of 4-nitrophenylphosphate using the copper(II) and nickel(II) complexes as catalyst were carried out. The tetra-N-substituted complexes have higher rate constants than the corresponding disubstituted complexes.     

Crystal structures and spectroscopic properties of copper(II)–dipicolinate complexes with benzimidazole ligands

The syntheses, crystal structures and spectroscopic properties of three Cu(II)–dipicolinate complexes with benzimidazole ligands, namely [Cu(bzim)(dipic)(MeOH)] (1), [Cu₂(2-Etbzim)₂(dipic)₂]_n·0.5nH₂O (2) and [Cu₂(2-ⁱPrbzim)₂(dipic)₂]_n (3), where dipic?=?dipicolinate, bzim?=?1-H-benzimidazole, 2-Etbzim?=?2-ethyl-1-H-benzimidazole and 2-iPrbzim?=?2-isopropyl-1-H-benzimidazole, are reported. Crystal structure studies revealed different coordination modes of the dipicolinate ligands; tridentate chelating for monomeric complex 1, and both tridentate chelating and bridging for similar polymeric complexes 2 and 3. Polymers 2 and 3 both contain two units, in which the Cu(II) central atoms Cu1 and Cu2 have different coordination polyhedra. The first unit {Cu(dipic)₂} with Cu1 is connected to the second via two bidentate carboxylate groups of an μ₃-bridging dipicolinate. In the second unit, Cu2 is coordinated by two imidazole nitrogen atoms from 2-ethyl-1-H-benzimidazole (2) or 2-isopropyl-1-H-benzimidazole (3) ligands. Complex 2 is of higher symmetry and has a localized Cu(II) atom Cu2 in a special position on the twofold axis. EPR spectra of all three Cu(II) complexes, which were measured at both room temperature and 98 K, indicate distorted tetragonal coordination spheres for all the Cu(II) atoms. The g-factor relation (g_//>?g_┴?>?2.0023) is consistent with a \(d_{{x^{2} - y^{2} }}\) ground electronic state in each case.     

Synthesis and characterization of a dipeptide–copper(II)– 2-aminomethylbenzimidazole ternary complex

A new ternary complex [Cu(glygly)(AMBZ)(H₂O)]Cl·H₂O (1) (glygly?=?glycylglycine anion, AMBZ?= 2-aminomethylbenzimidazole) has been prepared and characterized by single-crystal X-ray diffractometry and ESR, electronic and IR spectroscopy. The copper(II) ion has a slightly distorted square-pyramidal coordination, being equatorially coordinated by the bidentate 2-aminomethylbenzimidazole and the bidentate glycylglycine anion and axially by a water molecule. The individual complex molecules are hydrogen bonded to their neighbors, forming a polymeric hydrogen-bonded lattice. Spectroscopic data are in accordance with the crystal structure.     

Transesterification of copper(II) β-ketoesterates and acylpyruvates with borneol

Transesterification of copper(II) acetoacetates, copper(II) trifluoroacetoacetate, and copper(II) acylpyruvates with borneol gives the copper(II) chelates of the corresponding bornyl esters in 92–95 % yields. Bornyl acetyl- and perfluoroacylpyruvates were synthesized for the first time by decomposing the respective chelates with hydrogen chloride. Bornyl acylpyruvates react with hydrazine hydrate to give 5-alkyl-3-bornyloxycarbonylpyrazoles.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 902–904, May, 1993.