Functional superoxide dismutase mimics. Structural characterization and magnetic exchange interactions of copper(II)-N-substituted sulfonamide dimer complexes.

Dinuclear copper(II) complexes with N-substituted sulfonamide ligands as superoxide dismutase (SOD) mimics have been investigated. The new N-(thiazol-2-yl)toluenesulfonamide (Htz-tol) and N-(thiazol-2-yl)naphthalenesulfonamide (Htz-naf) ligands have been prepared and structurally characterized. The complexes derived from these ligands, [Cu(2)(tz-tol)(4)] (1) and [Cu(2)(tz-naf)(4)] (2), have been synthesized, and their crystal structure, magnetic properties, and EPR spectra were studied in detail. In both compounds the metal centers are bridged by four nonlinear triatomic NCN groups. The coordination geometry of the coppers in the dinuclear entity of 1 and 2 is distorted square planar with t…

Mn(II) complexes with sulfonamides as ligands.

Abstract Sulfonamides derived from 8-aminoquinoline react with Mn(II) and Mn(III) salts to form Mn(II) complexes; the Mn(III) species are reduced to the divalent state in the presence of 1,10 phenanthroline and bipyridine. Their molecular structure, determined by single crystal X‐ray diffraction, show that all the complexes present a distorted octahedral geometry, in which the deprotonated sulfonamide acts as a bidentate ligand. UV–visible spectroscopy and changes in the melting temperature (Tm) of calf thymus DNA show a strong interaction of these complexes with DNA. The significant hypochromicity of the charge transfer transition at 370 nm without an appreciable change in wavelength and t…

Metal complexes of sulfanilamide derivatives. Spectroscopic characterization of the dichloro disulfathiazole methanol copper(II) complex

The synthesis and spectral characterization of the [Cu(Hstz)2(MeOH)Cl2] complex are described. Both polycrystalline powder EPR and single crystal EPR spectra recorded at room temperature show rhombic distortion with values of g1=2.25, g2=2.09 and g3=2.03 in agreement with a copper polyhedron, intermediate between trigonal bipyramid and square pyramidal.

Copper(II) Polyamine Complexes withN-Benzothiazole Sulfonamides as Counterions — Synthesis, Crystal Structures, and Properties of [Cu(dien)2](L1)2[HL1 =N-2-(benzothiazole)naphtalenesulfonamide, dien = diethylentriamine] and [Cu(en)2(H2O)2](L2)2[HL2 =N-2-(6-chlorobenzothiazole)toluenesulfonamide, en = ethylenediamine] — Superoxide Dismutase-like Activity

Copper(II) complexes of new N-benzothiazole sulfonamides (HL1= N-2-(benzothiazole)naphtalensulfonamide and HL2 = N-2-(6-chlorobenzothiazole)toluenesulfonamide) with ethylenediamine (en) and diethylenetriamine (dien) have been synthesized and characterised. The crystal structures of [Cu(dien)2](L1)2 (1) and [Cu(en)2(H2O)2](L2)2 (2) compounds have been determined. The metal centre adopts a “4+2” distorted octahedral environment in both complexes. Unusually, the sulfonamidate anions act as counterions. Spectroscopic properties are in good agreement with the crystal structures. The superoxide dismutase (SOD)-like activity of complex 2 has been tested. Kupfer(II)-Polyamin-Komplexe mit N-Benzothi…

Structural basis and effect of copper(II) complexes with 4-oxo-thiazolidine ligands on DNA binding and nuclease activity

Abstract Seven novel Copper(II) complexes, namely [Cu(Am4DHotaz)(H2O)2](ClO4) (1), [Cu(Am4DHotaz)(NO3)(MeOH)]·H2O (2), [Cu(Am4Motaz)2(H2O)](ClO4)2·0.83H2O (3), [Cu(Am4Motaz)2(NO3)]NO3·MeOH (4), [Cu(Am4Eotaz)2(NO3)]3(NO3)3·2H2O (5), [Cu(Am4Eotaz)2(ClO4)](ClO4) (6) and [Cu(Am4Eotaz)(ClO4)(H2O)](ClO4) (6a) (HAm4DHotaz = N′-(4-oxothiazolidin-2-ylidene)pyridine-2-carbohydrazonamide, Am4Motaz = N′-(3-methyl-4-oxothiazolidin-2-ylidene)pyridine-2-carbohydrazonamide and Am4Eotaz = N′-(3-ethyl-4-oxothiazolidin-2-ylidene)pyridine-2-carbohydrazonamide), have been successfully synthesized and characterized by several physicochemical techniques and, for 1–6 complexes, single crystal X-ray diffraction. Ha…

DNA cleavage reaction induced by dimeric copper(II) complexes of N-substituted thiazole sulfonamides

A new dinuclear copper(II) complex has been synthesised and structurally characterised: [Cu2(tz-ben)4] (Htz-ben = N-thiazol-2-yl-benzenesulfonamide). Its crystal structure, magnetic properties and electronic paramagnetic resonance (EPR) spectra were studied in detail. In the compound the metal centres are bridged by four non-linear triatomic NCN groups. The coordination geometry of the copper ions in the dinuclear entity is distorted square pyramidal (4+1). Two thiazole N and two sulfonamido N atoms occupy the equatorial positions and one sulfonamido O atom is in the axial position. Magnetic susceptibility data show a strong antiferromagnetic coupling, -2J = 114.1 cm(-1). The EPR spectra of…

Antibacterial studies, DNA oxidative cleavage, and crystal structures of Cu(II) and Co(II) complexes with two quinolone family members, ciprofloxacin and enoxacin

Nine coordination compounds of Cu(II) and Co(II) with Ciprofloxacin (HCp) and Enoxacin (HEx) as ligands have been prepared and characterized. Single crystal structural determinations of [Cu(HCp)2(ClO4)2].6H2O (1) and [Co(HEx)2(Ex)]Cl.2CH(3)OH.12H2O (4) are reported. The crystal of 1 is composed of [Cu(HCp)2(ClO4)2] units with the two perchlorate anions semicoordinated, and uncoordinated water molecules. The copper ion, at a crystallographic inversion centre, is in a tetragonally distorted octahedral environment. The structure of 4 consists of cationic monomeric [Co(HEx)2(Ex)]+ units, chloride anions, and uncoordinated methanol and water molecules. The complex is six-coordinate, with a sligh…

New Cu(II) and Zn(II) complexes of benzolamide with diethylenetriamine: synthesis, spectroscopy and X-ray structures

Abstract New benzolamide (H2bz, 5-phenylsulfonamide-1,3,4-thiadiazole-2-sulfonamide) zinc(II) and copper(II) complexes with diethylenetriamine were synthesized and characterized. The crystal structures of the [M(Hbz)2(dien)] (M=Cu(II), Zn(II); dien=diethylenetriamine) complexes were determined. The metal centre adopts a near regular square pyramidal geometry. The benzolamidate anion acts as a monodentate ligand through the thiadiazole N atom contiguous to the deprotonated sulfonamido group. Spectroscopic properties are in good agreement with the crystal structures. The EPR and electronic spectroscopic studies showed that the copper(II) species doped into the zinc(II) complex adopts a near s…

Metal complexes of the carbonic anhydrase inhibitor methazolamide (Hmacm). Crystal structure of the Zn(macm)2 (NH3)2. Anticonvulsant properties of the Cu(macm)2 (NH3)3(H2O)

Complexes of Co(II), Cu(II), and Zn(II) with deprotonated methazolamide and ammonia are synthesized and characterized. The complex Zn(macm)2(NH3)2 crystallizes in the monoclinic C2/c space group with a = 13.468(1), b = 6.759(1), c = 23.014(2) A, beta = 90.27(1), and Z = 4. The structure was refined to R = 0.049 (Rw = 0.053). The Zn(II) ion is coordinated to two deprotonated sulfonamido nitrogen atoms of the macm- ligand and two nitrogen atoms of the ammonia ligands in a distorted tetrahedron. The Zn(macm)2(NH3)2 complex is shown to be a simple model for the methazolamide inhibition of CA. EHMO calculations applied to fractional coordinates of the Zn(macm)2(NH3)2 complex indicate that the at…

Oxidative DNA cleavage by copper ternary complexes of 1,10-phenanthroline and ethylenediamine-sulfonamide derivatives

Abstract Ternary copper(II) complexes (1–3) of 1,10-phenanthroline and ethylenediamine-R-sulfonamide derivatives (R = benzene, toluene and naphthalene rings) have been synthesized and characterized with the aid of X-ray diffraction and spectroscopic and electrochemical techniques. The crystal structures of the complexes show that the coordination polyhedron around copper(II) is distorted square planar. Both 1,10-phenanthroline and ethylenediamine-R-sulfonamide act as bidentate ligands. The three structures are stabilized by π–π stacking interactions. The interaction of the complexes with calf thymus DNA has been investigated by thermal denaturation studies which indicated that DNA was stabi…

Structural and functional models for the dinuclear copper active site in catechol oxidases

Two new mu-methoxo-bridged dinuclear copper(II) complexes with a N-substituted sulfonamide, [Cu(mu-OMe)(L)(NH(3))](2) (1) and [Cu(mu-OMe)(L)(DMSO)](2) (2) [HL, N-2-(4-methylbenzothiazole)benzenesulfonamide], have been prepared and characterized by single-crystal X-ray difraction analyses. Compound 1 crystallizes in the monoclinic space group C(2)/c with a=22.0678(18), b=7.9134(7), c=21.1186(18)A, beta=113.788(4) degrees and Z=8. Compound 2 crystallizes in the monoclinic space group C(2)/c with a=18.0900(10), b=9.5720(10), c=24.2620(10) A, beta=98.7120(10) degrees and Z=8. In both complexes the copper atoms have square-planar environments bridged by two oxygen atoms from methoxide groups. Ma…

Synthesis, crystallographic and spectroscopic characterization and magnetic properties of dimer and monomer ternary copper(II) complexes with sulfonamide derivatives and 1,10-phenanthroline. Nuclease activity by the oxidative mechanism

Abstract Three dinuclear and one mononuclear copper(II)-1,10-phenanthroline ternary complexes, [Cu(L1)(phen)(OH)]2 (1), [Cu(L2)(phen)(OH)]2·3H2O (2), [Cu(L3)(phen)(OH)]2 (3) and [Cu(L4)2(phen)(H2O)] (4), with thiadiazole sulfonamide derivative ligands: HL1 (N-(5-ethyl-1,3,4-thiadiazol-2-yl)naphthalene-1-sulfonamide), HL2 (N-(5-ethylthio)-1,3,4-thiadiazol-2-yl)-4-methylbenzenesulfonamide), HL3 (N-(5-ethyl-1,3,4-thiadiazol-2-yl)benzenesulfonamide) and HL4 (N-(5-ethyl-1,3,4-thiadiazol-2-yl)-4-methylbenzenesulfonamide) have been synthesized and characterized. In the four complexes each copper atom is five-coordinated. The structure of complexes 1, 2 and 3 consists of a dimeric unit with a C2 sy…

Crystal structures and spectroscopic properties of copper(II)–bis(2-pyridylcarbonyl)amide–chlorobenzoate complexes

The reaction of 2,4,6-tris(pyridyl)-1,3,5-triazine (ptz) and copper(II) salts in DMF–water (4:1) resulted in the hydrolysis of ptz, giving rise to the bis(2-pyridylcarbonyl)amide anion ( ptO 2 - ) and affording the complexes [Cu(ptO 2 )(2-Clbenz)(H 2 O)] ( 1 ), [Cu(ptO 2 )(3-Clbenz)] ( 2 ), and [Cu(ptO 2 )(4-Clbenz)(DMF)] ( 3 ). This report includes the chemical and spectroscopic characterization of all these compounds along with the crystal structures of the Cu(II) complexes thus formed. The coordination spheres of Cu(II) in 1 and 3 are best described as distorted square based pyramidal, while for 2 the coordination sphere is distorted square planar.

Synthesis, structure, and nuclease properties of several binary and ternary complexes of copper(II) with norfloxacin and 1,10 phenantroline

Three new binary Cu(II) complexes of norfloxacin have been synthesized and characterized. We also report the synthesis, characterization and X-ray crystallographic structures of a new binary compound, [Cu(HNor)(2)]Cl(2).2H(2)O (2) and two new ternary complexes norfloxacin-copper(II)-phen, [Cu(Nor)(phen)(H(2)O)](NO(3)).3H(2)O (4), and [Cu(HNor)(phen)(NO(3))](NO(3)).3H(2)O (5). The structure of 2 consists of two crystallographically independent cationic monomeric units of [Cu(HNor)(2)](2+), chloride anions, and uncoordinated water molecules. The Cu(II) ion is placed at a center of symmetry and is coordinated to two norfloxacin ligands which are related through the inversion center. The struct…

DNA interaction of new copper(II) complexes with sulfonamides as ligands

New copper(II) complexes with sulfonamide ligands have been prepared and characterized. Sulfonamide ligands were prepared through a reaction between 8-aminoquinoline and either 2-mesitylene (Hqmesa), 4-tert-butylbenzene (Hqtbsa), or alpha-toluene (Halphaqtsa) sulfonyl chlorides. The structural analysis carried out for complex [Cu(alphaqtsa)(2)] indicated that the local environment of the Cu(II) cation is between a square planar and a tetrahedral geometry, with stacking of the benzene rings of the sulfonyl ligands between neighbor molecules. Powder EPR spectra at room temperature gave rhombic spectra for the [Cu(alphaqtsa)(2)] and [Cu(qmesa)(2)] complexes and an axial spectrum for the [Cu(qt…

Efficient DNA Cleavage Induced by Copper(II) Complexes of Hydrolysis Derivatives of 2,4,6‐Tri(2‐pyridyl)‐1,3,5‐triazine in the Presence of Reducing Agents

The reaction of 2,4,6-tri(pyridyl)-1,3,5-triazine (ptz) and copper(II) salts in dmf/water (1:1) results in the hydrolysis of ptz and formation of the anions bis(2-pyridylcarbonyl)amide (ptO2–) and bis(2-pyridylamine)amide (ptN2–), which are found in the complexes [Cu(ptN2)(OAc)]·3H2O (1), [Cu(ptO2)(OAc)(H2O)]·H2O (2), [Cu(ptN2)(for)]·3H2O (3) (for = formate), [Cu(ptO2)(for)(H2O)] (4), [Cu(ptO2)(benz)]·H2O (5) (benz = benzoate), and [Cu(ptO2)F(H2O)]2·3H2O (6). This report includes the chemical and spectroscopic characterization of all these complexes along with the crystal structures of 4–6. The coordination spheres of CuII in 4 and 5 are best described as distorted tetragonal square pyramid…

Strong protective action of Copper(II) N-substituted sulfonamide complexes against reactive oxygen species.

Copper(II) complexes of N -benzothiazolsulfonamides, [Cu( N -2-(5,6-dimethylbenzothiazole)toluenesulfonamidate) 2 (dmso) 2 ] ( 1 ), [Cu( N -2-(6-chlorobenzothiazole)benzenesulfonamidate) 2 (dmso) 2 ] ( 2 ) and [Cu( N -2-(6-chlorobenzothiazole)toluenesulfonamidate) 2 (dmso) 2 ] ( 3 ) with interesting protective properties against superoxide radicals have been prepared. The compounds have been characterized by X-ray diffraction and their chemical properties have been studied by spectroscopic methods. The crystal structure of 1 shows that the copper(II) is surrounded by two benzothiazole N atoms from the sulfonamide ligands and two O atoms from the dimethylsulfoxide molecules in a square plana…

Biological Activity of Flavonoids Copper Complexes

Three flavonoid copper(II) complexes Cu2(quercetin)(CH3COO)3(CH3OH) (1), Cu(anthrarufin)(CH3COO)·1/2H2O (2) and Cu(naringin)(OCH3)(CH3OH)2 (3) have been synthesized and characterized by elemental analysis, IR, electronic absorption and EPR (X-band) spectroscopy. The complexes have a strong protective action over the Δsod1 mutant of S. cerevisiae against reactive oxygen radicals generated by an external source of free radicals (H2O2 or the superoxide-generating, menadione). On the other hand, the complexes cleave DNA efficiently even in the absence of reducing agents. The main reactive oxygen species responsible for the DNA strand cleavage have been determined using radical scavengers. A pro…

Syntheses, crystal structures, and oxidative DNA cleavage of some Cu(II) complexes of 5-amino-3-pyridin-2-yl-1,2,4-triazole

Three new monomeric Cu(II) complexes of 5-amino-3-pyridin-2-yl-1,2,4-triazole (Hapt), [Cu(Hapt)(H(2)O)(2)(SO(4))] (1), [Cu(Hapt)(2)(H(2)O)(NO(3))](NO(3)) (2), and [Cu(Hapt)(2)(NCS-N)](NCS).H(2)O (3), have been prepared and characterized by single crystal X-ray diffraction. One distorted [CuN(2)O(2)+O(')] square-pyramidal (1), one distorted [CuN(3)O+N(')+O(')] octahedral (2), and one distorted [CuN(4)+N(')] intermediate between square-pyramidal and trigonal-bipyramidal (3) coordination configuration were found and are suggested to be due to the chelating nature of the ligand, which interacts with Cu(II) through the N4(triazole) and N(pyridine) atoms. Spectral properties of these chelates are…

Copper-mediated DNA photocleavage by a tetrapyridoacridine (tpac) ligand.

Abstract We have focused our interest on the tetrapyridoacridine ligand tetrapyrido[3,2- a :2′,3′- c :3′′,2″- h : 2‴,3‴- j ]acridine (tpac), as a model system for the preparation of novel copper-based artificial nucleases. The complex of copper(II)–tpac cleaves supercoiled pUC18 plasmid DNA in an oxidative manner by photoactivation with visible light, exhibiting maximum cleaving efficiency at 1:2 metal–ligand stoichiometric ratio. We propose an interaction of the copper–tpac complex with DNA through both major and minor grooves and a photocleavage mechanism via the formation of hydroxyl radicals and singlet oxygen or singlet oxygen-like species.

A Co(III) complex of carbonic anhydrase inhibitor methazolamide and the amino-imino ‘aib’ ligand formed by reaction of acetone and ammonia

Abstract Reaction of Co(NO 3 ) 2 ·6H 2 O with methazolamide {[ N -(3-methyl-5-sulfamoyl-1,3,4-thiadiazol-2(3 H )-ylidene)acetamide] (Hmacm)} and ammonia in acetone to produce [Co(methazolamidate)(2-methyl-2-amino-4-iminopentane) 2 (NH 3 )](NO 3 ) 2 ·2H 2 O is described. The ligand 2-methyl-2-amino-4-iminopentane (aib) is the product obtained from the condensation of two ammonia and two acetone molecules. The complex crystallizes in the monoclinic space group P 2 1 / c with a =16.713(5), b =9.180(1), c =20.273(1) A, β=97.44(4)° for Z =4. The R value is 0.081 for 2150 significant reflections. The Co(III) ion exhibits a nearly regular octahedral arrangement with the CoN bond distances in the …

Nuclease activity of [Cu(sulfathiazolato)2(benzimidazole)2]2MeOH. Synthesis, properties and crystal structure

The [Cu(sulfathiazolato)(2)(benzimidazole)(2)]2MeOH complex has been synthesised and characterised. It crystallises in the monoclinic system, space group C1c1, with unit cell dimensions a=18.829(7) A, b=12.206(3) A, c=17.233(5) A, alpha=90.06(2) degrees, beta=97.28(3) degrees, gamma=90.21(3) degrees and Z=4. The geometry around the copper(II) ion is intermediate between tetrahedral and square planar. The complex produces cleavage of plasmid pUC18 in presence of reducing agents. The efficiency of cleavage reaction of the title compound with pUC18 and with different reducing agents follows the order ascorbate-H(2)O(2)>ascorbate>MPA>dithiothreitol>H(2)O(2).

Crystal structure, magnetic and spectroscopic properties of copper(II) formato dimethylformamide: a new tetracarboxylato-bridged copper(II) dimer

Abstract The crystal and molecular structure of a new tetracarboxylato copper(II) dimer [bis(dimethylformamide)tetrakis(μ-formato)dicopper(II)], has been determined by X-ray diffraction methods. The crystal structure consists of a centrosymmetric dimer [Cu2(HCOO)4(dmf)2], where four bidentate formato anions form syn–syn bridges between the metal ions which are in a 4+1 environment. Magnetic susceptibility data show that the copper ions are strongly antiferromagnetically coupled with J=−470 cm−1. The EPR spectrum shows a characteristic pattern of a triplet state with a D zero field splitting value of 0.27 cm−1.

Acetazolamide-M(II) [M(II) = Co(II), Ni(II), Cu(II)] complexes with ethylamine, diethylamine, triethylamine, and potassium hidroxide

Abstract Complexes of Co(II), Ni(II), and Cu(II) with dideprotonated Acm are synthesized and characterized. Acm acts as bidentate ligand through the N-sulfonamido atom and the N-thiadiazole atom except for K6CoAcm4·6H2O in which Acm behaves as monodentate through the N-sulfonamido atom.

Synthesis and copper-mediated nuclease activity of a tetracationic tris(2,2′-bipyridine) ligand

Abstract We report herein the synthesis of a novel tetracationic tris(2,2′-bipyridine) ligand 4 . We show that this ligand metalated with copper(II), and in the presence of ascorbate as a reducing agent, strongly damages pUC18 plasmid DNA. Copper complex formation was demonstrated by ESI-MS (electrospray ionization-mass spectrum) at a 1:3 ligand to metal ratio. Binding of both 4 and its copper(II) complex to CT-DNA (calf thymus DNA) was characterized by viscosimetry, thermal denaturation and fluorescence-based competition assays. The viscosimetric data indicated that 4 and its copper(II) complex bind DNA through partial intercalation and thermal denaturation studies revealed a significant i…

Coordination behaviour of methazolamide [N(-4-methyl-2-sulfamoyl-Δ2-1,3,4-thiadiazolin-5-ylidene)] acetamide, an inhibitor of carbonic anhydrase enzyme. Synthesis, crystal structure and properties of bis(methazolamidate)tetrammine nickel(II)

Abstract The interaction of methazolamide (Hmacm) with Ni(II) ion and ammonia molecules gives rise to the complex of formula [Ni(macm)2(NH3)4]. The complex crystallizes in the monoclinic P21/n space group with a = 14.255(4), b = 7.126(2), c = 12.444(3) A, β = 113.12(3)° and Z = 2. The structure was refined to R = 0.065 (Rw = 0.065). The complex consists of monomeric units which interact through hydrogen bonds and van der Waals contacts. The Ni(II) ion is coordinated with the deprotonated sulfonamido nitrogen of the macm− ligand in axial sites and the ammonia molecules in equatorial positions. IR, electronic spectra and 1H NMR results are also reported.

Oxidative DNA cleavage induced by an iron(III) flavonoid complex: synthesis, crystal structure and characterization of chlorobis(flavonolato)(methanol) iron(III) complex.

A flavonol iron(III) complex, [Fe(flavonolato)(2)Cl(MeOH)], has been prepared. The compound has been characterized by X-ray crystallography, spectroscopy, magnetism and electronic paramagnetic resonance (EPR) at X- and Q-band. The geometrical environment around the metal is best described as rhombic distorted octahedral. This distortion has also been inferred from the magnetic measurements and from the EPR spectra at different temperatures, E/D(rhombicity parameter) approximately 0.06. The DNA cleavage activity of the iron(III) complex with and without ascorbate/hydrogen peroxide is reported. Mechanisms of the oxidative cleavage have been proposed when DNA strand scission is performed both …

Coordination compounds of methazolamide. Synthesis, spectroscopic studies and crystal structures of [M(Methazolamidato)2(py)2(OH2)2] (M  CoII, NiII and CuII)

Abstract The synthesis and X-ray crystallographic characterization of three monomeric transition-metal coordination compounds with the ligand methazolamide {[N(4-methyl-2- sulphamoyl-Δ21,3,4-thiodiazolin-5-ylidene)],acetamide} (abbreviated as Hmacm) are described, via [M(macm)2(py)2(OH2)2] [M  Co(1), Ni(2) and Cu(3)]. In all the compounds the metal ion, lying on the centre of symmetry, is surrounded by two sulphonamidato nitrogen atoms and two pyridine nitrogen atoms in equatorial sites and two oxygen water molecules in axial positions. The coordination geometry of the metal is an almost regular octahedron around the cobalt(II) and nickel(II) ions. In contrast, the copper(II) ion has a sig…

Strong Ferromagnetic Coupling in Linear Mixed μ-Acetato, μ-Hydroxo Trinuclear Copper(II) Complexes withN-sulfonamide derivatives − Synthesis, Structure, EPR and Magnetic Properties

Synthesis, structure and biological properties of several binary and ternary complexes of copper(II) with ciprofloxacin and 1,10 phenanthroline

In this study, a new binary complex [Cu(HCip) 2 ](NO 3 ) 2  · 6H 2 O ( 1 ) has been synthesized and then characterized by X-ray structure analyses. In this compound, each ciprofloxacin acts as a bidentate ligand resulting in a crystallographically planar configuration; the nitrate anions are located in apical positions with an axial distance significantly larger than the equatorial distances, which would be consistent with a very weak metal ion interaction due to the Jahn–Teller effect. In addition, both the synthesis and characterization of two new ternary complexes of ciprofloxacin–copper(II)–1,10-phenanthroline, [Cu(phen)(Cip)](NO 3 ) · 4H 2 O ( 2 ) and Cu(phen)(HCip)(NO 3 ) 2  · H 2 O (…

Coordinative versatility of the carbonic anhydrase inhibitor benzolamide in zinc and copper model compounds

New benzolamide (H 2 bz, 5-phenylsulfonamide-1,3,4-thiadiazole-2-sulfonamide) zinc(II) and copper(II) complexes with tris(2-benzimidazolyl-methylamine) (L) and ammonia are reported. The crystal structures of the Zn(II) complexes were determined. The [Zn(Hbz)L]ClO 4 · H 2 O compound crystallizes in the triclinic space group with a =11.006(1), b =14.777(2), c =14.918(2) A, α =114.30(1), β =98.90(1), γ =107.36(1)° and Z =2. In this compound the Zn(II) has a distorted trigonal bipyramidal geometry. The {[Zn 2 (bz) 2 (NH 3 ) 4 ] · 2H 2 O} ∞ crystallizes in the monoclinic space group C 2/ c with a =23.530(3), b =10.4124(11), c =15.428(2) A, β =110.591(9)° and Z =4. The metal centre is in a distor…

Spectroscopic, magnetic, and electrochemical studies of a dimeric N-substituted-sulfanilamide copper(II) complex. X-ray and molecular structure of the Cu2(N-(pyridin-2-yl)biphenyl-4-sulfonamidate)4 complex

Abstract A dinuclear copper(II) complex with a N-substituted sulfonamide as ligand has been investigated. The new N-(pyridin-2-yl)biphenyl-4-sulfonamide ligand has been prepared and structurally characterized. The copper(II) complex has been synthesized and its crystal structure, magnetic properties and EPR spectra were studied in detail. The metal centers are bridged by four nonlinear triatomic NCN groups. The coordination geometry of the copper(II) ions in the dinuclear entity is distorted square planar with two N-pyridyl and two N-sulfonamido atoms. Magnetic susceptibility data show a moderate antiferromagnetic coupling, with −2 J = 284 cm−1. The EPR spectrum of the polycrystalline sampl…

Thermal studies of sulphonamide derivative complexes

Abstract A thermal study of a new series of acetazolamidate complexes of Co(II), Ni(II) and Cu(II) using the TG, DTG and DTA techniques in flowing air, static air and N 2 atmospheres is described. From the TG-DTG and DTA curves, different thermal behaviours can be observed. Although in all the complexes the processes of dehydration, deammination and pyrolysis can be clearly observed, in some cases they appear as several well-separated steps and, in others, as continuous stages which take place simultaneously. The differences observed between the pyrolytic decomposition in flowing air and in nitrogen are described. In flowing air, metal sulphate is formed from the thiadiazole ring, except fo…

Zinc complexation to N-substituted sulfonamide ligands. Preparation, properties and crystal structure of copper(II) doped ?[Zn(sulfamethizolate)2(py)]·H2O?∞

Abstract The single crystal structure and spectroscopic properties of the copper(II) doped {[Zn(sulfamethizolate) 2 (py)]·H 2 O} ∞ are reported. The complex is a polymer where the Zn(II) ions are coordinated by four N atoms in a very distorted tetrahedral environment. The sulfamethizolate anion acts as a monodentate ligand through the thiadiazole N atom and as a bridging ligand via the amino and thiadiazole N atoms. The compound is studied by EPR, by 13 C NMR in solid state and by 1 H and 13 C NMR in DMSO-d 6 solution. The similarity between the 13 C NMR spectrum in solution and the solid 13 C NMR spectrum indicates that the structure of the compound remains in solution. The EPR spectrum sh…

Comparison of Protective Effects against Reactive Oxygen Species of Mononuclear and Dinuclear Cu(II) Complexes with N-Substituted Benzothiazolesulfonamides

Copper(II) complexes of N-benzothiazolesulfonamides (HL1=N-2-(4-methylphenylsulfamoyl)-6-nitro-benzothiazole, HL2=N-2-(phenylsulfamoyl)-6-chloro-benzothiazole, and HL3=N-2-(4-methylphenylsulfamoyl)-6-chloro-benzothiazole) with ammonia have been synthesized and characterized. The crystal structures of the [Cu(L1)2(NH3)2].2MeOH, [Cu(L2)2(NH3)2], and [Cu(L3)2(NH3)2] compounds have been determined. Compounds and present a distorted square planar geometry. In both compounds the metal ion is coordinated by two benzothiazole N atoms from two sulfonamidate anions and two NH3 molecules. Complex is distorted square-pyramidal. The Cu(II) ion is linked to the benzothiazole N and sulfonamidate O atoms o…

Synthesis and characterization of acetazolamide complexes of Ni(II), Cd(II), Hg(II), and Ag(I)

The preparation and characterization of K2Ni2(Acm)3·5H2O, Cd(Acm)·32 H2O, Hg(Acm)·12H2O, Ag2(Acm), and Ag2(Acm)(NH3) complexes are described. The spectral properties suggest that Acm interacts with the metal ions through the doubly deprotonated form as observed in the [Cu(Acm)(NH3)2(OH2)]2·2H2O complex, whose crystalline structure has been previously reported. The crystal field parameters of the Ni(II) complex indicate an octahedral environment for the metal ion in the solid and its aqueous, DMSO, and DMF solutions. UV spectra of all the Acm complexes until now synthesized are discussed.

Coordination behaviour of sulfanilamide derivatives.

Abstract Hg(II), Cd(II) and Zn(II) complexes with the ligands sulfadimethoxine, sulfamethoxypyridazine, sulfadiazine, sulfamerazine, sulfadimidine and sulfamethoxazole have been prepared and characterised by spectral data. 1H and 13C NMR have been used to interpret the structural characteristics of the complexes in solution. The X-ray crystal structures of [Hg(sulfamethoxypyridazinato)2] (2a), [Cd(sulfadimidinato)2(H2O)]·2H2O (4b) and [Zn(sulfamethoxazolato)2(py)2(H2O)2] (6d) have been determined. In complex 2a the Hg(II) ion lies on an inversion centre and exhibits linear coordination by two sulfonamidic nitrogen atoms [Hg–N(1)=2.071(4) A] of the two deprotonated sulfamethoxypyridazinato l…

Coordination chemistry of sulfamethizole: crystal structures of [Cu(sulfamethizolate)2(py)2(OH2)]·H2O, [M(sulfamethizolate)2(py)2(OH2)2] [M=Co and Ni] and {Cu(sulfamethizolate)2(dmf)2}∞

Abstract The synthesis and characterisation of copper, cobalt, nickel and zinc compounds with sulfamethizole (4-amino-N-(5-methyl-1,3,4-thiadiazole-2-yl)sulfanilamide) (Hsmtz) are described. The first crystal structures of ternary sulfamethizole complexes are reported. The crystal structures of Cu(smtz)2(py)2(OH2)·H2O (1), M(smtz)2(py)2(OH2)2 [M=Co (2), Ni (3)] and {Cu(smtz)2(dmf)2}∞ (5) were determined by X-ray diffraction. The Cu(II) ion exhibits a square pyramidal geometry in complex 1, while in the other compounds the metal ion presents a distorted octahedral environment. In compounds 1, 2 and 3 the deprotonated sulfamethizole acts as monodentate ligand coordinating through the thiadiaz…

Copper complexes modelling the interaction between benzolamide and Cu-substituted carbonic anhydrase. Crystal structure of Cu(bz)(NH3)4 complex

New copper benzolamide (H 2 bz, 5-phenylsulfonamide-1,3,4-thiadiazole-2-sulfonamide) complexes with ammonia, diethylentriamine (dien) and dipropylentriamine (dipn) have been prepared. The complex [Cu(bz)(NH 3 ) 4 ] crystallises in the monoclinic space group P 2 1 / n with a = 7.621(3), b = 19.91(5), c = 11.291(3) A, β = 93.17(4)° and Z = 4. The Cu(II) is five-coordinated with an almost regular square pyramidal geometry. The dideprotonated sulfonamide behaves as monodentate ligand interacting with the metal ion through the N atom of the unsubstituted sulfonamide group. In the EPR spectrum, exchange coupling between Cu(II) polyhedra of different orientations in the unit cell is observed. The …

Influence of tetrahedral distortion of CuN4 complexes on spectroscopic properties. Synthesis, characterization and crystal structures of [Cu(N-(2-methylpyridyl)benzenesulfonylamidate)2], [Cu(N-(2-methylpyridyl)toluenesulfonylamidate)2] and [Cu(N-(2-methylpyridyl)naphthalenesulfonylamidate)2] compounds

Abstract A series of new N-sulfonamide ligands and their copper(II) complexes, [Cu(N-(2-methylpyridyl)toluenesulfonylamidate)2] (1), [Cu(N-(2-methylpyridyl)benzenesulfonylamidate)2] (2) and [Cu(N-(2-methylpyridyl)naphthalenesulfonylamidate)2] (3), have been synthesized and characterized. Single crystal X-ray analysis of the three complexes revealed that all of them present a tetracoordinate CuN4 chromophore. The ligands act as bidentate, coordinating the metal ion through the pyridine and sulfonamido N atoms. The main structural difference among the compounds is the varied degree of distortion of square-planar stereochemistry. Complex 1 exhibits a regular square-planar geometry. In complexe…

Coordination behavior of sulfathiazole. Crystal structure of [Cu (sulfathiazole) (py)3Cl] superoxide dismutase activity

Abstract The preparation, spectroscopic, magnetic properties, and crystal structure of [Cu(stzxpy) 3 Cl] (stz − stands for the deprotonated form of sulfathiazole, 4-amino-N-2-thiazolylbencenosulfonamide) are reported. Crystals are orthorhombic, space group Pbca, with cell constants a = 15.834(2), b = 17.512(4), and c = 18.79(2) A, and Z = 8. The structure was solved and refined to R = 0.041 (R W = 0.040). The structure consists of mononuclear units linked via hydrogen bonds to form the tridimensional pyramid. The geometry of CuN3N*NCl chromophore is distorted square-pyramid. The superoxide-dismutase mimetic activity of the compound is measured and compared with those of the SOD enzyme, the …

Countercomplementarity and Strong Ferromagnetic Coupling in a Linear Mixed μ-Acetato, μ-Hydroxo Trinuclear Copper(II) Complex. Synthesis, Structure, Magnetic Properties, EPR, and Theoretical Studies

The structural and magnetic data of the trinuclear compound [Cu3(L)2(CH3COO)2(OH)2(dmf)2] (HL = N-(2-methylpyridyl)toluensulfonylamide) are reported. The compound crystallizes in the monoclinic system, space group P2(1)/n (no. 14), with a = 11.6482(6) A, b = 13.5772(6) A, c = 13.5306(7) A, alpha = 90 degrees, beta = 92.859(5) degrees, gamma = 90 degrees, and Z = 2. The three copper atoms form an exact linear arrangement. Neighboring coppers are connected by a hydroxo bridge and a bidentate syn-syn carboxylato group. The coordination spheres of the terminal copper atoms are square pyramidal with a dmf molecule as the apical ligand. The central copper has a regular square planar geometry. The…

Spectroscopic, Magnetic, and Electrochemical Studies of a Dimeric N-Substituted-Sulfanilamide Copper(II) Complex. X-ray and Molecular Structure of the Cu(2)(sulfathiazolato)(4) Complex.

A copper(II) complex of formula Cu(2)(stz)(4) (stz(-) = sulfathiazolato) has been synthesized and characterized by single-crystal X-ray diffraction. The compound crystallizes in the orthorhombic system, space group P2(1)cn with a = 10.595(7) Å, b = 14.274(3) Å, c = 29.65(1) Å, and Z = 4. The structure consists of dinuclear copper(II) units which contain four sulfathiazolato ligands bridging the metal ions through a nonlinear NCN group. The copper atoms are four-coordinated, the chromophore being CuN(4). The Cu.Cu bond distance is 2.671(2) Å. Magnetic susceptibility data in the temperature range 7-300 K show the occurrence of intramolecular antiferromagnetic coupling with 2J = -61.5 cm(-1). …

Genotoxic Potential of N ‐(Benzothiazolyl)sulfonamide Copper(II) Complexes on Yeast Cells Transformed with YEGFP Expression Constructs Containing the RAD54 or RNR2 Promoter

Four ternary complexes [Cu(L)2(phen)] where L is an N(benzothiazol-2-yl)sulfonamide derivative have been prepared and their ability to cleave DNA has been studied. The complexes were structurally characterized with the aid of single-crystal X-ray crystallography. Whereas the molecular structure of the [Cu(L1)2(phen)] (1) [HL1 = N-(6-chlorobenzothiazol-2-yl)benzenesulfonamide] and [Cu(L3)2(phen)] (3) [HL3 = N-(benzothiazol-2-yl)benzenesulfonamide] complexes can best be described as having a distorted squareplanar geometry, that of the [Cu(L4)2(phen)] (4) [HL4 = N(benzothiazol-2-yl)toluenesulfonamide] complex shows a strictly square-planar geometry. The [Cu(L2)2(phen)MeOH] (2) [HL2 = N-(6-chl…

Cu(II) complexes with a sulfonamide derived from benzoguanamine. Oxidative cleavage of DNA in the presence of H2O2 and ascorbate

Reaction between benzoguanamine (2,4-diamino-6-phenyl-1,3,5-triazine) and 2-mesitylenesulfonyl chloride leads to formation of a sulfonamide able to form two mononuclear Cu(II) complexes with a CuL(2) stoichiometry. The local environment of the metal cation is a distorted octahedron, with two ligands and two solvent molecules; both complexes crystallize in the monoclinic structure, space group P2(1), with Z=2. In the presence of ascorbate/H(2)O(2,) the two complexes significantly cleavage double-strand pUC18 DNA plasmid. Both complexes exhibit more nuclease efficiency that the copper phenantroline complex. From scavenging reactive oxygen studies we conclude that the hydroxyl radical and a si…

Superoxide dismutase activity of ternary copper complexes of sulfathiazole and imidazole derivatives. Synthesis and properties of [CuL2(R-Him)2] [HL=4-amino-N-(thiazol-2-yl)benzenesulfonamide, R-Him=4-methylimidazole, 4,4-dimethylimidazoline or 1,2-dimethylimidazole]. Crystal structure of [CuL2(4,4-dimethylimidazoline)2]

Abstract New ternary copper(II) complexes of sulfathiazole (4-amino-N-(thiazol-2-yl)benzenesulfonamide)(HL) and methyl imidazole derivatives have been synthesised and characterised. The crystal structure of the complex [CuL2(4,4-dmHim)2] (1) [4,4-dmHim=4,4-dimethylimidazoline] has been determined. The copper centre has a quasi regular square planar environment with Cu-nitrogen bond lengths ranging from 1.952 to 2.010 A. From the spectroscopic properties of the complexes [CuL2(1,2-dmHim)2] (2) [1,2-dmHim=1,2-dimethylimidazole] and [CuL2(4-mHim)2] (3) [4-mHim=4-methylimidazole] a distorted tetragonal octahedral geometry is deduced. The compounds showed SOD mimetic activity in fact, a low conc…

Toward the development of metal-based synthetic nucleases: DNA binding and oxidative DNA cleavage of a mixed copper(II) complex with N-(9H-purin-6-yl)benzenesulfonamide and 1,10-phenantroline. Antitumor activity in human Caco-2 cells and Jurkat T lymphocytes. Evaluation of p53 and Bcl-2 proteins in the apoptotic mechanism

Abstract The complex [Cu(N9-ABS)(phen) 2 ]·3.6H 2 O, H 2 N9-ABS  = N -(9 H -purin-6-yl)benzenesulfonamide and phen = 1,10-phenanthroline, has been synthesized and then characterized with the aid of X-ray diffraction, analytical, and spectroscopic techniques. The geometry of Cu(II) is distorted square pyramidal with the equatorial positions occupied by three N atoms from two phenantroline molecules and one N atom from the adenine ring of the sulfonamide ligand. The interaction of the complex with DNA was studied by means of viscosity measurements and fluorescence spectroscopy. The results pointed to a classic intercalation of the complex between the DNA base pairs. The complex was found to b…

Comparison of the interaction of cobalt bovine carbonic anhydrase II with acetazolamide and methazolamide and the reaction of apoenzyme with cobalt(II) complexes of acetazolamide and methazolamide: Spectrophotometric study

The metalloenzyme carbonic anhydrase (CA) is an attractive choice for a research-based bioinorganic laboratory course. In this project the interaction of cobalt bovine carbonic anhydrase II (CoBCAII) with acetazolamide and methazolamide and the reaction of apoenzyme with cobalt(II) complexes of acetazolamide and methazolamide is studied by UV-visible spectroscopy. Prior to this spectroscopic study students are given native BCAII, and they prepare apoBCAII and CoBCAII. A major aim is to provide experience in handling metalloproteins and in the study of metal complexes-protein interactions.

Metal complexes of sulfanilamide derivatives. Crystal structure of [Zn(sulfathiazole)2]·H2O

Abstract The crystal structure of the Zn(sulfathiazole) 2 ·H 2 O complex is reported. The complex crystallizes in the monoclinic space group C 2/ c . The cell dimensions are a = 9.098(3) A, b = 17.871(5) A, c = 14.61(1) A, β = 99.44(6)°, V = 2343(2) A 3 , Z = 4, and D x = 1.68 g/cm 3 . The final conventional R-factor = 0.027 for 2669 “observed” reflections and 191 variables. The Zn ion is surrounded in a regular tetrahedral arrangement by two N amino and two N thiazole atoms pertaining to four sulfathiazole (Hstz) ligands. Each stz anion, acting as a bidentate ligand, chelates to two Zn ions as a bridge through the N thiazole and the N amino atoms. The IR, 13 C NMR in solid state, 1 H NMR, …

Oxidative nuclease activity of ferromagnetically coupled μ-hydroxo-μ-propionato copper(II) complexes [Cu3(L)2(μ-OH)2(μ-propionato)2] (L=N-(pyrid-2-ylmethyl)R-sulfonamidato, R=benzene, toluene, naphthalene)

Three doubly-bridged, trinuclear copper(II) compounds with hydroxo and carboxylato bridges, ∞ 1 [Cu 3 (L1) 2 (μ-OH) 2 (μ-propionato) 2 ] ∞ 1 [ Cu 3 ( L 1 ) 2 ( μ - OH ) 2 ( μ - propionato ) 2 ] (1) , [Cu 3 (L2) 2 (μ-OH) 2 (μ-propionato) 2 (DMF) 2 ] (2) and ∞ 1 {[Cu 3 (L3) 2 (μ-OH) 2 (μ-propionato) 2 ]} ∞ 1 { [ Cu 3 ( L 3 ) 2 ( μ - OH ) 2 ( μ - propionato ) 2 ] } [Cu 3 (L3) 2 (μ-OH) 2 (μ-propionato) 2 (DMF) 2 ]} (3) [HL1 =  N -(pyrid-2-ylmethyl)benzenesulfonylamide, HL2 =  N -(pyrid-2-ylmethyl)toluenesulfonylamide, HL3 =  N -(pyrid-2-ylmethyl)naphthalenesulfonylamide], have been synthesized and characterized. 1 is built from [Cu 3 (L1) 2 (μ-OH) 2 (μ-propionato) 2 ] clusters. Each unit contai…

Tetrakis[(mu-hydroxo)(mu-sulfathiazolato)copper(II)] tetrakis(dimethyl sulfoxide): a new square-planar tetranuclear copper(II) complex containing four hydroxo and four NCN-sulfathiazolato bridges. Electrochemical synthesis, crystal structure, and magnetic properties.

CCDC 1941350: Experimental Crystal Structure Determination

Related Article: Gloria Alzuet, Alfonso Castiñeiras, Iago Cores, Isabel García-Santos, Marta González-Álvarez, Manuel Saa|2020|J.Inorg.Biochem.|203|110902|doi:10.1016/j.jinorgbio.2019.110902

CCDC 1941352: Experimental Crystal Structure Determination

Related Article: Gloria Alzuet, Alfonso Castiñeiras, Iago Cores, Isabel García-Santos, Marta González-Álvarez, Manuel Saa|2020|J.Inorg.Biochem.|203|110902|doi:10.1016/j.jinorgbio.2019.110902

CCDC 1941349: Experimental Crystal Structure Determination

Related Article: Gloria Alzuet, Alfonso Castiñeiras, Iago Cores, Isabel García-Santos, Marta González-Álvarez, Manuel Saa|2020|J.Inorg.Biochem.|203|110902|doi:10.1016/j.jinorgbio.2019.110902

CCDC 1941351: Experimental Crystal Structure Determination

Related Article: Gloria Alzuet, Alfonso Castiñeiras, Iago Cores, Isabel García-Santos, Marta González-Álvarez, Manuel Saa|2020|J.Inorg.Biochem.|203|110902|doi:10.1016/j.jinorgbio.2019.110902

CCDC 1941353: Experimental Crystal Structure Determination

Related Article: Gloria Alzuet, Alfonso Castiñeiras, Iago Cores, Isabel García-Santos, Marta González-Álvarez, Manuel Saa|2020|J.Inorg.Biochem.|203|110902|doi:10.1016/j.jinorgbio.2019.110902

CCDC 1941348: Experimental Crystal Structure Determination

Related Article: Gloria Alzuet, Alfonso Castiñeiras, Iago Cores, Isabel García-Santos, Marta González-Álvarez, Manuel Saa|2020|J.Inorg.Biochem.|203|110902|doi:10.1016/j.jinorgbio.2019.110902