Synthesis,crystal structures,and urease inhibition studies of two new Schiff-base copper complexes derived from n-butylamine

Two Schiff-base copper(II) complexes, bis(N-n-butyl-5-chlorosalicylaldiminato) copper(II) (1) and bis(N-n-butyl-4-methoxysalicylaldiminato) copper(II) (2), were synthesized and their solid-state structures were determined by X-ray crystallography. Complex 1 displays a distorted square-planar geometry, while 2 possesses square-planar geometry. Copper(II) complexes 1 and 2 showed strong inhibitory activity against jack bean urease (IC₅₀?=?2.7, 3.5?µmol?L^?1), compared with acetohydroxamic acid (IC₅₀?=?63.00?µmol?L^?1). A molecular modeling study was carried out via the DOCK program to gain understanding of the potent inhibitory activity of these copper species against jack bean urease.     

Synthesis,characterization, and urease inhibitory activity of two copper(II) complexes of cyclohexanecarboxylate

The crystal structures of two copper(II) complexes of the cyclohexanecarboxylate ligand, namely [Cu(C₆H₁₁CO₂)₂(H₂O)₂]·H₂O (1) and [Cu(dpyam)₂(C₆H₁₁CO₂)](NO₃)·H₂O (2) (C₆H₁₁CO₂H = cyclohexanecarboxylic acid; dpyam = di-2-pyridylamine), have been determined by single-crystal X-ray analysis. Complex 1 contains the square-planar trans-CuO₄ chromophore, while 2 shows the square pyramidal cis-distorted octahedral CuN₄OO′ chromophore. Both complexes were found to show strong inhibitory activity against jack bean urease (IC₅₀ = 1.75 and 8.57 μM for 1 and 2, respectively), when compared with acetohydroxamic acid (IC₅₀ = 63.12 μM).     

Synthesis,structure, and biological evaluation of three Cu(II) and Ni(II) (E)-3-(3,4-dimethoxyphenyl)acrylate complexes with organic diamines as potential urease inhibitors

Three new complexes (1–3) have been synthesized and characterized by X-ray single crystal determination and evaluated for inhibitory activity on jack bean urease. All the complexes contained a new cinnamic acid derivative as the ligand (C₁₁H₁₂O₄), (E)-3-(3,4-dimethoxyphenyl)acrylic acid, and crystallized in monoclinic C2/c space group. Complex 1 (C₁₁H₁₁O₄)₄(C₃N₂H₈)₂Cu₂ (C₃N₂H₈?=?1,2-diaminopropane) was obtained with a?=?20.488(2), b?=?19.596(2), c?=?15.2500(13), β?=?93.502(2)°, V?=?6111.2(10)?ų, Z?=?4, R ₁ ?=?0.0616, and wR ₂ ?=?0.2059. Complex 2 (C₁₁H₁₁O₄)₄(C₃N₂H₈)₂Cu₂ (C₃N₂H₈=1,3-diaminopropane) was obtained with a?=?20.2494(12), b?=?19.5732(12), c?=?14.8940(8), β?=?96.884(2)°, V?=?5860.6(6)?ų, Z?=?4, R ₁ ?=?0.0409, and wR ₂ ?=?0.1107. Complex 3 (C₁₁H₁₁O₄)₂(C₂N₂H₆)₂Ni₂·H₂O (C₂N₂H₆?=?ethylenediamine) was obtained with a?=?28.359(2), b?=?6.5422(5), c?=?16.8587(14), β?=?101.359(2)°, V?=?3066.5(4)?ų, Z?=?4, R ₁ ?=?0.0422, and wR ₂ ?=?0.1190. It was found that copper(II) complexes 1 [IC₅₀?=?4.71?μM] and 2 [IC₅₀?=?3.15?μM] showed strong inhibitory activity against jack bean urease compared with acetohydroxamic acid [IC₅₀?=?10.01?μM] as a positive reference. Unfortunately, 3 exhibited no inhibitory activity.     

Synthesis,crystal structure,and urease inhibition studies of copper(II) and cobalt(III) complexes with bi(2-fluorobenzylaminoethyl)amine

Three new mononuclear Cu(II) and Co(III) complexes [Cu(L)Cl]ClO₄ (1), [Cu(L)Cl(SCN)] (2), and [Co(L)(N₃)₃] (3), where L is a reduced Schiff-base ligand bi(2-fluorobenzylaminoethyl)amine, were synthesized and characterized. X-ray crystallographical analysis reveals that the Cu(II) atom adopts a square-planar environment in complex 1, while the geometry in 2 can be described as distorted square-pyramidal. The Co(III) atom in 3 is in a distorted octahedral geometry. Three complexes were investigated for their inhibitory activities in vitro against jack bean urease. The Cu(II) complexes 1 and 2 were found to have excellent inhibitory activities. The Co(III) complex 3 was also shown to have activity comparable to that of acetohydroxamic acid.     

Synthesis,structure, and urease inhibitory activities of Co(III), Mn(II) and Zn(II) complexes with hydrazone derived from protocatechuic acid

[Co^III(L₁)₂·H₂O]NO₃ (1), [Mn^II(L₁)₂·H₂O] (2), and [Zn^II(L₁)₂·H₂O] (3) with a hydrazone derived from protocatechuic acid (HL₁ = C₁₅H₁₃N₃O₃) were designed, synthesized, and characterized by C, H, N elemental analyses, single-crystal X-ray diffraction, and IR spectra, which revealed that the three complexes are similar structures. Docking study has been done. The urease inhibitory activities of the three complexes were tested. Complexes 1 and 3 showed strong inhibitory activity against jack bean urease with IC₅₀ values of 45.9 and 11.64 μM. Complex 2 had no obvious inhibitory activity to urease; the IC₅₀ was > 50 μM.     

Synthesis,structure and bioactivity of Ni2+ and Cu2+ acylhydrazone complexes

Two acylhydrazone complexes, bis{6‐methyl‐N′‐[1‐(pyrazin‐2‐yl‐κN¹)ethylidene]nicotinohydrazidato‐κ²N′,O}nickel(II), [Ni(C₁₃H₁₂N₅O)₂], (I), and di‐μ‐azido‐κ⁴N¹:N¹‐bis({6‐methyl‐N′‐[1‐(pyrazin‐2‐yl‐κN¹)ethylidene]nicotinohydrazidato‐κ²N′,O}nickel(II)), [Cu₂(C₁₃H₁₂N₅O)₂(N₃)₂], (II), derived from 6‐methyl‐N′‐[1‐(pyrazin‐2‐yl)ethylidene]nicotinohydrazide (HL) and azide salts, have been synthesized. HL acts as an N,N′,O‐tridentate ligand in both complexes. Complex (I) crystallizes in the orthorhombic space group Pbcn and has a mononuclear structure, the azide co‐ligand is not involved in crystallization and the Ni²⁺ centre lies in a distorted {N₄O₂} octahedral coordination environment. Complex (II) crystallizes in the triclinic space group P and is a centrosymmetric binuclear complex with a crystallographically independent Cu²⁺ centre coordinating to three donor atoms from the deprotonated L^? ligand and to two N atoms belonging to two bridging azide anions. The two‐ and one‐dimensional supramolecular structures are constructed by hydrogen‐bonding interactions in (I) and (II), respectively. The in vitro urease inhibitory evaluation revealed that complex (II) showed a better inhibitory activity, with the IC₅₀ value being 1.32±0.4 µM. Both complexes can effectively bind to bovine serum albumin (BSA) by 1:1 binding, which was assessed via tryptophan emission–quenching measurements. The bioactivities of the two complexes towards jack bean urease were also studied by molecular docking. The effects of the metal ions and the coordination environments in the two complexes on in vitro urease inhibitory activity are preliminarily discussed.     

Synthesis,characterization, and structural determination of copper(II) complexes with alkyl derivatives of hydroxybenzophenones

Four mononuclear copper(II) complexes, [Cu(LFQM-115)₂] (1), [Cu(LFQM-116)₂] (2), [Cu(LFQM-117)₂] (3) and [Cu(octyloxy)₂] (4) [LFQM-115 = 2-hydroxy-4-O-methylbenzophenone (C₁₄H₁₁O₃), LFQM-116 = 2-hydroxy-4-O-butylbenzophenone (C₁₇H₁₈O₃), LFQM-117 = 2-hydroxy-4-O-(33-dimethylallyl)benzophenone (C₁₈H₁₈O₃) and octyloxy = 2-hydroxy-4-O-octylbenzophenone (C₂₁H₂₅O₃)], have been prepared and investigated by infrared spectroscopy, thermal analysis, and powder and single crystal X-ray diffraction. Even though the synthesis and infrared analysis of 1, 2, and 4 have been reported previously, their crystal structures were elucidated for the first time here. In addition, the crystal structures of LFQM-116 and LFQM-117 were also determined by single crystal X-ray diffraction. The pseudo-translational symmetry found in LFQM-116 and the isomorphism between LFQM-115 and LFQM-117 are discussed. The complexes were prepared from a reaction of copper(II) nitrate trihydrate and the respective ligand in a (1:2) molar ratio in methanol (for 1 and 2) or THF (for 3 and 4) with addition of NaOH. Furthermore, crystallographic studies show that each copper(II) exhibits a square planar geometry, coordinated by four oxygens of two ligands. The nature and crystal packing of the intermolecular interactions are discussed. Compounds 2 and 3 are isomorphic crystals and all structures have the same supramolecular synthon.     

Dimeric copper(II) 3,3‐dimethyl­butyrate adducts with ethanol, 2‐methylpyridine, 3‐methylpyridine, 4‐methylpyridine and 3,3‐dimethylbutyric acid

In the crystals of the five title compounds, tetrakis‐(μ‐3,3‐dimethylbutyrato‐O:O′)bis(ethanol‐O)dicopper(II)–ethanol (1/2), [Cu₂(C₆H₁₁O₂)₄(C₂H₆O)₂]·2C₂H₆O, (I), tetrakis(μ‐3,3‐dimethylbutyrato‐O:O′)bis(2‐methylpyridine‐N)di­copper(II), [Cu₂(C₆H₁₁O₂)₄(C₆H₇N)₂], (II), tetrakis‐(μ‐3,3‐dimethylbutyrato‐O:O′)bis(3‐methylpyridine‐N)di‐copper(II), [Cu₂(C₆H₁₁O₂)₄(C₆H₇N)₂], (III), tetrakis‐(μ‐3,3‐dimethylbutyrato‐O:O′)bis(4‐methylpyridine‐N)di‐copper(II), [Cu₂(C₆H₁₁O₂)₄(C₆H₇N)₂], (IV), and tetrakis‐(μ‐3,3‐dimethylbutyrato‐O:O′)bis(3,3‐dimethylbutyric acid‐O)dicopper(II), [Cu₂(C₆H₁₁O₂)₄(C₆H₁₂O₂)₂], (V), the di­nuclear Cu^II complexes all have centrosymmetric cage structures and (IV) has two independent molecules. The Cu?Cu separations are: (I) 2.602 (3) Å, (II) 2.666 (3) Å, (III) 2.640 (2) Å, (IV) 2.638 (4) Å and (V) 2.599 (1) Å.     

Syntheses,urease inhibition activities,and fluorescent properties of transition metal complexes

Four transition metal complexes with Schiff base and 1,10-phenanthroline, [Cu(L)(phen)]₂·C₂H₅OH (1), [Zn(L)(phen)]₂·C₂H₅OH (2), [Ni(L)(phen)]₂·C₂H₅OH (3), and [Co(L)(phen)]₂·C₂H₅OH (4) (H₂L?=?1-((2-hydroxynaphthalen-1-yl)methylene)thiosemicarbazide; phen?=?1,10-phenanthroline) were synthesized and characterized by physico-chemical methods. The crystal structure of 1 was determined by X-ray single-crystal diffraction analysis. 1 crystallizes in the orthorhombic space group Pbca with a?=?15.008(9), b?=?16.100(10), c?=?37.54(2)?Å, V?=?9070(10)?ų, Z?=?8, GOOF?=?1.002, R ₁?=?0.0626, and wR ₂?=?0.0912. The fluorescence and urease inhibitory activities of the compounds were tested. The enzymatic activity study indicated that 3 possessed potent inhibition against jack bean urease, with IC₅₀?=?1.2?±?0.1?μM, and about 35 times more than 42.1?±?0.4 acetohydroxamic acid as positive reference. This suggests that inhibitory efficiency of these complexes can be strongly influenced by different transition metal ions.     

Tracking the dissolution–recrystallization structural transformation (DRST) of copper(II) complexes: a combined crystallographic,mass spectrometric and DFT study

Methanol‐ and temperature‐induced dissolution–recrystallization structural transformation (DRST) was observed among two novel Cu^II complexes. This is first time that the combination of X‐ray crystallography, mass spectrometry and density functional theory (DFT) theoretical calculations has been used to describe the fragmentation and recombination of a mononuclear Cu^II complex at 60 °C in methanol to obtain a binuclear copper(II) complex. Combining time‐dependent high‐resolution electrospray mass spectrometry, we propose a possible mechanism for the conversion of bis(8‐methoxyquinoline‐κ²N,O)bis(thiocyanato‐κN)copper(II), [Cu(NCS)₂(C₁₀H₉NO)₂], Cu1 , to di‐μ‐methanolato‐κ⁴O:O‐bis[(8‐methoxyquinoline‐κ²N,O)(thiocyanato‐κN)copper(II)], [Cu₂(CH₃O)₂(NCS)₂(C₁₀H₉NO)₂], Cu2 , viz. [Cu(SCN)₂( L )₂] ( Cu1 ) → [Cu( L )₂] → [Cu( L )]/ L → [Cu₂(CH₃O)₂(NCS)₂( L )₂] ( Cu2 ). We screened the antitumour activities of L (8‐methoxyquinoline), Cu1 and Cu2 and found that the antiproliferative effect of Cu2 on some tumour cells was much greater than that of L and Cu1 .     

Effect of pH on the charge‐assisted hydrogen‐bonded assembly of the anionic [Cu(oxalate)2]2− building unit and N,N′‐ditopic cations

By the solvothermal reaction under acidic conditions of Cu(NO₃)₂·3H₂O, Na₂C₂O₄ and the N,N′‐ditopic organic coligands 1‐(pyridin‐4‐yl)piperazine (ppz) and 1,2‐bis(pyridin‐4‐yl)ethane (bpa), two novel anionic copper(II) coordination compounds were obtained, namely the one‐dimensional coordination polymer catena‐poly[4‐(pyridin‐1‐ium‐4‐yl)piperazin‐1‐ium [[(oxalato‐κ²O¹,O²)copper(II)]‐μ‐oxalato‐κ³O¹,O²:O^1′]], {(C₉H₁₅N₃)[Cu(C₂O₄)₂)]}_n or {(H₂ppz)[Cu(C₂O₄)₂]}_n, (I), and the discrete ionic complex 4,4′‐(ethane‐1,2‐diyl)dipyridinium bis(oxalato‐κ²O¹,O²)copper(II), (C₁₂H₁₄N₂)[Cu(C₂O₄)₂] or (H₂bpa)[Cu(C₂O₄)₂], (II). The products were characterized by single‐crystal X‐ray diffraction, elemental analysis, powder X‐ray diffraction, thermogravimetric analyses and UV and IR spectroscopic techniques. The [Cu(C₂O₄)₂]²⁻ units for (I) and (II) are stabilized by H₂ppz²⁺ and H₂bpa²⁺ cations, respectively, via charge‐assisted hydrogen bonds. Also, a study of the pH‐controlled synthesis of this system shows that (I) was obtained at pH values of 2–4. When using bpa, a two‐dimensional square‐grid network of [Cu(C₂O₄)(bpa)]_n was obtained at a pH of 4. This indicates that the pH of the reaction also plays a key role in the structural assembly and coordination abilities of oxalate and N,N′‐ditopic coligands.     

Four‐ and five‐coordinate copper(II) complexes with N‐(4,4‐diphenyl‐5‐oxo‐4,5‐dihydro‐1H‐imidazol‐2‐yl)glycine

The two title mononuclear compounds are four‐coordinate bis[N‐(5‐oxo‐4,4‐diphenyl‐4,5‐dihydro‐1H‐imidazolidin‐2‐ylidene)glycinato]copper(II) dimethylformamide disolvate, [Cu(C₁₇H₁₄N₃O₃)₂]·2C₃H₇NO, (I), and five‐coordinate aquabis[N‐(5‐oxo‐4,4‐diphenyl‐4,5‐dihydro‐1H‐imidazolidin‐2‐ylidene)glycinato]copper(II) dimethylformamide disolvate, [Cu(C₁₇H₁₄N₃O₃)₂(H₂O)]·2C₃H₇NO, (II). In (I), the Cu^II ion lies on an inversion centre with one‐half of the complex molecule in the asymmetric unit, while in (II) there are two independent ligand molecules in the asymmetric unit, with the Cu^II ion and coordinated water molecule located on a general position. In both crystal structures, the complex molecules assemble in ribbons via N—H...O hydrogen‐bond networks.     

Dimeric copper(II) trimethylsilyl­acetate adducts with pyridine, 2‐­methylpyridine, 3‐methylpyridine and quinoline,and a polymeric copper(II) trimethylsilylacetate

In the crystals of bis(pyridine‐N)tetrakis(μ‐trimethylsilylacetato‐O:O′)dicopper(II), [Cu₂(C₅H₁₁O₂Si)₄(C₅H₅N)₂], (I), the dinuclear Cu^II complexes have cage structures with Cu?Cu distances of 2.632 (1) and 2.635 (1) Å. In the crystals of bis(2‐­methylpyridine‐N)tetrakis(μ‐trimethylsilylacetato‐O:O′)dicopper(II), [Cu₂(C₅H₁₁O₂Si)₄(C₆H₇N)₂], (II), bis­(3‐methylpyridine‐N)tetrakis(μ‐trimethylsilylacetato‐O:O′)dicopper(II), [Cu₂(C₅H₁₁O₂Si)₄(C₆H₇N)₂], (III), and bis(quinoline‐N)­tetrakis(μ‐­trimethylsilylacetato‐O:O′)dicopper(II), [Cu₂(C₅H₁₁O₂Si)₄(C₉H₇N)₂], (IV), the centrosymmetric dinuclear Cu^II complexes have a cage structure with Cu?Cu distances of 2.664 (1), 2.638 (3) and 2.665 (1) Å, respectively. In the crystals of catena‐poly­[tetrakis(μ‐trimethylsilylacetato‐O:O′)dicopper(II)], [Cu₂(C₅H₁₁O₂Si)₄]_n, (V), the dinuclear Cu^II units of a cage structure are linked by the cyclic Cu—O bonds at the apical positions to form a linear chain by use of a glide translation.     

Acetone salicyloylhydrazone of Ni(II): synthesis,molecular structures,and properties

Two new mononuclear Ni(II) complexes, [Ni(C₁₀H₁₂O₂N₂)₂(C₅H₅N)₂](NO₃)₂ (1) and [Ni(C₁₀H₁₂O₂N₂)₂(H₂O)₂](NO₃)₂ (2), have been synthesized and characterized by elemental analysis, infrared, UV-Vis spectroscopy, and single-crystal X-ray diffraction. The coordination geometry around each Ni(II) can be described as an octahedron with each Ni(II) coordinated to two imino nitrogens, two carbonyl oxygens, and two solvent molecules (pyridine for 1 and water for 2). In the synthesis, the original ligand changes from o-carboxybenzaldehyde salicyloylhydrazone (C₁₅H₁₂O₄N₂) into acetone salicyloylhydrazone (C₁₀H₁₂O₂N₂). The thermal stability of the complexes at three different heating rates (β = 5, 10, and 15°C min^?1) show that all the complexes exhibit three thermal decomposition stages and their thermal stability is 1 > 2. Complexes 1 and 2 both display DNA binding ability, ascertained by UV-Vis titration.     

A tetranuclear copper(II) complex: crystal structure,assembly, EPR,electrochemistry and magnetism

A tetranuclear copper(II) complex, [Cu₂L]₂(ClO₄)₂ · 4H₂O (1), where H₃L = N,N′-bis(4-(3′-formyl-5′-chlorosalicyclidene)iminoethyl)-4-chloro-2,6-bimethyliminophenol, has been synthesized and structurally characterized by ES-MS, IR and X-ray crystallography. The complex is a dimer of two dinuclear copper(II) acylic enantiomorph subunits ([Cu₂L]ClO₄ · 2H₂O), held together by π–π, coordination and hydrogen bond interactions. The Cu–Cu separation in each subunit, bridged by one phenoxide, is 3.228 Å, and the shortest distance of Cu–Cu between the two subunits is 3.252 Å. There are two crystallographically unique copper(II) environments, one (Cu1) is square-based pyramidal with O₃N₂ donor set, another (Cu2) square planar with O₂N₂ donor set. The cyclic voltammogram of the complex shows that it undergoes two stepwise reduction processes, E _pc = ?0.707 and ?0.850 V, respectively. Magnetic measurements in the 2–300 K range indicate strong antiferromagnetic interactions between Cu(II) ions in each subunit with the exchange constant J = ?211(2) cm^?1. The observation has been rationalized on the basis of the effective magnetic pathway.     

Dinuclear cobalt and nickel complexes of a mercaptoacetic acid substituted 1,2,4‐triazole ligand: syntheses,structures and urease inhibitory studies

Because of its versatile coordination modes and strong coordination ability, the mercaptoacetic acid substituted 1,2,4‐triazole 2‐{[5‐(pyridin‐2‐yl)‐4H‐1,2,4‐triazol‐3‐yl]sulfanyl}acetic acid ( H₂L ) was synthesized and characterized. Treatment of H₂L with cobalt and nickel acetate afforded the dinuclear complexes {μ‐3‐[(carboxylatomethyl)sulfanyl]‐5‐(pyridin‐2‐yl)‐4H‐1,2,4‐triazol‐4‐ido‐κ²N¹,N⁵:N²,O}bis[aqua(methanol‐κO)cobalt(II)] methanol disolvate, [Co₂(C₉H₆N₄O₂S)₂(CH₃OH)₂(H₂O)₂]·2CH₃OH ( 1 ), and {μ‐3‐[(carboxylatomethyl)sulfanyl]‐5‐(pyridin‐2‐yl)‐4H‐1,2,4‐triazol‐4‐ido‐κ²N¹,N⁵:N²,O}bis[diaquanickel(II)] methanol disolvate dihydrate, [Ni₂(C₉H₆N₄O₂S)₂(H₂O)₄]·2CH₃OH·2H₂O ( 2 ), respectively. Complex 1 crystallized in the monoclinic space group P2₁/c, while 2 crystallized in the tetragonal space group I4₁/a. Single‐crystal X‐ray diffraction studies revealed that H₂L is doubly deprotonated and acts as a tetradentate bridging ligand in complexes 1 and 2 . For both of the obtained complexes, extensive hydrogen‐bond interactions contribute to the formation of their three‐dimensional supermolecular structures. Hirshfeld surface analysis was used to illustrate the intermolecular interactions. Additionally, the urease inhibitory activities of 1 , 2 and H₂L were investigated against jack bean urease, where the two complexes revealed strong urease inhibition activities.     

The crystal and molecular structures of three copper‐containing complexes and their activities in mimicking galactose oxidase

The structures of three copper‐containing complexes, namely (benzoato‐κ²O,O′)[(E)‐2‐({[2‐(diethylamino)ethyl]imino}methyl)phenolato‐κ³N,N′,O]copper(II) dihydrate, [Cu(C₇H₅O₂)(C₁₃H₁₉N₂O)]·2H₂O, 1 , [(E)‐2‐({[2‐(diethylamino)ethyl]imino}methyl)phenolato‐κ³N,N′,O](2‐phenylacetato‐κ²O,O′)copper(II), [Cu(C₈H₇O₂)(C₁₃H₁₉N₂O)], 2 , and bis[μ‐(E)‐2‐({[3‐(diethylamino)propyl]imino}methyl)phenolato]‐κ⁴N,N′,O:O;κ⁴O:N,N′,O‐(μ‐2‐methylbenzoato‐κ²O:O′)copper(II) perchlorate, [Cu₂(C₈H₇O₂)(C₁₂H₁₇N₂O)₂]ClO₄, 3 , have been reported and all have been tested for their activity in the oxidation of d ‐galactose. The results suggest that, unlike the enzyme galactose oxidase, due to the precipitation of Cu₂O, this reaction is not catalytic as would have been expected. The structures of 1 and 2 are monomeric, while 3 consists of a dimeric cation and a perchlorate anion [which is disordered over two orientations, with occupancies of 0.64 (4) and 0.36 (4)]. In all three structures, the central Cu atom is five‐coordinated in a distorted square‐pyramidal arrangment (τ parameter of 0.0932 for 1 , 0.0888 for 2 , and 0.142 and 0.248 for the two Cu centers in 3 ). In each species, the environment about the Cu atom is such that the vacant sixth position is open, with very little steric crowding.     

Synthesis,crystal structures and characterizations of three new copper(II) complexes including anti‐inflammatory diclofenac

Three new diclofenac‐based copper(II) complexes, namely tetrakis{μ‐2‐[2‐(2,6‐dichloroanilino)phenyl]acetato‐κ²O:O′}bis(methanol‐κO)copper(II), [Cu₂(μ‐dicl)₄(CH₃OH)₂] ( 1 ), bis{2‐[2‐(2,6‐dichloroanilino)phenyl]acetato‐κ²O,O′}bis(1‐vinyl‐1H‐imidazole‐κN³)copper(II), [Cu(dicl)₂(vim)₂] ( 2 ), and bis{2‐[2‐(2,6‐dichloroanilino)phenyl]acetato‐κ²O,O′}bis(1H‐imidazole‐κN³)copper(II), [Cu(dicl)₂(im)₂] ( 3 ) [dicl is diclofenac (C₁₄H₁₀Cl₂NO₂), vim is 1‐vinylimidazole (C₅H₆N₂) and im is imidazole (C₃H₄N₂)], have been synthesized and characterized by elemental analysis, FT–IR spectroscopy, thermal analysis and single‐crystal X‐ray diffraction. X‐ray diffraction analysis shows that complex 1 consists of dimeric units in which the dicl ligand exhibits a bidentate syn,syn‐μ₂ coordination mode linking two copper(II) centres. Complexes 2 and 3 have mononuclear units with the general formula [Cu(dicl)₂L₂] (L is vim or im) in which the Cu^II ions are octahedrally coordinated by two L and two dicl chelating ligands. The L and dicl ligands both occupy the trans positions of the coordination octahedron. The different coordination modes of dicl in the title complexes were revealed by Fourier transform IR (FT–IR) spectroscopy. The spin matching between the copper(II) centres in the dimeric [Cu₂(μ‐dicl)₄(CH₃OH)₂] units was also confirmed by magnetic data to be lower than the spin‐only value and electron paramagnetic resonance (EPR) spectra. The thermal properties of the complexes were investigated by thermogravimetric (TG) and differential thermal analysis (DTA) techniques.     

Three complexes of bis(N‐methyl­benzo­hydro­xamato‐O,O′)copper(II)

The first single‐crystal studies of three bis‐transoid Cu–hydrox­amate salts, bis(3‐methoxy‐4,N‐dimethyl­benzo­hydrox­amato‐O,O′)copper(II), [Cu(C₁₀H₁₂NO₃)₂], bis(4‐chloro‐N‐methyl­benzo­hydro­xamato‐O,O′)copper(II), [Cu­(C₈­H₇­Cl­NO₂)₂], bis(N‐methyl‐3,5‐di­nitro­benzo­hydro­xamato‐O,O′)copper(II)–chloro­form (1/2), [Cu­(C₈­H₆­N₃O₆)₂]·­2CHCl₃, are presented. The Cu atom in each of the title compounds sits at a center of inversion and displays a nearly square‐planar geometry with the hydro­xamate‐O atoms connected to it in a syn configuration. The N atoms are in a transoid configuration. Each five‐membered Cu–hydro­xamate ring is planar, thus providing evidence that a planar N atom is present in each ring. The phenyl groups are twisted with respect to the hydro­xamate group by ～40–54°. The angular strain of the sp² carbonyl oxy­gen is significant (～10° from ideal).     

Synthesis and biological evaluation of Cu(II), Zn(II), and Ni(II) 3-(4-nitrophenyl)acrylic acid complexes with diamines as potential urease inhibitors

Five new Cu(II), Zn(II), and Ni(II) 3-(4-nitrophenyl)acrylic acid complexes were synthesized and evaluated for inhibitory activity on jack bean urease. All five complexes were structurally determined by single crystal X-ray analysis. Compared with the positive reference acetohydroxamic acid (IC₅₀?=?13.25?μM), Cu(II) complexes 3 and 4 showed the strongest inhibitory activity against jack bean urease (IC₅₀?=?1.23 and 1.17?μM). Ni(II) and Zn(II) complexes also exhibited inhibitory activities (IC₅₀?=?10.09–13.10?μM).