Search

In this work, gallium(III) complex with cloxyquin (5-chloro-8-quinolinol, HClQ) ligands is shown to effectively inhibit proliferation of rhabdomyosarcoma cells, the frequent, aggressive, and poorly treatable cancer of children. It offers striking selectivity to cancer cells compared to noncancerous human fibroblasts. The data reveal that the complex induces ferroptosis in rhabdomyosarcoma cells, likely due to interfering with iron metabolism. Importantly, it can kill both bulk and stem rhabdomyosarcoma cells. To the best of our knowledge, this is the first compound based on metal other than Fe capable of inducing ferroptosis in cancer cells.

Seven new zinc(II) complexes, K[Zn(dClQ)3]·2DMF (1), K[Zn(dClQ)3]·2DMF·H2O (2), [Zn(dBrQ)2(H2O)]2·DMF·H2O (3), [Zn(BrQ)2(H2O)]2·H2O (4), (HdClQ)2[ZnCl4]·2H2O (5), [Zn(dClQ)2(H2O)2]·H2O (6) and [Zn(CQ)2(H2O)2] (7) (5,7-dichloroquinolin-8-ol (dClQ), protonated 5,7-dichloroquinolin-8-ol (HdClQ), 5,7-dibromoquinolin-8-ol (dBrQ), 7-bromoquinolin-8-ol (BrQ), 5-chloro-7-iodoquinolin-8-ol (CQ)) have been prepared. All complexes were characterized by IR spectroscopy, elemental analysis and, except 7, by X-ray structure analysis. Stability of complexes in dimethyl sulfoxide was verified by NMR spectra. Antimicrobial activity was tested against nine strains of pathogenic bacteria, five mould species and two yeast species. Cytotoxic activity was tested against colon cancer cell line HCT 116 and non-cancerous cell line CCD-18Co. While all complexes showed higher cytotoxicity than cisplatin, poor selectivity to normal cells was observed.

The five coumarin derivatives 3-(1-(2-hydroxypropylamino)ethylidene)-chroman-2,4-dione (L1), 3-(1-(phenylamino)ethylidene)-chroman-2,4-dione (L2), 3-(1-(o-toluidino)ethylidene)-chroman-2,4-dione (L3), 3-(1-(m-toluidino)ethylidene)-chroman-2,4-dione (L4), 3-(1-(2-mercaptoethylamino)ethylidene)-chroman-2,4-dione (L5) and its corresponding complexes 3-(1-(2-hydroxypropylamino)-ethylidene)-chroman-2,4-dione-palladium(II) (C1), 3-(1-(phenylamino)-ethylidene)-chroman-2,4-dione-palladium(II) (C2), 3-(1-(o-toluidino)-ethylidene)-chroman-2,4-dione-palladium(II) (C3), 3-(1-(m-toluidino)ethylidene)-chroman-2,4-dione-palladium(II) (C4), 3-(1-(2-mercaptoethylamino)ethylidene)-chroman-2,4-dione-palladium(II) (C5), were synthesized and characterized with microanalysis, infrared, 1H and 13C NMR spectroscopy. The proposed structures of ligands L3 and L4 were confirmed on the basis of the X-ray structural study. The ligands and their complexes were tested for their in vitro antimicrobial activity against 17 species of bacteria and fungi. Testing is performed by the microdilution method, with the minimum inhibitory concentration (MIC) and the minimum microbicidal concentration (MMC) being determined.

From the system CuCl2–biq–NaN(CN)2 (biq is 2,2′-biquinoline), the binuclear molecular complex bis(μ-dicyanamido-κ2 N 1:N 5)bis[(2,2′-biquinoline-κ2 N,N′)(dicyanamido-κN 1)copper(II)], [Cu2(C2N3)4(C18H12N2)2] or [Cu2(biq)2(dca)2(μ1,5-dca)2] (1) [dca is dicyanamide, N(CN)2 −] was isolated and characterized by crystal structure analysis, and spectral, thermal and magnetic measurements. IR spectroscopy confirmed the presence of the biq and dca ligands in 1. Its solid-state structure consists of discrete centrosymmetric binuclear copper(II) units with double end-to-end dca bridges. Each CuII atom is in a distorted square-pyramidal environment with the equatorial plane formed by two nitrile N atoms from bridging dca groups, one of the two N atoms of the chelate biq molecule and one nitrile N atom from a terminal dca ligand, whereas the second biq N atom occupies the axial position. Thermal decomposition of 1 in an air atmosphere proceeds gradually, with copper(I) cyanide being the final decomposition product. Magnetic measurements revealed the formation of alternating spin chains and a relatively strong exchange interaction within the binuclear units was also confirmed by Broken Symmetry DFT (density functional theory) calculations.

Two copper(II) complexes with ligands derived from β-amino acids, 2-(1-aminocyclohexyl)acetic acid L1 and 2-(1-amino-4-(tert-butyl)cyclohexyl)acetic acid L2, were synthesized and characterized by microanalysis, infrared, UV–Vis and EPR spectra. The spectroscopically predicted structure of the square-planar copper(II) complex with 2-(1-aminocyclohexyl)-acetic acid C1 was confirmed by single-crystal X-ray analysis. The biological activities (antitumor activities and interaction with DNA) of the compounds were also investigated. The interactions of both complexes with calf thymus (CT) and herring testes (HT) DNA were examined by stopped-flow spectroscopy, by absorption (UV–Vis) and by emission spectral studies (ethidium bromide displacement studies). Both complexes were found to react a bit faster with HT-DNA than with CT-DNA. The obtained binding constants suggested a moderate intercalative binding mode between the complexes and DNA. In addition, fluorescence spectrometry of bovine serum albumin with the complexes showed a good fluorescence quenching of the complexes. The obtained copper(II) complexes have a relatively low cytotoxic effect on murine mammary carcinoma cell line, 4T1, a moderate effect on murine colon carcinoma cell line, CT26, and a relatively high cytotoxicity toward murine lung cancer cells, LLC1.

From the system CuCl2 – pbi – NaN(CN)2 −, polymeric [CuCl(μ1,5-dca)(pbi)]n·nH2O (1) complex (dca=dicyanamide, pbi=2-(2-pyridyl)benzimidazole) was isolated and characterized by structure analysis, spectral and magnetic measurements. Infrared spectroscopy confirmed the presence of pbi, dca and water molecules in 1. Its solid-state structure is formed by infinite chains running along the b axis. In the chain, the Cu(II) atom is penta-coordinated by two nitrogen atoms of chelate pbi ligand, by two nitrile nitrogen atoms of bridging μ1,5-dca and by chloride ligand which occupies the apical position of tetragonal pyramid around the Cu(II) atom. Asymmetric unit is supplemented by one molecule of solvated water, which along with chlorine atom serves as acceptors in intermolecular hydrogen bonds and along with π–π interactions create a 3D supramolecular structure. Magnetic measurements revealed the presence of a weak ferromagnetic exchange interaction J/kB =0.11 K.

The complex (2,2′-biquinoline-κ2 N,N′)(carbamoylcyanonitrosomethanide-κ2 N,O)chloridocopper(II) acetonitrile monosolvate, [Cu(C3H2N3O2)Cl(C18H12N2)]·CH3CN or [Cu(ccnm)Cl(biq)]·acn (acn is acetonitrile, biq is 2,2′-biquinoline and ccnm is carbamoylcyanonitrosomethanide), (I), was prepared as a result of nucleophilic addition of water to the dicyanonitrosomethanide ion in the presence of CuII and biq. IR spectroscopy confirmed the presence of ccnm, biq and acn in (I). The solid-state structure consists of the neutral complex containing ccnm and biq ligands, coordinated to the CuII atom in a bidendate chelating manner, and a chloride ligand, resulting in a distorted tetragonal pyramidal coordination of CuII. The asymmetric unit is supplemented by one molecule of solvated acn which, along with the nitrile group of ccnm, serves as an acceptor in intermolecular hydrogen bonding, creating infinite chains along the b axis. Magnetic measurements revealed a paramagnetic behaviour with a very small Weiss temperature Θ = −0.32 K and high anisotropy of the g tensor (g x = 2.036, g y = 2.120 and g z = 2.205).

Acridine thiosemicarbazones 3a–g, obtained through a two-step reaction between aromatic isothiocyanates and hydrazine followed by the treatment with acridin-9-carbaldehyde, in reaction with bifunctional reagents; methyl bromoacetate (MBA) and diethyl acetylenedicarboxylate (DEAD) afforded acridin-thiazolidinone derivatives 4a–g and 7a–f and not their regioisomers 6a–g and 9a–f. Derivatives 4a–g and 7a–f exhibit ZC2N6EN7C8 configuration. Upon standing in DMSO-d6 the thiazolidinones 4a–g and 7a–f spontaneously isomerized into ZC2N6ZN7C8 isomers 5a–g and 8a–f to give a mixture of the both stereoisomers. All compounds were fully characterized by multinuclear NMR, mass spectrometry (MS) and X-ray crystal structure of 4b is also described. X-ray diffraction study revealed that the representative compound 4b crystallized in the monoclinic crystal system with the C2/c space group and Z = 4. Intramolecular C1′ H1′⋯N-7 hydrogen bond between the acridine proton H-1′ and nitrogen N-7 of linker existed. This hydrogen bond is responsible for the E isomerism on C-8 atom which was observed in the NMR experiments. Quantum-chemical calculations and NOESY experiments confirmed ZC2N6ZN7C8 configuration of the transformed stereoisomers 5a–g and 8a–f.

In this contribution, four new compounds synthesized from 4-hydroxycoumarin and tyramine/octopamine/norepinephrine/3-methoxytyramine are characterized spectroscopically (IR and NMR), chromatographically (UHPLC-DAD), and structurally at the B3LYP/6-311++G*(d,p) level of theory. The crystal structure of the 4-hydroxycoumarin-octopamine derivative was solved and used as a starting geometry for structural optimization. Along with the previously obtained 4-hydroxycoumarin-dopamine derivative, the intramolecular interactions governing the stability of these compounds were quantified by NBO and QTAIM analyses. Condensed Fukui functions and the HOMO-LUMO gap were calculated and correlated with the number and position of OH groups in the structures. In vitro cytotoxicity experiments were performed to elucidate the possible antitumor activity of the tested substances. For this purpose, four cell lines were selected, namely human colon cancer (HCT-116), human adenocarcinoma (HeLa), human breast cancer (MDA-MB-231), and healthy human lung fibroblast (MRC-5) lines. A significant selectivity towards colorectal carcinoma cells was observed. Molecular docking and molecular dynamics studies with carbonic anhydrase, a prognostic factor in several cancers, complemented the experimental results. The calculated MD binding energies coincided well with the experimental activity, and indicated 4-hydroxycoumarin-dopamine and 4-hydroxycoumarin-3-methoxytyramine as the most active compounds. The ecotoxicology assessment proved that the obtained compounds have a low impact on the daphnia, fish, and green algae population.

Four N-oxides, 8-quinolinol N-oxide (8-HQNO), 5,7-dichloro-8-quinolinol N-oxide (HdClQNO), 5,7-dibromo-8-quinolinol N-oxide (HdBrQNO) and 7-iodo-8-quinolinol N-oxide (HIQNO) as well as their six copper complexes, CuCl2(8-HQNO)2(H2O) (1), CuCl2(HdClQNO)2(H2O)2 (2), Cu(dClQNO)2(CHCl3) (3), Cu(dClQNO)2(H2O) (4), {[Cu(dBrQNO)2]•2H2O}n (5) and CuCl2(HIQNO)2(H2O)4 (6) were synthesised as possible anticancer agents. Crystal structures of N-oxides contain planar molecules held together via hydrogen bonds involving oxygen atoms of N-oxide groups as acceptors. Crystal structure of 5 represents the first structure of a copper(II) complex with an N-oxide ligand derived from 8-HQNO and is formed by infinite chains. In the chain, the Cu(II) atom coordinates to six oxygen atoms from two bidentate chelating dBrQNO ligands occupying apexes of elongated tetragonal bipyramid with bridging oxygen atoms of N-oxide groups in axial positions. Antiproliferative activity of prepared N-oxides as well as their complexes was studied using in vitro MTT assay against the MDA-MB-231, HCT-116 and A549 cancer cell lines and their selectivity was verified on MSCs cells. Among the tested cancer cell lines, A549 and MDA-MB-231 cells were the most sensitive to the tested complexes. Complex 1 showed the highest cytotoxicity against both tumor cell lines. At concentration, which could be tested in animal models, 1 induced cell death in more than 50% of cancer cells and in 20% of MSCs indicating its selectivity.

Ionic cobalt(II) complex [Co(dcnm)(H2O)(phen)2](dcnm) (1) (dcnm = dicyanonitrosomethanide, phen = 1,10-phenantroline) has been prepared by a diffusion technique. Its structure is formed by [Co(dcnm)(H2O)(phen)2]+ complex cation and free dcnm counterion in the lattice which acts as a hydrogen-bond acceptor to the hydrogen bonds from the water ligand coordinated to the Co atom. The Co atom is six-coordinated in the form of a distorted octahedron by two chelate phen molecules (one of them is disordered over two equivalent positions), one O-coordinated dcnm ligand and one water molecule which is cis-coordinated to O atom of dcnm ligand. The structure is stabilized by the system of hydrogen bonds and π–π interactions. Magnetic properties of 1 are dominated by a strong easy-plane anisotropy yielding to the energy difference between the two lowest Kramers doublets higher than 150 cm−1. Two field-induced relaxation channels were observed by AC susceptibility study and were shown to be dominated by the direct spin-phonon relaxation at low temperatures. One of the relaxation channels is identified to be mediated by the electron-nuclear interaction.

New Pd(II) complexes with 7-bromo-quinolin-8-ol (BrQ), [Pd(BrQ)2] (1a) and (1b) and HBrQ[PdCl2(BrQ)] (2) have been synthesized and characterized. X-ray structure analysis of 1a and 1b revealed that the molecular structures of these square-planar polymorphs are very similar, nevertheless in the supramolecular structure the molecules are differently arranged and held by different intermolecular forces. The structure of 2 in DMSO solution was elucidated using one- and two-dimensional NMR experiments which showed that the complex decomposes to BrQ ligand. Antimicrobial activity of soluble complex 2 was tested by determining the minimum inhibitory concentration and minimum microbicidal concentration against 9 strains of bacteria and 5 strains of fungi; its activity on Proteus mirabilis is more than 250 times higher than a positive control. Complex 2 is also significantly more cytotoxic against human colorectal cancer cells HCT116 than cisplatin at all tested concentrations and this effect is particularly pronounced at low concentrations; cytotoxicity of BrQ is four times higher than cytotoxicity of 2 at these concentrations and is selectively cytotoxic. Interaction of 2 with DNA was investigated using UV–VIS spectroscopy and fluorescence spectroscopy; the binding studies indicate that complex 2 can interact with ctDNA through intercalation mechanism.

The new coumarine derivate with methyl ester of 2-((Z)-1(2,4-dioxochroman-3-ylidene)ethylamino)-3-methylbutanoic acid and the corresponding palladium(II) complex are synthesized and characterized by microanalysis, infrared, 1H and 13C NMR spectroscopy. The proposed structure of the ligand was confirmed based on the X-ray structural study.

Molecular [CoIII(acnm)(bpy)(cenm)]·H2O (1) complex (acnm = amidocarbonyl(cyano)nitrosomethanide; bpy = 2,2′-bipyridine and cenm = cyano[imino(ethoxy)methyl]nitrosomethanide) was prepared as a result of simultaneous nucleophilic addition of water and ethanol to dicyanonitrosomethanide ions in the presence of Co(II) and bpy, and represents the first example of compound comprising both acnm and cenm ligands. Infrared spectroscopy confirmed the presence of acnm, bpy, cenm and water molecules in 1. Its solid state structure consists of neutral complexes containing acnm, cenm and bpy ligands bidentate chelate coordinated to Co(III) atom to form a distorted octahedron. Asymmetric unit is supplemented by one molecule of crystal water which along with amido and imine groups serves as donor in intermolecular hydrogen bonds creating infinite wave-like 2D sheets in the bc plane. One- and two-dimensional NMR experiments confirmed the structure of the complex unit in DMSO solution. Results of UV–VIS spectroscopy and magnetic measurements are consistent with the presence of Co(III) atom and therefore diamagnetic character of 1 and thermal analysis was used to follow its decomposition.

Starting from well-defined NH2(CH3)2[PdCl2(XQ)] complexes, coordination compounds of general formula Cat[PdCl2(XQ)] have been prepared by cationic exchange of NH2(CH3)2+ and Cat cations, where XQ are biologically active halogen derivatives of quinolin-8-ol (5-chloro-7-iodo-quinolin-8-ol (CQ), 5,7-dibromo-quinolin-8-ol (dBrQ) and 5,7-dichloro-quinolin-8-ol (dClQ)) and Cat is K+ or Cs+. The cation exchange of all prepared complexes, K[PdCl2(CQ)] (1), K[PdCl2(dClQ)] (2), K[PdCl2(dBrQ)] (3), Cs[PdCl2(CQ)] (4), Cs[PdCl2(dClQ)] (5) and Cs[PdCl2(dBrQ)] (6) was approved using IR spectroscopy, their structures in DMSO solution were elucidated by one- and two-dimensional NMR experiments, whereas their stability in solution was verified by UV-VIS spectroscopy. Interaction of complexes to ctDNA was investigated using UV-VIS and fluorescence emission spectroscopy. The minimum inhibitory concentration and the minimum microbicidal concentration values were detected against 15 bacterial strains and 4 yeast strains to examine the antimicrobial activity for the complexes. The in vitro antitumor properties of the complexes were studied by testing the complexes on leukemic cell line L1210, ovarian cancer cell line A2780 and non-cancerous cell line HEK293. The majority of the prepared compounds exhibited moderate antimicrobial and very high cytotoxic activity.

Two new complexes, [Co II ( bpy ) 2 (dca) 2 ] ( 1 ) and [Co II ( bpy ) 2 (tcm) 2 ] ( 2 ) ( bpy = 2,2-bipyridine, dca = dicyanamide and tcm = tricyanomethanide) were prepared as powders. During their recrystallization on air, two other new complexes, [Co III ( bpy ) 2 CO 3 ]dcg (dcg = N,N′-dicyanoguanidine, (H 2 N)C(NCN) 2 ) ( 3 ) and [Co III ( bpy ) 2 CO 3 ]tcm·2H 2 O ( 4 ), have been prepared. Composition of both complexes was supported by the results of thermal analyses. The presence of Co(III) atom in 3 and 4 was confirmed by UV–Vis spectra, while the presence of dcg and tcm as free anions was proved by IR spectra of these complexes. Moreover, quantum chemical calculations confirmed that dcg in 3 is present in its anionic form. Single crystal X-ray structure determination of 3 and 4 revealed the presence of [Co III ( bpy ) 2 CO 3 ] + complex cations with dcg, its structure has not been published yet, and tcm counter anions, respectively. In both structures, a supramolecular networks built up from strong N–H⋯N, O–H⋯N, as well as weak C–H⋯N, C–H⋯O hydrogen bonds and aromatic π–π stacking besides electrostatic forces of attraction help to consolidate the packing.

Three gallium(III) complexes, [Ga(NQ)3] (1), Na3[Ga(SQ)3]·7H2O·3NaCl (2) and [Ga(ClNQ)3]·MeOH (3) were synthesised as possible anticancer agents (H-NQ = 5-nitro-8-quinolinol, H-SQH = 5-sulfo-8-quinolinol, H-ClNQ = 5-chloro-7-nitro-8-quinolinol) and characterised by elemental analysis, IR and NMR spectroscopy. Single crystal structure analysis of 1 revealed two crystallographically independent [Ga(NQ)3] molecules in the asymmetric part of the unit cell. Stability of the complexes 1 and 2 in solution was determined by 1H NMR spectroscopy. Complex 3 was not further studied due to the low solubility. Antiproliferative activity of complexes 1 and 2 was studied using in vitro MTT assay against the A2780, HCT116 and MDA-MB-231 cancer cell lines and the selectivity of the complexes was verified on noncancerous MRC5 pd30 cell line. Complex 1 showed high antiproliferative potency (IC50 = 3.6 ± 0.8 μM for HCT116) and noticeable selectivity of 1 against the cancer cell lines (IC50 = 32 ± 4 μM for normal MRC5 pd30 cell line) was also found. The complex 2 displayed the highest antioxidant activity of all tested complexes and free ligands.

Four new Pd(II) complexes with halogenderivatives of 8-quinolinol (HXQ) were prepared: [PdCl(NH(CH3)2)(CQ)] (1), [PdCl(NH(CH3)2)(dClQ)] (2), [PdCl(NH(CH3)2)(dBrQ)] (3) and [PdCl(NH(CH3)2)(BrQ)] (4), where HCQ is 5-chloro-7-iodo-8-quinolinol, HdClQ is 5,7-dichloro-8-quinolinol, HdBrQ is 5,7-dibromo-8-quinolinol and HBrQ is 7-bromo-8-quinolinol. The infrared spectroscopy confirmed the presence of XQ moiety in all complexes as well as dimethylamine ligands resulting from the decomposition of DMF used as solvent. Subsequent X-ray structural analysis confirmed that XQ ligands are chelate bind to Pd(II) atom through oxygen and nitrogen atoms, the dimethylamine molecules are attached via nitrogen atom, wherein the nitrogen atoms of XQ and of dimethylamine are in trans-positions. The fourth coordination place is occupied by chloride ligand, suggesting a square planar configuration of the central Pd(II) atom. The structures are stabilized by both H-bonds and π-π interactions while observing the formation of 2D or 3D structures. 1H and 13C NMR spectra of 1–4 confirmed their stability in dimethylsulfoxide. The radical scavenging experiments revealed relatively low antioxidant properties with 1 being the most potent antioxidant among prepared complexes. In vitro antiproliferative properties of the newly prepared complexes were studied on adenocarcinomic human alveolar basal epithelial cells A549, human colon cancer cell line HCT116, human breast cancer cell line MDA-MB-231 and their selectivity was studied on non-cancerous mouse mesenchymal stem cells MSCs. All the prepared complexes were toxic to the tumor cells and the higher cytotoxicity was induced by complex 1 against A549 cells at very low concentrations which would provide new potential antitumor drug that deserves much more attention in lung cancer research.

Isoalkyl (isoalkyl = isopropyl-(L1), isobutyl-(L2) and isoamyl-(L3)) derivatives of thiosalicylic acid (TSA) were prepared by alkylation of TSA with corresponding isoalkyl-chlorides in the alkaline water-ethanol solution. The new free copper(II)-complexes with corresponding S-isoalkyl derivatives of TSA (C1-copper(II)-complex with S-isopropyl derivative of thiosalicylic acid, C2-copper(II)-complex with S-isobutyl derivative of thiosalicylic acid and C3-copper(II)-complex with S-isoamyl derivative of thiosalicylic acid) have been synthesized by direct reaction of copper(II)-nitrate with ligand precursor and then characterized by microanalysis, infrared spectra (IR) and EPR (electron paramagnetic resonance) spectra. The spectroscopically predicted structure of the obtained binuclear copper(II)-complex with S-isopropyl derivative of thiosalicylic acid was confirmed by X-ray analysis. Single crystals suitable for X-ray measurements were obtained by slow crystallization from a water solution. Newly synthesized precursors S-isoalkyl derivatives of thiosalicylic acid and corresponding copper(II)-complexes moderately reduced viability of human and murine lung cancer cells, they showed similar cytotoxic effect on human colorectal cancer cells as cisplatin and lower cytotoxic effect than cisplatin toward normal fibroblasts, evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) colorimetric technique. All new complexes exhibited apoptotic effect toward lung cancer cells, stronger than cisplatin, whereas only C3 induced significant apoptosis of colorectal cancer cells. Complex C1 showed significant antiproliferative effect against murine lung cancer cells, LLC1, while C2 reduced expression of Ki67 in human colorectal cancer cells. All tested complexes induced cell cycle arrest of HCT116 cells in G2/M phase.

A series of new 3d metal complexes with 5-chloro-quinolin-8-ol (ClQ), [Mn(ClQ)2] (1), [Fe(ClQ)3] (2), [Co(ClQ)2(H2O)2] (3), [Ni(ClQ)2(H2O)2] (4), [Cu(ClQ)2] (5), [Zn(ClQ)2(H2O)2] (6), [Mn(ClQ)3]·DMF (7) and [Co(ClQ)3]·DMF·(EtOH)0.35 (8) (DMF=N,N-dimethylformamide), has been synthesized and characterized by elemental analysis, IR spectroscopy and TG-DTA thermal analysis. X-ray structure analysis of 7 and 8 revealed that these molecular complexes contain three chelate ClQ molecules coordinated to the central atoms in a deformed octahedral geometry and free space between the complex units is filled by solvated DMF and ethanol molecules. Antimicrobial activity of 1-6 was tested by determining the minimum inhibitory concentration and minimum microbicidal concentration against 12 strains of bacteria and 5 strains of fungi. The intensity of antimicrobial action varies depending on the group of microorganism and can be sorted: 1>ClQ>6>3/4>2>5. Complexes 1-6 exhibit high cytotoxic activity against MDA-MB, HCT-116 and A549 cancer cell lines. Among them, complex 2 is significantly more cytotoxic against MDA-MB cells than cisplatin at all tested concentrations and is not cytotoxic against control mesenchymal stem cells indicating that this complex seems to be a good candidate for future pharmacological evaluation. Interaction of 1-6 with DNA was investigated using UV-VIS spectroscopy, fluorescence spectroscopy and agarose gel electrophoresis. The binding studies indicate that 1-6 can interact with CT-DNA through intercalation; complex 2 has the highest binding affinity. Moreover, complexes 1-6 inhibit the catalytic activity of topoisomerase I.

Five new ionic [Cu(L)2X]C(CN)3 (L = 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen), X = Cl−, Br− or CH3COO−) complexes: [Cu(bpy)2Cl]C(CN)3 (1), [Cu(phen)2Cl]C(CN)3·H2O (2), [Cu(bpy)2Br]C(CN)3·H2O (3), [Cu(phen)2Br]C(CN)3·0.5H2O·0.5EtOH (4) and [Cu(phen)2Br0.7(CH3COO)0.3]C(CN)3·0.5H2O (5), have been synthesized and characterized by IR and UV–Vis spectroscopy. X-ray structural analysis revealed that the structures of all discussed compounds consist of [Cu(L)2X]+ complex cations and uncoordinated C(CN) 3 − counteranions; water molecules were found in 2, 3, 4 and 5; a molecule of ethanol was found in 4, too. The shapes of coordination polyhedra around the copper atoms, which are pentacoordinated by two bidentate bpy or phen molecules and Cl−, Br− or CH3COO− ligands monodentately coordinated in the equatorial plane, are distorted trigonal bipyramids. Structures of 1–5 are stabilized by weak π–π interactions and by hydrogen bonds. Magnetic properties of complexes 1–4 are characterized by the presence of weak antiferromagnetic exchange couplings.

Violet crystals of {[Cu(pn)2]2[Pt(CN)4]}[Pt(CN)4]·2H2O (1, pn=1,2-diaminopropane) and blue crystals of [Cu(pn)Pt(CN)4]n·nH2O (2) were prepared under hydrothermal conditions and characterized using elemental analysis, IR and UV–vis spectroscopy and by X-ray crystal structure analysis. Different number of ν(C≡N) absorption bands of these two compounds reflects their different structures. An X-ray crystal structure analysis has shown that complex 1 is of ionic character and is formed from trinuclear [Cu(pn)2–Pt(CN)4–Cu(pn)2]2+ complex cation and discrete [Pt(CN)4]2– anion together with two molecules of crystal water. On the other hand, complex 2 is of polymeric character and is formed by 2D networks of [Cu(pn)Pt(CN)4]n composition and completed by n molecules of crystal water. Magnetic measurements show the presence of a weak antiferromagnetic exchange interaction in complex 1 (Θ = –0.2 K), while the magnetic susceptibility of complex 2 is well described by the model of uniform S = 1/2 spin chain with exchange interaction J/kB = –1.64 K.

A series of mononuclear hexacoordinate Co(ii) complexes with the 4-amino-3,5-bis(2-pyridyl)-1,2,4-triazole (abpt) ligand and various linear and non-linear pseudohalides, such as NCSe (selenocyanate), N{C(CN)2}2 (1,1,3,3-tetracyano-2-azapropenide, tcap), NO2C(CN)2 (nitrodicyanomethanide, nodcm), C(CN){C(CN)2}2 (1,1,2,3,3-pentacyanopropenide, pcp), NO2NCN (nitrocyanamide, nca), and ONC(CN)2 (nitrosodicyanomethanide, ndcm), was prepared. X-ray analyses revealed the formation of the complexes with the general compositions [Co(abpt)2(solv)2]X2 (solv = H2O and X = tcap (1), solv = H2O and X = nodcm (2), solv = CH3OH and X = pcp (3)) or [Co(abpt)2(X)2] (X = nca (4), X = NCSe (5), X = ndcm (6)). The impact of axial co-ligands (solv or X) on the magnetic properties was investigated experimentally by measuring temperature- and field-dependent static (DC) and dynamic magnetic (AC) data as well as theoretically using the CASSCF/NEVPT2, AILFT, and AOM methods. Large magnetic anisotropy was found for all complexes 1-6 and was treated either by the spin Hamiltonian or with the Hamiltonian including the orbital angular momentum. Furthermore, the AC susceptibility measurements confirmed the slow relaxation of the magnetization in a non-zero static magnetic field, thus these complexes can be classified as field-induced single-molecule magnets with an estimated energy barrier Ueff up to 100 K.

The octahedral cobalt(III) complexes with (S,S)-ethylenediamine-N,N-di-2-propionic (S,S-eddp) and (S,S)-ethylenediamine-N,N-di-2-(3-methyl)-butanoic (S,S-eddv) acids and oxalato and malonato ligands, as additional bidentate ligands, were prepared and characterized. The complexes were purified by ionexchange chromatography. The geometry of the complexes has been supposed on the basis of the infrared, electronic absorption and NMR spectra. The A absolute configurations of the isolated complexes have been predicted on the basis of their circular dichroism (CD) spectra and it was confirmed by single-crystal X-ray analysis of potassium-Delta-(-)(589)-s-cis-oxalato-(S,S)-ethylenediamine-N,N-di-(2-propanoato)-cobaltate(III)-semihydrate, K-Delta-(-)(589)-s-cis-[Co(S,S-eddp)(ox)]center dot 0.5H(2)O. Antimicrobial activity of ligands and obtained cobalt(III) complexes was evaluated by determining the minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) in relation to 13 species of microorganisms (five strains of pathogenic bacteria, five species pathogenic fungi and three species of probiotic). Tested ligands and complexes demonstrated moderate and low antibacterial and antifungal activity. There was no difference in activities between the ligands and complexes. (C) 2014 Elsevier Ltd. All rights reserved.

From the systems Co(II) – L – C(CN)3−/N(CN)2− (L = 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen)) two dicyanamide (dca, N(CN)2−) and three tricyanomethanide (tcm, C(CN)3−) complexes, [Co(phen)2(dca)2] (1a, 1b) [Co(phen)3](tcm)2 (2), [{Co(phen)2(μ1-tcm)}2(μ1,5-tcm)]tcm·H2O (3), [Co(bpy)(μ1,5-tcm)2]n (4) and [Co(bpy)(μ1,5-dca)2]n (5), were isolated and characterized by X-ray crystallography, spectral and magnetic measurements. The Co(II) atoms in all the prepared complexes are coordinated by six nitrogen atoms forming a distorted octahedral environment. The mononuclear molecular complexes 1a and 1b are isomers, in which the Co(II) atoms are coordinated by two phen ligands and two dca anions in cis positions, while 2 is an ionic compound with the [Co(phen)3]2+ complex cation and two uncoordinated tcm anions. Their structures are stabilized by a combination of intermolecular π–π interactions between phen ligands and weak C–H⋯N hydrogen bonds. Compound 3 is ionic too, containing the binuclear [{Co(phen)2(μ1-tcm)}2(μ1,5-tcm)]+ complex cation, in which the Co(II) atoms are separated by 7.149 A, one uncoordinated tcm anion and one disordered molecule of crystal water. Intermolecular π–π interactions between the phen ligands, C–N⋯Cg (π–ring) contacts between tcm anions and phen ligands and hydrogen bonds link the individual components in 3 into a three-dimensional network. Both molecules of the pseudohalide ligands in the isostructural polymeric complexes 4 and 5 act as bridging ligands and link neighboring Co(II) atoms by double bridges, giving zig-zag chains which are connected by π–π interactions between L molecules from neighboring chains to form a two-dimensional network. The magnetic properties of the mononuclear complexes 1 and 2 are dominated by a considerable zero-field splitting, D/hc = 80–100 cm−1. In the dinuclear complex 3 only a weak exchange interaction of an antiferromagnetic nature applies. In the polymeric complexes 4 and 5 the exchange coupling again is low so that a model of mononuclear complexes with sizable zero-field splitting is appropriate.

Two new ionic [Fe(bpy)3](ONC(CN)2)2·2HONC(CN)2 (1) and [Fe(phen)3](ONC(CN)2)2 (2) complexes have been synthesized (bpy is 2,2′-bipyridine, phen is 1,10-phenanthroline). X-ray structural analysis ((1): P21/n, a=11.7294(5), b=22.0774(11), c=16.2415(8) Å, β=98.910(5)°; (2): P21/c, a=9.4951(3), b=21.6640(9), c=17.3365(6) Å, β=92.483(3)°) revealed that their structures consist of one [Fe(bpy)3]2+ or [Fe(phen)3]2+ complex cation and two uncoordinated nitrosodicyanomethanide, ONC(CN)2 - counteranions; two molecules of unique nitrosodicyanomethanide acid HONC(CN)2 were found in (1), too. In the cations, the Fe(II) atom is coordinated by six nitrogen atoms of chelate coordinated neutral ligands forming a distorted octahedron coordination geometry. Both structures are stabilized by π-π interactions and hydrogen bonds, which are very strong in (1).

The synthesis of novel platinum(IV) complex of formula [PtBr2(S,S-eddv)]·H2O (S,S-eddv = ethylenediamine-N,N′-di-S,S-2-(3-methyl)butanoate ion) is reported. The complex has been obtained by direct reaction of potassium-hexabromidoplatinate(IV) with neutralized ethylenediamine-N,N′-di-S,S-2-(3-methyl)butanoic acid (H2-S,S-eddv). The ligand and complex were characterized by elemental analysis, infrared, 1H and 13C NMR spectroscopy. The spectroscopically predicted geometrical configuration of the obtained complex was confirmed by X-ray analyses of the crystal structure of the s-cis-[PtBr2(S,S-eddv)]·H2O. The asymmetric unit of the complex contains three crystallographically independent s-cis-[PtBr2(S,S-eddv)] and water molecules. The Pt(IV) atom in each complex molecule exhibits a distorted octahedral coordination geometry, built up by two cis-coordinated bromido ligands and one cis-N,N′ and trans-O,O′ coordinated S,S-eddv ligand (configuration index: OC-6-33). In the crystal structure, intermolecular N–H⋯O hydrogen bonds are found between the complex and water molecules.

Two new diamagnetic coordination compounds, [Fe(phen)3][C(CN)3]2, (I), and [Fe(bpy)3][C(CN)3]2·1.5H2O, (II), have been synthesized and characterized by single-crystal X-ray diffraction analysis, and IR and UV–Vis spectroscopy (phen is 1,10-phenanthroline, C12H8N2, and bpy is 2,2′-bipyridine, C10H8N2). Both compounds are ionic with distorted octahedral [Fe(phen)3]2+ or [Fe(bpy)3]2+ complex cations, with average Fe—N distances of 1.977 (2) and 1.971 (3) Å, respectively, and two uncoordinated planar tricyanomethanide, or [C(CN)3]−, counter-anions balancing the positive charges of the cations. Solvent water molecules and tcm anions in (II) are linked via O—H...N hydrogen bonds into negatively charged layers and the interlayer space is filled by [Fe(bpy)3]2+ cations. The structures of (I) and (II) are stabilized by π–π interactions between the stacked aromatic rings of the phen ligands of two adjacent cations and by O—H...N hydrogen bonds, respectively, and also by π–π stacking interactions between phen and tcm units in (I).

Three novel palladium(II) complexes, NH2(CH3)2[PdCl2(CQ)] (1) (CQ=5-chloro-7-iodo-quinolin-8-ol), NH2(CH3)2[PdCl2(dClQ)] (2) (dClQ=5,7-dichloro-quinolin-8-ol) and NH2(CH3)2[PdCl2(dBrQ)] (3) (dBrQ=5,7-dibromo-quinolin-8-ol) have been prepared and characterized. Their structures contain square-planar [PdCl2(XQ)](-) complex anions in which deprotonated XQ ligands are coordinated to the Pd atoms via the pyridine nitrogen and the phenolato oxygen atoms, other two cis-positions are occupied by two chlorido ligands. Negative charges of these anions are balanced by uncoordinated dimethylammonium cations. Coordination of the XQ ligands to Pd(II) atom was confirmed by the differences in the stretching ν(OH) and ν(CN) vibrations in the IR spectra of ligands and prepared complexes while bands of aliphatic CH and NH stretching vibrations observed in the spectra of 1-3 confirm the presence of dimethylammonium cations in the complexes. The binding of complexes 1-3 to calf thymus DNA was investigated using UV-visible and fluorescence emission spectrophotometry. The fluorescence spectral results indicate that the complexes can bind to DNA through an intercalative mode. The Stern-Volmer quenching constants obtained from the linear quenching plot are in the 1.04 × 10(4) to 4.35 × 10(4) M(-1) range. The complexes exhibit significant anticancer activity tested on A2780 cells and cisplatin resistant cell line A2780/CP.

Five 3d metal [M(H2O)2(SQ)]n complexes, where M is Mn (1), Co (2), Ni (3), Zn (4) and Cu (5), and SQ is the dianion of 8-hydroxyquinoline-5-sulfonic acid have been prepared and characterized by IR spectroscopy and elemental analysis. X-ray structure analysis of 1 and 5 in combination with IR spectroscopy of all five complexes showed that complexes 1–4 are isostructural 2D polymers, while 5 is 1D polymer due to the different bonding character of SQ. Stability of all complexes in DMSO was proved by UV–Vis spectroscopy and for 4 also verified by 1H and 13C NMR spectroscopy. Cytotoxic activity tests against cervical carcinoma HeLa, colon carcinoma HCT116 and normal human fibroblast MRC-5 cell lines showed moderate but selective cytotoxicity of all complexes. Complex 1 exhibited highest activity with IC50 = 39.1 and 33.4 µM, respectively, but is lower than activity of cisplatin (CP) which IC50 = 24.3 and 14.3 µM, respectively. However, their cytotoxic activity against healthy MRC-5 cells (IC50 > 92 µM) is much lower than CP (IC50 = 19.7 µM). Antimicrobial activity of all complexes against 9 strains of pathogenic bacteria, five mould species and two yeast species is negligible.

Violet crystals of [Cu2(teta)2Pt(CN)4]2[Pt(CN)4]2 (1, teta = N,N’-bis(2-aminoethyl)-1,2-diaminoethane; triethylenetetramine) and {[Cu3(bapen)3Pt(CN)4][Pt(CN)4]2·13H2O}n (2, bapen = N,N′-bis(3-aminopropyl)-1,2-diaminoethane) were crystallized from the water–methanol or aqueous solutions containing Cu(II) salt, teta or bapen ligand and K2[Pt(CN)4]. Both compounds were characterized using elemental analysis, IR and UV–Vis spectroscopy, thermal and X-ray crystal structure analysis. Two ν(C N) absorption bands in the IR spectra of the complexes imply non-equivalency of cyanido groups meaning the presence of both, terminal and bridging ones and together with the results of elemental analysis indicate simple chain-like structure. Thermal decompositions of the prepared complexes are few-step processes which comprise liberation of crystal water (only for 2), decay of N-donor ligands L and release of cyanido groups. Finally, an X-ray crystal structure analysis has shown their complicated crystal structures. On one hand, complex 1 is of ionic character and is formed from a couple of trinuclear [Cu(teta)-Pt(CN)4-Cu(teta)]2+ complex cations and a couple of discrete [Pt(CN)4]2− anions. On the other hand, complex 2 is of polymeric character and is formed by 1D chains of {[Cu3(bapen)3Pt(CN)4]4+}n composition, 2n single [Pt(CN)4]2− anions and 13n molecules of crystal water.

(Dicyanamido-κN1)bis(5,5′-dimethyl-2,2′-bipyridine-κ2N,N′)copper(II) tetrafluoroborate, [Cu{N(CN)2}(C12H12N2)2]BF4, (I), and (dicyanamido-κN1)bis(5,5′-dimethyl-2,2′-bipyridine-κ2N,N′)copper(II) perchlorate, [Cu{N(CN)2}(C12H12N2)2]ClO4, (II), are isomorphous and consist of [Cu{N(CN)2}(mbpy)2]+cations (mbpy is 5,5′-dimethyl-2,2′-bipyridine) and BF4−or ClO4−anions, respectively. The CuIIcations in both structures are five-coordinated in distorted trigonal bipyramidal environments by four N atoms of two mbpy ligands and one N atom of the dicyanamide anion, which is coordinated in a monodentate manner in the equatorial plane, with Cu—N distances of 1.980 (3) and 1.977 (2) Å in (I) and (II), respectively. The two axial Cu—Nmbpybonds have very similar values [1.986 (1) Å on average] and are shorter than the other two equatorial Cu—Nmbpybonds. These have different values in the individual compounds but nevertheless form two pairs of similar bonds in (I) and (II) [2.066 (8) and 2.112 (2) Å, respectively, on average]. Besides the ionic forces in both structures, the structures are stabilized by C—H...N and C—H...Xhydrogen bonds (X= F and O, respectively), and by π–π interactions between the pyridine rings of neighbouring mbpy molecules.

The investigated compound of {[Zn(CQ)2(H2O)2]2[Zn(CQ)2(H2O)]3}·5DMF·2H2O (1) composition (where CQ = 5-chloro-7-iodo-quinolin-8-ol, DMF = N,N-dimethylformamide) was prepared by simple mixing of ZnCl2 and CQ. Infrared spectroscopy confirmed the presence of CQ, DMF and H2O molecules in the prepared compound. X-ray structural analysis revealed that the structure of the title compound consists of five independent Zn(II) atoms, which are coordinated by two bidentately coordinated molecules of CQ. Three of these central atoms are also coordinated by one water molecule, while the other two have two water molecules in the coordination sphere. The structure of 1 also includes five solvated DMF and two water molecules involved in thirteen hydrogen bonds, which interconnect different complex species to form four “triplets”, in the centre of which are units with hexacoordinated Zn atoms surrounded by two units with pentacoordinated Zn atoms. These triplets are linked together to chains parallel with the b axis by two kinds of π–π interactions.

Three new ionic [Fe(phen)3](N(CN)2)2 · 4.5 H2O (1), [Fe(dmeophen)3](N(CN)2)2 · 1.5 H2O (2) and [Fe(dmeophen)3](C(CN)3)2 (3) complexes have been synthesized (phen is 1,10-phenanthroline, dmeophen is 4,7-dimethoxy-1,10-phenanthroline). X-ray structural analysis ((1): C2/c, a = 18.1041(3), b = 16.8244(3), c = 24.6691(5) Å, β = 92.138(2)°; (2): C2/c, a = 22.0291(10), b = 18.8654(5), c = 11.6914(5) Å, β = 114.872(5)°; (3): Pbca, a = 12.0841(5), b = 22.0624(13), c = 34.2729 (16) Å) revealed that the structures of all discussed complexes consist of one [Fe(phen)3]2+ or [Fe(dmeophen)3]2+ complex cation and two uncoordinated tcm or dca counteranions (tcm is tricyanomethanide, dca is dicyanamide); water molecules were found in (1) and (2), too. In the cations, the Fe(II) atom is coordinated by six nitrogen atoms of chelate coordinated neutral ligands forming a distorted octahedron coordination geometry. One of the anions in each structure is disordered. Weak π–π interactions between planar dca anions and pyridine rings of phen in (1) and O—H … O and O—H … N hydrogen bonds in (1) and (2) stabilize their structures.

The new coumarine derivative, 3-(1-(3-hydroxypropylamino)ethylidene)chroman-2,4-dione, and corresponding palladium(II) complex have been synthesized and characterized by microanalysis, infrared, 1H and 13C NMR spectroscopy. The structure of the ligand, solved using a monocrystal X-ray structural analysis, consists of two crystallographic different pseudocentrosymmetrically related molecules of 3-(1-(3-hydroxypropylamino)ethylidene)chroman-2,4-dione, while the structure of the square-planar palladium(II) complex was proposed on the basis of DFT calculations. The palladium(II) complex decreased viability of U251 human glioma and B16 mouse melanoma cells in a dose and time dependent manner, while its ligand exhibited only moderate cytotoxicity. Inorganica Chimica Acta (2017), 466: 188-196

From the systems Cu(II)–L–[Pt(CN)4]2− (L = aliphatic tridentate N-donor ligands: aepn (3-(2-aminoethylamine)-propylamine), bapa (bis(3-aminopropyl)amine) and dien (bis(2-aminoethyl)amine)) four tetracyanidoplatinate complexes, [Cu(aepn)(NH3)Pt(CN)4]n·nH2O (1), [Cu(aepn)Pt(CN)4]n (2) and [Cu(bapa)Pt(CN)4]n (3) and [Cu(dien)Pt(CN)4]n (4), were isolated. The prepared compounds are formed by zigzag chains, which consist of [Cu(aepn)(NH3)]2+ (for 1) or [Cu(L)]2+ (for 2–4) moieties bridged by [Pt(CN)4]2− units. The different arrangement of two bridging cyanido groups on the copper (trans-coordination in 1 and cis-coordination in 2–4) and platinum atoms (trans-coordination in 4 and cis-coordination in 1–3) results in three different and atypical types of chains. The Cu(II) atoms in 2–4 are pentacoordinated by one L molecule and two bridging cyanido ligands in a form of a deformed square pyramid, while the Cu(II) atom in 1 is hexacoordinated in the form of strongly elongated octahedron. Higher number of ν(C N) absorption bands observed in IR spectra of 1–4 agrees with a higher number of crystallographically different cyanido groups of both, bridging and terminal, types. Thermal decompositions of the prepared complexes are few-step processes which comprise liberation of water and ammonia molecules (only for 1), decay of triamine molecules L and finally a pyrolysis of cyanido groups. The magnetic properties of 1–4 have been investigated in the temperature range 2–300 K and prepared complexes exhibit the antiferromagnetic exchange. The different magnetic behavior is ascribed to the different coordination (cis vs. trans) of bridging cyanido groups on the Pt(II) atoms.

Coordination compounds of first row transition metals from Mn to Zn with clioquinol (5-chloro-7-iodo-8-hydroxyquinoline, CQ) were prepared and characterized by infrared spectroscopy and thermal analysis. The composition of these compounds determined by elemental analysis is [M(CQ)2(H2O)2] for Mn and Zn, [M(CQ)2] for Fe, Co, Ni, and Cu, and NH2(CH3)2[Ni(CQ)3]·DMF·H2O (DMF = N,N-dimethylformamide). X-ray structure analysis revealed that the [Ni(CQ)2] complex is a molecular coordination compound with Ni(II) square-planarly coordinated by nitrogen and oxygen atoms of two trans-arranged bidentate molecules of clioquinol. On the other hand, NH2(CH3)2[Ni(CQ)3]·DMF·H2O is an ionic compound containing three clioquinol molecules coordinated to the central atom in a deformed octahedral geometry thus forming a complex anion. Its negative charge is balanced by the dimethylammonium cation and the structure also contains solvated water and DMF molecules. Long-range interactions and hydrogen bonds in these two complexes were also investigated.

Violet ( 1 ) and blue ( 2 ) polymorphous modifications of [Cu( men ) 2 Pt(CN) 4 ] n ( men = N -methyl-1,2-diaminoethane) have been prepared and investigated by IR and UV–vis spectroscopy, thermal analysis, measurement of magnetic data and X-ray structural analysis. Both modifications are formed by similar but differently packed zigzag chains, which consist of [Cu( men ) 2 ] 2+ moieties bridged by two trans arranged cyanido groups of [Pt(CN) 4 ] 2− units. The Cu(II) atoms in both structures are hexacoordinated by four nitrogen atoms in the equatorial plane from two molecules of bidentate men ligands with the average Cu–N(Me) and Cu–N(H 2 ) bond lengths of 2.046(8) and 2.008(8) A, respectively, and by two nitrogen atoms from bridging cyanido groups in the axial positions at average distance of 2.50(7) A. Broad nearly symmetric bands observed in the UV–vis spectra of 1 and 2 of 2 B 1g → 2 E g transitions are consistent with a deformed octahedral coordination of the CuN 6 chromophoric groups. One and two ν (C N) absorption bands observed in the IR spectra of 1 and 2 , respectively, are in agreement with different local symmetries of [Pt(CN) 4 ] 2− units and different Cu–N(cyanido) bond lengths in these polymorphs and are subject of discussion on the spectral–structural correlations in 1D compounds. The complexes are stable up to 238 °C when their two-stage thermal decompositions start and ending up with a mixture of CuO and metallic Pt as the most probable final thermal decomposition products. The temperature dependence of the magnetic susceptibility suggests the presence of a weak antiferromagnetic exchange coupling between Cu(II) atoms in 1 , J / hc = −0.17 cm −1 and in 2 , J / hc = −1.3 cm −1 .

From the systems Cu(II)–cyclam–[M(CN)4]2− (cyclam = 1,4,8,11-tetraazacyclotetradecane; M = Ni, Pd, Pt), three cyanidocomplexes Cu(cyclam)M(CN)4 [M = Ni (1), Pd (2), Pt (3)] were isolated and characterized by chemical analysis, IR and UV–VIS spectroscopy. The three compounds are isostructural, and their crystal structures are formed by quasi-linear chains exhibiting [–Cu(cyclam)–μ–NC–M(CN)2–μ–CN–]n composition. The Cu(II) atoms reside on centres of symmetry and are coordinated in the form of an elongated octahedron with mean equatorial Cu–N bonds of 2.015(12), 2.017(13) and 2.011(11) Å in (1), (2) and (3), respectively, and weakly N-bonded bridging cyanido ligands in the axial positions [2.5321(9) Å in (1), 2.518(2) Å in (2) and 2.549(3) Å in (3)]. Hydrogen bonds of the N–H···Ncyanido···H–N type link neighbouring chains, and a topologically square network of paramagnetic Cu(II) atoms is formed. The magnetic susceptibilities of all three complexes follow the Curie-Weiss law with a weak antiferromagnetic exchange coupling below 5 K., This work was supported by the Slovak grant agency APVV under contracts Nos. APVV-VVCE-0058-07 and APVV-0006-07, and by grant agency VEGA (1/0089/09 and 1/0079/ 08). Funding from the Ministry of Science and Innovation (Spain) under grants MAT2008-04350 and CONSOLIDER 25200, and from the Diputación General de Aragón is gratefully acknowledged.

The synthesis, structural analysis, spectroscopic studies, susceptibility and specific-heat measurements of {l_brace}[Cu(bmen){sub 2}][Pt(CN){sub 4}]{r_brace}{sub n} (bmen=N,N'-dimethylethylenediamine) are presented. X-ray crystal-structure analysis revealed that the [Pt(CN){sub 4}]{sup 2-} building blocks are combined with [Cu(bmen){sub 2}]{sup 2+} units to form a chain-like structure along the a axis. The Cu(II) atoms are hexacoordinated by four nitrogen atoms in the equatorial plane belonging to two molecules of bidentate bmen ligands with average Cu-N distance of 2.043(18) A. The axial positions are occupied by two nitrogen atoms from bridging [Pt(CN){sub 4}]{sup 2-} anions at a longer axial Cu-N distance of 2.490(4) A. The compound is characterized by the presence of a weak antiferromagnetic exchange coupling J/k{sub B}=0.6 K. Despite the one-dimensional (1D) character of the structure, the analysis of the magnetic properties and specific heat at very low temperatures shows that [Cu(bmen){sub 2}][Pt(CN){sub 4}] behaves as a two-dimensional (2D) square-lattice Heisenberg magnet with weak interlayer coupling. - Graphical abstract: The synthesis, structural analysis, spectroscopic studies, susceptibility and specific-heat measurements of {l_brace}[Cu(bmen){sub 2}][Pt(CN){sub 4}]{r_brace}{sub n} (bmen=N,N'-dimethylethylenediamine) are presented. X-ray crystal-structure analysis revealed that the [Pt(CN){sub 4}]{sup 2-} building blocks are combined with [Cu(bmen){sub 2}]{sup 2+} units to form a chain-like structure. The compound is characterized bymore » the presence of a weak antiferromagnetic exchange coupling J/k{sub B}=-0.6 K. Despite the one-dimensional character of the structure, the analysis of the magnetic properties and specific heat at very low temperatures shows that [Cu(bmen){sub 2}][Pt(CN){sub 4}] behaves as a two-dimensional square-lattice Heisenberg magnet with weak interlayer coupling.« less