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A palladium complex of non-innocent ligand a was synthesized, and characterized by IR, UV-Vis, 1H and 13C NMR spectroscopies and elemental analysis.

Adenylate kinases (AK) play a pivotal role in the regulation of cellular energy. The aim of our work was to achieve the overproduction and purification of AKs from two groups of bacteria and to determine, for the first time, the comprehensive biochemical and kinetic properties of adenylate kinase from Gram-negative Aquifex aeolicus (AKaq) and Gram-positive Geobacillus stearothermophilus (AKst). Therefore we determined KMand Vmaxvalues, and the effects of temperature, pH, metal ions, donors of the phosphate groups and inhibitor Ap5A for both thermophilic AKs. The kinetic studies indicate that both AKs exhibit significantly higher affinity for substrates with the pyrophosphate group than for adenosine monophosphate. AK activation by Mg2+and Mn2+revealed that both ions are efficient in the synthesis of adenosine diphosphate and adenosine triphosphate; however, Mn2+ions at 0.2–2.0 mmol/L concentration were more efficient in the activation of the ATP synthesis than Mg2+ions. Our research demonstrates that zinc ions inhibit the activity of enzymes in both directions, while Ap5A at a concentration of 10 µmol/L and 50 µmol/L inhibited both enzymes with a different efficiency. Sigmoid-like kinetics were detected at high ATP concentrations not balanced by Mg2+, suggesting the allosteric effect of ATP for both bacterial AKs.

The six-coordinated bis-o-iminosemiquinone complex, NiL2BIS, in which LBIS is the o-iminosemiquinone 1-electron oxidized form of the tridentate o-aminophenol benzoxazole-based ligand H2LBAP, was synthesized and characterized. The crystal structure of the complex reveals octahedral geometry with a NiN4O2 coordination sphere in which Ni(II) has been surrounded by two tridentate LBIS ligands. This compound exhibits (SNi = 1) with both spin and orbital contribution to the magnetic moment and antiferromagnetic coupling between two electrons on two LBIS ligands which results in a triplet spin ground state (S = 1). The electronic transitions and the electrochemical behavior of this open-shell molecule are presented here, based on experimental observations and theoretical calculations. The electrochemical behavior of NiL2BIS was investigated by cyclic voltammetry and indicates ligand-centered redox processes. Three-component coupling of aldehydes, amines and alkynes (A3-coupling) was studied in the presence of the NiL2BIS complex, and the previously reported four-coordinated bis-o-iminosemiquinone NiL2NIS. Furthermore, among these two o-iminobenzosemiquinonato(1−) complexes of Ni(II) (NiL2NIS and NiL2BIS), NiL2NIS was found to be an efficient catalyst in A3-coupling at 85 °C under solvent-free conditions and can be recovered and reused for several cycles with a small decrease in activity.

The platinum(II) complexes of general formula [PtCl2(dstp)(S-donor)] were dstp 5,7-dimethyl-1,2,4-triazolo[1,5-a]-pyrimidine (dmtp), 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp), 5-methyl-7-isobutyl-1,2,4-triazolo[1,5-a]pyrimidine (ibmtp) or 5,7-diphenyl-1,2,4-triazolo[1,5-a]pyrimidine (dptp), whereas S-tetrahydrothio-phene-1-oxide (TMSO) or diphenyl sulfoxide (DPSO) were synthesized in a one-pot reaction. Here, we present experimental data (1H, 13C, 15N, 195Pt NMR, IR, X-ray) combined with density functional theory (DFT) computations to support and characterize structure–spectra relationships and determine the geometry of dichloride platinum(II) complexes with selected triazolopyrimidines and sulfoxides. Based on the experimental and theoretical data, factors affecting the stability of platinum(II) complexes have been determined.

A series of new chiral benzisoselenazol-3(2H)-ones and their corresponding diselenides bearing an o-amido function substituted on the nitrogen atom with various aliphatic and aromatic moieties were synthesized. All derivatives representing pairs of enantiomers or diastereoisomers were obtained to thoroughly evaluate the three-dimensional structure–activity correlation. First, bensisoselenazol-3(2H)-ones were synthesized by reacting 2-(chloroseleno)benzoyl chloride with an appropriate enantiomerically pure amine. Then, the Se–N bond was cleaved by a reduction–oxidation procedure using sodium borohydride and then air oxidation to obtain the corresponding diselenides. All derivatives were tested as antioxidants and anticancer agents. In general, the diselenides were more reactive peroxide scavengers, with the highest activity observed for 2,2′-diselenobis[N-(1S,2S)-(-)-trans-2-hydroksy-1-indanylbezamide]. The most cytotoxic derivative towards human promyelocytic leukemia HL-60 and breast cancer MCF-7 cell lines was N-[(1S,2R)-(-)-cis-2-hydroksy-1-indanyl]-1,2-benzizoselenazol-3(2H)-one. The structure–activity relationship of the obtained organoselenium derivatives was discussed.

In this study, a novel Mn(III)–Schiff base complex was synthesized and characterized. The structure of this complex was determined to be a deformed octahedral coordination sphere by single-crystal X-ray diffraction analysis. The Mn(III)–Schiff base complex was supported on silica-coated iron magnetic nanoparticles via axial coordination by one-step complex anchoring to produce a heterogenized nanocatalyst. After this, the complex was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), and powder X-ray diffraction (XRD). Moreover, atomic absorption spectroscopy was used to determine the amount of the loaded metal. The heterogenized nanocatalyst effectively catalyzed the oxidation of a broad range of sulfides and alkenes with H2O2 in the presence of a glassy carbon electrode, applying voltage to the reaction mixture. The results showed that the application of a potential to the reaction mixture could significantly decrease the reaction time when compared with the case of similar chemical oxidation reactions. In addition, an excellent value of turnover frequency (17 750 h−1) was achieved for the electrochemical oxidation of styrene. Moreover, the nanocatalyst showed good recoverability without significant loss of its activity within six successive runs in the electrochemical oxidation of methyl phenyl sulfide and cyclooctene. The electrochemical properties and stability of Fe3O4@SiO2-[MnL(OAc)] were investigated by cyclic voltammetry measurements and chronoamperometry technique.

The synthesis and characterization of a new Cu(II) complex, LNIS2CuII (LNIS = o-iminobenzosemiquinone), are reported. X-ray crystallography studies showed that two o-iminobenzosemiquinone radicals form a distorted square-planar geometry around the Cu(II) center of LNIS2CuII. Magnetic measurements revealed the paramagnetic character of the complex caused by the presence of three unpaired electrons located on the o-iminobenzosemiquinonate ligands and the CuII center. Magnetochemical experiments, and EPR and DFT studies prove that the ground state of the complex is a doublet, which is consistent with the ferromagnetic coupling between Cu(II) and o-iminobenzosemiquinone centers and stronger antiferromagnetic coupling between the iminobenzosemiquinone moieties. The ligand-centered redox reactions of the complex were studied by cyclic voltammetry. Aerobic oxidation of alcohols to aldehydes with TEMPO was studied in the presence of LNIS2CuII. Furthermore, LNIS2CuII was found to be an efficient catalyst in homo-coupling of terminal alkynes.

A new Ni(II) complex, was synthesized from the reaction of a non-innocent o-aminophenol ligand, and Ni(OAc)2. The crystal structure of NiIIL2NIS (in which, IS stands for iminosemiquinone radical ligand with cyanide (shown by N in NIS) substituent on phenolate rings) exhibits the square planar environment of Ni(II). The complex has been crystalized in the monoclinic system and Ni(II) was surrounded by two oxygen and two nitrogen atoms of two ligands. Variable-temperature magnetic susceptibility measurement for crystalline samples of complex shows the effective magnetic moment per molecule (μeff) of near zero and the diamagnetic nature of the complex (S = 0) which emphasize that strong antiferromagnetic coupling prevailed between the two unpaired electrons of LNIS ligands and Ni(II) high spin electrons. The complex is EPR silent which confirms the diamagnetic character of the Ni(II) complex. Electrochemical measurement (CV) indicates the redox-active character of ligand and metal. NiIIL2NIS complex proved to be effective for free metal- or base counterpart homocoupling of phenyl acetylene at room temperature. To the best of our knowledge, this is the first example of using Ni(II) complex without using any reducing agent due to the promotion ancillary effect of non-innocent o-aminophenol ligand which acts as an “electron reservoir” and can reversibly accept and donate electrons in the catalytic cycle. The theoretical calculation confirms the magnetostructure, electronic spectrum and confirmed the suggested mechanism of phenyl acetylene homocoupling with emphasis on the role of non-innocent ligand electro-activity and the effect of ligand substituent on the efficiency and stability of the complex.

New ligands obtained in the reaction of o-phenylenediamine and series of aldehydes (L1-L5) were synthesized. Molecular architecture of the synthesized ligands L1-L5 has been determined by the X-ray crystal structure analysis. 1H NMR NOE diff. spectra (differential Nuclear Overhauser Effect) of ligands indicate that they have different conformation in the solution in comparison to the solid state (crystal structure). The substrates molar ratio and the reaction time allowed the controlled synthesis of mono substituted o-phenylenediamine or benzimidazole derivatives with no catalyst used. For all compounds the relatively high fluorescence efficiency was observed in the range 0.41–0.83 in MeCN and 0.48–0.96 in CH2Cl2 solution. Based on DFT calculations the fluorescence mechanism was associated with HOMO→LUMO transition between aromatic rings and benzimidazole moieties.

Adenylate kinases (AK) play a pivotal role in the regulation of cellular energy. The aim of our work was to achieve the overproduction and purification of AKs from two groups of bacteria and to determine, for the first time, the comprehensive biochemical and kinetic properties of adenylate kinase from Gram-negative

Within the broad group of Fe non-heme oxidases, our attention was focused on the catechol 1,2- and 2,3-dioxygenases, which catalyze the oxidative cleavage of aromatic rings. A large group of Fe complexes with N/O ligands, ranging from N3 to N2O2S, was developed to mimic the activity of these enzymes. The Fe complexes discussed in this work can mimic the intradiol/extradiol catechol dioxygenase reaction mechanism. Electronic effects of the substituents in the ligand affect the Lewis acidity of the Fe center, increasing the ability to activate dioxygen and enhancing the catalytic activity of the discussed biomimetic complexes. The ligand architecture, the geometric isomers of the complexes, and the substituent steric effects significantly affect the ability to bind the substrate in a monodentate and bidentate manner. The substrate binding mode determines the preferred mechanism and, consequently, the main conversion products. The preferred mechanism of action can also be affected by the solvents and their ability to form the stable complexes with the Fe center. The electrostatic interactions of micellar media, similar to SDS, also control the intradiol/extradiol mechanisms of the catechol conversion by discussed biomimetics.

Statins are the most effective cholesterol-lowering drugs. They also exert many pleiotropic effects, including anti-cancer and cardio- and neuro-protective. Numerous nano-sized drug delivery systems were developed to enhance the therapeutic potential of statins. Studies on possible interactions between statins and human proteins could provide a deeper insight into the pleiotropic and adverse effects of these drugs. Adenylate kinase (AK) was found to regulate HDL endocytosis, cellular metabolism, cardiovascular function and neurodegeneration. In this work, we investigated interactions between human adenylate kinase isoenzyme 1 (hAK1) and atorvastatin (AVS), fluvastatin (FVS), pravastatin (PVS), rosuvastatin (RVS) and simvastatin (SVS) with fluorescence spectroscopy. The tested statins quenched the intrinsic fluorescence of hAK1 by creating stable hAK1-statin complexes with the binding constants of the order of 104 M−1. The enzyme kinetic studies revealed that statins inhibited hAK1 with significantly different efficiencies, in a noncompetitive manner. Simvastatin inhibited hAK1 with the highest yield comparable to that reported for diadenosine pentaphosphate, the only known hAK1 inhibitor. The determined AK sensitivity to statins differed markedly between short and long type AKs, suggesting an essential role of the LID domain in the AK inhibition. Our studies might open new horizons for the development of new modulators of short type AKs.

We investigate the emission properties of four organic dyes containing a strong electron-donating N(CH3)2 group and an NBF2O-bearing heterocyclic moiety acting as the electron-accepting group. The four studied compounds differ in the number and positions of the fused benzo rings included in the heterocyclic moiety. They exhibit strong emission in solution, with fluorescence quantum yields (Φf) systematically exceeding 0.8 at least in one of the solvents used, regardless of the benzannulation architecture. The strong dipolar character, achieved by substitution with the N(CH3)2 group and benzannulation, enhances the photoinduced charge transfer and appears to be an effective strategy to tune the photophysical properties of these dyes in solution. Indeed, red-shifted absorption spectra are obtained without deteriorating the emission properties. However, the present joint theory–experiment study clearly demonstrates that such a molecular design is not effective for solid-state applications, as only one derivative still exhibits significant emission in the crystalline form, namely the most compact one. We show that the combination of benzannulation in the presence of the strong amino donor leads to substantial changes in crystal packing and that a different network of intermolecular interactions can be found in the crystal. More specifically, going from the parent compound to its benzannulated derivatives induces a stronger π⋯π stacking combined with multiple CH⋯π interactions involving the fused benzo rings and the hydrogen atoms of the dimethylamino group, which impedes efficient emission of the crystals.

The six-coordinated bis

Herein, we present dicarboxylate platinum(II) complexes of the general formula [Pt(mal)(DMSO)(L)] and [Pt(CBDC)(DMSO)(L)], where L is dbtp 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine) or ibmtp (7-isobutyl-5-methyl-1,2,4- triazolo[1,5-a]pyrimidine), as prospective prodrugs. The platinum(II) complexes were synthesized in a one-pot reaction between cis-[PtCl2(DMSO)2], silver malonate or silver cyclobutane-1,1-dicarboxylate and triazolopyrimidines. All platinum(II) compounds were characterized by FT-IR, and 1H, 13C, 15N and 195Pt NMR, and their square planar geometries with one monodentate N(3)-bonded 5,7-disubstituted-1,2,4-triazolo[1,5-a]pyrimidine, one S-bonded molecule of dimethyl sulfoxide and one O,O-chelating malonato (1, 2) or O,O-chelating cyclobutane-1,1-dicarboxylato (3, 4) was determined. Additionally, [Pt(CBDC)(dbtp)(DMSO)] (3) exhibited (i) substantial in vitro cytotoxicity against the lung adenocarcinoma epithelial cell line (A549) (IC50 = 5.00 &micro, M) and the cisplatin-resistant human ductal breast epithelial tumor cell line (T47D) (IC50 = 6.60 &micro, M), and (ii) definitely exhibited low toxicity against normal murine embryonic fibroblast cells (BALB/3T3).

We report a new mononuclear molybdenum(iv) complex, MoOL

A new Ni(ii) complex, was synthesized from the reaction of a non-innocent

In order to investigate photophysical properties and crystallization medium effects, three Cu complexes, [CuI(PCy3)]2 (1), [Cu(I)(PPh2Me)]4 (2), and [Cu4(I)4(PPh2py)2] (3) were prepared and characterized using single crystal X-ray crystallography, solid state NMR, UV–Vis, and IR spectroscopy. In 1, as previously reported, Cu2I2 core is a square dimer with alternating copper and iodides positioned in the corners. Each copper atom is surrounded by two bridging iodides and a terminal tricyclohexylphosphine ligand. The cluster 2 adopts a cubane-like Cu4I4 core, while in cluster 3 (as thf solvate) a Cu4I2 distorted octahedral core is decorated with two bridging iodides and two chelating P^N ligands. The solid state 31P NMR analysis showed the presence in the powder of several polymorphs, the most abundant of which being, in the case of 2, the cubane-like structure resolved by XRD methods, and in the case of 3, a butterfly structure, different from that found for 3·thf. The solid state blue photoluminescence intensity in 1 is dependent upon its poly- or single-crystallinity. While dimer 1 in polycrystalline form is a stronger blue light emitter under 254 nm light irradiation than in 365 nm, in single crystalline phase it shows a similar higher intensity blue luminescence under lower energy light (365 nm) irradiation. On the other hand, clusters 2 and 3 do not show phase-dependent luminescence intensity variation. Time-dependent Density Functional Theory (TD-DFT) showed that the emission in 1 and 3 is assigned to a mixed metal to ligand and halide to ligand charge transfer, (X + M)LCT. In 2, a dual emission band at low temperature was observed which was attributed to 3CC (LE band) and 3XLCT (HE band). Thermochromism and mechanochromism of complexes 1–3 were also investigated.

6-Methoxy-2-[(E)-Aryliminomethyl]-phenol (Aryl = Phenyl; 2,6-dimethyl; 2,6-diisopropylphenyl; 2,6-dichlorophenyl), comprising L1–L4 ligands, and palladium complexes [Pd(Ln)2, n = 1–4] have been synthesized. The geometries of the [Pd(Ln)2] complexes were derived from single X-ray crystallography experiments. The central Pd(II) ion is four-coordinated and surrounded by N2O2 environment, adopting a square planar geometry. The ligand is bidentate, coordinating via imine nitrogen and phenolate oxygen atoms to the metal center. Analysis of the valence geometry within the phenolate rings suggests that in all complexes, the O1–C1 has a double bond character. FT-IR, 1H, 13C NMR and single X-ray crystal structures were reported. The cytotoxicity effect of four Pd(II) complexes was assessed on three cancerous cell lines: MCF-7 (breast carcinoma), A549 (lung carcinoma) and SKOV3 (ovarian carcinoma) and compared with that for cis-platin. One out of four metal complexes, Pd(L1)2, exhibited the highest anti-proliferative activity on three investigated cancerous cells lines which is more effective than cis-platin. The results showed that this complex could effectively induce apoptotic death in cancerous cells, probably due to direct interaction by cellular DNA.

In the present work, the synthesis and characterization of a novel binuclear oxo-bridged iron(III) complex, (FeLAPIP)2O, where LAPIP is the deprotonated form of a tetradentateo-aminophenol-iminopyridine ligand, is described. The iron complex was characterized using different techniques including X-ray crystallography, infrared spectroscopy, UV-Vis, magnetic susceptibility and cyclic voltammetry. The X-ray structure analysis revealed that in the structure of the (FeLAPIP)2O complex, each iron(III) is coordinated in a distorted square pyramidal arrangement by an oxo group, three amine nitrogens and one oxygen atom of the o-aminophenolate ligand. The variable-temperature magnetic measurement exhibits strong antiferromagnetic coupling between two iron(III) centers. Cyclic voltammetry measurements showed two kinds of quasireversible events, suggesting the formation of a phenoxyl radical species in the region of the anodic peaks and a metal-centered redox (FeIII/FeII) process at low potential. The catalytic activity of this Fe-complex was evaluated in coupling of 2-aminophenol and benzyl alcohols for the one-pot synthesis of benzoxazoles. The catalyst system showed high catalytic activity in this transformation and benzoxazole derivatives were obtained in good to excellent yields. tert-Butyl hydroperoxide was used as an oxidant and 1.2 mol% of catalyst was needed to accomplish the reaction in water as the green solvent.

Au(III) chloride compounds with 7,8-benzoquinoline (bqn) – [Au(bqn)Cl3] and [Au(bqn∗)Cl2] (bqn∗ being deprotonated, at the C(10) carbon, monoanionic form of bqn) were studied by 1H–13C, 1H–15N HMQC and HMBC–NMR. 1H, 13C and 15N coordination shifts were discussed in relation to the molecular structures, revealing characteristic variability patterns. Analogous NMR measurements were performed for the new (bqnH+)2(AuCl4−)Cl− salt, studied also by single crystal X-ray diffraction. All compounds exhibited fluorescence.

The crystal and molecular structures and magnetic properties of two new complexes (HMepy)2[CuCl4]·2H2O, 2, and (H2Me2ppz)[CuCl4], 3, formed by tetrachlorocuprate(II) anions and organic heterocyclic cations, bis(3-amino-2-chloro-5-methylpyridinium) (HMepy) and trans-2,5-dimethylpiperazinium (H2Me2ppz), respectively, have been determined by the analysis of their X-ray diffraction data, magnetic susceptibility behaviour and EPR spectral parameters. These characteristics differentiate the [CuCl4]2− anions in 2 and 3 as well as that previously reported in (H2bipip)[CuCl4]·H2O, 1, (bipip = 4,4′-bipiperidine) (Tuikka et al., CrystEngComm, 2013, 15, 6177; Wikaira et al., J. Coord. Chem., 2016, 69(1), 57). The present study reveals a significant effect of the organic cations on the geometry and magnetic properties of the [CuCl4]2− anions caused evidently by the changes in the crystal packing structure. A characteristic relationship was observed between the average cis-angles around the Cu(II) ions in [CuCl4]2− for 1–3, affected by the Cu(II) coordination geometry, and g-tensor components derived from the EPR spectra, a measure of interaction of copper(II) unpaired electrons in the [CuCl4]2− anions with an external magnetic field. The magneto-structural correlations revealed weak antiferromagnetic exchange interactions between the [CuCl4]2− anions transmitted by different pathways.

New silver complexes with ligands obtained from 2(2-pirydyl)ethylamine (epy) or o-phenylenediamine and series of aldehydes were obtained and characterized by their crystalline, molecular and spectroscopic (UV-Vis, fluorescence, IR, NMR) features. Molecular architecture of the synthesized complexes [Ag2(epy(5-Brthca))2(NO3)2] 1 and [Ag(bzim-anthr)2]+NO3−2 has been determined by X-ray crystal structure analysis. 1H NMR NOE diff. spectra of Ag complexes reveal different ligand conformations in the solution and the solid state (crystal structure). Thin (13–113 nm average thickness), homogenous layers of the studied silver(I) complexes were obtained by the spin coating method. The new materials were also characterized with AFM, SEM/EDX and ellipsometry. Calculated band-gap energies related to conformational transitions in layers of complexes 3, 1 and 2 on Si(111) were 2.83 ± 0.02 eV (438 ± 3 nm), 2.90 ± 0.01 eV (428 ± 2 nm) and 2.95 ± 0.02 eV (420 ± 3 nm), respectively. The fluorescence bands of layers observed in the range 470–580 nm revealed significant intensity and were bathochromically shifted in comparison with those observed for the complexes solutions. Influence of polarity of the solvent on fluorescence properties of the obtained complexes was studied. The highest quantum yield of the fluorescence was achieved in methylene chloride for 2 with ϕ2 = 0.52 (λex = 335–385 nm) and is related to the anthracene moiety.

Tropical diseases currently constitute a major health problem and thus a challenge in the field of drug discovery. The current treatments show serious disadvantages due to cost, toxicity, long therapy duration and resistance, and the use of metal complexes as chemotherapeutic agents against these ailments appears to be a very attractive alternative. Herein, we describe three newly synthesized ruthenium complexes with a bioactive molecule, the purine analogue 5,6,7-trimethyl-1,2,4-triazolo[1,5- a ]pyrimidine (tmtp): cis,fac -[RuCl 2 (dmso) 3 (tmtp)] ( 1 ), mer -[RuCl 3 (dmso)(H 2 O)(tmtp)]·2H 2 O ( 2 ) and fac,cis -[RuCl 3 (H 2 O)(tmtp) 2 ] ( 3 ). Their structures were characterized using X-ray and spectroscopic methods (IR, NMR or EPR). The stability of the synthesized complexes 1 – 3 in various buffered solutions (pH = 3–7.4) was monitored using conventional and stopped-flow techniques. The in vitro antiproliferative activity of all ruthenium complexes against promastigote forms of Leishmania spp . ( L. infantum , L. braziliensis , and L. donovani ) and epimastigote forms of Trypanosoma cruzi was investigated. Notably, the results showed that the activity of 1 against L. brasiliensis was more than three-fold higher than that of glucantime, and 1 showed no appreciable toxicity towards J774.2 macrophages. Additionally, 2 displayed even 141-fold lower toxicity against host cells than glucantime, demonstrating significantly higher selectivity than the reference drug. Therefore, 1 and 2 appear to be excellent candidates for further development as potential drugs for the effective treatment of leishmaniasis and Chagas disease. All novel complexes were also shown to be potent inhibitors of Fe-SOD in the studied species, while their effects on human CuZn-SOD were very low.

Ag(I) complexes with a series of optically active Schiff bases derived from (1R,2R)(-)cyclohexanediamine and different aldehydes were obtained and characterized by 1H, 13C, NMR in a solution and in the solid state, UV–Vis, fluorescence, and IR spectroscopy. X-ray crystal structure of (1R,2R)(-)chxn(5-Br-3OCH3baH)2 (4) was solved. Moreover, intermolecular interactions in the crystal structure of (1R,2R)(-)chxn(5-Br-3OCH3baH)2 were analyzed using 3D Hirshfeld surfaces and the related 2D fingerprint plots. The obtained complexes have been used for preparation of thin layers on Si(1 1 1) to test the possibility of their use as the fluorescent materials. Thin layers of silver(I) complexes were deposited on Si(1 1 1) using the spin coating method and characterized by scanning electron microscopy (SEM/EDS), atomic force microscopy (AFM), and fluorescence spectroscopy. [Ag(1R,2R)(-)chxn(5-Br-3OCH3baH)2NO3] (4a) complex exhibited significantly increase of the fluorescence intensity in comparison with ligand (4). The fluorescence of silver complexes solutions was observed between 395 and 470 nm. For silver(I) layers, from intraligand transitions (depending on the exciton wavelengths), the most intensive bands were observed between 390 and 560 nm. The intensity of the fluorescence bands registered for the layers obtained at 1100 rpm or 2000 rpm/min and 30 s time was highest.

A novel, magnetically recoverable Mn-Schiff base catalyst has been prepared by the adsorption on silica-coated magnetic nanoparticles. X-ray crystallography studies reveal that the Mn-complex adopt a distorted octahedral six-coordinate configuration formed by the tetradentate Schiff base ligand and two oxygen atoms of acetate anion. The heterogeneous catalyst was characterized by powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometer, thermo-gravimetric analysis, the energy-dispersive X-ray spectroscopy and FTIR spectroscopy. The catalyst loading on the magnetic support was determined by atomic absorption spectroscopy. Highly chemoselective oxidation of sulfides with excellent yield to the corresponding sulfoxides, and epoxidation of olefins in ethanol at room temperature were efficiently enhanced under the influence of the magnetically separable catalyst. The separation and recycling of the catalyst is simple, effective, and economic in this clean oxidation method. The electrochemical properties of the Mn-complex were investigated.

Copper(II) Schiff base complex has been immobilized onto graphene oxide (GO) via covalent bonding. The nanocomposite was characterized using powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and UV–visible spectroscopies, transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermo-gravimetric analysis (TGA) and the energy-dispersive X-ray spectroscopy (EDX). The amount of catalyst loading on the solid support was determined by atomic absorption spectroscopy. The thermogravimetric analysis (TGA) demonstrated that the nanocatalyst was stable up to almost 220 °C, exhibiting high thermostability. Highly active and selective catalyst was found with excellent turnover numbers (up to 47,000 for oxidation of styrene) for the epoxidation of olefins in ethanol using aqueous hydrogen peroxide as oxidant. It could be readily reused for successive ten times without discernible activity and selectivity deterioration, which displays potential for practical applications.

New Ag(I) complexes with Schiff bases derived from 9-anthracenecarboxaldehyde and 2-thiopheneethylamine thet(9-anthraceneca) (L1) or (1R,2R)(+)-diphenylethylenediamine (1R,2R)(+)-diphenen(9-anthraceneca) (L2) were obtained and characterized by 1H, 13C, 15N NMR, 1H differential Nuclear Overhauser Effect (NOE diff.) NMR technique, UV–Vis, CD and IR spectroscopy in solution and in the solid phase. X-ray crystal structure of [Ag(thet(9-anthraceneca))2]NO3] (1), revealed silver(I) linearly coordinated by the ligand imine nitrogen atoms. X-ray crystal structure detremination and DFT calculations for complexes and ligands, related confirming their geometry in solution and in the solid phase. 1H NMR NOE diff. spectra indicate that both Schiff bases adopt different conformation in solution and in the solid state. For Ag complexes with (L1) and (L2) the significant NOE enhacement between the imine hydrogen atoms and hydrogen of the aromatic rings was observed, indicating changes of the silver ion coordination sphere in solution. The highest quantum yield of the fluorescence was achieved for (2) with φ2 = 0.52 (λex = 347 nm). For all investigated compounds the fluorescence is related to the excitation HOMO → LUMO + 1 or HOMO → LUMO in the anthracene moiety. The homogeneous layers of complexes uniformly covering the silicon substrate have been obtained with a spin- or dip-coating techniques and characterized by scanning electron microscopy (SEM/EDS) and atomic force microscopy (AFM). The complex [Ag2((1R,2R)(+)-diphenen(9-anthraceneca))(NO3)2] (2) was deposited on Si(1 1 1) covered with PMMA. Fluorescence spectra of [Ag(thet(9-anthraceneca))2]NO3] (1)/Si materials exhibit emission at 480 nm from intra-ligand transitions (λex = 360 nm) and differ slightly from the spectra obtained for the solid complexes or their solutions. The highest fluorescence intensity was noted for the layers obtained by a multistage deposition at variable spin rates and deposition time 5 s.

Six novel platinum(II) complexes containing purine-mimetic ligands (5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine (dmtp), 7-isobutyl-5-methyl-1,2,4-triazolo[1,5-a]pyrimidine (ibmtp), 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp)) and dicarboxylato ligands (glutarato (glut) or cyclobutane-1,1-dicarboxylato (CBDC)) have been prepared and characterized with multinuclear magnetic resonance (1H, 13C, 15N, 195Pt) NMR, infrared (IR) and X-ray crystallography. Spectroscopic data in solid state and in solution unambiguously confirm the square-planar geometry of Pt(II) with two monodentate N3-bonded 5,7-disubstituted-1,2,4-triazolo[1,5-a]pyrimidine ligands and one O-chelating dicarboxylato ligand. Next, the effect of all the platinum(II) compounds on the viability of normal or cancer cells and their putative mechanisms of action have been investigated. Of the studied platinum(II) complexes, two ([Pt(glut)(dbtp)2] and [Pt(CBDC)(dbtp)2]) overcame the cisplatin resistance in human ovarian tumor cells (A2780cis or OVCAR-3) and arrested the cell cycle at S phase in mice mammary gland cancer cells (4T1), which indicates a mechanism of action different from that of cisplatin. Interestingly, preliminary in vivo toxicity assays revealed that both compounds tested in mice ([Pt(glut)(dbtp)2] 3 and [Pt(CBDC)(dbtp)2] 6) were less toxic in vivo than cisplatin or oxaliplatin. Additionally, compound 6 did not cause myelosuppression and showed over fivefold less accumulation in the liver than its glutarato analog 3.

Two types of ruthenium(ii) complexes containing 1,2,4-triazolo[1,5-a]pyrimidines of the general formulas [RuCl2(dmso)3(L)] ((1)-(3)) and [RuCl2(dmso)2(L)2] ((4)-(6)), where L represents 1,2,4-triazolo[1,5-a]pyrimidine (tp for (1)), 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine (dmtp for (2)), 7-isobutyl-5-methyl-1,2,4-trizolo[1,5-a]pyrimidine (ibmtp for (3)), 5,7-diethyl-1,2,4-triazolo[1,5-a]pyrimidine (detp for (4)), 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp for (5)) and 5,7-diphenyl-1,2,4-triazolo[1,5-a]pyrimidine (dptp for (6)), have been synthesized and characterized by elemental analysis, infrared, multinuclear magnetic resonance spectroscopic techniques (1H, 13C, and 15N), and X-ray (for (3), (4), and (5)). All these complexes have been thoroughly screened for their in vitro cytotoxicity against melanoma cell lines A375 and Hs294T, indicating cis,cis,cis-[RuCl2(dbtp)2(dmso)2] (5) as the most active representative, in addition to being non-toxic to normal human fibroblasts (NHDF) and not inducing hemolysis of human erythrocytes. In order to develop an intravenous formulation for (5), liposomes composed of soybean phosphatidylcholine (SPC), cholesterol (Chol) and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)-2000] (DSPE-PEG2000) were prepared and subsequently characterized. (5)-Loaded liposomes, with spherical morphology, assessed by transmission electron microscope (TEM), exhibited satisfactory encapsulation efficiency and stability. In in vitro experiments, PEG-modified (5)-loaded liposomes were more effective (10-fold) than free (5) for growth inhibition of both human melanoma cell lines. Furthermore, such an approach resulted in the reduction of cancer cell viability that was even 10-fold greater than that observed for free cisplatin.

We report a new mononuclear molybdenum(IV) complex, MoOLBISLSQ, in which LSQ (2,4-di-tert-butyl o-semibenzoquinone ligand) has been prepared from the reaction of the o-iminosemibenzoquinone form of a tridentate non-innocent benzoxazole ligand, LBIS, and MoO2(acac)2. The complex was characterized by X-ray crystallography, elemental analysis, IR and UV-vis spectroscopy and magnetic susceptibility measurements. The crystal structure of MoOLBISLSQ revealed a distorted octahedral geometry around the metal centre, surrounded by one O and two N atoms of LBIS and two O atoms of LSQ. The effective magnetic moment (μeff) of MoOLBISLSQ decreased from 2.36 to 0.2 μB in the temperature range of 290 to 2 K, indicating a singlet ground state caused by antiferromagnetic coupling between the metal and ligand centred unpaired electrons. Also, the latter led to the EPR silence of the complex. Cyclic voltammetry (CV) studies indicate both ligand and metal-centered redox processes. MoOLBISLSQ was applied as a catalyst for the oxidative cleavage of cyclohexene to adipic acid and selective oxidation of sulfides to sulfones with aqueous hydrogen peroxide.

Tetradentate Schiff base (H2L) derived from 2,2′-dimethylpropandiamine and its nickel(II) and oxo-vanadium(IV) complexes (NiL, VOL) have been prepared and characterized. The crystal structure of NiL has been determined. The reported structure contains two molecules of the complex revealing slightly different conformation and the coordination sphere around nickel is distorted square planar. The electrochemical properties of the Ni and oxo-vanadium Schiff base complexes were investigated in CH3CN by cyclic voltammetry. The catalytic activities of the complexes were studied in the oxidation of sulfides in ethanol. Under the optimized reaction conditions, in the presence of NiL, 89% and VOL, 100% conversion of methyl phenyl sulfide with 100% selectivity for sulfoxide were obtained.

New Schiff bases were obtained in the reaction of 2-thiopheneethylamine with 3-methyl-2-thiophenecarboxaldehyde (for thet(3-methca), L1) or 5-bromo-2-thiophenecarboxaldehyde (for thet(5-Brthca), L2) and characterized by 1H, 13C and 15N NMR spectra and a 1H differential Nuclear Overhauser Effect (NOE diff.) experiment. The synthesized ligands were used for the complexation of silver(I) ions, resulting in new complexes of the formula [Ag(thet(3-methca))2(NO3)] (1) and [Ag(thet(5-Brthca))2(NO3)] (2). The X-ray crystal structure analysis of (1) revealed a distorted tetrahedral geometry of the coordination sphere with two monodentately N bonded Schiff base (L1) molecules and a bidentately coordinated nitrate anion. In [Ag(thet(5-Brthca))2(NO3)] (2), a twofold [y, x, −z] symmetry of the molecule is found, with the symmetry axis coinciding with the double N O bond in the nitrate ligand. The silver(I) ion binds the Schiff base and nitrate anion identically to that in (1), but also bonds to two sulfur donors, thereby having a strongly deformed octahedral coordination sphere. 1H NOE diff. spectra revealed a significant NOE enhancement for the imine hydrogen atoms and the hydrogen atoms in the aromatic rings in closest proximity. The UV–Vis and fluorescence spectra of the ligands and complexes were measured. All the compounds exhibit a higher intensity fluorescence in the solid state than in solution. The geometries of the complexes, optimized in DFT simulations, have been used to assist in the interpretation of the fluorescence experiments and absorption spectra. The obtained complexes have been used for preparation of thin layers on Si(1 1 1) to test the possibility of their use as fluorescent materials. Thin layers of the complexes were deposited by spin and dip coating techniques on Si(1 1 1) substrates and were characterized by scanning electron microscopy (SEM/EDX) and atomic force microscopy (AFM). The fluorescence spectra of [Ag(thet(3-methca))2(NO3)] (1)/Si and [Ag(thet(5-Brthca))2(NO3)] (2)/Si layers revealed the highest fluorescence intensity when a multistage deposition was applied at different spin rates and deposition times. The obtained layers have better parameters than materials which were used successfully as gas sensing materials.

Four copper complexes of three-dentate benzoxazole-containing o-aminophenol based ligand (H2LBAP) have been synthesized and characterized by IR spectroscopy, UV–Vis spectroscopy, electronic structure calculations, single crystal X-ray diffraction, magnetic susceptibility studies and cyclic voltammetry techniques indicating that the ligand is oxidized to the o-iminosemiquinone form [LBIS]− in copper complexes, CuLBISX, (X = Br−, I−, N3−, NO3−). LBISCuIINO3 is square pyramidal complex while the three other complexes show a distorted tetrahedral geometry. In all structures the ligand is coordinated to CuII via the benzoxazole, as well as the nitrogen and oxygen atoms from the o-iminosemiquinone moiety. The monodentate bromide, iodide, azide, and bidentate nitrate groups occupy the fourth and/or fifth positions in LBISCuX, respectively. The magnetic susceptibility and EPR studies confirm that all complexes are diamagnetic due to the interaction of d9 CuII center and iminosemiquinone radical ligand. Electrochemical redox and consequently catalytic results of complexes revealed that they have been tuned by X anion coordinated to Cu(II).

In this joint experimental–theoretical work, the crystal structures of 5-methyl-7-isobutyl-1,2,4-triazolo[1,5-a]pyrimidine (ibmtp) (1) and its three mononuclear chlorido platinum(II) complexes, cis-[PtCl2(ibmtp)2] (2), cis-[PtCl2(dmso)(ibmtp)] (3), and cis-[PtCl2(ibmtp)(NH3)] (4), have been determined. The structures of the compounds (1–4) have been supported by X-ray, IR and multinuclear 1H, 13C, 15N and 195Pt NMR spectroscopy along with density functional theory (DFT) calculations. In complex (2) the coordination sphere of Pt(II) consists of two monodentate ibmtp ligands and two cis chlorido ions. However, in complexes (3) and (4) with a single ibmtp ligand and two cis chlorido ions, the square planar geometry around Pt(II) is completed by either dmso or ammonia ligands, respectively. This is supported by DFT calculations which show good agreement with the experimental data. Notably, DFT calculations allow us to suggest that compound (3) in the presence of dimethylformamide undergoes a slow cis–trans isomerization. In addition, compounds (2–4) have been tested for in vitro cytotoxic activity against three human tumor cell lines: T47D (breast cancer), A549 (non-small cell lung carcinoma), and LoVo (colon cancer), and one healthy cell line BALB/3T3 (mouse embryonic fibroblast). The tests indicate that the in vitro cytotoxicity for compounds (2–4) strongly correlates with the nature of the non-leaving ligands and the geometry around platinum(II).

Zinc complexes of ZnLAPIPX (L = 2,4-di-tert-butyl-6-(((E)-2-(((E)-pyridin-2-lmethylene)amino)benzylidene)amino)phenol) bearing different axial ligands (X = OAc, Cl, Br, I) have been successfully synthesized and characterized. It is evident from X-ray crystallography analysis that ZnLAPIPX exists as a distorted square-pyramid in which ZnII is coordinated by an o-aminophenolate-based ligand and an X moiety in the axial position. These easily synthesized complexes have been shown to perform as effective catalysts for the coupling of epoxides and carbon dioxide to generate cyclic carbonates. Their axial ligand was found to play an important role in enhancing their catalytic activity. The ZnLAPIPI complex represents a versatile bifunctional catalyst due to the synergistic effect of both an electrophilic zinc ion and a nucleophilic iodide in one molecule to achieve a high-yield of cyclic carbonates, while ZnLAPIPOAc in cooperation with a co-catalyst affords a productive system for this coupling reaction. The effects of reaction variables such as temperature, time and pressure were systematically investigated. This solvent free route is relevant to the context of green chemistry as it provides an atom-efficient protocol for the conversion of CO2 into valuable cyclic carbonates.

Two mononuclear manganese(III) complexes of bis(phenol) diamine ligands (H2LNEX) and 2,3,4,5-tetrabromocatechol (TBC), MnLNEX(TBC), were synthesized as models for enzyme–catechol adducts of the intradiol Fe-dependent catechol dioxygenases. X-ray analysis of the complexes has revealed that the manganese center in the model compounds has a distorted octahedral coordination sphere and is surrounded by the LNEX ligand and two oxygen atoms of TBC. The phenolate moieties of MnLNEX(TBC) were electrochemically oxidized to phenoxyl radicals. Consistent with the electrochemical results, quantum chemical calculations showed that the HOMO and LUMO levels on both complexes are on the phenolate moieties. The paramagnetic properties of the manganese(III) center of the complexes have been investigated by magnetic susceptibility measurements. H2LNEX/MnCl2 showed quite good enzyme-mimicking reactivity. It utilized molecular oxygen in carrying out the cleavage of di-tert-butyl catechol at room temperature. To the best of our knowledge this is the second report where a manganese complex can perform oxygenase and not oxidase activity.

Three structurally different mononuclear dichlorido platinum(II) complexes with 5,7-diethyl-1,2,4-triazolo[1,5- a ]pyrimidine (detp) were synthesized and characterized through multinuclear magnetic resonance ( 1 H, 13 C, 15 N, 195 Pt) and infrared spectroscopy. The X-ray structure of cis -[PtCl 2 (detp)(dmso)] ( 2 ) was determined using the single-crystal X-ray diffraction technique. The molecular structure of ( 2 ) exhibits a square planar geometry surrounding the Pt(II) ion with a unique placement of two chlorido ligands in the cis position in the presence of a S-dmso molecule in the coordination sphere. All NMR data obtained in solution unambiguously confirmed the square planar geometry of Pt(II) with monodentate N3-bonded detp, a monodentate second ligand (detp or NH 3 or dmso) and two chlorido ligands in the cis geometry. Cytotoxicity tests using human carcinoma cell lines, specifically the T47D (breast cancer), A549 (non-small cell lung carcinoma), and LoVo (colon cancer) cell lines, and the healthy cell line BALB/3T3 (mouse embryonic fibroblast), indicated that only cis -[PtCl 2 (detp) 2 ] ( 1 ) possesses similar in vitro cytotoxicity against T47D and sevenfold lower toxicity than cisplatin.

Four new mixed ligand iron(III) complexes of N,N′-dimethylethylenediamine based bis(phenol) di-amine (H2LNER) and 8-hydroxyquinoline (HQ) ligands have been synthesized and characterized by spectroscopic methods, X-ray diffraction, magnetic susceptibility measurements and cyclic voltammetry techniques. X-ray structure analysis revealed iron complexes with monoclinic or triclinic structures in which the H2LNEX and HQ ligands are coordinated to the Fe(III) center. The variable temperature magnetic susceptibility indicated a paramagnetic iron(III) center in the complexes. Electrochemical studies of the complexes with cyclic voltammetry showed cathodic peaks corresponding to an FeIII to FeII reduction. An anodic peak was found that corresponded to phenolate ligand oxidation to phenoxyl radicals in the positive potential regions. To the best of our knowledge, synthesis reports on mixed-ligand 8-hydroxyquinolinato iron(III) complexes are very rare.

A series of neutral half-sandwich organometallic ruthenium(II) complexes of the general formula [(η6-p-cym)Ru(L)Cl2], where η6-p-cym – p-cymene, was prepared by the direct reaction of a dichloride p-cymene ruthenium(II) dimer, [{(η6-p-cym)Ru(μ-Cl)}2Cl2], with corresponding 1,2,4-triazolo[1,5-a]pyrimidine ligands (L), namely, L-1,2,4-triazolo[1,5-a]pyrimidine (tp) (1), 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine (dmtp) (2), 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp) (3), 7-isobutyl-5-methyl-1,2,4-triazolo[1,5-a]pyrimidine (ibmtp) (4), and 5,7-diphenyl-1,2,4-triazolo[1,5-a]pyrimidine (dptp) (5). The complexes were prepared in molar ratios of 1:2 (except (1), for which an excess of tp was used). The structures of the complexes were determined by multinuclear magnetic resonance (1H, 13C, 15N) spectroscopy and X-ray diffraction. According to all the spectroscopic data, the molecules adopted the usual “piano-stool” geometry with a monodentate N3 triazolopyrimidine ligand. Studies on these lipophilic ruthenium(II) complexes revealed rather low in vitro antiproliferative activities against two human cell lines.

Mononuclear cobalt(III) complexes of 3,5-di-tert-butylcatecholato cobalt complex of the substituted bis(phenol) diamine ligands of H2LNEX (CoLNEX(DTBC) which X: BM, Bu and OB stands for 2-(tert-butyl)-4-methyl, 2,4-di-tert-butyl and 2-(tert-butyl)-4-methoxy phenols, respectively, and DTBC is an abbreviation for 2,4-di-tert-butylcatechol, as models for enzyme-substrate adducts of catechol dioxygenases, have been synthesized and characterized by different techniques. X-ray structure analysis has revealed that cobalt centers were surrounded by two phenolates, two amine nitrogens and two oxygen atoms of catechol ligand. For all three compounds, the magnetic susceptibility increases with decreasing temperature as expected for non-interacting, magnetic moments which confirm the monomeric structure of cobalt complexes and valence tautomerism between Co(II) and Co(III) oxidation state. Crystal structures confirm the nature of Co(II)/Co(III) character consistent with the magnetic experiments. In electronic absorption spectra of two complexes, the position of LMCT bands show the phenolate(π)-to- Co(II) or Co(III) (dπ*) charge transfer. The cyclic voltammetry studies, show the ligand-centered oxidation of phenolate group to phenoxyl radical.

A method of purifying cyclododecyl 2,4-dihydroxybenzoate as a potential replacement template molecule for preparation of molecularly-imprinted polymers for isolation of zearalenone in urine was developed. Full physicochemical characteristics of cyclododecyl 2,4-dihydroxybenzoate for the first time included crystallographic analysis and molecular modelling, which made possible the determination of the similarity between the cyclododecyl 2,4-dihydroxybenzoate and zearalenone molecules. The obtained molecularly-imprinted polymers show very high in vitro selectivity towards zearalenone due to specific interactions (e.g., hydrogen bonding, molecular recognition interaction). The achieved extraction recovery exceeds 94% at the tested concentration levels (20&ndash, 500 ng&middot, mL&minus, 1) with a relative standard deviation below 2%. Immunosorbents were found to have lower recoveries (below 92.5%) and RSD value between 2 and 4% for higher concentrations of the studied substance (400 ng&middot, 1).

Redox interplay between a ligand and a metal can provide a profound driving force for the promotion of unprecedented reactions. This work presents an intriguing water-assisted oxidative transformation of imine to amide with no formal change in the metal oxidation state in the copper and nickel complexes of an aminophenol ligand versus a zinc analogue.

X-ray structures of two Ru(III) complexes of the “Keppler-type”, [(CH3)2NH2]trans-[RuCl4(HmtpO)2] (1a) and [H2mtpO]trans-[RuCl4(HmtpO)2]·3H2O (1b), have been determined. The structures of both compounds established two monodentate heterocycle ligands (HmtpO) via N3 in axial positions and four equatorial chloride ions. The complexes differ only in the counter ion, which is a protonated dimethylamine [(CH3)2NH2]+ for (1a) and a protonated [H2mtpO]+ for (1b). Additionally, (1a) was characterized by EPR spectroscopy, and the effective magnetic moment measurement supports the paramagnetic character, corresponding to the expected 4d5 (S = 1/2) electron configuration for a Ru(III) core. CD studies on hydrophilic (1a) (logP = −1.28) suggested Ru(III) mechanisms of biological action that involve activation by reduction (with Ered = −0.053 V versus NHE) and selective delivery by apotransferrin. Furthermore, it is suggested that the described (1a)-BSA adducts might form in vivo and might be relevant for the biological properties of this complex, and thus adducts may be tested as specific carriers of the ruthenium complex to cancer cells.

Mononuclear copper complexes of four-dentate N 2 O 2 bis(phenol) diamine ligands (H 2 L NEX X: C and OB in which C and OB are chloro and tert -butyl-methoxy substituents on phenol groups) have been synthesized and characterized by IR, UV–Vis, single crystal X-ray diffraction, magnetic susceptibility studies and cyclic voltammetry techniques. The CuL NEX complexes show the square pyramid geometry of the coordination sphere with the copper centers surrounded by two nitrogen and oxygen atoms from the coordinating ligand and an axially bound water molecule. The effective magnetic moments of 1.7 and 1.8 BM confirm a monomer complex with copper(II) center. Electrochemical oxidation of these complexes yielded the corresponding Cu(II)-phenoxyl radical species. In addition, CuL NEX complexes, have shown efficient catalytic activities for TEMPO-mediated oxidation of a set of alcohols to the corresponding aldehydes in the presence of molecular oxygen as oxidant at room temperature.

Two nitrocatecholato(HNC) iron(III) complexes, [FeLAMPX(H-NC)]. NEt3, of the tetradendate ligand (2-aminomethylpyridine)bis(2-pyridylmethyl)amine (H2LAMPX) were synthesized and structurally characterized. These structural models for catechol-bound 3,4-PCD were characterized by IR, UV–vis, elemental analysis and magnetic measurements. X-ray crystallography studies revealed that in both complexes the iron(III) centers are distorted octahedral and coordinated by two phenolate oxygen's, two amine nitrogen's of the ligand and mono anionic nitrocatecholate group (HNC). The variable-temperature magnetic susceptibility studies revealed paramagnetic properties of the reported complexes. The effective magnetic moments for the complexes lie between 5.3 and 5.4 BM correspond to the reported values for high spin Fe(III) center. The ligand-centered oxidation and metal-centered reduction of complexes was studies using cyclic voltammetry (CV) technique.

An efficient methodology for the synthesis of diphenyl diselenides o-substituted by O(S,Se)-caranyl moieties has been presented. 4-Caranyl and 4-isocaranyl groups have been connected to the phenyl ring by an oxygen, sulfur or selenium atom. The influence of the selenium–heteroatom interactions on the diastereoselectivity of the methoxyselenenylation of styrene has been evaluated. The best result was obtained for diselenide with an O-caranyl group substituted in the ortho-position. X-ray crystal structure of this compound was determined and the observed intramolecular interactions were discussed. Additionally diselenides bearing a sulfur atom were transformed to the corresponding methyl o-(S-caranyl) and o-(S-isocaranyl)-substituted phenyl selenides, and were tested as catalysts in the Tsuji–Trost allylic alkylation and Henry reaction.

This study is a report on atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) using a ligand, N-methylbis[2-(dodecylthio)ethyl]amine (SNS), which is tridentate ligand with mixed donor atoms. This ligand was synthesized in a simple way and at a low cost and was used to prepare a Cu catalyst complex (Cu/SNS) during the process of polymerization. The effects of various factors such as different molar ratios (100, 300, and 700 [monomer]:[initiator]) and cuprous halides (Br and Cl) on the polymerization of this ligand were investigated. The resulting catalyst complex mediated a living polymerization of MMA, yielding polymers with controlled molecular weights and narrow molecular weight distributions (1.09 < PDI < 1.4). The Highest PDI values were observed in the polymerization of the 700 molar ratio. The ligand, catalyst crystals formed at the end of polymerization, and synthesized polymers were characterized via UV-VIS, FTIR, CV, NMR, and GPC spectroscopy and single crystal X-ray crystallography as appropriate. The X-ray results for catalyst crystals showed that the catalyst was the deactivator (CuII Br2/SNS) of the ATRP equation and existed as a mononuclear catalyst complex.