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The coordination ability of the antisecretor agent Famotidine (FMT) was explored using Ni(II) as central ion. [NiFMTH-2] and [Ni(FMT)2]Cl2 were obtained by the solvent evaporation method from the corresponding starting solutions at pH 8 and 4, respectively; the crystal structure was elucidated by single crystal X-ray diffraction in both cases.[NiFMTH-2] resulted in a distorted square-planar geometry, where FMT acts as a tetradentate dianionic ligand through nitrogen atoms belonging to the guanidine group, the thiazolic ring and the side chain, and a sulfur atom from the thioether moiety. [Ni(FMT)2]Cl2 exhibits an octahedral environment composed by two FMT molecules that coordinate by nitrogen atoms deriving from guanidine and thiazole ring moieties, and the thioether sulfur atom. The physicochemical characterization was completed by means of FTIR and UV–Vis spectroscopies, and thermal analysis. Solubility measurements were performed and the results could be satisfactorily correlated with the solvation Gibbs free energy (ΔGsolv) values in aqueous solution obtained using the SDM model by DFT calculations. Ni(II) and famotidine form an octahedral complex at pH 4 where famotidine acts as a tridentate neutral ligand. In basic medium, it behaves as a tetradentate dianion, resulting in a quasi-planar complex. Spectroscopic and thermal data are consistent with single crystal X-ray diffraction structural elucidation. The relative stabilities were assessed by theoretical studies. [ABSTRACT FROM AUTHOR]

Complexes with general formula [RuCl(η6-p-cymene)(P–NR–P)]X (R = CH2Py (Py = pyridine) – [1a]+, CH2Ph (Ph = phenyl) – [1b]+, Ph – [1c] and p-tol (p-tol = p-tolyl) – [1d]+; X = PF6− or BF4−) were evaluated as cytotoxic agents against two cancer cell lines (HeLa and MDA-MB-231). All metal complexes are active in the range of concentrations tested (up to 100 μmol L−1). The IC50 (μmol L−1) values for the metal complexes are lower than that found for cisplatin. The activities are up to 6- and 15-fold higher than cisplatin for HeLa and MDA-MB-231 cancer cell lines, respectively. Studies of DNA binding and DNA cleavage were performed. DNA binding studies revealed a modest hypochromic shift in the metal complexes electronic spectra, indicating a weak interaction with Kb values in the range of 1.7 × 103–1.6 × 104. Although the cleavage tests revealed that in the dark DNA is not a biological target for these metal complexes, upon blue light irradiation they are activated causing DNA cleavage. Electrochemical studies showed the presence of two independent redox processes, one attributed to the oxidation process of Ru2+ → Ru3+ (EC process) and the other one to the reduction of Ru2+ → Ru1+, which is further reduced to Ru0 (ECE mechanism). In both processes, coupled chemical reactions were observed. DFT calculations were performed to support the electrochemical/chemical behavior of the complexes. The reactivity of complex [1b]BF4 with CH3CN was evaluated and two complexes were isolated [2b]BF4 and [3b]BF4. The complex mer-[RuCl(CH3CN)3(P–NCH2Ph–P)]BF4 ([2b]BF4) was isolated after refluxing the precursor [1b]BF4 in CH3CN. Isomerization of [2b]BF4 in CH3CN resulted in the formation of fac-[RuCl(CH3CN)3(P–NCH2Ph–P)]BF4. An attempt to isolate the fac-isomer by adding diethyl ether was unsuccessful, and the complex [3b]BF4 was observed as the major component. The complex [Ru2(μ-Cl3)(CH3CN)2(P–NCH2Ph–P)2]BF4 ([3b]BF4) proved to be very stable and can be obtained from both the mer- and the fac-isomers. The molecular structures of [1b]BF4 and [3b]BF4 were solved by single-crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

We herein report the synthesis and characterization of Ru(II)/amino acid complexes with general formula [Ru(AA-H)(dppb)(4-mebipy)](PF6), where AA-H means the deprotonated amino acids Gly, Ala, Val, Met, Trp, Tyr, and Ser; dppb is 1,4-bis(diphenylphosphino)butane and 4-mebipy = 4,4′-dimethyl-2,2′-bipyridine. The complexes were characterized by31P{1H},13C, and1H NMR spectroscopy, as well as X-ray crystallographic analysis of [Ru(DL-Ala-H)(dppb)(4-mebipy)]+, suggesting the presence of diastereoisomers. The complexes exhibit IC50values against breast tumor cells (MDA-MB-231) comparable with cisplatin. In addition, the Ru(II)-based complex with tryptophan inhibited tumor cell adhesion to collagen type I. Therefore, the use of ruthenium complexes containing amino acids can be an interesting tool for development of new therapeutic agents. [ABSTRACT FROM AUTHOR]

Abstract: Complexes [RuCl(H4NO2Fo4M)(bipy)(dppb)]PF6 (1), [RuCl(H4NO2Fo4M)(Mebipy)(dppb)]PF6 (2), [RuCl(H4NO2Fo4M)(phen)(dppb)]PF6 (3), [RuCl(H4NO2Ac4M)(bipy)(dppb)]PF6 (4), [RuCl(H4NO2Ac4M)(Mebipy)(dppb)]PF6 (5) and [RuCl(H4NO2Ac4M)(phen)(dppb)]PF6 (6) with N4 -methyl-4-nitrobenzaldehyde thiosemicarbazone (H4NO2Fo4M) and N4 -methyl-4-nitroacetophenone thiosemicarbazone (H4NO2Ac4M) were obtained from [RuCl2(bipy)(dppb)], [RuCl2(Mebipy)(dppb)], and [RuCl2(phen)(dppb)], (dppb = 1,4-bis(diphenylphospine)butane; bipy = 2,2′-bipyridine; Mebipy = 4,4′-dimethyl-2,2′-bipyridine; phen = 1,10-phenanthroline). In all cases the thiosemicarbazone is attached to the metal center through the sulfur atom. Complexes (1–6), together with the corresponding ligands and the Ru precursors were evaluated for their ability to in vitro suppress the growth of Trypanosoma cruzi. All complexes were more active than their corresponding ligands and precursors. Complexes (1–3) and (5) revealed to be the most active among all studied compounds with ID50 = 0.6–0.8 μM. In all cases the association of the thiosemicarbazone with ruthenium, dppb and bipyridine or phenanthroline in one same complex proved to be an excellent strategy for activity improvement. [Copyright &y& Elsevier]

Graphical abstract Highlights • New nickel(II) complexes with N -R-sulfonyldithiocarbimate and phosphines are described. • Their structures were investigated by X-ray diffraction, IR, NMR and UV–Vis spectroscopies. • The complexes with PPh 3 present intramolecular anagostic interactions of the type Ni H C. • The complexes inhibit the germination of Hemileia vastatrix and Phakopsora pachyrhizi at low doses. • The best results were achieved when the phosphine is PPh 3 and with R = butyl and 4-isopropylphenyl. Abstract Nickel(II) complexes of general formula [Ni(RSO 2 N = CS 2)(PPh 3) 2 ] (2a – h) or [Ni(RSO 2 N = CS 2)dppe] (3a – h), where R = methyl (a), ethyl (b), butyl (c), octyl (d), phenyl (e), 4-isopropylphenyl (f) , 4- tert -butylphenyl (g) , 2-naphthyl (h), PPh 3 = triphenylphosphine and dppe = 1,2-bis(diphenylphosphine)ethane were prepared, from which six are new substances (2f – h and 3f – h). The new compounds were characterized by elemental analysis of C, H, N and Ni, and by IR, UV–Vis and 1H, 13C and 31P NMR spectroscopies. The data were consistent with the formation of square planar nickel(II) complexes with mixed ligands, what was confirmed by single crystal X-ray diffraction studies on compounds 2f and 2h. These complexes present intramolecular Ni H C anagostic interactions. All complexes inhibited the germination of Hemileia vastatrix and Phakopsora pachyrhizi , the causal agents of devastating diseases on soybean and coffee cultures. The most active compounds presented IC 90 values as low as 405 µM against H. vastatrix , and 280 μM against P. pachyrhizi. Thus, the title compounds are target molecules for the development of new agrochemicals against the Asian soybean rust and Coffee leaf-rust diseases. [ABSTRACT FROM AUTHOR]

Four new complexes of the general formula: (Ph 4 P) 2 [Sn(CH 3 ) 2 (RSO 2 N CS 2 ) 2 ], where Ph 4 P = tetraphenylphosphonium cation and R = CH 3 , ( 1 ), CH 3 CH 2 ( 2 ), C 6 H 5 ( 3 ), 4-FC 6 H 4 ( 4 ), were prepared by the reaction of the appropriate potassium N -R-sulfonyldithiocarbimates, K 2 (RSO 2 N CS 2 ), and tetraphenylphosphonium chloride with dimethyltin dichloride. The compounds 1 – 4 were characterized by 1 H, 13 C and 119 Sn NMR, 119 Sn Mössbauer, vibrational spectroscopy and by elemental analyses of C, H, N and Sn. The crystal structure of 1 was determined by X-ray diffraction techniques. The in vitro antifungal activity of the tin(IV) complexes were evaluated against the fungi Rhizoctonia solani and Botrytis cinerea by the Poisoned food test. The new compounds showed comparable activities to the fungicides manzate and ziram. [ABSTRACT FROM AUTHOR]

Reaction of fac- [RuCl 3 (NO)(P–N)] (1) with the triarylphosphines PR 3 in MeOH allows for isolation of the monocationic Ru(II) complexes [RuCl 2 (NO)(P–N)(PR 3 )]PF 6 ; P–N = o -diphenylphosphino- N , N -dimethylaniline, and R = p -MeO-C 6 H 4 (complex 2 ), p -Me-C 6 H 4 ( 3 ), Ph ( 4 ), and p -F-C 6 H 4 ( 5 ). The complexes were characterized by elemental analysis, 31 P{ 1 H}, 1 H NMR and IR spectroscopies, ESI-MS, CV, and X-ray structural data for complexes 3 – 5 . The 31 P{ 1 H} spectra display two doublets with 2 J pp values consistent with cis P-atoms. The ESI-MS spectra reveal the molecular ion [RuCl 2 (NO)(P–N)(PR 3 )] + and the fragmentation ions [M−PR 3 ] + , [M−PR 3 −Cl] + , and [M−PR 3 −2Cl] + . CV data show a one-electron, quasi-reversible reduction process centred at the Ru–NO unit that depends on the p K a of the PR 3 . The IR spectra reveal ν NO bands for coordinated NO + . A known, empirical inverse correlation between the δ P value and the Ru–P bond length of the P–N ligand that exists for a series of cis - and trans -RuX 2 (L)(P–N)(PR 3 ) complexes (X = Cl or Br), where L is a range of small molecules, is extended with L = NO + and now covers the respective ranges of about 30–80 ppm and 2.39–2.17 Å. [ABSTRACT FROM AUTHOR]

Four nickel(II) complexes of general formula [Ni(RSO 2 N CS 2 ) (PPh 3 ) 2 ] where R = CH 3 ( 2a ), CH 3 CH 2 ( 2b ), CH 3 (CH 2 ) 3 ( 2c ) and CH 3 (CH 2 ) 7 ( 2d ) and PPh 3 = triphenylphosphine; and two nickel(II) complexes of general formula [Ni(RSO 2 N CS 2 )dppe] where R = CH 3 (CH 2 ) 3 ( 3c ) and CH 3 (CH 2 ) 7 ( 3d ) and dppe = 1,2-bis(diphenylphosphine)ethane) were prepared. These new complexes were obtained by the reaction of nickel(II) chloride hexahydrate with potassium N -alkylsulfonyldithiocarbimates and the appropriate phosphine using ethanol/water as solvent. The IR, UV–Vis and 1 H, 13 C and 31 P NMR spectra, elemental analysis of Ni and the HR-ESI-MS were consistent with the formation of square planar nickel(II) complexes with mixed ligands. The structures of the compounds 2b and 2c were determined by single crystal X-ray diffraction. The compounds are isostructural and crystallize in the space group P 1 ¯ of the triclinic system. The activities of the complexes were investigated in vitro against Botrytis cinerea , Colletotrichum acutatum and Alternaria solani , fungi species that affect various commercially important plants. All the complexes were active. [ABSTRACT FROM AUTHOR]

Chiral molecules in nature are involved in many biological events; their selectivity and specificity make them of great interest for understanding the behavior of bioactive molecules, by providing information about the chiral discrimination. Inspired by these conformational properties, we present the design and synthesis of novel chiral platinum(II) complexes featuring phosphine and chloroquine ligands with the general formula [PtCl(P)2(CQ)]PF6 (where (P)2 = triphenylphosphine (PPh3) (5), 1,3-bis(diphenylphosphine)propane (dppp) (6), 1,4-bis(diphenylphosphine)butane (dppb) (7), 1,1'-bis(diphenylphosphine)ferrocene (dppf) (8), and CQ = chloroquine] and their precursors of the type [PtCl2(P)2] are described. The complexes were characterized by elemental analysis, absorption spectroscopy in the infrared and ultraviolet-visible (UV-vis) regions, multinuclear (¹H, 13C, 31P, 15N, and 195Pt) NMR spectroscopy, cyclic voltammetry, and mass spectrometry (in the case of chloroquine complexes). The interactions of the new platinum-chloroquine complexes with both albumin (BSA), using fluorescence spectroscopy, and DNA, by four widely reported methods were also evaluated. These experiments showed that these Pt-CQ complexes interact strongly with DNA and have high affinities for BSA, in contrast to CQ and CQDP (chloroquine diphosphate), which interact weakly with these biomolecules. Additional assays were performed in order to investigate the cytotoxicity of the platinum complexes against two healthy cell lines (mouse fibroblasts (L929) and the Chinese hamster lung (V79-4)) and four tumor cell lines (human breast (MDA-MB-231 and MCF-7), human lung (A549), and human prostate (DU-145)). The results suggest that the Pt-CQ complexes are generally more cytotoxic than the free CQ, showing that they are promising as anticancer drugs. [ABSTRACT FROM AUTHOR]

This work reports on the synthesis and characterization of new complexes of the type [Cu(O–O)(N–N)X], where O–O = 4,4,4-trifluoro-1-phenyl-1,3-butanedione (HBTA), 1-(4-chlorophenyl)-4,4,4-trifluoro-1,3-butanedione (HBTACl) or 2-thenoyltrifluoroacetone (HTTA); N–N = 2,2-bipyridine (Bipy) or 1,10-phenanthroline (Phen) and X = NO 3 − or ClO 4 − . These complexes were characterized by elemental analyses, conductivity measurements, FT-IR, UV–Vis, EPR, High-resolution Electrospray Ionization Mass Spectrometry (HRESIMS) and TG/DTA. The X-ray structural analysis of two representative compounds indicates that the geometry around the copper ion is distorted square-pyramidal and it is coordinated to β-diketone via the oxygen atoms and to N -donor heterocyclic ligands via its two nitrogen atoms. A perchlorate or nitrate ion weakly bonded occupies the apical position, completing the coordination sphere. The crystal packing is stabilized by non-classical hydrogen bonds and weak interactions π–π stacking. The cytotoxic activity of compounds was investigated in a chronic myelogenous leukemia cell line. The complexes with 1,10-phenanthroline are more active than carboplatin. As example, the compound [Cu(BTACl)(Phen)NO 3 ] inhibits the growth of K562 cells with an IC 50 value equal to 2.1 μM. [ABSTRACT FROM AUTHOR]

Three promising antimycobacterium tuberculosis ruthenium(II) complexes with the deprotonated ligands 2-hydroxynicotinic acid (2-OHnicH), 6-hydroxynicotinic acid (6-OHnicH) and 3-hydroxypicolinic acid (3-OHpicH) were synthesized and characterized. Structural analysis revealed three different coordination modes depending of the hydroxypyridinecarboxylate ligand. In the complex [Ru(2-OHnic)(dppb)(bipy)]PF 6 ( 1 ), the 2-OHnic anion is coordinated by the O,O-chelating mode (via carboxylate group and phenolate oxygen), in the [Ru(6-OHnic)(dppb)(bipy)]PF 6 ( 2 ) a O–O chelation by the carboxylate group is observed for the 6-OHnic ligand and for the complex [Ru(3-OHpic)(dppb)(bipy)]PF 6 ( 3 ) a N,O-chelating mode (via carboxylate) occurs to the 3-OHpic anion. The compounds were evaluated for activity against Mycobacterium tuberculosis H 37 Rv ATCC 27294 using Resazurin Microtitre Assay (REMA) plate method and cytotoxicity in VERO CCL-81 cell line. All the synthesized compounds exhibited good antimycobacterial activity and a completely lack of cytotoxicity activity, indicating a good selectivity index. [ABSTRACT FROM AUTHOR]

In the search for new compounds with antitumor activity, coordination complexes with different metals are being studied by our group. This work presents the synthesis and characterization of six copper complexes with general stoichiometry [Cu(L-dipeptide)(phen)]·nH2O (were phen=1,10-phenanthroline) and their cytotoxic activities against tumor cell lines. To characterize these systems, analytical and spectroscopic studies were performed in solid state (by UV-visible, IR, X-ray diffraction) including the crystal structure of four new complexes (of the six complexes studied): [Cu(Ala-Phe)(phen)]·4H2O, [Cu(Phe-Ala)(phen)]·4H2O, [Cu(Phe-Val)(phen)]·4.5H2O and [Cu(Phe-Phe)(phen)]·3H2O. In all of them, the copper ion is situated in a distorted squared pyramidal environment. The phen ligand is perpendicular to the dipeptide, therefore exposed and potentially available for interaction with biological molecules. In addition, for all the studied complexes, structural information in solution using EPR and UV-visible spectroscopies were obtained, showing that the coordination observed in solid state is maintained. The lipophilicity, DNA binding and albumin interaction were also studied. Biological experiments showed that all the complexes induce cell death in the cell lines: HeLa (human cervical adenocarcinoma), MCF-7 (human metastatic breast adenocarcinoma) and A549 (human lung epithelial carcinoma). Among the six complexes, [Cu(Ala-Phe)(phen)] presents the lowest IC50 values. Taken together all these data we hypothesize that [Cu(Ala-Phe)(phen)] may be a good candidate for further studies in vivo. [ABSTRACT FROM AUTHOR]

Abstract: The complexes [RuCl(SpymMe2-N,S)2(NO)] (1) and [Ru(dppb)(SpymMe2-N,S)2] (2) (dppb=1,4-bis(diphenylphosphino)butane, SpymMe2 =deprotonated 4,6-dimethyl-2-mercaptopyrimidine) were obtained and characterized by elemental analysis, spectroscopic techniques including X-ray crystallography, conductimetry and cyclic voltammetry. Energy Decomposition Analysis (EDA) calculation indicated strong intermolecular interaction between monomers of complex 1, as suggested by the 1H NMR spectrum of this complex, in chloroform solution. Additionally, preliminary tests were carried out, in order to evaluate the cytotoxicity activity on cancer cell lines of the new complexes, and the free ligands, against MDA-MB-231 (breast cancer), Hela (cervical cancer), U251 (glioma cancer) tumor cell lines and the V79 (Chinese lung fibroblast hamster) cell line. The best result was obtained for the complex 1 with IC50 value of 0.11±0.02, against MDA-MB-231 tumor cells. [Copyright &y& Elsevier]

Highlights: [•] Two solvate forms of fac-[RuCl3(NO)(dppb)] were obtained. [•] Guest acetone and chloroform were identified by XRD and FT-IR analysis. [•] Solvent inclusion affects the molecular structure of the complex. [•] Weak intermolecular interactions kept the solvent caged. [ABSTRACT FROM AUTHOR]

Abstract: The new europium binuclear complex [Eu2(dcpz)2(suc)(H2O)8]·(H2O)1.5 (dcpz=3,5-dicarboxypyrazolate and suc=succinate) has been synthesized and structurally characterized by single crystal X-ray diffraction methods. The binuclear complex crystallizes in the triclinic space group and consists of two lanthanide ions linked by two different bridging organic ligands. 3D supramolecular framework is constructed by hydrogen bonds. The compound shows strong red emission under UV excitation at room temperature associated to IL transitions indicating a ligand to metal energy transfer mechanism since the triplet energy level lies higher than that of europium 5D0 level. Magnetic susceptibility studies showed weak temperature dependence characteristic of the Van Vleck paramagnetism. [Copyright &y& Elsevier]

Abstract: Nowadays, the research for new and better antimicrobial compounds is an important field due to the increase of immunocompromised patients, the use of invasive medical procedures and extensive surgeries, among others, that can affect the incidence of infections. Another big problem associated is the occurrence of drug-resistant microbial strains that impels a ceaseless search for new antimicrobial agents. In this context, a series of heterocyclic-sulfonamide complexes with Co(II) was synthesized and characterized with the aim of obtaining new antimicrobial compounds. The structural characterization was performed using different spectroscopic methods (UV–Vis, IR, and EPR). In spite of the fact that the general stoichiometry for all the complexes was Co(sulfonamide)2·nH2O, the coordination atoms were different depending on the coordinated sulfonamide. The crystal structure of [Co(sulfamethoxazole)2(H2O)2]·H2O was obtained by X-ray diffraction showing that Co(II) is in a slightly tetragonal distorted octahedron where sulfamethoxazole molecules act as a head-to-tail bridges between two cobalt atoms, forming polymeric chains. Besides, the activity against Mycobacterium tuberculosis, one of the responsible for tuberculosis, and the cytotoxicity on J774A.1 macrophage cells were evaluated. [Copyright &y& Elsevier]

Abstract: The synthesis and characterization of ruthenium compounds of the type [RuCl2(P)2(N–N)] [(P)2 =(PPh3)2, dppb=1,4-bis(diphenylphosphino)butano; dppp=1,3-bis(diphenylphosphino)propane; N–N=5,5′-dimethyl-2,2′dipyridyl (5,5′-mebipy) or 4,4′-dimethyl-2,2′dipyridyl (4,4′-mebipy)] are described. The complexes were characterized using elemental analysis, UV–Vis and infrared spectroscopies, cyclic voltammetry, and X-ray crystallography. In vitro evaluation of the complexes, using the MTT methodology, revealed their cytotoxic activities in a range of 5.4–15.7μM against the MDA-MB-231 breast tumor cells and showed that, in this case, they are more active than the reference metallodrug cisplatin. The in vitro antimycobacterial activities of the complexes had their Minimum Inhibitory Concentration (MIC) for MTB cell growth measured, by the REMA method. The MICs for these complexes were found to be between 12.5 and 25.0μg/mL. The results are comparable with the “second line” drug cycloserine (MIC=12.5–50.0μg/mL), commonly used in the treatment of TB. [Copyright &y& Elsevier]

Abstract: The arene–ruthenium complex [Ru(η6-C10H14)(dppf)Cl]PF6 (1) was used as a precursor for the syntheses of the [Ru(η6-C10H14)(dppf)Br]PF6 (2), [Ru(η6-C10H14)(dppf)I]PF6 (3), [Ru(η6-C10H14)(dppf)SnF3]PF6 (4) and [Ru(η6-C10H14)(dppf)Cl][SnCl3]·0.45CH2Cl2 (5) complexes by its reactions with KBr, KI, SnF2 and SnCl2, respectively. All of the compounds were characterized by NMR, IR, 57Fe and 119Sn-Mössbauer spectroscopy, and cyclic voltammetry. The single-crystal X-ray structure analysis of the [Ru(η6-C10H14)(dppf)Cl][SnCl3]·0.45CH2Cl2 complex revealed the expected piano-stool geometry. Cyclic voltammograms of the complexes showed only one quasi-reversible electrochemical process, involving the oxidation of Fe(II) and Ru(II) at the same potential, which was confirmed by exhaustive electrolysis experiments. 57Fe-Mössbauer parameters obtained for the complexes (1–5) were fitted with one doublet corresponding to a site of one iron(II). The 119Sn-Mössbauer parameters of the complex (4) indicate that tin is tetra covalent. [Copyright &y& Elsevier]

Abstract: Phosphine ruthenate complexes containing the non-innocent ligands 4-chloro-1,2-phenylenediamine (opda-Cl) and 3,3′,4,4′-tetraamminebiphenyl (diopda) were synthesized and characterized by means of X-ray diffraction, electrochemistry, 31P{1H} NMR and electronic spectroscopies. Crystals of cis-[RuCl2(dppb)(bqdi-Cl)] complex were isolated as a mixture of two conformational isomers due to different positions of the chlorine atoms of the o-phenylene ligand in relation to the P1 atom of the phosphine moiety. [Copyright &y& Elsevier]

Five new complexes of general formula: [Ni(RSO2N=CS2)(dppe)], where R = C6H5 (1), 4-ClC6H4 (2), 4-BrC6H4 (3), 4-IC6H4 (4) and dppe=1,2-bis(diphenylphosphino)ethane and [Ni(4-IC6H4SO2N=CS2)(PPh3)2] (5), where PPh3 = triphenylphosphine, were obtained in crystalline form by the reaction of the appropriate potassium N-R-sulfonyldithiocarbimate K2(RSO2N=CS2) and dppe or PPh3 with nickel(II) chloride in ethanol/water. The elemental analyses and the IR, 1H NMR, 13C NMR and 31P NMR spectra are consistent with the formation of the square planar nickel(II) complexes with mixed ligands. All complexes were also characterized by X-ray diffraction techniques and present a distorted cis-NiS2P2 square-planar configuration around the Ni atom. Quantum chemical calculations reproduced the crystallographic structures and are in accord with the spectroscopic data. Rare C–H···Ni intramolecular short contact interactions were observed in the complexes 1–5. [ABSTRACT FROM AUTHOR]

Abstract: [(SO3)Co(cyclam)(NCS)] and [(SO3)Co(cyclam)-NCS-Ru(NH3)4(NCS)](BF4) complexes were synthesized and characterized by means of X-ray diffraction, electrochemistry, elemental analysis, and spectroscopic techniques. Crystallographic and FTIR data indicated NCS− ligand is coordinated to Co through the nitrogen atom in the monomer species. Electrochemistry and FTIR data of the material isolated after reductive electrolysis of [(SO3)Co(cyclam)(NCS)] hint that NCS− and SO3 2− are released thus forming [Co(cyclam)(L)2]2+, where L is solvent molecules. The formation of the heterobimetallic mixed-valence complex induced a thermodynamic stabilization of Co and Ru metal atoms in the oxidized and reduced states, respectively. According to the Robin and Day classification, a Class II system with a comproportionation constant of 5.78×106 is suggested for the mixed-valence complex based on the electrochemical and UV–Vis–NIR results. [Copyright &y& Elsevier]

Abstract: Complex fac-[RuCl3(NO)(P–N)] (1) was synthesized from the reaction of [RuCl3(H2O)2(NO)] and the P–N ligand, o-[(N,N-dimethylamino)phenyl]diphenylphosphine) in refluxing methanol solution, while complex mer,trans-[RuCl3(NO)(P–N)] (2) was obtained by photochemical isomerization of (1) in dichloromethane solution. The third possible isomer mer,cis-[RuCl3(NO)(P–N)] (3) was never observed in direct synthesis as well as in photo- or thermal-isomerization reactions. When refluxing a methanol solution of complex (2) a thermally induced isomerization occurs and complex (1) is regenerated. The complexes were characterized by NMR (31P{1H}, 15N{1H} and 1H), cyclic voltammetry, FTIR, UV–Vis, elemental analysis and X-ray diffraction structure determination. The 31P{1H} NMR revealed the presence of singlet at 35.6 for (1) and 28.3ppm for (2). The 1H NMR spectrum for (1) presented two singlets for the methyl hydrogens at 3.81 and 3.13ppm, while for (2) was observed only one singlet at 3.29ppm. FTIR Ru–NO stretching in KBr pellets or CH2Cl2 solution presented 1866 and 1872cm−1 for (1) and 1841 and 1860cm−1 for (2). Electrochemical analysis revealed a irreversible reduction attributed to RuII–NO+ →RuII–NO0 at −0.81V and −0.62V, for (1) and (2), respectively; the process RuII →RuIII, as expected, is only observed around 2.0V, for both complexes. Studies were conducted using 15NO and both complexes were isolated with 15N-enriched NO. Upon irradiation, the complex fac-[RuCl3(NO)(P–N)] (1) does not exchange 14NO by 15NO, while complex mer,trans-[RuCl3(NO)(P–N)] (2) does. Complex mer,trans-[RuCl3(15NO)(P–N)] (2′) was obtained by direct reaction of mer,trans-[RuCl3(NO)(P–N)] (2) with 15NO and the complex fac-[RuCl3(15NO)(P–N)] (1′) was obtained by thermal-isomerization of mer,trans-[RuCl3(15NO)(P–N)] (2′). DFT calculation on isomer energies, electronic spectra and electronic configuration were done. For complex (1) the HOMO orbital is essentially Ru (46.6%) and Cl (42.5%), for (2) Ru (57.4%) and Cl (39.0%) while LUMO orbital for (1) is based on NO (52.9%) and is less extent on Ru (38.4%), for (2) NO (58.2%) and Ru (31.5%). [Copyright &y& Elsevier]

Abstract: The “Ru(P–P)” unit (P–P=diphosphine) is recognized to be an important core in catalytic species for hydrogenation of unsaturated organic substrates. Thus, in this study we synthesized six new complexes containing this core, including the binuclear complex [(dppb)(CO)Cl2Ru-pz-RuCl2(CO)(dppb)] (pz=pyrazine) which can be used as a precursor for the synthesis of cationic carbonyl species of general formula [RuCl(CO)(dppb)(N–N)]PF6 (N–N=diimine). Complexes with the formula [RuCl(py)(dppb)(N–N)]PF6 were synthesized by exhaustive electrolysis of these carbonyl compounds or from the precursors [RuCl2(dppb)(N–N)]. The new complexes were characterized by microanalysis, conductivity measurements, IR and 31P{1H} NMR spectroscopy, cyclic voltammetry and X-ray crystallography. [Copyright &y& Elsevier]

Abstract: The reaction of cis-[RuCl2(P–P)(N–N)] type complexes (P–P=1,4-bis(diphenylphosphino)butane or (1,1′-diphenylphosphino)ferrocene; N–N=2,2′-bipyridine or 1,10-phenantroline) with monodentate ligands (L), such as 4-methylpyridine, 4-phenylpyridine and benzonitrile forms [RuCl(L)(P–P)(N–N)]+ species. Upon characterization of the isolated compounds by elemental analysis, 31P{1H} NMR and X-ray crystallography it was found out that the type of the L ligand determines its position in relation to the phosphorus atom. While pyridine derivatives like 4-methylpyridine and 4-phenylpyridine coordinate trans to the phosphorus atom, the benzonitrile ligand (bzCN), a good π acceptor, coordinates trans to the nitrogen atom. A 31P{1H} NMR experiment following the reaction of the precursor cis-[RuCl2(dppb)(phen)] with the benzonitrile ligand shows that the final position of the entering ligand in the complex is better defined as a consequence of the competitive effect between the phosphorus atom and the cyano-group from the benzonitrile moiety and not by the trans effect. In this case, the benzonitrile group is stabilized trans to one of the nitrogen atoms of the N–N ligand. A differential pulse voltammetry experiment confirms this statement. In both experiments the [RuCl(bzCN)(dppb)(phen)]PF6 species with the bzCN ligand positioned trans to a phosphorus atom of the dppb ligand was detected as an intermediate complex. [Copyright &y& Elsevier]

• Dibenzylamine derivates were obtained by classic synthesis and microwave. • Dibenzyldithiocarbamates and Ni(II)–Cu(II) complexes were full characterized. • Two new compounds were characterized by single crystal X-ray diffraction. • All the DTC compounds showed greater activity against different type of bacteria. In this work, the study of the synthesis methodology to obtain dibenzylamine derivates as intermediates for the formation of dithicarbamate ligands (DTC) and its coordination compounds was conducted. Four molecules derived from dibenzylamine were synthesized by two methodologies: classical (reflux) and microwave. From these amines, Four dithiocarbamate ligands (DTC): dibenzyldithiocarbamate, N -benzyl-1-(4-methoxyphenyl)dithiocarbamate, N -benzyl-1-(4-chlorophenyl)dithiocarbamate, and N -benzyl-1-(3-nitrophenyl)dithiocarbamate, and eight coordination complexes with general formula [M(DTC) 2 ]nH 2 O (M= Cu(II) and Ni(II)) were obtained. All the compounds were characterized using different spectroscopic and thermal techniques such as Fourier-transform infrared spectroscopy (FT-IR), ultraviolet–visible spectroscopy (UV–VIS), proton and carbon-13 nuclear magnetic resonance (1H and 13C NMR), thermogravimetric analysis–differential scanning calorimetry (TGA-DSC). Additionally, it was possible to characterize two new crystalline phases of salts through single-crystal X-ray diffraction: dibenzyl ammonium nitrate and N -benzyl-1-(3-nitrophenyl)ammonium chloride. Additionally, microbial inhibition tests were conducted using the dibenzildithiocarbamate derivates. All DTC compounds showed important activity against Pseudomonas aeruginosa and Staphylococcus aureus but less sensitivity against Escherichia coli and Mycobacterium smegmatis. Among the coordination compounds, only [Cu(N -benzyl-1-(3-nitrophenyl)dithiocarbamate) 2 ] presented a moderate activity against M. smegmatis mc2 155. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: The synthesis and characterization of trans/cis-[RuCl2(dppf)(diimines)], dppf=1,1′-bis(diphenylphosphino)ferrocene; diimines=2,2′-bipyridine (trans/cis-(1)), the new complexes with 4,4′-dimethyl-2,2′-bipyridine (trans/cis-(2)) and 1,10-phenanthroline (cis-(3)) are presented. The complexes were synthesized using two routes and the trans/cis-isomer formation is dependent upon conditions and the precursor applied. The trans-isomer (kinetic) readily isomerizes to the cis-isomer (thermodynamic) when exposed to light (fluorescent) and this process was followed by cyclic voltammetry and UV–vis. The electrochemical studies on these complexes reveal that Fe(III)/Fe(II) couples are insensitive to the isomer (trans/cis) formed, but the Ru(III)/Ru(II) couples are dependent on the isomer. Transfer-hydrogenation reactions for reduction of acetophenone were conducted using complexes cis-(1) and cis-(2) and the results are compared with that obtained for similar complexes. X-ray structure for cis-(3) are presented and discussed. [Copyright &y& Elsevier]