Platinum(II) chloride indenyl complexes: electrochemical and biological evaluation

Four platinum(II) complexes of general formula [PtCl(??¹-C₉H₇)L₂] [where L₂ is 1,2-bis(diphenylphosphino)ethane (dppe) 1 or cycloocta-1,5-diene (cod) 3] and [PtCl₂L₂] (where L₂ is dppe 2 or cod 4) were studied. Inhibition growth assays on human tumor cell lines evidenced for 1 and 3 an antiproliferative effect and, interestingly, the cytotoxic effect exerted by 1 is similar to that of cisplatin. Electrochemical and NMR measurements allowed us to determine the structural and redox properties. Investigation of the mechanism of action responsible for the cytotoxicity demonstrated a weak capacity of interacting with DNA. Some experiments performed on rat liver mitochondria indicate that 1 acts as an inducer of the mitochondrial permeability transition, thus leading to the release of proapoptotic factors, such as cytochrome?c and apoptosis-inducing factor.     

Synthesis and structures of zinc complexes with new binucleating ligands containing alkoxide bridges, and their activities in the hydrolysis of tris(p-nitrophenyl)phosphate

Four new binucleating ligands featuring a hydroxytrimethylene linker between two coordination sites (1,3-bis{N-[3-(dimethylamino)propyl]-N-methylamino}propan-2-ol, HL¹; 1,3-bis{N-[2-(dimethylamino)ethyl]-N-methylamino}propan-2-ol, HL²; 1,3-bis[bis(2-methoxyethyl)amino]propan-2-ol, HL³; and 1-bis[(2-methoxyethyl)amino]-3-{N-[2-(dimethylamino)ethyl]-N-methylamino}propan-2-ol, HL⁴) were synthesized, along with the corresponding zinc complexes. The structures of three dinuclear zinc complexes ([Zn₂L¹(μ-CH₃COO)₂]BPh₄ (1), [Zn₂L³(μ-CH₃COO)₂]BPh₄ (3), and [Zn₂L⁴(μ-CH₃COO)(CH₃COO)(EtOH)]BPh₄ (4)) and a tetranuclear zinc complex ({[Zn₂L²(μ-CH₃COO)]₂(μ-OH)₂}(BPh₄)₂ (2)) were revealed by X-ray crystallography. Hydrolysis of tris(p-nitrophenyl)phosphate (TNP) by these zinc complexes in an acetonitrile solution containing 5% Tris buffer (pH 8.0) at 30 °C was investigated spectrophotometrically and by ³¹P NMR. Although zinc complexes 1, 3, and 4 did not show hydrolysis activity, the tetranuclear zinc complex 2, containing μ-hydroxo bridges, was capable of hydrolyzing TNP. This suggests that the hydroxide moiety in the complex may have an important role in the hydrolysis reaction.     

Synthesis, structures and ligating properties of 2,6-bis(phosphino)thiophenol derivatives

New t-butyl-aryl thioethers where the aryl group is 2,6-bis(phosphino)phenyl have been synthesized. The syntheses were completed via sequential ortho-lithiations of t-butylphenylsulfide, followed by chlorophosphine (ClPR₂) quenches; symmetric (2,6-bis(diphenylphosphino)phenyl, (4a)) and unsymmetric (2-diisopropylphosphino-6-diphenylphosphino)phenyl, (4b) aryl groups were obtained. Treatment of 4a with Li or Na naphthalenide yielded 2,6-bis(diphenylphosphino)thiophenol 5. Reactions of 4a or 5 with NiCl₂ · 6H₂O yielded nickel bis(phosphinothiophenolate) 6. Compounds 4a,b, 5 and 6 were characterized by ¹H and ³¹P NMR, and by mass-spectrometry. In addition, 4a, 5 and 6 were characterized by single crystal X-ray diffraction methods.     

Preparation, characterisation and crystal structure of two zinc(II) benzoate complexes with pyridine-based ligands nicotinamide and methyl-3-pyridylcarbamate

Two benzoate complexes namely tetrakis(μ₂-benzoato-O,O^′)-bis(μ₂-benzoato-O,O)-bis(nicotinamide-N)-tri-zinc(II), [Zn₃(benz)₆(nia)₂] (I) and bis(benzoato-O)-bis(methyl-3-pyridylcarbamate-N)-zinc(II), [Zn(benz)₂(mpcm)₂] (II) (benz=benzoate anion, nia=nicotinamide, mpcm=methyl-3-pyridylcarbamate) were prepared and characterised by elemental analysis, IR spectroscopy, thermal analysis and X-ray structure determination. The structure of the complex I is centrosymmetric, formed by a linear array of three zinc atoms. The central zinc atom shows octahedral coordination and is bridged to each of the terminal zinc atoms by three benzoate anions. Two of them act as bidentate, one as monodentate ligand. By additional coordination of the nia ligand, the terminal Zn atoms adopt tetrahedral surrounding. The structure of complex II contains two crystallographically independent [Zn(benz)₂(mpcm)₂] molecules. In each molecule, the zinc atom is tetrahedrally coordinated by two monodentate benzoate and two methyl-3-pyridylcarbamate ligands. Intermolecular hydrogen bonds of the N-H?O type connect molecules in the structures of complexes I and II to form a two-dimensional network. The three different types of carboxylate binding found in the complexes were distinguished also by values of carboxylate stretching vibrations in FT-IR spectra as well as by thermal decomposition of the complexes in nitrogen.     

Synthesis, characterisation and natural abundance Os NMR spectroscopy of hydride bridged triosmium clusters with chiral diphosphine ligands

Treatment of [Os₃(μ-H)₂(CO)₁₀] with the chiral diphosphines BINAP, tolBINAP [(R)-2,2′-bis(di-4-tolylphosphino)-1,1′-binaphthyl], DIOP [(4R,5R)-(−)-O-isopropenylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane] affords [Os₃(μ-H)₂(CO)₈(μ-L)] (L = BINAP (1), tolBINAP (2), DIOP (4)) in high yield. The X-ray structures for 1, 2 and 4 are reported, and structural and spectroscopic comparisons are made between these clusters and [Os₃(μ-H)₂(CO)₈(μ-L)] (L = dppm (5), dppe (6), dppp (7)) which were synthesised similarly. Compounds 5 to 7 were previously synthesised by hydrogenation of 1,2-[Os₃(CO)₁₀(μ-L)] but the route from [Os₃(μ-H)₂(CO)₁₀] is preferable. The H-bridged Os?Os distances are similar in 1, 2 and 4 indicating that these species are formally unsaturated 46-electron clusters. The P?P distances vary from 4.24 to 4.30 Å in 1 and 2, respectively, to 4.53 Å in 4 and there are related changes in the angles associated with the ligand set around the H-bridged osmium atoms. Introduction of the diphosphine ligands completely suppresses the ability to add CO, to insert acetylene to form a μ-η¹,η²-vinyl compound, and to exchange hydride ligands with styrene-d₈, which are reactions characteristic of [Os₃(μ-H)₂(CO)₁₀]. Clusters 2 and 5-7 were also used to examine the potential of natural abundance ¹⁸⁷Os NMR spectroscopy through techniques based on inverse detection by HMQC, HSQC and HMBC spectroscopy.     

Syntheses, thermal analyses, crystal structures and antimicrobial properties of silver(I)-saccharinate complexes with diverse diamine ligands

Five new silver(I)-saccharinate complexes [Ag₂(sac)₂(tmen)₂] (1), [Ag₂(sac)₂(deten)₂] (2), [Ag₂(sac)₂(dmen)₂] (3), [Ag(sac)(N,N-eten)] (4), and [Ag(sac)(dmpen)]_n (5); (sac = saccharinate, tmen = N,N,N′,N′-tetramethylethylenediamine, deten = N,N′-diethylethylenediamine, dmen = N,N′-dimethylethylenediamine, N,N-eten = N,N-diethylethylenediamine and dmpen = 1,3-diamino-2,2-dimethylpropan) have been synthesized and characterized by elemental analyses, IR, thermal analyses, single crystal X-ray diffraction and antimicrobial activities. The crystallographic analyses show that all the complexes crystallize in monoclinic space group P2₁/c. In 1, the sac ligand acts as a bridge to connect the silver centres through its imino N and carbonyl O atoms forming an eight-membered bimetallic ring in a chair conformation. Complex 2 has also a dimeric structure in which the monomeric [Ag(sac)(deten)] units are linked by Ag?Ag interactions. In 3, saccharinate ligand acts as a bridging bidentate ligand between two silver(I) centres through sulfonyl group and imino N atom, forming an alternating polymeric chain through the direction [0 1 0]. In 4, the inter-molecular N-H?O hydrogen bonds form one-dimensional polymeric chains through the a axis, and these linear chains are inter-connected to each other by N-H?O hydrogen bonds, which produce a chain of edge-fused and rings along [1 0 0]. Complex 5 is a coordination polymer in which the monomeric [Ag(dmpen)(sac)]_n units are linked by Ag?Ag interactions, and the dmpen ligand acts as a bridge between the silver(I) ions, forming a two-dimensional network parallel to the (1 0 0) plane.     

Mono- and dinuclear (o-thioetherphenolato)-copper(II) complexes. Structural models for galactose oxidase

Three new o-thioetherphenol ligands have been synthesized: 1,2-bis(3,5-di-tert-butyl-2-hydroxyphenylsulfanyl)ethane (H₂bse), 1,2-bis(3,5-di-tert-butyl-2-hydroxyphenylsulfanyl)benzene (H₂bsb), and 4,6-di-tert-butyl-2-phenylsulfanylphenol (Hpsp). Their complexes with copper(II) were prepared and investigated by UV-Vis-, EPR-spectroscopy; their electro- and magnetochemistry have also been studied: [Cu^II(psp)₂] (1), [Cu^II₂(bse)₂] (2), [Cu^II₂(bsb)₂] (3), [Cu^II(bsb)(py)₂] (4). The crystal structures of the ligands H₂bse, H₂bsb, Hpsp and of the complexes 1, 2, 3, 4 have been determined by X-ray crystallography.     

Preparation, characterization and redox chemistry of oxo-centered triruthenium dimers linked by bis(diphenylphosphino)anthracene and -ferrocene

Diphosphine-bridged dimers of oxo-centered triruthenium-acetate cluster units, i.e., [{Ru₃O(OAc)₆(py)₂}₂(dppan)](PF₆)₂ (2) and [{Ru₃O(OAc)₆(py)₂}₂(dppf)](PF₆)₂ (3) were prepared by reaction of 2.3 equivalent [Ru₃O(OAc)₆(py)₂(CH₃OH)](PF₆) with 9,10-bis(diphenylphosphino)anthracene (dppan) or 1,1′-bis(diphenylphosphino)ferrocene (dppf), respectively. Apparent redox wave splitting is observed in complex 2, revealing the presence of electronic communication between two triruthenium units mediated through bridging dppan. The complexes were characterized by elemental analysis, IR, UV-Vis, ³¹P NMR, and ES-MS spectroscopies, and cyclic and differential-pulse voltammetry. The crystal structure of complex 3 was determined by X-ray crystallography.     

Synthesis, characterization, crystal structure and antitumor activity of organotin(IV) compounds bearing ferrocenecarboxylic acid

Four new organotin(IV) complexes [(Bu₃Sn)(FcCOO)]_n (1), [(μ-Bu₂Sn)₂(μ-Bu₂SnFcCOO)₂(μ₃-O)₂(μ-OCH₃)₂]₂ (2), [Ph₃Sn(FcCOO)(H₂O)](phen) (3) and [{Ph₃Sn(FcCOO)}₂(4,4′-bipy)] (4) [Fc = (η⁵-C₅H₅)Fe(η⁵-C₅H₄)] have been synthesized and characterized by elemental analyses, IR, (¹H and ¹³C) NMR spectra and X-ray single-crystal diffraction analyses. The structure analyses show that all tin atoms in complexes 1-4 are five-coordinated with trigonal bipyramid geometry. Complexes 1-4 and FcCOOH undergo reversible one-electron oxidations in methanol solution. The antitumor activities of complexes 1-4 have also been tested. Complexes 1 and 2 exhibit medium activity towards P388 cell lines and Hela cell lines. Complexes 3 and 4 exhibit medium activity towards P388 cell lines but strong activity towards Hela cell lines. This may result from complexes 3 and 4 including the neutral molecules 1,10-phenanthroline and 4,4′-bipy.     

Preferential azido bridging regulating the structural aspects in cobalt(III) and copper(II)-Schiff base complexes: Syntheses, magnetostructural correlations and catalytic studies

A tridentate NNO donor Schiff base ligand [(1Z,3E)-3-((pyridin-2-yl)methylimino)-1-phenylbut-1-en-1-ol = LH] in presence of azide ions coordinates with cobalt(II) and copper(II) ions giving rise to three new coordination complexes [Co₂(L)₂(μ_1,1-N₃)₂(N₃)₂] (1), [Cu₂(L)₂(μ_1,3-N₃)]·ClO₄ (2) and [(μ_1,1-N₃)₂Cu₅(μ-OL)₂(μ_1,1-N₃)₄(μ_1,1,1-N₃)₂]_n (3). The complexes have been characterized by elemental analysis, FT-IR, UV-Vis spectral studies, and single crystal X-ray diffraction studies. These complexes demonstrate that under different synthetic conditions the azide ions and the Schiff base ligand (LH) show different coordination modes with cobalt(II) and copper(II) ions, giving rise to unusual dinuclear and polynuclear species (1, 2 and 3) whose structural variations are discussed. Magneto-structural correlation for the very rare singly μ_1,3-N₃ bridged Cu^II-Schiff base dinuclear species (2) has been studied. In addition, the catalytic properties of 1 for alkene oxidation and the general catalase-like activity behavior of 2 have been discussed.     

Synthesis, structure and spectroscopic properties of 2,3-bis(diphenylphosphino)quinoxaline (dppQx) and its copper(I) complexes

Phosphinoquinoxalines were prepared by treatment of 2,3-dichloroquinoxaline (3) with phosphorus nucleophiles. The Arbuzov reaction of 3 with PPh(O-i-Pr)₂ gave a mixture of diastereomers of 2,3-(PPh(O)(O-i-Pr))₂quinoxaline (6); the crystal structure of rac-6 was determined, but attempts at reduction to yield bis(phenylphosphino)quinoxaline 7 resulted in P-C cleavage and formation of phenylphosphine. The bis(secondary phosphine) 7 could be generated from 3 and LiPHPh(BH₃), but was not isolated in pure form. Copper-catalyzed coupling of PHPh₂ with 3 gave 2,3-bis(diphenylphosphino)quinoxaline (4, dppQx), whose coordination chemistry was investigated, with comparison to data for the analogous 1,2-bis(diphenylphosphino)benzene (dppBz) complexes. Reaction of dppQx with [Cu(NCMe)₄][PF₆] gave [Cu(dppQx)₂][PF₆] (8); CuCl yielded [Cu(dppQx)Cl]₂ (9). Reaction of [Cu(NCMe)₄][PF₆] with one equiv of DPEphos, followed by one equiv of dppQx, gave [Cu(dppQx)(DPEphos)][PF₆] (10). Ligand 4 and copper complexes 8 and 9 were crystallographically characterized. The UV-Vis spectra of dppQx and its copper complexes were red-shifted from those of the dppBz analogs; in contrast to results for the dppBz complexes, those of dppQx were not luminescent in solution.     

Syntheses, crystal structures, spectroscopic, fluorescence and thermal properties of silver(I) 5,5-diethylbarbiturato complexes with some aminopyridines

Three new silver(I) complexes of 5,5-diethlybarbiturate (barb), [Ag(barb)(apy)]·H₂O (1), {[Ag(μ-ampy)][Ag(μ-barb)₂]}_n (2) and [Ag(barb)(dmamhpy)] (3) [apy = 2-aminopyridine, ampy = 2-aminomethylpyridine and dmamhpy = 2-(dimethylaminomethyl)-3-hydroxypyridine] have been synthesized and characterized by elemental analysis and FT-IR. Single crystal X-ray diffraction analyses showed that complexes 1 and 3 are mononuclear. In 1, the silver(I) ion is linearly coordinated by a barb anion and a ampy ligand, while a bidentate dmamhpy ligand together with an N-coordinated barb anion forms a trigonal coordination geometry around silver(I) in 3. Complex 2 is a one-dimensional coordination polymer in which silver(I) ions are bridged by ampy ligands, leading to a cationic chain . The [Ag(barb)₂]⁻ units contains two N-bonded barb ligands, bridging the silver centers in the cationic and anionic units via the carbonyl O atoms. Thus, complex 2 contains two-coordinated and four-coordinated silver ions. All complexes display hydrogen-bonded network structures and exhibit appreciable fluorescence at room temperature. Thermal analysis (TG-DTA) data are in agreement with the structures of the complexes.     

Synthesis, characterization, X-ray structure and in vitro antimycobacterial and antitumoral activities of Ru(II) phosphine/diimine complexes containing the "SpymMe2" ligand, SpymMe2=4,6-dimethyl-2-mercaptopyrimidine

The reaction of cis-[RuCl₂(dppb)(N-N)], dppb = 1,4-bis(diphenylphosphino)butane, complexes with the ligand HSpymMe₂, 4,6-dimethyl-2-mercaptopyrimidine, yielded the cationic complexes [Ru(SpymMe₂)(dppb)(N-N)]PF₆, N-N = bipy (1) and Me-bipy (2), bipy = 2,2′-bipyridine and Me-bipy = 4,4′-dimethyl-2,2′-bipyridine, which were characterized by spectroscopic and electrochemical techniques and X-ray crystallography and elemental analysis. Additionally, preliminary in vitro tests for antimycobacterial activity against Mycobacterium tuberculosis H37Rv ATCC 27264 and antitumor activity against the MDA-MB-231 human breast tumor cell line were carried out on the new complexes and also on the precursors cis-[RuCl₂(dppb)(N-N)], N-N = bipy (3) and Me-bipy (4) and the free ligands dppb, bipy, Me-bipy and SpymMe₂. The minimal inhibitory concentration (MIC) of compounds needed to kill 90% of mycobacterial cells and the IC₅₀ values for the antitumor activity were determined. Compounds 1-4 exhibited good in vitro activity against M. tuberculosis, with MIC values ranging between 0.78 and 6.25 μg/mL, compared to the free ligands (MIC of 25 to >50 μg/mL) and the drugs used to treat tuberculosis. Complexes 1 and 2 also showed promising antitumor activity, with IC₅₀ values of 0.46 ± 0.02 and 0.43 ± 0.08 μM, respectively, against MDA-MB-231 breast tumor cells.     

Cytotoxicity of half sandwich ruthenium(II) complexes with strong hydrogen bond acceptor ligands and their mechanism of action

Neutral and cationic organometallic ruthenium(II) piano stool complexes of the type [(η⁶-cymene)RuCl(X)(Y)] (complexes R1-R8) has been synthesized and characterized. In cationic complexes, X, Y is either a η² phosphorus ligand such as 1,1-bis(diphenylphosphino)methane (DPPM) and 1,2-bis(diphenylphosphino)ethane (DPPE) or partially oxidized ligands such as 1,2-bis(diphenylphosphino)methane monooxide (DPPMO) and 1,2-bis(diphenylphosphino)ethane monooxide (DPPEO) which are strong hydrogen bond acceptors. In neutral complexes, X is chloride and Y is a monodentate phosphorous donor. Complexes with DPPM and DPPMO ligands ([(η⁶-cymene)Ru(η²-DPPM)Cl]PF₆ (R2), [(η⁶-cymene)Ru(η²-DPPMO)Cl]PF₆ (R3), [(η⁶-cymene)Ru(η¹-DPPM)Cl₂] (R5) and [(η⁶-cymene)Ru(η¹-DPPMO)Cl₂] (R6) show good cytotoxicity. Growth inhibition study of several human cancer cell lines by these complexes has been carried out. Mechanistic studies for R5 and R6 show that inhibition of cancer cell growth involves both cell cycle arrest and apoptosis induction. Using an apoptosis PCR array, we identified the sets of anti-apoptotic genes that were down regulated and pro-apoptotic genes that were up regulated. These complexes were also found to be potent metastasis inhibitors as they prevented cell invasion through matrigel. The complexes were shown to bind DNA in a non intercalative fashion and cause unwinding of plasmid DNA in cell-free medium by competitive ethidium bromide binding, viscosity measurements, thermal denaturation and gel mobility shift assays.     

Syntheses and characterization of luminescent dinuclear and polynuclear Cu(I) complexes containing 4,4′-bis(diphenylphosphino)biphenylene bridge

The dinuclear complex [Cu₂(dpbp)₂(NCMe)₄][BF₄]₂ (1) has been prepared by treating [Cu(NCMe)₄][BF₄] with 4,4′-bis(diphenylphosphino)biphenylene (abbreviated as dpbp). Reactions of 1 with 2,2′-bipyridine and 1,1′-bis(diphenylphosphino)ferrocene (abbreviated as dppf) afford [Cu₂(dpbp)₂(2,2′-bipy)₂][BF₄]₂ (2) and [Cu₂(dpbp)(dppf)₂][BF₄]₂ (3), respectively. In contrast, compound 1 reacts with tetra(2-pyridyl)ethyl-1,4-diaminobutane (abbreviated as tpyda) to produce the polymeric complex {[Cu₂(dpbp)(tpyda)][BF₄]₂}_n (4). Compounds 1-4 are photoluminescent with the emission band (λ_max) in the range 510-554 nm. The crystal structures of 1 and 4 have been determined by an X-ray diffraction study.     

Effect of factor XIII levels and polymorphisms on the risk of myocardial infarction in young patients

The aim of this work was the synthesis, characterization, and cytotoxicity evaluation of three new Ru(II) complexes with a general formula [Ru(Spy)(bipy)(P-P)]PF₆ [Spy = pyridine-6-thiolate; bipy = 2,2′-bipyridine; P-P = 1,2-bis(diphenylphosphine)ethane (1); 1,3-bis(diphenylphosphine) propane (2); and 1,1′-bis(diphenylphosphino)ferrocene] (4). Complex (3) with the 1,4-bis(diphenylphosphine)butane ligand, already known from the literature, was also synthesized, to be better studied here. The cytotoxicities of the complexes toward two kinds of cancerous cells (K562 and S-180 cells) were evaluated and compared to normal cells (L-929 and PBMC) by MTT assay. The complex [Ru(Spy)(bipy)(dppb)]PF₆ (3) was selected to study both the cellular and molecular mechanisms underlying its promising anticancer action in S-180 cells. The results obtained from this study indicated that complex (3) induces cell cycle arrest in the G0/G1 phase in S-180 cells associated with a decrease in the number of cells in S phase. After 24 and 48 h of exposure to complex (3), the cell viability decreased when compared to the negative control. Complex (3) does not appear to be involved in the DNA damage, but induced changes in the mitochondrial membrane potential in S-180 cells. Furthermore, there was also an increase in the gene expression of Bax, Caspase 9, and Tp53. According to our results, complex (3) induces cell apoptosis through p53/Bax-dependent intrinsic pathway and suppresses the expression of active antiapoptotic Bcl-2 protein.     

Heterocyclic thioamide derivatives of coinage metals (Cu, Ag): Synthesis, structures and spectroscopy

Heterocyclic thioamides, namely, imidazolidine-2-thione (imdzSH), 1-methyl-1, 3-imidazoline-2-thione (mimzSH), thiazolidine-2-thione (tzdSH) and 2,4-dithiouracil (dtucH₂) with silver(I)/copper(I) salts in presence of triphenyl phosphine (PPh₃) have yielded complexes of different nuclearity: mononuclear, [Ag(η¹-S-HL)(PPh₃)₂Cl] (HL = imdzSH 1, mimzSH 2, tzdSH 3), dinuclear, [Ag₂(η¹-S-tzdSH)₂(μ-S-tzdSH)₂(PPh₃)₂](NO₃)₂4, and polynuclear, {Cu(μ-S,S-dtucH₂)(PPh₃)₂X} (X = Cl 5, Br 6, I 7). All complexes have been characterized using analytical data, IR and multinuclear NMR spectroscopy (¹H, ¹³C and ³¹P) and single crystal X-ray crystallography. The thio-ligands are bonded to the metal centers as neutral sulfur donors. The geometry around each metal center is distorted tetrahedral. Complexes 5-7 represent first examples of polymers of 2,4-dithiouracil in its coordination chemistry with metal salts. The hydrogen bonding interactions lead to the formation of 1D (2, 3, 7) and 2D (1, 4-6) sheet structures.     

Heterobimetallic assemblies of Ni(II) complexes with a tetradentate amine ligand and diamagnetic cyanidometallates

Syntheses and crystal structures of nickel(II) complexes containing teta (teta = N,N′-bis(2-aminoethyl)ethane-1,2-diamine) as a tetradentate blocking ligand and cyanidometallic bridging complexes are described. The complexes [Ni(teta)(cis-μ²-Ni(CN)₄)] (1) and [{Ni(teta)}₃(μ⁶-Co(CN)₆)] (ClO₄)₃ (2) exhibit a 1D-polymeric structure whereas the heterometallic trinuclear complex [Ni(teta)(μ¹-Ag(CN)₂)₂] (3) forms a unique network. The weak antiferromagnetic exchange was found in polymeric species 1 and 2 by analyzing the magnetic data with several models in which either only susceptibility was treated or simultaneous fitting of temperature and magnetic field dependences of the magnetization was applied using the finite-size closed ring approach. Moreover, an effect of the zero-field splitting phenomenon (ZFS) was considered for 2 by advanced modeling of magnetic properties for varying axial ZFS parameter/isotropic exchange (D/J) ratios.     

Coordination chemistry of 2,2-bis(diphenylphosphinomethyl)propionic acid

The coordination chemistry of the diphosphine ligands 2,2-bis(diphenylphosphinomethyl)propionic acid, 1, and 2,2-bis(diphenylphosphinomethyl)propionate, 2, with copper(I), silver(I), gold(I), palladium(II) and platinum(II) is described. Structure determinations show that the carboxylic acid group in 1 can hydrogen bond to solvent molecules, to anions or to the carboxylic acid group of a neighboring complex, as in the complexes [MCl₂(1)] · 2DMSO (M = Pd or Pt), [Pt(1)₂](OTf)₂ or [Pd(NCMe)₂(1)](OTf)₂, respectively. The tridentate diphosphine-carboxylate ligand 2 forms oligomeric or polymeric complexes, such as [{Ag(2)}_n], [{PdCl(2)}_n] or [{PtMe(2)}_n].     

Structural diversity, photoluminescence and magnet properties of complexes based on a V-shaped polycarboxylate

The self-assembly of a V-shaped ligand 3,3′,4,4′-diphenylsulfonetetracarboxylate (dstc) and metal salts in the presence of a series of N-donor ligands yielded four new complexes, namely, [Cu₄(H₂dstc)₄(phen)₄]·12H₂O (1), {[Cu₂(dstc)(bpe)(H₂O)₂]·4H₂O}_n (2), [Cu₃(dstc)(bipy)(μ₂-OH)₂(H₂O)₂]_n (3), {[Cd₅(dstc)₂(bipy)₂(μ₃-OH)₂(H₂O)₄]·4H₂O}_n (4) (phen = 1,10-phenanthroline; bpe = 1,2-bis(4-pyridyl)ethene; bipy = 4,4′-bipyridine). All the complexes were structurally determined by single-crystal X-ray diffraction and characterized by elemental analyses, IR spectra, X-ray powder diffraction and TG analyses. Complex 1 is a discrete tetranuclear unit, which further assembles into a 3D supramolecular framework by intermolecular hydrogen bonding interactions. Complex 2 is composed of 2D 4⁴ grid-like layers based on dinuclear copper units. Complex 3 features a rare 3D (6,8)-connected topological net consisting of trimetallic clusters. 12-connected pentanuclear cadmium clusters are observed in complex 4 and the resulting structure shows an uncommon (4,12)-connected topology. The structural differences among 1-4 demonstrate that the nature of the N-donor assistant ligands and metal ions can play critical roles in the formation and structures of the resulting complexes. Magnetic studies showed antiferromagnetic interactions for 1 and 3. In addition, the luminescent property of 4 was also studied.