Diaminodithioether complexes of nickel(II) and palladium(II): A unique case of dealkylation of S,S′-thioether

Summary Nickel(II) and palladium(II) complexes of the 1,3-di(o-aminophenylthio) propane (H₂L¹) and 1,2-di(o-aminophenylthio)xylene (H₂L²) ligands have been prepared and characterized. The hydrobromide salt of H₂L¹ gave a 12 ligand-metal complex of Pd^II, whereas free H₂L¹ formed the usual 1:1 species. The reaction of Na₂PdCl₄ with H₂L² resulted in S,S-dealkylation of the ligand and formation of a mononuclear complex of the corresponding thiol, i.e. 2-aminobenzenethiol. NiCl₂, NiBr₂ and Ni(ClO₄)₂ did not react directly with H₂L². Ni^II is a fairly hard ion and therefore does not coordinate to the soft thioether moiety in H₂L² in the absence of soft anions which symbiotically motivate Ni^II to act as a soft acceptor. It thus does not react with H₂L² in the presence of hard ions such as Cl^–, Br^- and ClO ₄ ^– , but, the in situ reaction of the constituents produced the tetrahedral Ni^II complex, contrary to earlier reports of similar types of octahedral species.     

One-and Two-photon Excited Fluorescence of Zinc(II),Cadmium(II)Complexes Containing Phenothiazine Ligand

In fluorescence imaging, two-photon excitation (TPE) has developed as an important alternative to traditional one-photon excitation (OPE) in fluorescence microscopy and spectroscopy1,2. The intrinsic advantages of the two-photon excitation include reduced background fluorescence from fluorophores outside the focal volume, decreased photobleaching, inherent optical sectioning capability, and lower photodamage of sensitive biological sample3. But, all the reported materials, which exhibit a …     

Synthesis and Crystal Structure of BIS(Imidazole)(µ-Succinato) Manganese(II)

The title complex was prepared by reaction of succinatomanganese(II) with imidazole in water-ethanol. The complex crystallizes in orthorhombic space group Pna 2 1 with a = 7.9990(15), b = 14.8690(15), c = 11.028(2) Å. The metal assumes a distorted octahedral coordination. In the crystal, each succinate dianion bridges three Mn(II) atoms to form a polymer with a layered structure.     

Blue Luminescent Zinc(II)-and Cadmium(II)-1,4-phenylenediacetate Complexes

1 INTRODUCTION The crystal engineering and design of solid-state coordination polymers have become a very attrac- tive field in recent years[1～4]. Many interesting fra- meworks with intriguing potential applications have been obtained through the self-assembly of selected metal centers and carboxylate ligands[5, 6]. Compared with aromatic carboxylate ligands such as terephtha- lic acid[7, 8], benzene tricarboxylic acid[9, 10], benzene tetracarboxylic acid[11, 12] and so on, those ligands …     

Complex Species in Aqueous Solutions of 4-Chloro-1,2-Phenylenediamine-N,N,N′,N,'-Tetraacetic Acid with Magnesium(II), Calcium(II), Strontium(II), Barium(II), Zinc(II) and Cadmium(II)

Abstract

The coordination in aqueous solution of 4-chloro-1,2-phenylenediamine-N',N',N',N'-tetraacetic acid (4-Cl-o-PDTA) with Be(II) and with the transition metal cations cobalt(II), nickel(II) and copper(II) was reported in earlier publications.^1,2 In this note a study is presented of the coordination in aqueous solution (25°C, 1 = 0.1 M in KC1) of 4-CI-o-PDTA acid with magnesium(II), calcium(II), strontium(II), barium(II), zinc(II) and cadmium(II).     

Mercury(II) complexes of pyrrolidinedithiocarbamate,crystal structure of bis{[μ2-(pyrrolidinedithiocarbamato-S,S ′)(pyrrolidinedithiocarbamato-S,S ′)mercury(II)]}

Mercury(II) complexes of pyrrolidinedithiocarbamate (PDTC) having the general formula [Hg(PDTC)X] (X = Cl^?, SCN^?, and CN^?) and [Hg(PDTC)₂] have been prepared and characterized by elemental analysis, IR, and NMR. The crystal structure of [Hg(PDTC)₂] has also been determined by X-ray crystallography, showing that the complex is a centrosymmetric dimer, [Hg₂(PDTC)₄] (bis[µ²-(pyrrolidinedithiocarbamato-S,S′)(pyrrolidinedithiocarbamato-S,S′)mercury(II)]) (1). The solid-state structure of 1 contains two crystallographically equivalent Hg(II) centers in a distorted tetrahedron.     

CRYSTAL STRUCTURE OF ADDUCT OF BIS(O,O''''-DIBUTYLDITHIOPHOSPHATO)-NICKEL (II) WITH BIPYRIDYL

<正> Ni[(C8H9O)2PS2]2 bipy, Mr=697.57, triclinic, Ci-Pl, a=9.469(1)A, b=14.638(3)A, c=14.637(2)A, α=69.64(1)° , β=71.16(1)°, r=89.99(1)°, V= 1785.6A3, Z=2, Dc=1.297g.cm-3, Mo kα radiation, λ=0.71073A, F(000)=736e, R=0.081 for 4986 independent reflections. Ni(II) is coordinated by four sulfur atoms and two nitrogen atoms to form a distorted octahedron. The angles between each two among planes N2Ni, NiS(11)S(12) and NiS(21)S(22) are nearly 90°.     

Structural characterization of dicyanidobis-(N,N′-dimethylthiourea-κS)cadmium(II)

A cadmium(II) complex dicyanidobis(N,N′-dimethylthiourea-S) cadmium(II) [Cd(Dmtu)₂(CN)₂] (1) is prepared and its structure in the solid state is determined by single crystal X-ray structural analysis. The cadmium(II) ion is four-coordinate having a distorted tetrahedral geometry composed of two cyanide C atoms and two thione S atoms of N,N′-dimethylthiourea (dmtu). The molecular structure is stabilized by intermolecular N-H…N(CN) hydrogen bonding interactions that lead to a 3D network structure. The complex was also characterized by IR and NMR spectroscopy.     

Functionalized zinc(II) dithiocarbamate complexes: Synthesis,spectral and molecular structures of bis(N-cyclopropyl-N-4-methoxybenzyldithiocarbamato-S,S′)zinc(II) and (2,2′-bipyridine)bis(N-cyclopropyl-N-4-methoxybenzyldithiocarbamato-S,S′)zinc(II)

Two new zinc and dithiocarbamate integrated metal complexes such as bis(N-cyclopropyl-N-4-methoxybenzyldithiocarbamato-S,S′)zinc(II) (1) and (2,2′-bipyridine)bis(N-cyclopropyl-N-4-methoxybenzyldithiocarbamato-S,S′)zinc(II) (2) have been synthesized and their spectral investigations viz., FT-IR, ¹H and ¹³C NMR as well as single crystal X-ray diffraction studies have been accomplished. Single crystal X-ray analysis of the complex 1 reveals the presence of distorted trigonal bipyramidal and tetrahedral coordination geometry around the zinc. The dithiocarbamate motif acts as bidentate chelating and bidentate bridging ligands between the zinc ions furnishing centrosymmetric dimeric molecules. In the complex 2, the zinc is in a distorted octahedral environment with a ZnS₄N₂ chromophore. The supramolecular frameworks in the complexes 1 and 2 have been sustained by CH?S, CH?O and CH?π (ZnCS₂, and chelate) interactions. Computational studies on complexes 1 and 2 have been executed utilizing DFT-B3LYP/ LANL2DZ method. In both the cases, the HOMO-LUMO calculations imply the occurrence of effective charge transfer within the molecule. Further, the MEP analysis of 1 and 2 implies the negative potential sites are sulfur of NCS₂ and oxygen of OCH₃ and the positive potential sites are nitrogen of NCS₂ in both the complexes along with 2,2′-bipyridine for complex 2. The former sites are susceptible for electrophilic reactions while the latter for nucleophilic reactions.     

SYNTHESIS,CRYSTAL STRUCTURE AND PROPERTIES OF TETRAETHYLAMMONIUM BIS[BIS(2-OXYPHENYL)DISULFIDE-O,O'''',S]MANGANESE

The synthesis,crystal structure and properties of the firstMn(III)-disulfide complex(Et_4N)[Mn(mp-mp)_2]were reported with the Mn(III)ion in a S_2O_4 octahedron distorted due to Jahn-Teller effect.Spectroscopicdata revealed its paramagnetic properties.     

Investigation of {1,2-bis(diphenylphosphino)ethane-P,P′}-(dithiocarbonato-S,S′)-nickel(II)

Summary The reaction of bis(iso-propylxanthato)nickel(II) with 1,2-bis(diphenylphosphino)ethane (dppe) in a 11 molar ratio affords [Ni(S₂CO)(dppe)], which, on the basis of its magneto-chemical and spectral properties, has been characterized as a square-planar Ni complex. The complex was one-electron irreversibly oxidized at a potential of 0.673 V versus s.c.e. The crystal and molecular structure of a twinned crystal of the complex has been elucidated, and consists of two crystallographically independent molecules in which each Ni atom is coordinated by two S atoms from the dithiocarbonate ligand and two P atoms from the dppe ligand in an approximately square-planar arrangement.     

Ternary Complexes of Cadmium(II) with Phenylalanine and Phenylalkylmalonates in Dioxane–Water Mixtures

The formation and stability of ternary complexes of cadmium(II) with phenylalanine and malonate, phenylmalonate benzylmalonate, 2-phenylethylmalonate, and 3-phenylpropylmalonate, have been studied by the potentiometric pH titration technique in 40% (v/v) dioxane–water at 25°C and 0.10—ionic strength (NaNO₃). All systems give stable ternary complexes, and the log K and _K values demonstrated that the complexes possess enhanced stability. The possible reasons that lead to these results are discussed in terms of –electron back donation from metal ions to ligands and intramolecular ligand–ligand aromatic ring-stacking interactions present in the complexes. The relative contribution of each interactions to the enhanced stability have also been evaluated.     

Cadmium(II) complexes: mimics of organophosphate pesticide degrading enzymes and metallo-β-lactamases

Cadmium(II) complexes of ethyl 4-hydroxy-3,5-bis(((2-hydroxyethyl)(pyridin-2-ylmethyl)amino)methyl)benzoate (CO(2)EtH(3)L1) and ethyl 4-hydroxy-3,5-bis(((2-methoxyethyl)(pyridin-2-ylmethyl)amino)methyl)benzoate (CO(2)EtHL2) are described. The two ligands possess an ethyl ester (CO(2)Et-) at the position para to the phenolic -OH; CO(2)EtHL2, with methyl ether donors in contrast to potentially nucleophilic alkoxide donors in CO(2)EtH(3)L1, offers a direct comparison of potential ligand-centered nucleophiles. The complex with CO(2)EtH(3)L1 was characterized using (1)H and (13)C NMR spectroscopy, mass spectrometry and microanalysis; X-ray crystallography defined a tetranuclear structure [Cd(4)(CO(2)EtH(2)L1)(2)(CH(3)COO)(3.75)Cl(0.25)(H(2)O)(2)](PF(6))(2). Functional studies of the cadmium(II) complexes were undertaken with the substrates bis(2,4-dinitrophenyl)phosphate (BDNPP), and nitrocefin to assess their phosphatase and β-lactamase activities, respectively. The complexes with CO(2)EtH(3)L1 and CO(2)EtHL2 are competent phosphoesterase mimics with K(M) = 9.4 ± 2.1 mM and 10.1 ± 3.4 mM, k(cat) = 9.4 ± 0.2 × 10(-3) s(-1) and 9.7 ± 2.7 × 10(-3) s(-1), respectively. Use of a solvent mixture containing H(2)(18)O/H(2)(16)O in the reaction with BDNPP showed that for the complex with CO(2)EtH(3)L1 the (18)O label was incorporated in the reaction product suggesting that the nucleophile involved is a Cd-OH moiety and not a metal bound alkoxide; for CO(2)EtHL2 the presence of the methyl-ether dictates that the active nucleophile must also be a hydroxide. The cadmium(II) complex with CO(2)EtH(3)L1 was furthermore found to be a competent β-lactamase mimic with k(cat) = 1.39 × 10(-2) ± 3 × 10(-3) s(-1), K(M) = 0.11 ± 0.03 mM, and pK(a) = 7.9 ± 0.1. Mass spectral evidence suggested that the active nucleophile in this reaction is the alkoxide; lack of β-lactamase activity of the complex with CO(2)EtHL2 supports this assignment. Similar to enzyme-catalyzed reactions, a blue reaction intermediate in the β-lactamase reaction of the CO(2)EtH(3)L1 complex was also identified. It is proposed that the Cd(II) complexes of CO(2)EtH(3)L1 and CO(2)EtHL2 react identically as phosphatases, with a terminal hydroxide as the nucleophile; the former exhibits β-lactamase activity with the alkoxide as a nucleophile, while the latter, without a potentially nucleophilic alkoxide, is inactive.     

Synthesis and Structural Characterization of a New Cadmium(II) Complex with a Double Betaine

1 INTRODUCTION The construction of supramolecular aggregates has received much attention due to their intriguing network topologies and potential functions as new classes of materials[1, 2]. Multiple noncovalent interac- tions, such as hydrogen bonds, π-π stacking and host- guest ionic interactions, play important roles in the supramolecular assembly of metal ions and organic ligands[3, 4]. In this context the multidentate ligands with conjugated groups are employed as building blocks in…     

Humidity-sensing and DNA-binding ability of bis(4-benzylpiperazine-1-carbodithioato-k2 S,S′)nickel(II)

Bis(4-benzylpiperazine-1-carbodithioato-k² S,S?)nickel(II), 1, was prepared by metathesis of sodium salt of 4-benzylpiperazine-1-carbodithioate with nickel(II) chloride in 2?:?1 ratio. Complex 1 was characterized by analytical techniques including elemental analysis, FT-IR, UV–visible spectroscopy, and X-ray single-crystal analysis. The latter technique confirmed square-planar geometry around Ni with the formation of NiS₄ core with two shorter and two longer Ni–S bonds. The packing diagram revealed a supramolecular chain structure mediated by unconventional H?H dihydrogen bonds that resulted in a chair and a ladder-like structure when viewed along the a-axis and c-axis, respectively. The thin-film coating resulted in a microporous film with a band gap of 1.69 eV. Complex 1-based sensor was fabricated to check the humidity-sensing properties of the material. Resistance of the device decreased by two orders of magnitude and capacitance was enhanced with the increase of relative humidity. The DNA binding study proved 1 to be a good DNA binder with binding constant value of 1.4 × 10⁴ M^?1.     

Cadmium(II) complexes of 5-nitro-salicylaldehyde and α-diimines: synthesis,structure and interaction with calf-thymus DNA

Five Cd(II) complexes with the anion of 5-NO₂-salicylaldehydeH (5-NO₂-saloH) in the absence or presence of the α-diimine 1,10-phenanthroline (phen), 2,2′-dipyridylamine (dpamH), 2,2′-dipyridine (bipy), or 2,9-dimethyl-1,10-phenanthroline (neoc) were synthesized and characterized as [Cd(5-NO₂-salo)₂(CH₃OH)₂] (1), [Cd(5-NO₂-salo)₂(phen)]·2CH₃OH·H₂O (2), [Cd(5-NO₂-salo)₂(dpamΗ)] (3), [Cd₃(5-NO₂-salo)₆(bipy)₂] (4), and [Cd(5-NO₂-salo)(neoc)(NO₃)]₂ (5). Based on spectroscopic results (IR, UV, NMR), elemental analysis and conductivity measurements an octahedral geometry around cadmium metal ion is suggested, with the 5-NO₂-salicylaldehyde ligand having different coordination modes. The structures determined by X-ray crystallography verified neutral mononuclear 1–3 and trinuclear 4. Simultaneous TG/DTG–DTA technique was used to analyze the thermal behavior of 1, 2, and 3. The complexes bind tightly to calf-thymus DNA mainly by intercalation, as concluded by DNA viscosity measurements and exhibit significant displacement of EB from the EB-DNA complex.     

Polymeric Structure and Solid ~(31)P, ~(113)Cd NMR Spectra of Cadmium(II) Dialkyldithiophosphate (Alkyl = n-butyl and i-butyl)

Owing to the particular affinity toward metal ion and changeable dentation, dialkyldithiophosphates are commonly used ligands in preparation of the transition metal complexes with variable structures1. For instances relevant to this work, the IIB metal complexes defined crystallographically so far have provided the examples as follows2-12 (Scheme 1). Scheme 1 The frameworks of IIB metal complexes of dialkyldithiophosphate MMMMMMMMMM a b c d …     

Synthesis and crystal structure of a dinuclear zinc(II)-dithiocarbamate complex,bis {[(μ 2-pyrrolidinedithiocarbamato-S,S′)(pyrrolidinedithiocarbamato-S,S′)zinc(II)]}

A new zinc(II) complex of pyrrolidinedithiocarbamate (PDTC), bis[(μ ²-pyrrolidinedithiocarbamato-S,S′)(pyrrolidinedithiocarbamato-S,S′)zinc(II)], [Zn₂(PDTC)₄] (1) has been prepared by reaction of ZnCl₂ with ammonium pyrrolidinedithiocarbamate in 1 : 1 and 1 : 2 ratio, respectively. The complex has been characterized by IR, NMR and X-ray crystallography. Compound 1 crystallizes in the triclinic space group P 1 in the form of a centrosymmetric dimer. The solid-state structure contains two crystallographically equivalent Zn⁺² centers in a tetrahedrally distorted ion sphere. A mixed-ligand complex, [Zn(PDTC)(MSC)]^? (MSC = mercaptosuccinate) was also prepared but the structure of the resulting complex was found to be the same as 1, suggesting that the thiolate ligand was replaced on addition of PDTC.     

Synthesis,structure and magnetic studies of copper(II)-nickel(II) complexes withN,N′-bis(2-aminopropyl)oxamidocopper(II)

Three novel heterobinuclear complexes have been prepared and identified as [Cu(oxap)Ni(L)₂](ClO₄)₂·ξH₂O, where oxap denotes theN,N′-bis(2-aminopropyl)oxamido dianion and L denotes 2,2′-bipyridine (bipy), 1,10-phenanthroline (phen) or 5-nitro-1,10-phenanthroline (NO₂-phen). The crystal structure of [Cu(oxap)Ni(phen)₂]-(ClO₄)₂·2H₂O has been determined. Crystal data: triclinic, space group , a=12.079 (6), b=12.409 (4), c=17.261 (8) ?, α=70.91 (2), β=86.72 (4), γ=89.19 (3)^o. At room temperature, Z=2. The Cu^II is in a square planar environment and the Ni^II is in an octahedral environment. The Cu−Ni distance is 5.292 ?. The temperature dependences of the magnetic susceptibilities of [Cu(oxap)Ni(phen)₂]-(ClO₄)₂·2H₂O and [Cu(oxap)Ni(bipy)₂](ClO₄)₂ have been studied in the 4.2–300 K range, giving the exchange integral J=−92.4 cm⁻¹ for bipy and J=−94.3 cm⁻¹ for phen. These results are commensurate with antiferromagnetic interactions between the adjacent metal ions.     

Synthesis, Structure and Properties of Tetrakis (thiourea) mercury (II) Tetrakis (thiocyanato-N) zinc (II)

Introduction In recent years, much attention has been paid to the research of novel, high-quality nonlinear optical (NLO) crystals, especially those metalorganic complex crystals that can generate high efficient second-harmonic blue-violet light using GaAlAs laser diodes. In order to find this type of crystals, much work has been done in our laboratory on the complex crystals of MM'(SCN)4 and MM'(SCN)·nL, where M = Zn, Cd, Mn; M' = Cd, Hg and L = adduct1-6. A 404.5nm blue-violet lig…