Zinc (II), palladium (II) and cadmium (II) complexes containing 4‐methoxy‐N‐(pyridin‐2‐ylmethylene) aniline derivatives: Synthesis,characterization and methyl methacrylate polymerization

A series of Zn (II), Pd (II) and Cd (II) complexes, [(L) _n MX ₂ ] _m (L = L‐a–L‐c; M = Zn, Pd; X = Cl; M = Cd; X = Br; n, m = 1 or 2), containing 4‐methoxy‐N‐(pyridin‐2‐ylmethylene) aniline ( L‐a ), 4‐methoxy‐N‐(pyridin‐2‐ylmethyl) aniline ( L‐b ) and 4‐methoxy‐N‐methyl‐N‐(pyridin‐2‐ylmethyl) aniline ( L‐c ) have been synthesized and characterized. The X‐ray crystal structures of Pd (II) complexes [L ₁ PdCl ₂ ] (L = L‐b and L‐c) revealed distorted square planar geometries obtained via coordinative interaction of the nitrogen atoms of pyridine and amine moieties and two chloro ligands. The geometry around Zn (II) center in [(L‐a)ZnCl ₂ ] and [(L‐c)ZnCl ₂ ] can be best described as distorted tetrahedral, whereas [(L‐b) ₂ ZnCl ₂ ] and [(L‐b) ₂ CdBr ₂ ] achieved 6‐coordinated octahedral geometries around Zn and Cd centers through 2‐equivalent ligands, respectively. In addition, a dimeric [(L‐c)Cd(μ ‐ Br)Br] ₂ complex exhibited typical 5‐coordinated trigonal bipyramidal geometry around Cd center. The polymerization of methyl methacrylate in the presence of modified methylaluminoxane was evaluated by all the synthesized complexes at 60°C. Among these complexes, [(L‐b)PdCl ₂ ] showed the highest catalytic activity [3.80 × 10⁴ g poly (methyl methacrylate) (PMMA)/mol Pd hr^?1], yielding high molecular weight (9.12 × 10⁵ g mol^?1) PMMA. Syndio‐enriched PMMA (characterized using ¹H‐NMR spectroscopy) of about 0.68 was obtained with T_g in the range 120–128°C. Unlike imine and amine moieties, the introduction of N‐methyl moiety has an adverse effect on the catalytic activity, but the syndiotacticity remained unaffected.     

Tweaking the affinity of aryl‐substituted diazosalicylato‐ and pyridine ligands towards Zn (II) and its neighbors in the periodic system of the elements,Cu (II) and Cd (II), and their antimicrobial activity

A series of six new Zn (II) compounds, viz., [Zn(HL^ASA)₂(Py)₂] ( 1 ), [Zn(HL^MASA)₂(Py)₂] ( 2 ), [Zn(HL^MASA)₂(4‐MePy)₂] ( 3 ), [Zn(HL^CASA)₂(4‐MePy)₂] ( 4 ), [Zn(HL^BASA)₂(Py)₂] ( 5 ), [Zn(HL^BASA)₂(4‐MePy)₂] ( 6 ) and representative Cu (II) and Cd (II) complexes, viz., [Cu(HL^ASA)₂(Py)₂(H₂O)] ( 7 ) and [Cd(HL^BASA)₂(Py)₃] ( 8 ) [(HL^XASA)^? = para‐substituted 5‐[(E)‐2‐(aryl)‐1‐diazenyl]‐2‐hydroxybenzoate with X = H (ASA), Me (MASA), Cl (CASA) or Br (BASA); Py = pyridine; 4‐MePy = 4‐methylpyridine] have been synthesized and characterized by spectroscopic techniques and single‐crystal X‐ray diffraction analysis. The structural characterization of the compounds revealed distorted tetrahedral ( 1 – 6 ), square‐pyramidal ( 7 ) and pentagonal‐bipyramidal ( 8 ) coordination geometries around the metal atom, in which the aryl‐substituted diazosalicylate ligands are coordinated only through the oxygen atoms of carboxylate groups, either in an anisobidentate or isobidentate mode; meanwhile, the 2‐hydroxy groups of the monoanionic ligand (HL^XASA)^? are involved only in intramolecular O‐H···O hydrogen bonds with the carboxylate function. In the crystal structures of 1 – 8 , the complex molecules are assembled by π‐stacking interactions giving mostly infinite 1D strands. The intermolecular binding in the solid state structures is accomplished by diverse additional non‐covalent contacts including C‐H···O, C‐H···N, C‐H···π, C‐H···Br, O···Br, Br···π and van der Waals contacts. Although the primary and secondary ligands in the Zn (II) complex series 1 – 6 carry different substituents at the periphery (X = H, Me, Cl, Br for (HL^XASA)^? and R = H, Me for 4‐Py‐R), five of the crystal structures were isostructural. Additionally, the antimicrobial activity of the pro‐ligands H₂L^XASA and their Zn (II), Cu (II) and Cd (II) compounds were studied in a comparative manner, showing high sensitivity (IZD ≥ 20) against Bacillus subtilis.     

Ionic iron(III) complexes bearing a dialkylbenzimidazolium cation: Efficient catalysts for magnesium‐mediated cross‐couplings of aryl phosphates with alkyl bromides

A series of ionic iron(III) complexes of general formula [HLⁿ ][FeX₄] (HL¹ = 1,3‐dibenzylbenzimidazolium cation, X = Cl, 1 ; HL¹, X = Br, 2 ; HL² = 1,3‐dibutylbenzimidazolium cation, X = Br, 3 ; HL³ = 1,3‐bis(diphenylmethyl)benzimidazolium cation, X = Br, 4 ) were easily prepared in high yields by the direct reaction of FeX₃ with 1 equiv. of [HLⁿ ]X under mild conditions. All of them were characterized using elemental analysis, Raman spectroscopy and electrospray ionization mass spectrometry, and X‐ray crystallography for 1 and 4 . In the presence of magnesium turnings and LiCl, these air‐ and moisture‐insensitive complexes showed high catalytic activities in direct cross‐couplings of aryl phosphates with primary and secondary alkyl bromides with broad substrate scope, wherein complex 4 was the most effective.     

Preparation,Structural Characterization,and Antifungal Activities of Complexes of Group 12 Metals with 2‐Acetylpyridine‐ and 2‐Acetylpyridine‐N‐oxide‐4N‐phenylthiosemicarbazones

Reaction of group 12 metal dihalides in ethanolic media with 2‐acetylpyridine ⁴N‐phenylthiosemicarbazone ( H4PL ) and 2‐acetylpyridine‐N‐oxide ⁴N‐phenylthiosemicarbazone ( H4PLO ) afforded the compounds [M(H4PL)X₂] (X = Cl, Br, M = Zn, Cd, Hg; X = I, M = Zn, Cd) ( 1–8 ), [Hg(4PL)I]₂ ( 9 ) and [M(H4PLO)X₂] (X = Cl, Br, I, M = Zn, Cd, Hg) ( 10–18 ). H4PL , H4PLO and their complexes were characterized by elemental analysis and by IR and ¹H and ¹³C NMR spectroscopy (and the cadmium complexes by ¹¹³Cd NMR spectroscopy), and H4PL , H4PLO , ( 5 · DMSO) and ( 9 ) were additionally studied by X‐ray diffraction. H4PL is N,N,S‐tridentate in all its complexes, including 9 , in which it is deprotonated, and H4PLO is in all cases O,N,S‐tridentate. In all the complexes, the metal atoms are pentacoordinate and the coordination polyhedra are redistorted tetragonal pyramids. In assays of antifungal activity against Aspergillus niger and Paecilomyces variotii, the only compound to show any activity was [Hg(H4PLO)I₂] ( 18 ).     

Two nickel(II) bis[(pyridin‐2‐yl)methyl]amine complexes with homophthalic and benzene‐1,2,4,5‐tetracarboxylic acids

Two new Ni^II complexes involving the ancillary ligand bis[(pyridin‐2‐yl)methyl]amine (bpma) and two different carboxylate ligands, i.e. homophthalate [hph; systematic name: 2‐(2‐carboxylatophenyl)acetate] and benzene‐1,2,4,5‐tetracarboxylate (btc), namely catena‐poly[[aqua{bis[(pyridin‐2‐yl)methyl]amine‐κ³N,N′,N′′}nickel(II)]‐μ‐2‐(2‐carboxylatophenyl)aceteto‐κ²O:O′], [Ni(C₉H₆O₄)(C₁₂H₁₃N₃)(H₂O)]_n, and (μ‐benzene‐1,2,4,5‐tetracarboxylato‐κ⁴O¹,O²:O⁴,O⁵)bis(aqua{bis[(pyridin‐2‐yl)methyl]amine‐κ³N,N′,N′′}nickel(II)) bis(triaqua{bis[(pyridin‐2‐yl)methyl]amine‐κ³N,N′,N′′}nickel(II)) benzene‐1,2,4,5‐tetracarboxylate hexahydrate, [Ni₂(C₁₀H₂O₈)(C₁₂H₁₃N₃)₂(H₂O)₂]·[Ni(C₁₂H₁₃N₃)(H₂O)₃]₂(C₁₀H₂O₈)·6H₂O, (II), are presented. Compound (I) is a one‐dimensional polymer with hph acting as a bridging ligand and with the chains linked by weak C—H...O interactions. The structure of compound (II) is much more complex, with two independent Ni^II centres having different environments, one of them as part of centrosymmetric [Ni(bpma)(H₂O)]₂(btc) dinuclear complexes and the other in mononuclear [Ni(bpma)(H₂O)₃]²⁺ cations which (in a 2:1 ratio) provide charge balance for btc⁴⁻ anions. A profuse hydrogen‐bonding scheme, where both coordinated and crystal water molecules play a crucial role, provides the supramolecular linkage of the different groups.     

Palladium(II)‐N‐Heterocyclic Carbene Complexes: Efficient Catalysts for the Direct C‐H Bond Arylation of Furans with Aryl Halides

This paper contains the synthesis and characterization of the seven new benzimidazolium salts and their corresponding new palladium(II)‐NHC complexes with the general formula [PdX₂(NHC)₂], (NHC = N‐heterocyclic carbene, X = Cl or Br), and also their catalytic activity in direct C‐H bond arylation of 2‐substituted furan derivatives with aryl bromides and aryl chlorides. Under the optimal conditions, these palladium(II)‐NHC complexes showed the good catalytic performance for the direct C‐H bond arylation of 2‐substituted furans with (hetero)aryl bromides, and with readily available and inexpensive aryl chlorides. The C‐H bond arylation regioselectively produced C5‐arylated furans by using 1 mol% of the palladium(II)‐NHC catalysts in moderate to high yields.     

Thermoanalytical behaviour of carbaryl and its copper(II) and zinc(II) complexes

Non-isothermal techniques, i.e. thermogravimetry (TG) and differential scanning calorimetry (DSC), have been applied to investigate the thermal behaviour of carbaryl (1-naphthyl-N-methylcarbamate = 1-Naph-N-Mecbm) and its complexes, M(1-Naph-N-Mecbm)₄X₂, where M = Cu, X = Cl, NO₃ and CH₃COO and M = Zn, X = Cl. Carbaryl and Zn(1-Naph-N-Mecbm)₄Cl₂ complex exhibit two-stage thermal decomposition while the copper(II) complexes exhibit three and four-stage decomposition in their TG curves. The nature of the metal ion has been found to play highly influential role on the nature of thermal decomposition products as well as energy of activation ‘E*’. The presence of different anions does not seem to alter the thermal decomposition patterns. The complexes display weak to medium intensity exothermic and endothermic DSC curves, while the free ligand exhibits two endothermic peaks. The kinetic and thermodynamic parameters namely, the energy of activation ‘E*’, the frequency factor ‘A’ and the entropy of activation ‘S*’ etc. have been rationalized in relation to the bonding aspect of the carbaryl ligand. The nature and chemical composition of the residues of the decomposition steps have been studied by elemental analysis and FTIR data.     

Anti‐proliferative activity of newly synthesized Cd(II), Cu(II), Zn(II),Ni(II), Co(II), VO(II), and Mn(II) complexes of 2‐((4,9‐dimethoxy‐5‐oxo‐5H‐furo[3,2‐g]chromen‐6‐yl)methylene) hydrazinecarbothioamide on three human cancer cells

Thiosemicarbazone ligand, 2‐((4,9‐dimethoxy‐5‐oxo‐5H‐furo[3,2‐g]chromen‐6‐yl)methylene) hydrazinecarbothioamide and its Cd(II), Cu(II), Zn(II), Ni(II), Co(II), VO(II), and Mn(II) complexes have been prepared and characterized by various spectroscopic and analytical techniques. Complexes molar conductance measurements displayed that all complexes (2–8) are non‐electrolyte. With general composition [M(H₃L)(CH₃COO)₂H₂O].nH₂O, where M = Cd(II), Cu(II), Zn(II), Ni(II), Co(II) and Mn(II) while complex (8) has [VO(H₃L)(SO₄)H₂O].2H₂O formula. Based on analytical and spectral measurements, the octahedral or distorted octahedral geometries suggested for complexes. Ligand and complexes anti‐proliferative activities were assessed against three various human tumor cell lines including breast cancer (MCF‐7), liver cancer (HepG2) and lung cancer (A549) using SRB fluorometric assay and cis‐platin as positive control. The anti‐proliferative activity result indicated that the ligand and its complexes have considerable anti‐proliferative activity analogous to that of ordinarily utilized anti‐cancer drug (cis‐platin). They do their anti‐cancer activities by modifying free radical's generation via raising the superoxide dismutase activity and depletion of intracellular reduced glutathione level, catalase, glutathione peroxidase activities, escorted by highly generation of hydrogen peroxide, nitric oxide and other free radicals leading to tumor cells death, as monitoring by decreasing the protein and nucleic acids synthesis.     

Zur Reaktion der Alkin‐Kupfer(I)‐Komplexe [CuX(S‐Alkin)] (X = Cl,Br, I; S‐Alkin = 3,3,6,6‐Tetramethyl‐1‐thia‐4‐cycloheptin) mit den Phosphanen PMe3 und Ph2PCH2CH2PPh2 (dppe)

Organometallic Compounds of Copper. XVIII. On the Reaction of the Alkyne Copper(I) Complexes [CuX(S‐Alkyne)] (X = Cl, Br, I; S‐Alkyne = 3,3,6,6‐Tetramethyl‐1‐thiacyclohept‐4‐yne) with the Phosphanes PMe₃ and Ph₂PCH₂CH₂PPh₂ (dppe) The alkyne copper(I) halide complexes [CuX(S‐Alkyne)]_n ( 2 ) ( 2 a : X = Cl, 2 b : X = Br, 2 c : X = I; S‐Alkyne = 3,3,6,6‐tetramethyl‐1‐thiacyclohept‐4‐yne; n = 2, ∞) add the phosphanes PMe₃ and Ph₂PCH₂CH₂PPh₂ (dppe) to form the mono‐ and dinuclear copper compounds [(S‐Alkyne)CuX(PMe₃)] ( 6 ) ( 6 a : X = Cl, 6 b : X = Br) and [(S‐Alkyne)CuX(μ‐dppe)CuX(S‐Alkyne)] ( 7 a : X = Cl, 7 b : X = Br, 7 c : X = I), respectively. By‐product in the reaction of 2 a with dppe is the tetranuclear complex [(S‐Alkyne)Cu(μ‐X)₂Cu(μ‐dppe)₂Cu(μ‐X)₂Cu(S‐Alkyne)] ( 8 ). In case of the compounds 7 prolonged reaction times yield the alkyne‐free dinuclear copper complexes [Cu₂X₂(dppe)₃] ( 9 ) ( 9 a : X = Cl, 9 b : X = Br, 9 c : X = I)). X‐ray diffraction studies were carried out with the new compounds 6 a , 6 b , 7 b , 8 , and 9 c .     

Structural and physicochemical characterization of zinc(II) and cadmium(II) complexes with 1,4‐dimethy‐lhomopiperazine

In order to know the relationship between structures and physicochemical properties of Group 12 metal(II) ions, the complexes with ‘simple’ ligands, such as alkyl cyclic diamine ligand and halide ions, were synthesized by the reaction of 1,4‐dimethylhomopiperazine (hp′) with MX₂ as metal sources (M = Zn, Cd; X = Cl, Br, I). The five structural types, [ZnX₂(hp′)] (X = Cl ( 1 ), Br ( 2 ) and I ( 3 )), [ZnX₃(Hhp′)] (X = Cl ( 1′ ) and Br ( 2′ )), [CdCl₂(hp′)]_n ( 4 ), [{CdCl₂(Hhp′)}₂(µ‐Cl)₂] ( 4′ ) and [{CdX(hp′)}₂(µ‐X)₂] (X = Br ( 5 ), I ( 6 )), were determined by X‐ray analysis. The sizes of both metal(II) and halide ions and the difference in each other's polarizability influence each structure. All complexes were characterized by IR, far‐IR, Raman and UV–Vis absorption spectroscopies. In the far‐IR and Raman spectra, the typical ν(M N) and ν(M X) peaks clearly depend on the five structural types around 540–410 cm⁻¹ and 350–160 cm⁻¹ respectively. The UV–Vis absorption band energy around 204–250 nm also reflects each structural type. Copyright © 2005 John Wiley & Sons, Ltd.     

Modified cyclopentadienyl molybdenum compounds with enhanced cytotoxic activity towards MOLT‐4 leukaemia cells

A series of new cyclopentadienyl molybdenum compounds bearing substituted phenanthroline ligands [(η⁵‐C₅H₄CH₂C₆H₄X‐4)Mo(CO)₂(^N,NL)][BF₄] (X = F, Cl, Br; ^N,NL = phen, 5‐NH₂‐phen, 4,7‐Ph₂‐phen) was prepared and characterized using infrared and NMR spectroscopies. Crystal structures of [(η⁵‐C₅H₄CH₂C₆H₄F‐4)Mo(CO)₂(NCMe)₂][BF₄], [(η⁵‐C₅H₄CH₂C₆H₄X‐4)Mo(CO)₂(phen)][BF₄] (X = F, Cl, Br) and [(η⁵‐C₅H₄CH₂C₆H₄Cl‐4)Mo(CO)₂(4,7‐Ph₂‐phen)][BF₄]⋅(4,7‐Ph₂‐phen)⋅HBF₄ were determined using X‐ray diffraction analysis. Biological studies revealed a strong cytotoxic effect of the chelating ligands. Although the cytostatic effect of the halogen in the side chain of the cyclopentadienyl ring is negligible, it could be used for future post‐modification of these types of cytotoxic active molybdenum‐based compounds.     

Syntheses,Spectroscopic, Structural,Fluorescent and Thermal Properties of Bis(saccharinato)copper(II) Complexes with two Bis(pyridylamine) Ligands

Two new copper(II) complexes of saccharinate (sac) with bis(2‐pyridylmethyl)amine (bpma) and N,N′‐bis[1‐(pyridin‐2‐yl)ethylidene]ethane‐1,2‐diamine (bapen), [Cu(bpma)(sac)₂] · H₂O ( 1 ) and [Cu(bapen)(sac)₂] ( 2 ), were synthesized and characterized by elemental analysis, TG‐DTA, X‐ray diffraction, and UV/Vis and IR spectroscopy, respectively. In 1 , the copper(II) ion is coordinated by two N‐bonded sac ligands, and three nitrogen atoms of bpma, in a distorted square‐pyramidal coordination arrangement, whereas the arrangement around the copper ion in 2 is a distorted octahedron with two N‐coordinated sac ligands and a tetradentate bapen ligand. In addition to hydrogen bonding involving the water molecule in 1 , the mononuclear species of 1 and 2 are further connected by weak intermolecular C–H ··· π and C–H ··· O interactions to form a three‐dimensional network. Both complexes are luminescent at room temperature and their emissions seem to be due to ligand‐based π–π* transitions.     

Preparation and in vitro investigations of triphenyl[ω‐(tetrahydro‐2H‐pyran‐2‐yloxy)alkyl]tin(IV) compounds

The reaction of SnPh₃Li with X(CH₂)_n O–THP (THP = tetrahydro‐2H ‐pyran‐2‐yl; n  = 3, 4, 6, 8, 11; X = Cl, Br) afforded organotin(IV) compounds with the general formula Ph₃Sn(CH₂)_n O–THP ( 1 – 5 ). The tetraorganotin(IV) compounds were characterized using multinuclear NMR and infrared spectroscopies and high‐resolution mass spectrometry. Anticancer activity of the synthesized compounds was tested in vitro against the A2780 (ovarian), A549 (lung), HeLa (adenocarcinoma) and SW480 (colon) tumour cell lines with SRB assay. The in vitro investigations revealed that when a shorter chain was present a higher activity was achieved; however compounds 1 – 5 were found to be less active than cisplatin. In addition, the most active compound, 1 , enters A2780 cells and causes apoptosis by triggering both intrinsic and extrinsic caspase pathways.     

Synthesis and Structural Characterization of Metal Complexes of 2‐Formylpyrrole‐4N‐ethylthiosemicarbazone (4 EL1) and 2‐Acetylpyrrole‐4N‐ethylthiosemicarbazone (4 EL2)

The reactions of ⁴N‐ethyl‐2‐[1‐(pyrrol‐2‐yl)methylidene(hydrazine carbothioamide ( 4 EL₁ ) and ⁴N‐ethyl‐2[1‐(pyrrol‐2‐yl)ethylidene(hydrazine carbothioamide ( 4 EL₂ ) with Group 12 metal halides afforded complexes of types [M(L)₂X₂] (M = Zn, Cd; L = 4 EL₁, 4 EL₂; X = Cl, Br, I; 1 – 6 , 14 – 19 ) and [M(L)X₂] (M = Hg; L = 4 EL₁, 4 EL₂; X = Cl, Br, I; 7 – 9 , 20 – 22 ). In addition, reaction of 4 EL₁ with salts of Cu^II, Ni^II, Pd^II and Pt^II afforded compounds of type [M(4 EL₁–H)₂] ( 10 – 13 ). The new compounds were characterized by elemental analysis, FAB mass spectrometry, IR and electronic spectroscopy and, for sufficiently soluble compounds, ¹H, ¹³C and, when appropriate, ¹¹³Cd or ¹⁹⁹Hg NMR spectrometry. The spectral data suggest that in their complexes with Group 12 metal cations, both thiosemicarbazones are neutral and S‐monodentate; and for [Zn(4 EL₁)₂I₂] ( 3 ), [Cd(4 EL₁)₂Br₂] ( 5 ) and [Hg(4 EL₁)Cl₂]₂ ( 7 ) this was confirmed by X‐ray diffractometry. By contrast, in its complexes with Cu^II and Group 10 metal cations, 4 EL₁ is monodeprotonated and S,N‐bidentate, as was confirmed by X‐ray diffractometry for [Ni(4 EL₁–H)₂] ( 11 ) and [Pd(4 EL₁–H)₂] ( 12 ).     

Structural and Infrared Spectroscopic Studies of Some Adducts of Divalent Metal Dihalides (MX2, M = Zn,Cd; X = CI,Br, I) with Variously Hindered Monodentate Nitrogen (Pyridine) Base Ligands (L = Pyridine, 2‐Methylpyridine,and Quinoline) of 1:2 Stoichiometry

Single crystal X‐ray structure determinations are described for a number of adducts of 1:2 MX₂:L stoichiometry, [M = divalent metal (Zn, Cd); X = halide (Cl, Br, I), L = (variously hindered) monodentate nitrogen (pyridine) base: py = pyridine, 2‐mpy = 2‐methylpyridine, quin = quinoline]: [(2‐mpy)₂ZnX₂] (X = Cl, Br) (isotypic, triclinic P , a ≈? 7.9₆, b ≈? 8.7, c ≈? 11.4 Å, α ≈? 86, β ≈? 79.3, γ ≈? 67°, Z = 2), [(2‐mpy)₂ZnI₂], [(quin)₂ZnX₂] (X = Br) (isotypic with the previously determined chloride, X = Cl, triclinic, P , a ≈? 8.7, b ≈? 9.6, c ≈? 11.1 Å, α ≈? 81, β ≈? 73, γ ≈? 72°, Z = 2); [(quin)₂ZnI₂]; [(2‐mpy)₂CdX₂], X = Br {isotypic with [(2‐mpy)₂ZnX₂], X = Cl, Br (above)}, X = I {isotypic with [(2‐mpy)₂ZnI₂] (above)}; [(quin)₂CdI₂]. A single molecule, with a four‐coordinate quasi‐tetrahedral metal atom, N₂MX₂, comprises the asymmetric unit of the structure in each of these. A one‐dimensional polymer is found for [(quin)₂Cd(μ‐Cl)₂]_(∞‖∞), similar to those recorded previously for CdX₂:py (1:2) (X = Cl, Br, I), the cadmium atom here lying on a 2‐axis in tetragonal space group P 2₁c, and the quin ligands coordinating trans in a six‐coordinate array about the cadmium, with successive cadmium atoms being linked by pairs of bridging chlorines. Adducts of MX₂:L (1:1) stoichiometry, defined for M = Cd: [(2,4,6‐trimethylpyridine)Cd(μ‐I)₂]_(∞‖∞) and [(quin)Cd(μ‐Br)₂]_(∞‖∞), are both infinite one‐dimensional polymers … (μ‐X)₂Cd(L)(μ‐X)₂Cd(L) … , with five‐coordinate trigonal bipyramidal cadmium atoms, the nitrogen donors being equatorial in the coordination spheres. The far‐IR spectra of [L₂MX₂] (L = py, 2‐mpy, quin; M = Zn, Cd; X = Cl, Br, I) are assigned and discussed in relation to the structures of the complexes.     

Antibacterial Activities and Nuclease Properties of Two New Ternary Copper(II) Complexes with 2‐(4′‐Thiazolyl)‐benzimidazole and 2,2′‐Bipyridine/1,10‐phenanthroline

Two new complexes: [Cu(TBZ)(bipy)Cl]Cl·H₂O ( 1 ) and [Cu(TBZ)(phen)Cl]Cl·H₂O ( 2 ) [TBZ=2‐(4′‐thiazolyl)‐ benzimidazole, phen=1,10‐phenanthroline and bipy=2,2′‐bipyridine] have been synthesized and characterized by elemental analysis, molar conductivity, IR, and UV‐vis methods. Complex 2 , structurally characterized by single‐crystal X‐ray crystallography, crystallizes in the monoclinic space group P2₁/c in a unit cell of a=0.85257(12) nm, b=2.5358(4) nm, c=1.15151(13) nm, β=118.721(8)°, V=2.183.2(5) nm³, Z=4, D_c=1.624 g·cm⁻³, µ=1.367 mm⁻¹. The complexes, free ligands and chloride copper(II) salt were each tested for their ability to inhibit the growth of two gram‐positive (B. subtilis and S. aureus) and two gram‐negative (Salmonella and E. coli) bacteria. The complexes showed good antibacterial activities against the microorganisms. The interaction between the complexes and calf thymus DNA in aqueous solution was investigated adopting electronic absorption spectroscopy, fluorescence spectroscopy, viscosity measurements and cyclic voltammetry. Results suggest that the two complexes can bind to DNA by intercalative mode. In addition, the result of agarose gel electrophoresis suggested that the complexes can cleave the plasmid DNA at physiological pH and room temperature. Mechanistic studies with different inhibiting reagents reveal that hydroxyl radicals, and a singlet oxygen‐like copper‐oxo species are all involved in the DNA scission process mediated by the complexes.     

Synthesis and Characterization of Copper(I) Complexes Containing Tri(2‐Pyridylmethyl)Amine Ligand

Reaction of copper halides CuX (X=Cl, Br, I) with tri(2‐pyridylmethyl)amine) (TPMA) in THF under N₂ affords a series of monomeric copper(I) complexes CuX(TPMA) (X=Cl ( 1 ), Br ( 2 ) and I ( 3 )). Treatment of [CuCl(TPMA)] ( 1 ) with 0.5 equivalent of 1,4‐diisocyanobenzene following by equimolar amount of NaBF₄ affords a novel binuclear complex [(TPMA)Cu(μ‐1,4‐CNC₆H₄NC)Cu(TPMA)](BF₄)₂ ( 4 ). The copper(I) halide TPMA complexes show interesting fluxional behaviors in temperature dependence in the ¹H NMR spectrum that can be explained by the dissociation and reassociation of the pyridyl group and alkylamine nitrogen of TPMA ligand. The crystal structures of 1 , 3 and 4 are determined by an X‐ray diffractometer. Complexes 1 and 3 are distorted tetrahedral coordinates with strong bonding between three pyridyl N atoms and the corresponding halide donor. Crystallographic results of 4 clearly indicates two Cu(I) ions are bridged by 1,4‐diisocyanobenzene, forming a centro‐symmetrical homobinuclear complex with a “dangling” uncoordinated pyridyl group.     

Tricarbonylrhenium(I) and -technetium(I) complexes with bis(2-pyridyl)phenylphosphine and tris(2-pyridyl)phosphine

(NEt₄)₂[Re(CO)₃Br₃] or (NEt₄)₂[Tc(CO)₃Cl₃] react with bis(2-pyridyl)phenylphosphine (PPhpy₂) or tris(2-pyridyl)phosphine (Ppy₃) under formation of neutral tricarbonyl complexes of the composition [M(CO)₃X(L)] (M = Re, X = Br; M = Tc, X = Cl; L = PPhpy₂ or Ppy₃). In all isolated products, the ligands coordinate solely via two of their nitrogen atoms. All attempts to force a tripodal coordination of the phosphinopyridines failed. Removal of the bromo ligands from (NEt₄)₂[Re(CO)₃Br₃] by the addition of AgNO₃ in THF/water, and subsequent reaction of the resulting [Re(CO)₃(THF)₃](NO₃)with Ppy₃ yielded the complex [Re(CO)₃(NO₃)(Ppy₃-N,N′)] with a monodentate coordinated nitrato ligand. The products have been characterized spectroscopically and by X-ray structure analyses.     

Structural and Coordinative Variability in Zinc(II), Cadmium(II), and Mercury(II) Complexes of 2‐Pyridineformamide 3‐Hexamethyleneiminylthiosemicarbazone

Sodium in dry methanol reduces 2‐cyanopyridine in the presence of 3‐hexamethyleneiminylthiosemicarbazide and produces 2‐pyridineformamide 3‐hexamethyleneiminylthiosemicarbazone, HAmhexim ( 1 ). Complexes with zinc(II ), cadmium(II ) and mercury(II ) have been prepared and characterized by spectroscopic techniques. In addition, the crystal structures of HAmhexim ( 1 ), [Zn(Amhexim)(OAc)]₂μ·μDMSO ( 2 ), [Cd(HAmhexim)Cl₂]μ·μDMSO ( 7 ), [Cd(Amhexim)₂] ( 8 ), [Cd(HAmhexim)Br₂]μ·μDMSO ( 9 ), [Cd(HAmhexim)I₂]μ·μEtOH ( 10 ), [Hg(HAmhexim)Cl₂]μ·μDMSO ( 11 ), [Hg(Amhexim)Br]₂ ( 13 ), [Hg₃(HAmhexim)(Amhexim)Br₅]μ·μH₂O ( 14 ) and [Hg(Amhexim)I]₂ ( 15 ) have been determined. Coordination of the anionic and neutral thiosemicarbazone ligand occurs through the pyridine nitrogen atom, imine nitrogen atom, and thiolato or thione sulfur atom. In [Zn(Amhexim)(OAc)]₂ one of the bridging acetato ligands has monodentate coordination and the other bridges in a bidentate manner. [Cd(Amhexim)₂] is a 6‐coordinate species while the other cadmium complexes are 5‐coordinate. In [Hg(Amhexim)Br]₂ and [Hg(Amhexim)I]₂ the thiolato sulfur atoms act as bridges between the Hg atoms to form dimeric compounds and [Hg₃(HAmhexim)(Amhexim)Br₅]μ·μH₂O is a trinuclear complex with three different centers — two metallic centers have a 5‐coordination and the another one has 4‐coordination. In addition, [Hg(HAmhexim)Cl₂]μ·μDMSO and [Hg₃(HAmhexim)(Amhexim)Br₅]μ·μH₂O shown a supramolecular one‐dimensional hydrogen‐bonded self‐assembling.     

Synthesis and characterization of three dinuclear copper(I) complexes of 1,2‐bis(diphenylphosphino)‐1,2‐dicarba‐closo‐dodecaborane

Three dinuclear copper(I) complexes, [Cu₂(µ‐Cl)₂(1,2‐(PPh₂)₂‐1,2‐C₂B₁₀H₁₀)₂]·2CH₂Cl₂ ( 1 ), [Cu₂(µ‐Br)₂(1,2‐(PPh₂)₂‐1,2‐C₂B₁₀H₁₀)₂]·2THF ( 2 ) and {Cu₂(µ‐I)₂[1,2‐(PPh₂)₂‐1,2‐C₂B₁₀H₁₀]₂} ( 3 ) have been synthesized by the reactions of CuX (X = Cl, Br and I) with the closo ligand 1,2‐(PPh₂)₂‐1,2‐C₂B₁₀H₁₀. All these complexes were characterized by elemental analysis, FT‐IR, ¹H and ¹³C NMR spectroscopy and X‐ray structure determination. Single crystal X‐ray structure determinations show that every complex contained di‐µ‐X‐bridged structure involving a crossed parallelogram plane formed by two Cu atoms and two X atoms (X = Cl, Br, I). The geometry at the Cu atom was a distorted tetrahedron, in which two positions were occupied by two P atoms of the PPh₂ groups connected to the two C atoms of carborane (Cc), and the other two resulted from two X atoms which bridged the other Cu atom at the same time. To the best of our knowledge, this is the first example of copper(I) complexes with 1,2‐diphenylphosphino‐1,2‐dicarba‐closo‐dodecaborane as ligand characterized by X‐ray diffraction. The catalytic property of the complex 3 for the amination of iodobenzene with aniline was also investigated. Copyright © 2005 John Wiley & Sons, Ltd.