Copper(I) Complexes of Bithiazoles

Several new copper(I) complexes of a group of bidentate bithiazole ligands have been isolated. The compounds prepared are bis(2,2′-dimethyl-4,4′-bithiazole)copper(I) perchlorate ([Cu(me-b)₂]ClO₄), bis(4,4′-dimethyl-2,2′-bithiazole)copper(I) perchlorate ([Cu(me-i)₂]ClO₄), bis(2,2′-diphenyl-4,4′-bithiazole) copper(I) perchlorate ([Cu(ph-b)₂]ClO₄), bis(4,4′-diphenyl-2,2′-bithiazole)copper(I) perchlorate ([Cu(ph-i)₂]ClO₄), bis(4,4′,5,5′-tetraphenyl-2,2′-bithiazole)-copper(I) perchlorate ([Cu(ph₄-i)₂]ClO₄, bis(2,2′-bithiazole)copper(l) perchlorate ([Cu(i)₂]CIO₄), 2,2′-bithiazolecopper(I) perchlorate ([Cu(i)ClO₄), (2,2′-bithiazole)bis(triphenylphosphinesulfide)copper(I) perchlorate ([Cu(i)(SPph₃)₂]ClO₄,(2,2′-bithiazole)bis-( triphenylphosphine)copper(I) perchlorate ([Cu(i)(Pph₃)₂]ClO₄), and (4,4′-bithiazole)bis(triphenylphosphine) copper(I) perchlorate ([Cu(b)(Pph₃)₂]ClO₄). Several synthetic techniques were required including one developed in this work which involved the conversion of [Cu(Pph₃)₄]ClO₄ into the thiophosphine complex by reaction with sulfur and subsequent use of this as a labile precursor complex. Optical spectra of the complexes indicate extensive solution dissociation. Several of the complexes ([Cu(ph-b)₂]ClO₄, [Cu(ph-i)₂]CIO₄, and [Cu(i)(Pph₃]ClO₄) were photoluminescent in the solid; one ([Cu(ph-b)₂]ClO₄) showed extensive loss of emission during irradiation. Most of the complexes prepared here appear to bind through the thiazole nitrogen atoms. However, infrared evidence suggests that in two of the complexes thiazole sulfur atoms participate in the bonding.     

Mercury(II) and Lead(II) complexes with 2,2′-Bis (4,5-dimethylimidazole) – syntheses,characterization and crystal structures of [M(DmImH)(SCN)2], (M = Hg2+ and Pb2+ )

Mercury(II) and lead(II) complexes with 2,2′-bis(4,5-dimethylimidazole) (DmImH), [Hg(DmImH)(SCN)₂] and [Pb(DmImH)(NCS)₂], have been synthesized and characterized by IR specta and elemental analyses. The molecular structure of [Pb(DmImH)(NCS)₂] _n is polymeric with four-coordinate lead atoms. The [Hg(DmImH)(SCN)₂] complex is built up of monomeric Hg(SCN)₂ units with one “DmImH” ligand coordinated to the Hg atom via the two N atoms in a distorted tetrahedral environment. The thiocyanate ligands are coordinated to lead via nitrogen, but to mercury via the sulfur. There are π–π stacking interactions between the parallel aromatic rings in the mercury(II) complex.     

Lead(II) complexes of 2,2′-diamino-4,4′-bithiazole (DABTZ) including crystal structure of a novel 1D chain polymer, [PB(DABTZ)(μ-SCN)(μ-NO3)] n

Three new 2,2′-diamino-4,4′-bithiazole (DABTZ) lead(II) complexes were synthesized and characterized by elemental analyses, IR-, ¹H-NMR-, and ¹³C-NMR-spectroscopy. The single crystal X-ray structural analysis of [Pb(DABTZ)(μ-SCN)(μ-NO₃)] _n shows the complex to be a 1D chain polymer as a result of sequential thiocyanate and nitrate bridging. The Pb atoms are seven-coordinated by two nitrogen atoms of the 2,2′-diamino-4,4′-bithiazole, three nitrate and two thiocyanate ligands. The arrangement of the 2,2′-diamino-4,4′-bithiazole, nitrate and thiocyanate ligands does not suggest a gap in the coordination around the Pb^II ion, caused by a stereo-active lone pair of electrons on lead(II) where the coordination around the lead atoms is the less common holodirected.     

Synthesis,characterization, and crystal structure determination of Cu(II) coordination compounds with 2,2′-dimethyl-4,4′-bithiazole

[{CuCl(dm4bt)}₂ μ-Cl)₂] (1) (dm4bt = 2,2′-dimethyl-4,4′-bithiazole) was prepared from the reaction of CuCl₂ · 2H₂O with 2,2′-dimethyl-4,4′-bithiazole in methanol; [Cu(dm4bt)₂NO₃](NO₃) (2) was prepared from the reaction of Cu(NO₃)₂ · 3H₂O with 2,2′-dimethyl-4,4′-bithiazole in methanol. Both complexes were characterized by IR, UV–Vis spectroscopy, and single-crystal structure. The structure of 1 consists of centrosymmetric dimeric [{CuCl(dm4bt)}(μ-Cl)], in which two chloro ligands bridge the coppers forming a four-membered ring; a terminal chloride and a bidentate chelating bithiazole complete five coordination at each Cu(II) in a highly distorted trigonal-bipyramidal geometry. The mononuclear structure 2 consists of a Cu(II), two 2,2′-dimethyl-4,4′-bithiazoles, one monodentate nitrate and one uncoordinated nitrate in a highly distorted square pyramid.     

Zinc(II), Cadmium(II), and Mercury(II) Complexes with the 2, 2′‐Diamino‐4, 4′‐bithiazole (DABTZ) Ligand — Syntheses and X‐Ray Crystal Structure of [Hg(DABTZ)(SCN)2]

Reaction of the ligand 2, 2′‐diamino‐4, 4′‐bithiazole (DABTZ) with Zn(ClO₄)₂, CdCl₂, and Hg(SCN)₂ gives complexes with composition [Zn(DABTZ)₂](ClO₄)₂, [Cd(DABTZ)₂Cl₂], and [Hg(DABTZ)(SCN)₂]. The complexes were characterized by elemental analyses and infrared spectroscopy. The crystal structure of the [Hg(DABTZ)(SCN)₂] was determined by X‐ray crystallography. The complex is built up of a monomeric Hg(SCN)₂ unit with one 2, 2′‐diamino‐4, 4′‐bithiazole ligand coordinated to the Hg atom via the two N atoms giving rise to a five‐member chelate ring in a distorted tetrahedral environment. There is π‐π stacking interaction between the parallel aromatic rings belonging to adjacent chain as planar species in which the mean molecular planes are close to parallel and separated by a distance of ～ 3.5Å, close to that of the planes in graphite. The coordinated 2, 2′‐diamino‐4, 4′‐bithiazole molecule is involved in hydrogen bonding acting as hydrogen‐bond donors with N atoms from the SCN ligand as potential hydrogen‐bond acceptors. The hydrogen bonding yields infinite chains parallel to the crystallographic vectors a and b. Each molecule is bonded to three neighbours. Both amine H atoms are hydrogen bonded to N atoms.     

Synthesis,characterization and fluorescence spectra of mixed ligand Zn(II), Cd(II) and Hg(II) complexes with 1,10-phenanthroline-5,6-dione ligand

The novel mixed ligand complexes [M(bpy)(phen-dione)](PF₆)₂ (M?=?Zn(II), Cd(II) and Hg(II), bpy?=?2,2^′-bipyridine and phen-dione?=?1,10-phenanthroline-5,6-dione) have been synthesized and characterized by elemental analysis, IR, ¹H NMR and electronic absorption spectroscopies. The ν(C=O) of coordinated phen-dione in these complexes are very similar to the free phen-dione ligand showing that phen-dione is not coordinated to metal ion from its C=O sites. Absorption spectra of the complexes show two absorption bands for intraligand transitions. These absorption bands show dependence to the dielectric constant of solvent. These complexes exhibit an intensive fluorescence band around 535?nm in DMF when the excitation wavelength is 260?nm at room temperature. The fluorescence intensity of these complexes is larger than that of the free ligand.     

Synthesis, crystal structure, spectroscopic and photoluminescence studies of manganese(II), cobalt(II), cadmium(II), zinc(II) and copper(II) complexes with a pyrazole derived Schiff base ligand

Varying coordination modes of the Schiff base ligand H₂L [5-methyl-1-H-pyrazole-3-carboxylic acid (1-pyridin-2-yl-ethylidene)-hydrazide] towards different metal centers are reported with the syntheses and characterization of four mononuclear Mn(II), Co(II), Cd(II) and Zn(II) complexes, [Mn(H₂L)(H₂O)₂](ClO₄)₂(MeOH) (1), [Co(H₂L)(NCS)₂] (2), [Cd(H₂L)(H₂O)₂](ClO₄)₂ (3) and [Zn(H₂L)(H₂O)₂](ClO₄)₂ (4), and a binuclear Cu(II) complex, [Cu₂(L)₂](ClO₄)₂ (5). In the complexes 1-4 the neutral ligand serves as a 3N,2O donor where the pyridine ring N, two azomethine N and two carbohydrazine oxygen atoms are coordinatively active, leaving the pyrazole-N atoms inactive. In the case of complex 5, each ligand molecule behaves as a 4N,O donor utilizing the pyridine N, one azomethine N, the nitrogen atom proximal to the azomethine of the remaining pendant arm and one pyrazole-N atom to one metal center and the carbohydrazide oxygen atom to the second metal center. The complexes 1-4 are pentagonal bipyramidal in geometry. In each case, the ligand molecule spans the equatorial plane while the apical positions are occupied by water molecules in 1, 3 and 4 and two N bonded thiocyanate ions in 2. In complex 5, the two Cu(II) centers have almost square pyramidal geometry (τ = 0.05 for Cu1 and 0.013 for Cu2). Four N atoms from a ligand molecule form the basal plane and the carbohydrazide oxygen atom of a second ligand molecule sits in the apex of the square pyramid. All the complexes have been X-ray crystallographically characterized. The Zn(II) and Cd(II) complexes show considerable fluorescence emission while the remaining complexes and the ligand molecule are fluorescent silent.     

OBSERVATIONS ON THE CONFORMATION OF IMINODIACETATE(2-) ION IN MIXED LIGAND COPPER(II) COMPLEXES WITH NITROGEN HETEROCYCLES AS SECONDARY LIGANDS. CRYSTAL STRUCTURE OF (2,2′-BYPIRIDINE)(IMINODIACETATO)COPPER(II) HEXAHYDRATE

Abstract

(2,2′-Bipyridine)(iminodiacetato)copper(II) hexahydrate, [Cu(IDA)(2,2′-bipy)]·6H₂O, has been obtained and studied by X-ray diffraction. The compound (triclinic system, space group P1, Z = 2; R = 0.036 and R = 0.040 for 7541 independent reflections) consists of asymmetric dinuclear entities, [Cu(IDA)(2,2′-bipy)]₂, and uncoordinated H₂O molecules in a hydrogen bonding network. Both Cu(II) atoms of each dinuclear entity are chemically very similar. Each Cu(II) atom exhibits a flattened, square pyramidal coordination. Two N atoms of 2,2′-bipy and the N and one O atoms of IDA are at the square base; another O atom of the same terdentate IDA is at the apical position. Two weak interactions between each Cu(II) atom and one O atom from IDA which chelates the second contribute to the dinuclear entity. On the basis of these results and the known structure of other Cu(II) complexes with IDA and imidazole or 4,4′-bipy, an attempt to rationalize the nearly coplanar or perpendicular conformation of the two five-membered IDA-Cu(II) chelate rings in such mixed-ligand copper(II) complexes is made.     

Synthesis and magnetic properties of binuclear cobalt(Ⅱ), nickel(Ⅱ) and copper(Ⅱ) complexes bridged by oxamidate group

Four binuclear Co(Ⅱ), Ni(Ⅱ) and Cu(Ⅱ) complexes bridged by oxamidate (oxd) group have been synthesized, namely Co2(byp)2(oxd)(ClO4)2 (1), Co2(Me2bpy)2(oxd)(ClO4)2.H2O (2), Ni2(bpy)2(oxd)(ClO4)2.2H2O (3) and Cu2(Me2bpy)2(oxd)(NO3)2 (4). (bpy=2,2'-bipyridyl, Me2-bpy=4,4'-dimethylbipyridyl, oxd=oxamidate) The complexes are characterized by IR, UV spectra, EPR and variable-temperature magnetic susceptibility (4-300 K). The susceptibility data for. complexes 1 and 3 were least-squares fit to the susceptibility equation derived from the spin Hamiltonian H=-2J . S1 . S2. The exchange integral, J, was found to be equal to -3.62 cm-1 in 1 and -1.82 cm-1 in 3. This indicates a weak antiferromagnetic spin exchange interaction between the metal ions.     

Synthesis and Characterization of Heteroleptic Ru(II) Complexes Based on 4,4′‐Bis((E)‐styryl)‐2,2′‐bipyridine as Ancillary Ligand and Application for Dye‐Sensitized Solar Cells

Heteroleptic Ru(II) complexes were designed based on 4,4′‐bis((E)‐styryl)‐2,2′‐bipyridine (bsbpy) as an ancillary ligand for dye‐sensitized solar cells (DSSCs), and those Ru(II) sensitizers, [Ru(L)(bsbpy)(NCS)₂][TBA] (TBA; tetrabutylammonium), were synthesized according to a typical one‐pot reaction of [RuCl₂(p‐cymene)]₂ with the corresponding anchoring ligands (where L = 4,4′‐dicarboxy‐2,2′‐bipyridine (dcbpy), 4,4′‐bis((E)‐carboxyvinyl)‐2,2′‐bipyridine (dcvbpy), 4,7‐dicarboxy‐1,10‐phenanthroline (dcphen), or 4,7‐bis((E)‐carboxyvinyl)‐1,10‐phenanthroline (dcvphen)). The new Ru(II) dyes, [Ru(L)(bsbpy)(NCS)₂][TBA] that incorporated vinyl spacer(s) into ancillary and/or anchoring ligand displayed red‐shifted bands over the overall UV/VIS region relative to the absorption spectra of N719 . A combination of bsbpy ancillary and dcphen anchoring ligand showed the best result for the overall power conversion efficiency (η); i.e., a DSSC fabricated with [Ru(dcphen)(bsbpy)(NCS)₂][TBA] exhibited a power conversion efficiency (η) of 2.98% (compare to N719 , 4.82%).     

Structural and solution studies of new cadmium(II) complexes with 2,2′-diamino-4,4′-bithiazole

Two new Cd(II) complexes, [Cd(DABT)(CH₃COO)₂] (1) and [Cd(DABT)(NO₃)₂] (2), DABT = 2,2′-diamino-4,4′-bithiazole, have been synthesized and characterized by single crystal X-ray crystallography. In 1, each cadmium is chelated by two nitrogens of one DABT and four oxygens of acetate, whereas 2 is a dinuclear complex and there are two Cd's with eight and six coordination: Cd₁O₆N₂ and Cd₂O₄N₂ units. The counter ion effect of the complex formation reaction between cadmium(II) nitrate and acetate with DABT has been studied by spectroscopy. The formation constants of the 1 : 1 and 1 : 2 (metal ion to ligand) complexes were evaluated by computer fitting of the absorbance–mole ratio data.     

Synthesis and characterization of lead(II) complexes with substituted 2,2′-bipyridines,trifluoroacetate, and furoyltrifluoroacetonate

Two substituted 2,2′-bipyridine lead(II) complexes, [Pb(5,5′-dm-2,2′-bpy)(tfac)₂] _n (1) (5,5′-dm-2,2′-bpy?=?5,5′-dimethyl-2,2′-bipyridine and tfac?=?trifluoroacetate) and [Pb₂(4,4′-dmo-2,2′-bpy)₂(ftfa)₄] (2) (4,4′-dmo-2,2′-bpy?=?4,4′-dimethoxy-2,2′-bipyridine and ftfa?=?furoyltrifluoroacetonate), have been synthesized and characterized by elemental analysis, IR, ¹H NMR, and ¹³C NMR spectroscopies, thermal behavior, and X-ray crystallography. Complexes 1 and 2 are 1D coordination polymer and dinuclear complex, respectively. The supramolecular features in these complexes are guided by weak directional intermolecular interactions.     

Synthesis, characterization, antitumor activity of nickel(Ⅱ) and cobalt (Ⅱ) complexes of 2,2''''-diamino-4,4''''-bithiazole and their interaction with dGMP

New complexes,of bis(2,2'-diamino-4,4'-bithiazole)sulfate nickel(Ⅱ) and bis(2,2'-diami-no-4,4'-bithiazole)sulfate cobalt(Ⅱ),have been prepared.The complexes were characterized by infrared and UV-Vis spectroscopy,1H NMR,elemental analyses and molar conductivity.The effect of these complexes on the DNA synthesis of sarcoma 180 cells has been studied by the technique of isotopic liquid scintillation.The results indicated that complexes show ability to inhibit DNA synthesis of the tumor cells.In order to provide a molecular basis for understanding the biological effects,the probe,[trana-en2Os(η2-H2)](CF3SO3)2 (en,ethylenediamine) as a monitor was first used to explore interaction of the complexes with 2'-deoxyguanosine-5'-monophosphate (dGMP).     

Synthesis and characterization of new HgS nanoparticles prepared by Hg(II)-triazole-3-thiol as precursor

Nine Hg(II) complexes, [Hg(DiphtS)₂(L-L)](2–7) {where, HDiphtS = 4,5-diphenyl-1,2,4-triazole-3-thiol; L-L = bis(diphenylphosphino)ethane (dppe) (2); 1,3-bis(diphenylphosphino)propane (dppp)(3); 1,4-bis(diphenylphosphino)butane (dppb)(4); 1,1′-bis(diphenylphosphino)ferrocene (dppf)(5); 2,2′-bipyridine (Bipy)(6) and 1,10-phenanthroline (Phen)(7) } or [Hg(DiphtS)₂(L)₂] (8–9) {where L = triphenylphosphine (Ph₃P) (8) and triphenylphosphine sulphide (Ph₃PS) (9)}, have been prepared form the reaction of [Hg(DiphtS)₂](1) with phosphine or amine as co-ligands. Then characterized by the IR, NMR (¹H and ³¹P) spectroscopy, elemental analysis, molar conductivity. The results supported the monodentate behaviour of HDiphtS ligand in all complexes (1–9) in anion form through the sulfur atom. Complexes 1, 2 and 6 have been used as single source precursors for the preparation of ethylene-diamine capped HgS-nanoparticles. Powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM), have been used to characterize the HgS nanoparticles.     

Synthesis,characterization, and anticancer activity of some azole‐heterocyclic complexes with gold(III), palladium(II), nickel(II), and copper(II) metal ions

Four new complexes of Au(III), Pd(II), Ni(II), and Cu(II) ions were synthesized, derived from a novel heterocyclic ligand (L) that has both triazole and tetrazole rings. The ligand synthesis was through successive steps to achieve both heterocyclic rings. The synthesized compounds were characterized using conventional techniques like infrared, ultra violet—visible and proton/carbon nuclear magnetic resonance spectroscopy, metal and thermal analyses, and molar conductivity. All complexes were suggested to have square planar geometry, gold, nickel, and palladium complexes were salts while copper neutral complexes have the chemical formulas; [AuL₂]Cl.2H₂O, [PdL₂]Cl₂.2H₂O, [NiL₂]Cl₂.2H₂O, and [CuL₂]. The cytotoxic effect was studied on breast cancer cell line (MCF‐7 cell line) at different concentrations by using the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay method, for the ligand (L) and complexes. The results showed that gold(III) and nickel(II) complexes have the highest cytotoxicity among all compounds against cancer cell lines.     

ZnII and HgII complexes of 2,2′-diamino-4,4′-bis(1,3-thiazole) (DABTZ), spectroscopic,thermal and structural studies

New zinc(II) and mercury(II) complexes of 2,2′-diamino-4,4′-bis(1,3-thiazole) (DABTZ), [M(DABTZ)(CH₃COO)₂], have been synthesized and characterized by elemental analysis, IR-, ¹H NMR-, ¹³C NMR spectroscopy and studied by thermal analysis and X-ray crystallography. The structural characterization of the [Zn(DABTZ)(CH₃COO)₂] complex shows the complex to be a monomer and the Zn coordinated by two nitrogen atoms of the “DABTZ” ligand and four oxygen atoms of the acetate anions.     

Syntheses and characterization of three mercury(II) complexes, [Hg(phen)2(SCN)2], [Hg(2,2′-bipy)2(SCN)2] and [Hg(phen)2(NO3)2], thermal and fluorescence studies

Mercury(II) complexes of 1,10-phenanthroline (phen) and 2,2′-bipyridine (bipy), [Hg(phen)₂(SCN)₂] (1), [Hg(2,2′-bipy)₂(SCN)₂] (2) and [Hg(phen)₂(NO₃)₂] (3) have been synthesized and characterized by elemental analysis, IR, ¹H NMR and ¹³C NMR spectroscopy. The thermal stability of 1–3 were studied by thermal gravimetric (TG) and differential thermal analyses (DTA). The structure of 1 has been confirmed by X-ray crystallography. The complex is a monomer and the Hg atom has an unsymmetrical six-coordinate geometry, formed by four nitrogen atoms of the two phen ligands and two sulfur atoms of the two thiocyanate anions. Solid-state luminescent spectra of phen, 2,2′-bipy and 1–3 indicate emission with the maximum intensity at ca 467 nm upon excitation at 295 nm.     

Syntheses and Characterization of Zinc,Cadmium, and Mercury(II) Complexes with N‐(2‐pyridyl)carbonylaniline (L), X‐ray Crystal Structure of [Hg(L)(SCN)2]

The reaction of N‐(2‐pyridyl)carbonylaniline (L) with Zn(NO₃)₂, CdCl₂, and Hg(SCN)₂ gives the following complexes: [Zn(L)₂](NO₃)₂, [Cd(L)₂Cl₂], and [Hg(L)(SCN)₂]. The new complexes were characterized by elemental analyses and IR‐, ¹H‐, ¹³C‐NMR spectroscopy. The crystal structure of the [Hg(L)(SCN)₂] was determined by single crystal X‐ray analysis. The monomeric complex is built up of a Hg(SCN)₂ unit with one N‐(2‐pyridyl)carbonylaniline (L) ligand coordinated to the Hg atom via the ring pyridinic nitrogen atom and the carbonyl oxygen atom forming a five‐membered chelate ring. The Hg atom has a distorted tetrahedral environment. There is π‐π stacking interaction between the parallel aromatic rings belonging to adjacent chain as planar species in which the mean molecular planes are close to parallel and separated by a distance of ～ 3.5Å, close to that of the planes in graphite. The coordinated N‐(2‐pyridyl)carbonylaniline (L) molecule is involved in hydrogen bonding acting as hydrogen‐bond donors with S and N atoms from SCN^— ligand as potential hydrogen‐bond acceptors. There is a shortest intermolecular contacts between the S and N atoms. The hydrogen bonding and shortest intermolecular contacts between the S and N atoms yields infinite chains parallel to the crystallographic vector c. Each molecule is bonded to two neighbors.     

Equilibrium and spectroscopic studies of ternary cadmium(II) and mercury(II) complexes with CMP and triamines

Formation of ternary Cd(II) and Hg(II) complexes with cytidine 5′-monophosphate (CMP) and triamines has been studied. Complexes M(CMP)(H _x PA) and M(CMP)(PA) (M?=?Cd, Hg; PA?=?polyamine) were detected and overall stability constants and equilibrium constants for their formation determined. The mode of coordination in the complexes has been proposed on the basis of the equilibrium and ¹³C, ³¹P NMR and IR studies. In the Hg(II) systems, metalation involves the donor endocyclic N(3) atom, the CMP phosphate group and nitrogen donor atoms of PA. Relative to the Hg/CMP binary systems, the presence of a polyamine in ternary systems does not change the metal–nucleotide mode of coordination. In ternary systems including Hg(II) ions, the occurrence of noncovalent interactions has not been detected. Cd(II) ions form molecular complexes as well as protonated species. Introduction of a polyamine to the Cd/CMP system changes the coordination mode of the nucleotide. The phosphate group of CMP is inactive in binary complexes (metalation by the N(3) atom) but is involved in coordination in heteroligand species. In contrast to other polyamines studied, in the system including 1,7-diamino-4-azaheptane (3,3-tri), the phosphate group of CMP in Cd(CMP)(H3,3-tri) does not participate in metalation but is engaged in intramolecular noncovalent interactions that stabilize the complex.