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1.  (Acetato-κO)(acetato-κO,O′)bis­(1,3-diazinane-2-thione-κS)cadmium(II) 
In the title complex, [Cd(CH3COO)2(C4H8N2S)2], the CdII cation is coordinated by three acetate O atoms and two S atoms of Diaz [Diaz = 1,3-diazinane-2-thione = 3,4,5,6-tetra­hydro­pyrimidine-2(1H)-thione]. The CdII coordination is augmented by one considerably longer Cd—O bond of 2.782 (3) Å to a carboxyl­ate O atom. The resulting coordination polyhedron around the CdII cations can be described as a highly distorted octa­hedron. The Diaz ligand and the acetate anions are linked by N—H⋯O hydrogen-bonding inter­actions.
PMCID: PMC3515111  PMID: 23284338
2.  [4,6-Dimethyl­pyrimidine-2(1H)-thione-κS]iodidobis(triphenyl­phosphane-κP)copper(I) 
In the mononuclear title complex, [CuI(C6H8N2S)(C18H15P)2], the CuI ion is in a slightly distorted tetra­hedral coordination geometry formed by two P atoms from two triphenyl­phosphane ligands, one S atom from a 4,6-dimethyl­pyrimidine-2(1H)-thione ligand and one iodide ion. There is an intra­molecular N—H⋯I hydrogen bond. In the crystal, π–π stacking inter­actions [centroid–centroid distance = 3.594 (1) Å] are observed.
PMCID: PMC3379106  PMID: 22719327
3.  The syntheses and structures of ‘3+2’ and ‘2+2+1’ oxorhenium mixed-ligand complexes employing 8-hydroxy-5-nitroquinoline as the bidentate N,O donor ligand 
Inorganica chimica acta  2000;308(1-2):80-90.
The syntheses and structural characterizations of a series of novel ‘3+2’ and ‘2+2+1’ mixed-ligand complexes carrying 8-hydroxy-5-nitroquinoline (HL) as the bidentate N,O donor atom system are reported. Thus one-pot reactions of [ReOCl3(PPh3)2] with dianionic tridentate ligands H2Ln (where H2L1=HOC6H4-2-CH=NC6H4-2-OH; H2L2=HOC6H4-2-CH=N–C6H4-2-SH; H2L3=HOC6H4-2-CH=NN=C(NHC6H5)–SH; H2L4=2-CH2OH–C5H3N-6-CH2SH; and H2L5=2-CO2H–C5H3N-6-CO2H) and HL afforded a series of ‘3+2’ oxorhenium complexes of the type [ReO(H2Ln)(L)] 2–6, which exhibit distorted octahedral geometries. Crystals of 1 are monoclinic space group C2/c, a=16.702(1), b=14.275(1), c=22.363(2) Å, β=108.083(1)° V=5068.2(7) Åβ and Z=8; those of 2 are monoclinic space group P21/n, a=8.5093(4) b=38.518(2), c=11.6092(5) Å, β=97.708(1)°, V=3770.7(3) Å3 and Z=8; those of 5 are triclinic, space group P1−, a=7.5899(8), b=10.322(1), c=11.905(1) Å, α=78.636(2)°, β=74.229(2)°, γ=71.391(2)°, V=844.3(2) Å3, and Z=2. Upon reaction of 2,6-pyridinedimethanol (H2L6) with the intermediate complex [ReOCl2(L)(PPh3)] (1), only one of the two methylene hydroxy group was deprotonated and a new ‘2+2+1’ complex [ReO(OCH3)(HL6)(L)]·CH3OH (7) was obtained. Crystal data for 7: monoclinic P21/n, a=12.0579(6), b=11.0993(6), c=14.9262(8) Å, β=107.872(1)°, V=1901.2(2) Å3, and Z=8. In the preparation of complex 3, cleavage of the C=N bond of the Schiff base H2L2 was observed and the ‘2+2+1’ complex 8 [ReO(PPh3)(η2-NHC6H4-2-S)(L)]·CH2Cl2 having 2-aminothiophenol as a dianionic bidentate ligand was isolated. Crystals of 8 are monoclinic space group C2/c, a=25.627(2), b=8.1305(6) c=31.404(2) Å β=96.147(1)°, V=6505.7(8) Å3, and Z=8. Reduction of HL to 8-hydroxy-5-aminoquinoline was realized during the formation of complex 6, and a new complex 9 was thus isolated involving the coordination of two sets of N,O donor atoms from L and 8-hydroxy-5-aminoquinoline while a methoxy oxygen atom completes the octahedral coordination geometry. Crystals of 9 are monoclinic space group P21/n, a=7.5330(6), b=15.095(1), c=16.394(1) Å, β=99.690(2)°, V=1837.7(3) Å3, and Z=4.
PMCID: PMC2893356  PMID: 20592939
Crystal structures; Rhenium complexes; Oxo complexes; N,O donor ligand complexes
4.  trans-Di-μ-iodido-bis­[(3H-1,2-benzodithiole-3-thione)iodidomercury(II)] 
The complete molecule of the dinuclear title compound, [Hg2I4(C7H4S3)2], is generated by crystallographic inversion symmetry. The complex has a dimeric structure in which each HgII ion adopts a tetra­hedral geometry and is coordinated by two bridging I atoms, one terminal iodide ion and one thio­carbonyl S atom (C=S) of the ligand. The square plane formed by the Hg and I atoms and their symmetry counterparts makes a dihedral angle of 89.66 (3)° with the DDT plane. There is no classical hydrogen bonding, but weak S⋯S inter­actions of 3.4452 (7) and 3.6859 (7) Å maintain the cohesion of the crystal structure.
PMCID: PMC2970135  PMID: 21577433
5.  catena-Poly[μ2-iodido-diiodidobis(μ3-pyridine-2-thione-κ3 S:S:S)(μ2-pyridine-2-thione-κ2 S:S)tricopper(I)] 
In the title compound, [Cu3I3(C5H5NS)3]n, a polymeric structure is formed along [100] through bridging iodide and pyridine-2-thione ligands. The metal atoms are engaged in [Cu3S3] and [Cu2S2] rings sharing Cu—S edges, with the [Cu2S2] rings located about inversion centers. CuI atoms bridged by iodide ions exhibit the shortest Cu⋯Cu separation in the polymer [2.8590 (14) Å]. The three independent CuI atoms all display distorted tetra­hedral coordination geometries.
PMCID: PMC3569186  PMID: 23424430
6.  Penta­carbon­yl(imidazolidine-2-thione-κS)tungsten(0) 
In the title complex, [W(C3H6N2S)(CO)5], the W atom displays an octa­hedral coordination with five CO mol­ecules and an imidazolidine-2-thione mol­ecule. The W(CO)5 unit is coordinated by the cyclic thione ligand through a W—S dative bond. The W—S and C—S bond lengths are 2.599 (2) and 1.711 (9) Å, respectively. This last distance is significantly longer than that of free cyclic thio­ureas. The geometry of the title compound suggests sp 3-hybridization of the S atom caused by the greatly polarized linkage W—S—C bond angle, which is close to tetra­hedral [109.50 (3)°]. In the crystal packing, N—H⋯O and N—H⋯S hydrogen-bonding inter­actions stabilize the structure and build up chains parallel to [101].
PMCID: PMC2979448  PMID: 21579284
7.  Synthesis, spectroscopic, coordination and biological activities of some organometallic complexes derived from thio-Schiff base ligands 
Graphical abstract
Synthesis, spectroscopic, coordination and biological activities of some organometallic complexes derived from thio-Schiff base ligands
•Thio Schiff base complexes derived from mono- and diacetyl ferrocene were synthesized.•The complexes are characterized by different spectroscopic techniques.•The complexes have different varieties of geometrical structures.•Biochemical studies were studied.
Two series of mono- and binuclear complexes cyclic or acyclic thio-ferocine Schiff base ligands, derived from the condensation of 2-aminobenzenthiol (L) with monoacetyl ferrocene in the molar ratio 1:1 or in the molar ratio 1:2 for diacetyl ferocine have been prepared. The condensation reactions yield the corresponding Schiff Base ligands, HLa-Maf and H2Lb-Daf. The chelation of the ligands to metal ions occurs through the sulfur of the thiol group as well as the nitrogen atoms of the azomethine group of the ligands. HLa-Maf acts as monobasic bidentate or dibasic tetradentate, while H2Lb-Daf behaves as twice negatively cargend tetradentate ligand. The structures of these ligands were elucidated by elemental analysis, infrared, ultraviolet–visible spectra, as well as 1H NMR spectra. Reactions of the Schiff bases ligands with ruthenium(III), oxovanadium(IV) and dioxouranium(VI) afforded the corresponding transition metal complexes. The properties of the newly prepared complexes were analyse by elemental analyses, infrared, electronic spectra, 1H NMR as well as the magnetic susceptibility and conductivity measurement. The metal complexes exhibits different geometrical arrangements such as octahedral and square pyramidal coordination. Schiff base ligands and their metal complexes were tested against two pathogenic bacteria as Gram-positive and Gram-negative bacteria as well as one kind of fungi to study their biological activity. All the complexes exhibit antibacterial and antifungal activities against these organisms.
PMCID: PMC3826106  PMID: 24070648
Monoacetylferrocene; 1,1′-Diacetylferrocene; Thio-Schiff base; Metal complexes; Spectroscopy; Biological activity
8.  4-Meth­oxy-4-methyl-6-phenyl-1,3-diazinane-2-thione 
In the title pyrimidine derivative, C12H16N2OS, the tetra­hydro­pyrimidine ring adopts an envelope conformation with the C atom of the methyl­ene –CH2– group as the flap. In the crystal, N—H⋯O and N—H⋯S hydrogen bonds connect mol­ecules into undulating sheets perpendicular to the a axis.
PMCID: PMC3588820  PMID: 23468785
9.  Mixed-Valence Nickel-Iron Dithiolate Models of the [NiFe]-Hydrogenase Active Site 
Inorganic Chemistry  2012;51(4):2338-2348.
A series of mixed-valence iron-nickel dithiolates is described. Oxidation of (diphosphine)Ni(dithiolate)Fe(CO)3 complexes 1, 2, and 3 with ferrocenium salts affords the corresponding tricarbonyl cations [(dppe)Ni(pdt)Fe(CO)3]+ ([1]+), [(dppe)Ni(edt)Fe(CO)3]+ ([2]+) and [(dcpe)Ni(pdt)Fe(CO)3]+ ([3]+), respectively, where dppe = Ph2PCH2CH2PPh2, dcpe = Cy2PCH2CH2PCy2, pdtH2 = HSCH2CH2CH2SH and edtH2 = HSCH2CH2SH. The cation [2]+ proved unstable, but the propanedithiolates are robust. IR and EPR spectroscopic measurements indicate that these species exist as Cs-symmetric species. Crystallographic characterization of [3]BF4 shows that Ni is square planar. Interaction of [1]BF4 with P-donor ligands (L) afforded a series of substituted derivatives of type [(dppe)Ni(pdt)Fe(CO)2L]BF4 for L = P(OPh)3 ([4a]BF4), P(p-C6H4Cl)3 ([4b]BF4), PPh2(2-py) ([4c]BF4), PPh2(OEt) ([4d]BF4), PPh3 ([4e]BF4), PPh2(o-C6H4OMe) ([4f]BF4), PPh2(o-C6H4OCH2OMe) ([4g]BF4), P(p-tol)3 ([4h]BF4), P(p-C6H4OMe)3 ([4i]BF4), PMePh2 ([4j]BF4). EPR analysis indicates that ethanedithiolate [2]+ exists as a single species at 110 K, whereas the propanedithiolate cations exist as a mixture of two conformers, which are proposed to be related through a flip of the chelate ring. Mössbauer spectra of 1 and oxidized S = ½ [4e]BF4 are both consistent with a low-spin Fe(i) state. The hyperfine coupling tensor of [4e]BF4 has a small isotropic component and significant anisotropy. DFT calculations using the BP86, B3LYP, and PBE0 exchange-correlation functionals agree with the structural and spectroscopic data, suggesting that the SOMOs in complexes of the present type are localized in a Fe(i)-centered d(z2) orbital. The DFT calculations allow an assignment of oxidation states of the metals and rationalization of the conformers detected by EPR spectroscopy. Treatment of [1]+ with CN- and compact basic phosphines results in complex reactions. With dppe, [1]+ undergoes quasi-disproportionation to give 1 and the diamagnetic complex [(dppe)Ni(pdt)Fe(CO)2(dppe)]2+ ([5]2+), which features square-planar Ni linked to an octahedral Fe center.
PMCID: PMC3288512  PMID: 22304696
10.  Cd(II) and Pb(II) complexes of the polyether ionophorous antibiotic salinomycin 
The natural polyether ionophorous antibiotics are used for the treatment of coccidiosis in poultry and ruminants. They are effective agents against infections caused by Gram-positive microorganisms. On the other hand, it was found that some of these compounds selectively bind lead(II) ions in in vivo experiments, despite so far no Pb(II)-containing compounds of defined composition have been isolated and characterized. To assess the potential of polyether ionophores as possible antidotes in the agriculture, a detailed study on their in vitro complexation with toxic metal ions is required. In the present paper we report for the first time the preparation and the structure elucidation of salinomycin complexes with ions of cadmium(II) and lead(II).
New metal(II) complexes of the polyether ionophorous antibiotic salinomycin with Cd(II) and Pb(II) ions were prepared and structurally characterized by IR, FAB-MS and NMR techniques. The spectroscopic information and elemental analysis data reveal that sodium salinomycin (SalNa) undergoes a reaction with heavy metal(II) ions to form [Cd(Sal)2(H2O)2] (1) and [Pb(Sal)(NO3)] (2), respectively. Abstraction of sodium ions from the cavity of the antibiotic is occurring during the complexation reaction. Salinomycin coordinates with cadmium(II) ions as a bidentate monoanionic ligand through the deprotonated carboxylic moiety and one of the hydroxyl groups to yield 1. Two salinomycin anions occupy the equatorial plane of the Cd(II) center, while two water molecules take the axial positions of the inner coordination sphere of the metal(II) cation. Complex 2 consists of monoanionic salinomycin acting in polydentate coordination mode in a molar ratio of 1: 1 to the metal ion with one nitrate ion for charge compensation.
The formation of the salinomycin heavy metal(II) complexes indicates a possible antidote activity of the ligand in case of chronic/acute intoxications likely to occur in the stock farming.
PMCID: PMC3184049  PMID: 21906282
11.  Chlorido[5-meth­oxy-1H-benzimidazole-2(3H)-thione-κS]bis­(tri­phenyl­phos­phane-κP)copper(I) methanol disolvate 
In the title complex, [CuCl(C8H8N2OS)(C18H15P)2]·2CH3OH, the CuI ion is coordinated by one chloride anion, one S atom from the 5-meth­oxy-1H-benzimidazole-2(3H)-thione ligand and two P atoms from two tri­phenyl­phosphine ligands in a distorted tetra­hedral geometry. One of the N-bound H atoms is involved in an intra­molecular N—H⋯Cl hydrogen bond, while another one inter­acts with the solvent methanol mol­ecule via an N—H⋯O hydrogen bond. Inter­molecular O—H⋯Cl and O—H⋯O hydrogen bonds link two further complex mol­ecules and four solvent mol­ecules into a centrosymmetric structural unit. The short distance of 3.624 (4) Å between the centroids of the five- and the six-membered rings of two benzimidazole fragments indicates the presence of π–π inter­actions.
PMCID: PMC3998264  PMID: 24764825
12.  [1H-1,2,4-Triazole-5(4H)-thione-κS]bis­(tri­phenyl­phosphane-κP)(nitrato-κO)silver(I) methanol monosolvate 
In the title complex, [Ag(NO3)(C2H3N3S)(C18H15P)2]·CH3OH, the AgI ion exhibits a distorted tetra­hedral coordination geometry formed by two P atoms from two tri­phenyl­phosphine ligands, one S atom from a 1H-1,2,4-triazole-5(4H)-thione ligand and one O atom from a nitrate ion. In the crystal, complex and solvent mol­ecules are linked by O—H⋯O and N—H⋯O hydrogen bonds forming a chain along the b-axis direction. The chains are linked by weak C—H⋯O hydrogen bonds forming a two-dimensional supra­molecular architecture parallel to (001). In addition, an intra­molecular N—H⋯O hydrogen bond is observed.
PMCID: PMC3998265  PMID: 24764826
13.  Iodido[5-methyl-1H-benzimidazole-2(3H)-thione-κS]bis­(triphenyl­phosphane-κP)copper(I) methanol monosolvate 
In the title compound, [CuI(C8H8N2S)(C18H15P)2]·CH3OH, the coordination environment around the CuI atom is distorted tetra­hedral, defined by two P atoms of two triphenyl­phosphane ligands, one S atom of a 5-methyl-1H-benzimidazole-2(3H)-thione ligand and one I atom. The complex mol­ecules and the methanol solvent mol­ecules are connected via N—H⋯O and O—H⋯I hydrogen bonds, forming a chain along [010]. An intra­molecular N—H⋯I hydrogen bond is also observed.
PMCID: PMC3470167  PMID: 23125611
14.  Chlorido[1H-1,2,4-triazole-5(4H)-thione-κS]bis­(triphenyl­phosphane-κP)copper(I) acetronitrile monosolvate 
In the title solvate, [CuCl(C2H3N3S)(C18H15P)2]·CH3CN, the CuI ion is bonded to two triphenyl­phosphane ligands, one 1H-1,2,4-triazole-5(4H)-thione ligand via its S atom and one chloride ion in a distorted CuP2SCl tetra­hedron. An intra­molecular N—H⋯Cl hydrogen bond, which closes an S(6) ring, helps to establish the conformation of the complex. In the crystal, N—H⋯Cl hydrogen bonds and C—H⋯π inter­actions link the components, generating (110) layers.
PMCID: PMC3588355  PMID: 23476332
15.  Synthesis, Structure, Electrochemistry, and Spectral Characterization of Bis-Isatin Thiocarbohydrazone Metal Complexes and Their Antitumor Activity Against Ehrlich Ascites Carcinoma in Swiss Albino Mice 
Metal-Based Drugs  2007;2008:362105.
The synthesis, structure, electrochemistry, and biological studies of Co(II), Ni(II), Cu(II), and Zn(II) complexes of thiocarbohydrazone ligand are described. The ligand is synthesized starting from thiocarbohydrazide and isatin. It is evident from the IR data that in all the complexes, only one part of the ligand is coordinated to the metal ion resulting mononuclear complexes. The ligand coordinates essentially through the carbonyl oxygen of the isatin fragment, the nitrogen atom of the azomethine group, and sulfur atom after deprotonation to give five membered rings. H1 NMR spectrum of the ligand shows only one set of signals for the aromatic protons, while the NH of isatin and NH of hydrazone give rise to two different singlets in the 11–14 ppm range. The formulations, [Cu(L)Cl]·2H2O, [Cu(L)(CH3COO)]·2H2O, [Ni(L)Cl], [Ni(L)(CH3COO)], [Co(L2)], and [Zn(L2)]·2H2O are in accordance with elemental analyses, physical, and spectroscopic measurements. The complexes are soluble in organic solvents. Molar conductance values in DMF indicate the nonelectrolytic nature of the complexes. Copper complex displays quasireversible cyclic voltametric responses with Ep near −0.659 v and 0.504 v Vs Ag/AgCl at the scan rate of 0.1 V/s. Copper(II) complexes show a single line EPR signals. For the observed magnetic moment and electronic spectral data possible explanation has been discussed. From all the available data, the probable structures for the complexes have been proposed. The compounds synthesized in present study have shown promising cytotoxic activity when screened using the in vitro method and at the same time were shown to have good activity when tested using the Ehrlich ascites carcinoma (EAC) model. The antimicrobial screening showed that the cobalt complex possesses enhanced antimicrobial activity towards fungi.
PMCID: PMC2259242  PMID: 18320020
16.  Hydrogen-bonding and π–π stacking inter­actions in tris­(1,10-phenanthroline-κ2 N,N′)nickel(II) bis­{[1-tert-butyl­imidazole-2(3H)-thione-κS]trichloridonickelate(II)} acetonitrile disolvate 
The asymmetric unit of the title complex, [Ni(C12H8N2)3][NiCl3(C7H12N2S)]2·2CH3CN, consists of one anion, one-half of a cation and one acetonitrile mol­ecule. The NiII atom in the [Ni(phen)3]2+ cation (phen is 1,10-phenanthroline) lies on an inversion centre in an octa­hedral environment, whereas in the [NiCl3(tm)]− anion [tm is 1-tert-butyl­imidazole-2(3H)-thione], the geometry is distorted tetra­hedral. In the crystal structure, inter­molecular C—H⋯Cl hydrogen bonds and π–π stacking inter­actions (centroid–centroid distance = 3.52 Å) lead to the formation of a three-dimensional framework. One of the methyl groups of the tert-butyl group of N-tert-butyl-2-thio­imidazole is disordered between two equally populated positions.
PMCID: PMC2961703  PMID: 21202789
17.  Crystal structure of di­chlorido­bis­(1,3-diisopropyl-4,5-dimethyl-2H-imidazole-2-thione-κS)zinc(II) 
The mol­ecular structure of the title compound, [ZnCl2(C11H20N2S)2], shows tetra­hedral Zn coordination from two Cl ligands and two thione groups. The Zn—Cl bond lengths differ sligthly at 2.2310 (10) and 2.2396 (11) Å while the Zn—S bond lengths are equal at 2.3663 (9) and 2.3701 (10) Å. The Cl—Zn—Cl angle is 116.04 (4) and S—Zn—S is 101.98 (3)°. All other angles at the central Zn atom range from 108.108 (3) to 110.21 (4)°. The C—S—Zn angles are 100.75 (10) and 103.68 (11)°, the difference most probably resulting from packing effects, as both the C—S and both the S—Zn bonds are equal in each case. The two imidazole ring planes make a dihedral angle of 67.9 (1)°. The CH3 groups of one isopropyl moiety are disordered over two sets of sites with occupation factors of 0.567 (15) and 0.433 (15). It may be noteworthy that the isomolecular Cu complex shows a different crystal packing (group–subgroup relation) with the Cu atom lying on a twofold rotation axis. In the crystal, the shortest non-bonding contact is a C—H⋯Cl inter­action. This leads to the formation of centrosymmetric dimers that are stacked along the c-axis.
PMCID: PMC4257301  PMID: 25484787
crystal structure; imidazoline­thio­nes; zinc(II) complex,
18.  Synthesis, characterization, electrospinning and antibacterial studies on triphenylphosphine-dithiphosphonates Copper(I) and Silver(I) complexes 
The novel amido and O-ferrocenyldithiophosphonates [FcP(S)(SH)(NHR1)] (Fc = Fe(η5-C5H5)(η5-C5H4), R1 = 1-(4-fluorophenylethyl and benzyloxycyclopentyl) and [FcP(S)(OR2)S−][H3N+C(CH3)3] (R2 = myrtanyl) were synthesized by the reaction of [(FcPS2)]2 (Fc = Fe(η5-C5H5)(η5-C5H4)) and chiral amines, such as (S)–(−)-1-(4-fluorophenylethyl) amine and (1S,2S)-(+)-benzyloxycyclopentyl amine, and of (1S), (2S), (5S)-myrtanol in toluene. The reaction of ferrocenyldithiophosphonates and [Cu(PPh3)2]NO3 or AgNO3 and PPh3 gave rise to copper(I) and silver(I) complexes in THF. [Ag2{FcP(OMe)S2}2(PPh3)2] and [Cu(PPh3)2]NO3 were embedded into nanofibers and their antimicrobial activities on fibers were also investigated.
The compounds have been characterized by elemental analyses, IR, NMR (1H-, 31P-) spectroscopy as well as MS measurements. Nanofibers were obtained by electrospinning method which is the simplest and most effective method to produce nanoscale fibers under strong electrical field. Antimicrobial activity of the compound 5, [Ag2{FcP(OMe)S2}2(PPh3)2], and [Cu(PPh3)2]NO3 on fibers were studied.
In this study, the new dithiophosphonate ligands were synthesized and utilized in the preparation of copper(I) and silver(I) complexes with ferrocenyldithiophosphonate and triphenylphosphine. Then, the compounds [Ag2{FcP(OMe)S2}2(PPh3)2] and [Cu(PPh3)2]NO3 were added into the PAN solutions (Co-PAN dissolved in dimethylacetamide) and the solutions were electrospun onto microscope slides and PP meltblown surfaces. Antimicrobial activity of the compounds [Ag2{FcP(OMe)S2}2(PPh3)2] and [Cu(PPh3)2]NO3 on fibers were determined in vitro against two indicator strains; M. luteus NCIB and E. coli ATCC25922. The obtained results indicated that these metals showed moderate level antimicrobial activities.
PMCID: PMC4004045  PMID: 24629061
Dithiophosphonates; Triphenylphosphine; Copper(I) and Silver(I) complexes; Nanofiber; Electrospinning; Antibacterial
19.  Luminescent Di and Polynuclear Organometallic Gold(I)-M (Au2, {Au2Ag}n and {Au2Cu}n) Compounds Containing Bidentate Phosphanes as Active Antimicrobial Agents 
The reaction of new dinuclear gold(I) organometallic complexes containing mesityl ligands and bridging bidentate phosphanes [Au2(mes)2(μ-LL)] (LL = dppe: 1,2-Bis(di-phenylphosphano)ethane 1a, and water-soluble dppy: 1,2-Bis(di-3-pyridylphosphano)ethane 1b) with Ag+ and Cu+ lead to the formation of a family of heterometallic clusters with mesityl bridging ligands of the general formula [Au2M(μ-mes)2(μ-LL)]A (M = Ag, A = ClO4−, L-L = dppe 2a, dppy 2b; M = Ag, A = SO3CF3−, L-L = dppe 3a, dppy 3b; M = Cu, A = PF6−, L-L = dppe 4a, dppy 4b). The new compounds were characterized by different spectroscopic techniques and mass spectrometry The crystal structures of [Au2(mes)2(μ-dppy)] 1b and [Au2Ag(μ-mes)2(μ-dppe)]SO3CF3 3a were determined by a single-crystal X-ray diffraction study. 3a in solid state is not a cyclic trinuclear Au2Ag derivative but it gives an open polymeric structure instead, with the {Au2(μ-dppe)} fragments “linked” by Ag(μ-mes)2 units. The very short distances of 2.7559(6) Å (Au-Ag) and 2.9229(8) Å (Au-Au) are indicative of gold-silver (metallophillic) and aurophilic interactions. A systematic study of their luminescence properties revealed that all compounds are brightly luminescent in solid state, at room temperature (RT) and at 77 K, or in frozen DMSO solutions with lifetimes in the microsecond range and probably due to the self-aggregation of [Au2M(μ-mes)2(μ-LL)]+ units (M= Ag or Cu; LL= dppe or dppy) into an extended chain structure, through Au-Au and/or Au-M metallophylic interactions, as that observed for 3a. In solid state the heterometallic Au2M complexes with dppe (2a–4a) show a shift of emission maxima (from ca. 430 to the range of 520–540 nm) as compared to the parent dinuclear organometallic product 1a while the complexes with dppy (2b–4b) display a more moderate shift (505 for 1b to a max of 563 nm for 4b).
More importantly, compound [Au2Ag(μ-mes)2(μ-dppy)]ClO4 2b resulted luminescent in diluted DMSO solution at room temperature. Previously reported compound [Au2Cl2(μ-LL)] (L-L dppy 5b) was also studied for comparative purposes. The antimicrobial activity of 1–5 and AgA (A= ClO4−, OSO2CF3−) against Gram-positive and Gram-negative bacteria and yeast was evaluated. Most tested compounds displayed moderate to high antibacterial activity while heteronuclear Au2M derivatives with dppe (2a–4a) were the more active (MIC 10 to 1 μg/mL). Compounds containing silver were ten times more active to Gram-negative bacteria than the parent dinuclear compound 1a or silver salts. Au2Ag compounds with dppy (2b, 3b) were also potent against fungi.
PMCID: PMC3371653  PMID: 22334444
luminescent; gold-silver; gold-copper; antimicrobial; synergism
20.  Molecular Oxygen and Sulfur Reactivity of a Cyclotriveratrylene (CTV) Derived Trinuclear Copper(I) Complex 
Inorganic chemistry  2009;48(17):8342-8356.
Our continuing efforts into developing copper coordination chemistry relevant to dioxygen-processing copper proteins has led us to design and synthesize a cyclotriveratrylene (CTV)-based trinucleating ligand, CTV-TMPA, which employs tetradentate tris(2-pyridylmethyl)-amine chelates (TMPA) for their copper ion binding sites. Binding of three copper ions per CTV-TMPA unit was established by various chemical and spectroscopic methods such as UV-vis and resonance Raman (rR) spectroscopies. The following complexes were observed: A tricopper(I) complex [(CTV-TMPA)CuI3]3+ (1), a CO adduct [(CTV-TMPA)CuI3(CO)3]3+ (1-CO; ν(C=O) = 2094 cm−1), a triphenylphosphine adduct [(CTV-TMPA)CuI3(PPh3)3]3+ (1-PPh3), a tricopper(II) complex [(CTV-TMPA)CuII3]3+ (1-Ox) and its tris-monochloride or tris-monobromide adducts. Also, introduction of dioxygen to the −80 °C solutions of 1 leads to O2-adducts, the first example of a synthetic copper complex which can stabilize a mononuclear CuII-superoxo and dinuclear peroxo species simultaneously within one complex {[Cu] = 1.53 mM in THF: (μ-1,2-peroxo complex, λmax = 543 (ε 9650) nm): ν(O-O) = 825 ((Δ18O2) = −47) cm−1; ν(Cu-O) = 506 ((Δ18O2) = −26) cm−1: (superoxo complex, λmax = 427 (ε 3150) nm): ν(O-O) = 1129 ((Δ18O2) = −60) cm−1; ν(Cu-O) = 463 ((Δ18O2) =−27) cm−1}. Elemental sulfur reacts reversibly with 1 leading to a (proposed) hexanuclear species [{(CTV-TMPA)CuII3}2(μ-1,2-S22−)3]6+ (1-S) {λmax = 544 (ε 7270 nm }, possessing one dicopper(II)-disulfide structural type: {THF solvent) ν(S-S) = 489 ((Δ34S) = −10) cm−1; ν(Cu-S) = 506 ((Δ34S) = −5) cm−1}. Derivation of spectroscopic, structural and chemical conclusions were aided by the study of a close mononuclear analogue with one pyridyl group of the TMPA parent possessing a 6-CH2OCH3 substituent, this being part of the CTV-TMPA architecture.
PMCID: PMC2917907  PMID: 19663454
21.  Metal-Based Antibacterial and Antifungal Agents: Synthesis, Characterization, and In Vitro Biological Evaluation of Co(II), Cu(II), Ni(II), and Zn(II) Complexes With Amino Acid-Derived Compounds 
A series of antibacterial and antifungal amino acid-derived compounds and their cobalt(II), copper(II), nickel(II), and zinc(II) metal complexes have been synthesized and characterized by their elemental analyses, molar conductances, magnetic moments, and IR, and electronic spectral measurements. Ligands (L1)−(L5) were derived by condensation of β-diketones with glycine, phenylalanine, valine, and histidine and act as bidentate towards metal ions (cobalt, copper, nickel, and zinc) via the azomethine-N and deprotonated-O of the respective amino acid. The stoichiometric reaction between the metal(II) ion and synthesized ligands in molar ratio of M : L (1 : 1) resulted in the formation of the metal complexes of type [M(L)(H2O)4]Cl (where M = Co(II), Cu(II), and Zn(II)) and of M : L (1 : 2) of type [M(L)2(H2O)2] (where M = Co(II), Cu(II), Ni(II), and Zn(II)). The magnetic moment data suggested for the complexes to have an octahedral geometry around the central metal atom. The electronic spectral data also supported the same octahedral geometry of the complexes. Elemental analyses and NMR spectral data of the ligands and their metal(II) complexes agree with their proposed structures. The synthesized ligands, along with their metal(II) complexes, were screened for their in vitro antibacterial activity against four Gram-negative (Escherichia coli, Shigella flexeneri, Pseudomonas aeruginosa, and Salmonella typhi) and two Gram-positive (Bacillus subtilis and Staphylococcus aureus) bacterial strains and for in vitro antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani, and Candida glaberata. The results of these studies show the metal(II) complexes to be more antibacterial/antifungal against one or more species as compared to the uncomplexed ligands. The brine shrimp bioassay was also carried out to study their in vitro cytotoxic properties. Five compounds, (3), (7), (10), (11), and (22), displayed potent cytotoxic activity as LD50 = 8.974 × 10−4, 7.022 × 10−4, 8.839 × 10−4, 7.133 × 10−4, and 9.725 × 10−4 M/mL, respectively, against Artemia salina.
PMCID: PMC1800917  PMID: 17497020
22.  catena-Poly[[[bis­(N,N-dimethyl­formamide)iron(II)]-{μ-2,2′-bis­(diphenyl­phosphino­yl)-N,N′-[(1R,2R)-cyclo­hexane-1,2-di­yl]dibenzamide}] bis­(perchlorate) N,N-dimethyl­formamide disolvate] 
The title extended solid coordination compound, {[Fe(C44H40N2O4P2)(C3H7NO)2](ClO4)2·2C3H7NO}n, was crystallized un­ex­pectedly from the reaction mixture containing the Trost ligand (1R,2R)-(+)-1,2-diamino­cyclo­hexane-N,N′-bis­(2′-di­phenyl­phosphinobenzo­yl) and Fe(ClO4)2·6H2O in a 1:1 ratio in dimethyl­formamide (DMF) under reflux conditions. The polymeric complex is characterized by FeII metal centers that are coordinated by two oxidized Trost ligands, each coordinated in a bidentate fashion in a square plane, along with two DMF mol­ecules above and below the plane [average Fe—ODMF = 2.086 (4) Å], forming an overall pseudo-octa­hedral geometry. The Trost ligand binds adjacent FeII centers, each FeII being bound through the O atom of one of the phosphine oxides [average Fe—OPPh2 = 2.115 (4) Å] and the carbonyl O atom of the adjacent amide [average Fe—Oamide = 2.192 (3) Å]. Disorder is observed in the co-solvated solvent: there are two DMF mol­ecules per FeII centre, which were modeled as one DMF mol­ecule with complete occupancy and the other being modeled in two positions with equal occupancy. Disorder was also observed with one of the perchlorate anions, which was modeled in two positions with 0.75:0.25 occupancy.
PMCID: PMC2971940  PMID: 21578561
23.  Crystal structure of [3-(4,5-di­hydro-1,3-thia­zolin-2-yl-κN)-1,3-thia­zolidine-2-thione-κS 2](1,3-thia­zol­idine-2-thione-κS 2)copper(I) nitrate 
In the mononuclear complex title salt, all of the non-H atoms of the cation lie on a mirror plane, as do the N and one O atom of the nitrate anion, such that the planes of the cation and anion are mutually orthogonal. In the crystal, layers parallel to (010) are generated by N—H⋯O hydrogen bonds, supported by short S⋯O [3.196 (4) and 3.038 (3) Å] and S⋯S contacts [3.4392 (13) Å].
The mononuclear complex salt, [Cu(C3H5NS2)(C6H8N2S3)]NO3, contains a [C9H13CuN3S5]+ cation and an NO3 − anion. All of the non-H atoms of the cation lie on a mirror plane, as do the N and one O atom of the nitrate anion, such that the planes of the cation and anion are mutually orthogonal. The cationic complex adopts a slightly distorted trigonal–planar geometry about the CuI cation. In the crystal, layers parallel to (010) are generated by N—H⋯O hydrogen bonds, supported by short S⋯O [3.196 (4) and 3.038 (3) Å] and S⋯S contacts [3.4392 (13) Å]. Adjacent layers are linked by C—H⋯O hydrogen bonds and weak π–π stacking inter­actions [centroid–centroid distance = 4.0045 (10) Å] between the thia­zoline rings, forming a three-dimensional network. This stacking also imposes a close contact, of approximately 3.678 Å, between the CuI cations and the centroids of the six-membered chelate rings of mol­ecules in adjacent layers.
PMCID: PMC4158518  PMID: 25249863
copper(II) complex; 1,3-thia­zolidine-2-thione; 3-(2-thia­zolin-2-yl)thia­zolidine-2-thione; crystal structure
24.  (Sulfasalazinato-κO)bis­(triphenyl­phosphine-κP)copper(I) 
The title mixed-ligand copper(I) complex, [Cu(C18H13N4O5S)(C18H15P)2], was synthesized via solvothermal reaction of [Cu(PPh3)2(MeCN)2]ClO4 and sulfasalazine [systematic name: 2-hydr­oxy-5-(2-{4-[(2-pyridylamino)sulfon­yl]phen­yl}diazen­yl)benzoic acid]. The mononuclear complex displays a trigonal coordination geometry for the Cu(I) atom, which is surrounded by two P-atom donors from two different PPh3 ligands and one O-atom donor from the monodentate carboxyl­ate group of the sulfasalazinate ligand. The latter ligand is found in a zwitterionic form, with a deprotonated amine N atom and a protonated pyridine N atom. Such a feature was previously described for free sulfasalazine. The crystal structure is stabilized by C—H⋯O, C—H⋯N, N—H⋯N and O—H⋯O hydrogen bonds.
PMCID: PMC2979139  PMID: 21579036
25.  Novel Zinc(II) Complexes of Heterocyclic Ligands as Antimicrobial Agents: Synthesis, Characterisation, and Antimicrobial Studies 
The synthesis and antimicrobial activity of novel Zn(II) metal complexes derived from three novel heterocyclic Schiff base ligands 8-[(Z)-{[3-(N-methylamino)propyl]imino}methyl]-7-hydroxy-4-methyl-2H-chromen-2-one, 2-[(E)-{[4-(1H-1,2,4-triazol-1-ylmethyl)phenyl]imino}methyl]phenol, and (4S)-4-{4-[(E)-(2-hydroxybenzylidene)amino]benzyl}-1,3-oxazolidin-2-one have been described. These Schiff base ligands and metal complexes are characterised by spectroscopic techniques. According to these data, we propose an octahedral geometry to all the metal complexes. Antimicrobial activity of the Schiff base ligand and its metal complexes was studied against Gram negative bacteria: E. coli and Pseudomonas fluorescens, Gram positive bacteria: Staphylococcus aureus, and also against fungi, that is, C. albicans and A. niger. Some of the metal complexes show significant antifungal activity (MIC < 0.2 μg/mL). The “in vitro” data has identified [Zn(NMAPIMHMC)2]·2H2O, [Zn(TMPIMP)2]·2H2O, and [Zn(HBABO)2]·2H2O as potential therapeutic antifungal agents against C. albicans and A. niger.
PMCID: PMC3953498  PMID: 24707242

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