Neutral Thiosemicarbazone Research Articles

Crystal Structure and Nanoparticles of Dinuclear Silver(I) Complex [Ag2(PPh3)2(μ-S-4nb-tsc)2(η1-S-4nb-tsc)2](NO3)2

Nanoparticles of a new dinuclear silver(I) complex [Ag2(PPh3)2(μ-S-4nb-tsc)2(η1-S-4nb-tsc)2](NO3)2, where 4nb-tsc = 4-nitrobenzylidenethiosemicarbazone and PPh3 = triphenylphosphine, were prepared in an ultrasonic bath and characterized by FT-IR and SEM. The crystal structure of a suitable single crystal prepared by slow evaporation was determined by single crystal X-ray diffraction. The compound crystallized in the triclinic system with space group P-1 and Z = 2. X-ray results showed that the neutral thiosemicarbazone ligand 4nb-tsc was coordinated to silver(I) ion in two different bonding modes, μ-S, and η1-S. The shortest distance between the sulfur-bridged Ag cations was 3.576(5) A. One P atom and three S atoms from three 4nb-tsc ligands coordinated to the silver(I) ion in a distorted tetrahedral geometry. In the crystal packing of the title compound, several hydrogen bonds were connecting the molecules of the complex.

Antiproliferative activity of cationic and neutral thiosemicarbazone copper(ii) complexes

Three new copper(ii) thiosemicarbazone complexes were synthesized and characterized. The DNA/protein binding and antiproliferative activity of the complexes have been described.

Neutral ferric complexes of salicylaldehyde thiosemicarbazone ligands: An exceptional family of complexes exhibiting discontinuous spin transition behavior

Three neutral thiosemicarbazone ferric complexes of general formulas [Fe(H5XThsa)(5XThsa)]·H2O have been prepared and studied by magnetic susceptibility, DSC and Mössbauer measurements. The three compounds exhibit an abrupt spin transition associated with thermal hysteresis, a still rarely observed behavior for ferric complexes. DSC and Mössbauer measurements allowed confirming that these spin transition processes are coupled with a first order crystallographic phase transition whose thermodynamical parameters have been determined. Finally, it can be highlighted from the comparison of properties observed for these compounds with the literature that the synthetic procedures are a crucial point for the magnetic properties.

Synthesis, characterization, crystal structure and biological activities of the unusual main group 8-coordinate bismuth (III) complex derived from 2-acetylpyrazine N4- pyridylthiosemicarbazone

Abstract Main group metal complex [Bi(HL)(NO3)3] (1), where HL = 2-acetylpyrazine N(4)-pyridylthiosemicarbazone, has been synthesized and characterized by elemental analysis, IR, MS and single-crystal X-ray diffraction studies. The interesting monomeric 8-coordinate bismuth(III) complex 1 is depicted with one electron pair (6 s2) of the bismuth(III) atom, one N2S tridentate neutral thiosemicarbazone, two monodentate and one bidentate nitrate ions, respectively. In vitro biological studies have indicated that the bismuth complex 1 has shown effective antibacterial and anticancer activities especially with MIC = 15.6 μg/mL against Gram positive bacteria Bacillus cereus and IC50 = 1.6 μM against K562 leukemia cell lines, respectively, comparable to positive control.

Polyoxometallate–Thiosemicarbazone Hybrid Compounds

AbstractNew polyoxometallate–thiosemicarbazone hybrid compounds derived from pyridine‐2‐carbaldehyde thiosemicarbazone (HL), pyridine‐2‐carbaldehyde N4‐methylthiosemicarbazone (HL′) and their copper(II) complexes have been synthesized. Their formulae are (H2L)4(Mo8O26)(H2O)4 (1), [{(HL)2H}2(Mo6O19)]·C3H6O·0.24H2O (2), [(H2L′)4(HL′)2(Mo8O26)(H2O)2] (3), [{Cu(L)}4(Mo8O26)(H2O)4] (4), [{Cu(HL)(H2O)}2(Mo8O26)] (5), [{Cu(L′)}4(Mo8O26)(H2O)14] (6), Na6[{Cu(HL′)(H2O)2}4({Cu(L′)}2{Mo36O116(H2O)12})]·20H2O (7), [{Cu(HL)}2{Cu(L)}4{Mo36O112(H2O)16}(H2O)26] (8), [{Cu(HL′)}4{Mo36O112(H2O)16}(H2O)30] (9) and [{Cu(HL)(H2O)}2{Cu(L)S}2(H4V10O28)]n·6nH2O (10). Compounds 1–6 contain octamolybdate [Mo8O26]4– or hexamolybdate [Mo6O19]2– anions together with (H2L)+, (H2L′)+, [Cu(L)]+, [Cu(HL)(H2O)]2+ or [Cu(L′)]+ cations and neutral thiosemicarbazone molecules. The polyoxometallates (POMs) in 7–9 are [Mo36O116(H2O)12]16–, {Mo36} (7), and [Mo36O112(H2O)16]8–, {Mo36′} (8, 9). [Cu(HL′)]2+/[Cu(L′)]+ and [Cu(HL)]2+/[Cu(L)]+ units complete the respective lattices. Compound 10 consists of decavanadate anions (H4V10O28)2– and thiosemicarbazone‐copper(II) entities forming 1D [{Cu(HL)(H2O)}2{Cu(L)S}2(H4V10O28)]n structures connected through the hydrogen bonds of chains of water molecules. Structures of 2, 5, 7 and 10 have been characterized by single‐crystal X‐ray diffraction and other instrumental techniques (infrared, thermal analysis, electron paramagnetic resonance, nuclear magnetic resonance, magnetic susceptibility and mass spectrometry) were used to analyse all the compounds presented herein. The structural parameters of more than 1000 published thiosemicarbazone‐metal complexes have been used to determine some of the differences between metal complexes that contain anionic and neutral thiosemicarbazone ligands.

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

AbstractSodium 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.

Spectral studies and X-ray crystal structures of three nickel(II) complexes of 2-pyridineformamide 3-piperidylthiosemicarbazone

Reduction of 2-cyanopyridine by sodium in dry methanol in the presence of 3-piperidylthiosemicarbazide produces 2-pyridineformamide 3-piperidylthiosemicarbazone, HAmpip. Complexes with nickel(II) have been prepared and characterized by magnetic susceptibility and spectroscopic techniques. The crystal structures of [Ni(Ampip) 2], [Ni(Ampip)OAc], and [Ni(HAmpip)Cl]Cl have been solved. Coordination of the anionic and neutral ligand is via the pyridyl nitrogen, imine nitrogen, and thiolato–thione sulfur. [Ni(Ampip) 2] is an approximately octahedral NiN 4S 2 center with the tridentate ligands in a meridonal arrangement. [Ni(Ampip)OAc] is essentially planar except for the acetato ligand, which is >80° out of the coordination plane, and the ionic [Ni(HAmpip)Cl]Cl involves the neutral thiosemicarbazone ligand.

Coordination of ZnII, CdII, and HgII by 2-Pyridineformamide-3-piperidyl-thiosemicarbazone

Sodium in dry methanol reduces 2-cyanopyridine in the presence of 3-piperidylthiosemicarbazide and produces 2-pyridine-formamide-3-piperidylthiosemicarbazone, HAmpip. Complexes with zinc(II), cadmium(II), and mercury(II) have been prepared and characterized by elemental analyses and spectroscopic techniques. In addition, the crystal structures of [Zn(Ampip) 2], [Zn(Ampip)(Oac)] 2, [Cd(HAmpip)Cl 2]·(CH 3) 2SO, [Cd(HAmpip)Br 2]·(CH 3) 2SO, [Cd(HAmpip)I 2]·(CH 3) 2SO, [Cd(Ampip) 2] and [Hg(HAmpip)Br 2]·(CH 3) 2SO have been solved. Coordination of the anionic and neutral thiosemicarbazone ligand is via the pyridyl nitrogen, imine nitrogen and thiolato/thione sulfur atom, respectively. In [Zn(Ampip)(OAc)] 2 one of the bridging acetato ligands has monodentate coordination and the other bridges in a bidentate manner. 113Cd NMR studies were carried out on the [Cd(HAmpip)X 2] (X = Cl, Br or I) and [Cd(Ampip)(OAc)] 2 complexes. The 113Cd chemical shifts are affected by the halogen and range from 411 to 301 ppm, and the spectrum of [Cd(Ampip)(OAc)] 2 shows two signals at 450 and 251 ppm. The 199Hg NMR spectrum of [Hg(HAmpip)Cl 2] also is discussed.

Synthesis, Characterization and Molecular Structure of 2-Pyridyl-formamide N(4)-Dimethylthiosemicarbazone and Some Five-Coordinated Zinc(II) and Cadmium(II) Complexes

Abstract Sodium in dry methanol reduces 2-cyanopyridine in the presence of N(4)-dimethylthiosemicarbazide to produce 2-pyridyl-formamide N(4)-dimethylthiosemicarbazone, HAm4DM. Com­plexes with zinc(II) and cadmium(II) of formulae [M(Am4DM)(OAc)]2 and [M(HAm4DM)X2] (M = Zn or Cd, X = Cl, Br or I) have been prepared and characterized by spectro­scopic techniques. In addition, the crystal structures of HAm4DM, [Zn(HAm4DM)Br2], and [Cd(HAm4DM)l2] DMSO have been solved. HAm4DM is in the zwitterionic form with a hydrogen bonding interaction between the iminium hydrogen and the thiolato sulfur atom. Co­ ordination of the neutral thiosemicarbazone ligand is via the pyridyl nitrogen, imine nitrogen and thione sulfur atoms, while the anionic ligand in [M(Am4DM)(OAc)]2 coordinates with the same two nitrogen atoms and a thiolato sulfur atom. The [M(HAm4DM)X2] complexes are 5-coordinate with the tridentate thiosemicarbazone and two halogen ligands approaching a square pyramidal stereochemistry.

Metal complexes of 2-acetylpyridine N(4)-dihexyl- and N(4)-dicyclohexylthiosemicarbazones

2-Acetylpyridine N(4)-dihexyl- and N(4)-dicyclohexylthiosemicarbazone, HAc4DHex and HAc4DCHex, respectively, and FeIII, CoII, CoIII, NiII, CuII and ZnII complexes have been prepared and characterized by molar conductivities, magnetic susceptibilities and spectroscopic techniques. For many of the complexes, loss of the N(2)H hydrogen occurs, and the ligands coordinate to the metal centres as NNS monoanionic, tridentate ligands, e.g., [M(NNS)X] (M = CoII, NiII, CuII, NNS = Ac4DHex or Ac4DCHex and X = Cl or Br), [Fe(NNS)2]ClO4, [Co(NNS)2]BF4, [Cu(NNS)NO3] and [Zn(NNS)OAc]. ZnII ion is also chelated by neutral ligands in [Zn(HNNS)X2] (X = Cl, Br). In addition, [Ni(Ac4DHex)-(HAc4DHex)]X (X = BF4, ClO4) and [Ni(HAc4DCHex)2]-(BF4)2 are reported where the neutral thiosemicarbazone is coordinated via the pyridyl nitrogen, azomethine nitrogen and thione sulfur. Crystal structure determinations of HAc4DCHex and [Cu(Ac4DHex)Br] show the former to contain the bifurcated hydrogen bonded form and the latter to be planar with no significant interaction between neighbouring centres.

Transition metal ion complexes of thiosemicarbazones derived from 2-acetylpyridine. Part 2. The4 N-dimethyl derivative

Metal ion complexes of the thiosemicarbazone,N-dimethyl-2-[1-(2-pyridinyl)ethylidene]hydrazinecarbothioamide (HL4DM) have been prepared and characterized spectrally. HL4DM coordinates primarily as the deprotonated tridentate ligand (i.e., pyridylN, azomethineN, and thione sulphur). In contrast to related thiosemicarbazones, oxidation to cobalt(III) does not occur during complex formation with cobalt(II) halides. Oxidation does occur on reflux with ethanolic Co(BF4)2, but we isolated a planar cobalt(II) complex as well. Only with the tetrafluoroborate salts of cobalt(II) and nickel(II) are complexes isolated containing the neutral thiosemicarbazone. Square planar [Ni(L4DM)X]complexes where X=Cl, Br, and OH have been isolated and e.s.r. spectra of a 1% Cu/Ni complex are compared to the results of other workers.

Copper(II) complexes of thiosemicarbazones derived from 2-acetylpyridine and its n-oxide

A series of Cu(II) complexes of the thiosemicarbazone, 3-azabicyclo[3.2.2]-nonene-3-thiocarboxylic acid 2-[1-(2-pyridinyl)ethylidene]hydrazide(HL) and the corresponding N-oxide (HLO) have been prepared and characterized. Both ligands undergo deprotonation and appear to coordinate via the thione sulfur, the imine nitrogen and the pyridyl nitrogen (or N-oxide oxygen). A single anionic ligand such as Cl −, Br −, NCS − and N − 3 completes the bonding to the Cu(II) center of these 4-coordinate complexes. When the complexes are prepared using Cu(II) perchlorate, the solids isolated contain a neutral thiosemicarbazone ligand as well as the deprotonated ligand. The solids are primarily characterized by IR, electronic and electron spin resonance spectroscopy. In addition, electronic and ESR spectra of their chloroform solutions were recorded. Most of the solids (except the nitrates) were unaltered upon dissolution. Simulation of the solution ESR spectra was used to estimate the coupling constants of the various coordinated nuclei.