F. Luna-Giles

Co(III), Ni(II), Zn(II) and Cd(II) complexes with 2-acetyl-2-thiazoline thiosemicarbazone: Synthesis, characterization, X-ray structures and antibacterial activity

The new ligand 2-acetyl-2-thiazoline thiosemicarbazone (HATtsc) and the complexes [Co(ATtsc)(2)](2)[CoCl(4)]·2H(2)O (1), [Co(ATtsc)(2)]NO(3)·H(2)O (2), [Ni(HATtsc)(2)](NO(3))(2) (3), [ZnCl(2)(HATtsc)]·CH(3)CN (4), [{CdCl(HATtsc)}(2)(μ-Cl)(2)]·2H(2)O (5) and [{Cd(NO(3))(HATtsc)}(2)(μ-NO(3))(2)] (6) were isolated and characterized by a variety of physico-chemical techniques and X-ray diffraction. The structure of HATtsc in 1 and 2 presented a thiolate form while in 3-6 the thione form was present, as it was in free ligand. In addition, we studied the antibacterial activity of the ligand and complexes 2-6 against some representative bacteria. Cd(II) complexes were more active against Staphylococcus epidermidis, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Bacillus subtilis than organic ligand. Conversely, Cd(II) compounds seemed to interfere in the cell separation of B. subtilis.

Coordination chemistry of thiazoline/thiazolidine derivatives. I: Crystal structure of 2-(2-pyridyl)imino-N-(2-thiazolin-2-yl)thiazolidine (PyTT) and study of its interaction with nickel(II)

Abstract The crystal structure of 2-(2-pyridyl)imino-N-(2-thiazolin-2-yl)thiazolidine (PyTT) is reported. The compound diaquabis[2-(2-pyridyl)imino-N-(2-thiazolin-2-yl)thiazolidine]nickel(II) chloride trihydrate has been isolated and characterized by IR, UV–Vis–NIR diffuse reflectance and X-ray diffraction. The complex cation has crystallographic C2 symmetry. The environment around the nickel atom may be described as a distorted octahedral geometry with the metallic atom coordinated to two water molecules [Ni–O(1)=2.114(2) A], two thiazolinic nitrogens [Ni–N(1)=2.061(2) A] and two imino nitrogens [Ni–N(3)=2.086(2) A]. Hydrogen bonding is present in the structure inter-linking PyTT ligands, water molecules and chloride ions.

The coordination chemistry of thiazoline/thiazolidine derivatives. II: synthesis and characterization of [CoCl2(PyTT)] and [ZnCl2(PyTT)] [PyTT = 2-(2-pyridyl)imino-n-(2-thiazolin-2-yl)thiazolidine]

Abstract The compounds dichloro[2-(2-pyridyl)imino-κ N  N -(2-thiazolin-κ N -2-yl)thiazolidine]cobalt(II) and dichloro[2-(2-pyridyl)imino-κ N  N -(2-thiazolin-κ N -2-yl)thiazolidine]zinc(II) have been isolated and characterized by single crystal X-ray diffraction and IR spectroscopy. Moreover, the cobalt(II) complex has been studied by means of magnetic susceptibility measurements and UV–Vis–NIR diffuse reflectance. Both complexes are isostructural. The environment around the cobalt(II) and zinc(II) atoms may be described as a distorted tetrahedral geometry with the metallic atoms coordinated to two chlorine atoms [CoCl(1)=2.241(1) A; CoCl(2)=2.221(1) A], [ZnCl(1)=2.235(1) A; ZnCl(2)=2.211(1) A], one thiazoline nitrogen [CoN(1)=1.982(2) A], [ZnN(1)=2.021(2) A] and one imino nitrogen [CoN(3)=2.009(1) A], [ZnN(3)=2.056(2) A].

Effects of the substituents of pyrazole/thiazine ligands on nuclearity of Cu(II) nitrate complexes

[Cu(H2O)(PzTz)2](NO3)2 (1), [Cu(μ-NO3)(NO3)(DMPzTz)] n (2), and [{Cu(NO3)(DPhPzTz)}2(μ-NO3)2] (3) [PzTz = 2-(1-pyrazolyl)-1,3-thiazine, DMPzTz = 2-(3,5-dimethyl-1-pyrazolyl)-1,3-thiazine, DPhPzTz = 2-(3,5-diphenyl-1-pyrazolyl)-1,3-thiazine] have been prepared and characterized by elemental analysis, electronic spectroscopy, IR spectroscopy, electron paramagnetic resonance spectroscopy, magnetic susceptibility measurements, and single-crystal X-ray diffraction. Influence of ligand size on coordination to Cu(II) has been analyzed. The three complexes are five-coordinate and the coordination geometry can be described as a distorted trigonal bipyramid for 1 or a distorted square pyramid for 2 and 3. As a consequence of the strain induced by the ligands, 1 is a monomeric complex cation whereas 2 is a polymer and 3 is a dimer.

Synthesis and characterization of new Ni(II) complexes with S,N-heterocycle ligands: influence of the steric strain of ligands on coordination

The complexes [NiCl2(PyTn)2] · 2H2O (1), [Ni(H2O)2(PyTn)2](NO3)2 (2), [Ni(H2O)2(PzTz)2]Cl2 (3) and [Ni(H2O)2(PzTz)2](NO3)2 (4) [PyTn = 2-(1-pyrazolyl)-2-thiazoline; PzTz = 2-(1-pyrazolyl)-1,3-thiazine] have been prepared and characterized by elemental analysis, electronic spectroscopy, IR spectroscopy and single crystal X-ray diffraction to determine if the size of the S,N-heterocycle influences coordination to Ni(II). The four complexes are six coordinate as a distorted octahedron. The disposition of chlorides and water is trans in 1 and 2, whereas 3 and 4 are cis, as a consequence of the steric strain induced by the larger S,N-ring.

Effects of the substituents of pyrazole/thiazine ligands on the magnetic properties of chloro-bridged Cu(II) complexes

We have synthesised and characterised the dimeric copper(II) complexes [{CuCl(PzTz)}2(μ-Cl)2], [{CuCl(DMPzTz)}2(μ-Cl)2] and [{CuCl(DPhPzTz)}2(μ-Cl)2] and the monomeric complex [CuCl2(DMPzTz)] (PzTz = 2-(1-pyrazolyl)-1,3-thiazine, DMPzTz = 2-(3,5-dimethyl-1-pyrazolyl)-1,3-thiazine and DPhPzTz = 2-(3,5-diphenyl-1-pyrazolyl)-1,3-thiazine). Single crystal X-ray diffraction studies show that the geometry around the copper(II) center in the dimeric units is a distorted squared pyramid, while the monomeric compound presents a distorted squared planar coordination. The electronic and magnetic properties of complexes are discussed on the basis of their X-ray structures and EPR spectral studies combined with DFT calculations. Magnetostructural comparisons with structurally similar copper(II) complexes are also carried out. DFT calculations indicate that the dinuclear species are more stable than the mononuclear ones, although the inclusion of methyl or phenyl substituents provokes an important stabilization of the mononuclear forms. DFT calculations fail to predict the sign of the magnetic coupling constants of the complexes whereas multiconfigurational methods, CASSCF/NEVPT2 calculations, predict the correct sign of the exchange coupling constant.

Chlorido[1-(4,5-dihydro-1,3-thia-zol-2-yl-κN)ethanone thio-semicarbazonato-κN,S]nickel(II).

In the title compound, [Ni(C6H9N4S2)Cl], the Ni atom is in a slightly distorted square-planar environment coordinated by a Cl atom and a deprotonated thiosemicarbazone ligand via its thiazoline N, azomethine N and thiolate S atoms. Short intermolecular N—H⋯Cl and C—H⋯S contacts are present in the crystal structure.