Gun Binzet

Synthesis, characterization and antimicrobial activities of transition metal complexes of N,N -dialkyl- N′ -(2-chlorobenzoyl)thiourea derivatives

N,N-di-n-propyl-N′-(2-chlorobenzoyl)thiourea (HL1) (1), N,N-diphenyl-N′-(2-chlorobenzoyl)thiourea (HL2) (2), and their NiII, CoII, CuII, ZnII, PtII, CdII and PdII complexes have been synthesized and characterized. HL1 and its copper complex were characterized by single-crystal X-ray diffraction methods. The ligands coordinate as bidentates yielding essentially neutral complexes of the type [ML2]. The complexes were screened for their in vitro antibacterial, antifungal activities and toxicity. All compounds showed antimicrobial activity, but antibacterial efficacy is greater than antifungal activity.

Synthesis and characterization of Cu(II) and Ni(II) complexes of some 4-bromo- N -(di(alkyl/aryl)carbamothioyl) benzamide derivatives

4-Bromo-N-(di-R-carbamothioyl)benzamide (R = methyl, ethyl, n-propyl, n-butyl and phenyl) ligands and their Ni(II) and Cu(II) complexes have been synthesized and characterized by elemental analyses, FT-IR and 1H-NMR spectroscopy. The crystal and molecular structure of bis(4-bromo-N-(di-n-propylcarbamothioyl)benzamido)nickel(II) has been determined from single crystal X-ray diffraction data. It crystallizes in the triclinic, space group P 1, Z = 2 with a = 9.286(2) Å, b = 13.215(3) Å, c = 14.125(3) Å, α = 64.180(5)°, β = 85.483(6)°, γ = 83.067(5)°, V = 1548.3(7) Å3 and D Calcd = 1.594 mg m−3. Loss of the N–H proton resonance and the N–H stretching vibration and the shift of the ν C=O and ν C=S stretching vibrations confirm formation of the metal complexes. These studies have shown that the metal complexes are neutral cis-[ML2].

Synthesis and characterization of N -(alky(aryl)carbamothioyl)cyclohexanecarboxamide derivatives and their Ni(II) and Cu(II) complexes

N-(R-carbamothioyl)cyclohexanecarboxamides (R: diethyl, di-n-propyl, di-n-butyl, diphenyl and morpholine-4) and their Ni(II) and Cu(II) complexes have been synthesized and characterized by elemental analyses, FT-IR and NMR methods. N-(diethylcarbamothioyl)cyclohexanecarboxamide, HL1, C12H22N2OS, crystallizes in the orthorhombic space group P212121, with Z = 4, and unit cell parameters, a = 6.6925(13) Å, b = 9.0457(18) Å, c = 22.728(5) Å. The conformation of the HL1 molecule with respect to the thiocarbonyl and carbonyl moieties is twisted, as reflected by the torsion angles O1–C6–N2–C5, C6–N2–C5–N1 and S1–C5–N2–C6 of 1.68°, −67.47° and 115.50°, respectively. The structure of HL1 also shows a delocalization of the π electrons of the thiocarbonyl group over the C–N bonds. The ring puckering analysis shows that the cyclohexane ring has a chair conformation. The bis(N-(morpholine-4-carbonothioyl)cyclohexane carboxamido)nickel(II) complex, Ni(L5)2, C24H38N4NiO4S2, crystallizes in the monoclinic space group P21/c, with Z = 4, and unit cell parameters, a = 16.919(3) Å, b = 8.3659(17) Å, c = 19.654(4) Å, β = 107.43(3)°. Ni(L5)2 is a cis-complex with a slightly distorted square-planar coordination of the central nickel by two oxygen and two sulfur atoms.

4-Chloro-N-[N-(6-methyl-2-pyrid­yl)car­bamo­thio­yl]benzamide

In the title compound, C14H12ClN3OS, the short exocyclic N—C bond lengths indicate resonance in the thiourea part of the molecule. The title compound is stabilized by an intramolecular N—H⋯N hydrogen bond, which results in the formation of a six-membered ring. In addition, it shows a synperiplanar conformation between the thiocarbonyl group and the pyridine group. Intermolecular N—H⋯S and C—H⋯O interactions are also present.

Synthesis and Characterization of N-(2,2-Diphenylacetyl)- N′-Substituted Thiourea Derivatives: The Crystal Structure of N-(2,2-Diphenylacetyl)-N′-(4-chloro phenyl)-thiourea

A series of new N-(2,2-diphenylacetyl)-N ′-substituted thiourea derivatives (1–9) have been prepared and characterized by elemental analyses, IR and 1H NMR spectroscopy. N-(2,2-diphenylacetyl)-N ′-(4-chlorophenyl)-thiourea was also characterized by a single crystal X-ray diffraction study. The compound crystallizes in the monoclinic space group P21/c with Z = 4 and a = 9.6551(19) Å, b = 20.060(4) Å, c = 9.894(2) Å, β = 104.29(3)°. The molecular conformation of the compound is stabilized by an intramolecular (N1-H1···O1) hydrogen bond that forms a pseudo-six-membered ring.

Synthesis and Characterization of Novel Thiourea Derivatives and Their Nickel and Copper Complexes

New benzoyl thiourea derivatives and their nickel and copper complexes were synthesized. The structure of the synthesized compounds were confirmed by elemental analysis, FT-IR, and 1H NMR techniques. Four of the synthesized compounds are analyzed by X-ray single crystal diffraction technique. Whereas N,N-dimethyl-N′-(4-fluorobenzoyl)thiourea, N,N-diethyl-N′-(4-fluorobenzoyl)thiourea, and N,N-di-n-butyl-N′-(4-fluorobenzoyl) thiourea crystallize in the monoclinic system, bis(N,N-di-n-propyl-N′-(4-fluorobenzoyl)thioureato) nickel(II) complex crystallizes in the triclinic system. These ligand molecules form dimers through strong intermolecular hydrogen bonds such as N–H⋯S, C–H⋯O, and N–H⋯O. Moreover, there are different types of intramolecular interactions in the crystal structures. Bis(N,N-dimethyl-N′-(4-fluorobenzoyl)thioureato) nickel(II) complex has a nearly square-planar coordination. The distance of nickel atom from the best plane through the coordination sphere is 0.029 A.

4-Bromo-N-(di-n-propyl­carbamothioyl)­benzamide

The synthesis of the title compound, C14H19BrN2OS, involves the reaction of 4-bromobenzoyl chloride with potassium thiocyanate in acetone followed by condensation of the resulting 4-bromobenzoyl isothiocyanate with di-n-propylamine. Typical thiourea carbonyl and thiocarbonyl double bonds, as well as shortened C—N bonds, are observed in the title compound. The short C—N bond lengths in the centre of the molecule reveal the effects of resonance in this part of the molecule. The asymmetric unit of the title compound contains two crystallographically independent molecules, A and B. There is very little difference between the bond lengths and angles of these molecules. In molecule B, one di-n-propyl group is twisted in a −antiperiplanar conformation with C—C—C—H = −179.1 (3)° and the other adopts a −synclinal conformation with C—C—C—H = −56.7 (4)°; in molecule A the two di-n-propyl groups are twisted in + and −antiperiplanar conformations, with C—C—C—H = −179.9 (3) and 178.2 (3)°, respectively. In the crystal, the molecules are linked into dimeric pairs via pairs of N—H⋯S hydrogen bonds.

Determination of the Ionization Constants of Some Benzoyl Thiourea Derivatives in Dioxane-Water Mixture

The stoichiometric ionization constants of N,N-dialkyl--(4-substituted benzoyl) thiourea (Substitutes: H, Cl, and Br; alkyl groups: ethyl, n-propyl, n-butyl, and phenyl) derivatives have been determined potentiometrically in dioxane-water (v:v, 50:50) mixture at ionic strength of 0.1 M and °C. The ionization constants were calculated with the BEST computer program and the formation curves using the data obtained from the potentiometric titrations. The effects of substituents and alkyl groups on the ionization constants of the benzoyl thiourea derivatives have been investigated. A comparison of the basicities of ethyl, n-propyl, and n-butyl thiourea derivatives shows that the n-butyl group is a more powerful electron-releasing group than the other groups in 50% dioxane-50% water mixture (v:v). So, the acidity of benzoyl thiourea derivative compounds decreases, while the length of alkyl chain increases. The orders of values for all thiourea derivatives are as expected in the light of steric, resonance and inductive effects of substituents. Furthermore, when the basicities of halogen derivatives of the same substitution pattern are compared, orders obtained (4-Br -Cl -H) can be explained by considering the total electronic substituent effect (electron-withdrawing and electron-donating effects) except the 4-Br_Ph derivative.

N-(Diphenyl­carbamothio­yl)-3-methyl­benzamide

The synthesis of the title compound, C21H18N2OS, involves the reaction of 3-methylbenzoyl chloride with potassium thiocyanate in dry acetone followed by condensation of the 3-methylbenzoyl isothiocyanate with diphenylamine. The carbonyl [C—O = 1.215 (2) Å] and thiocarbonyl [C—S = 1.6721 (17) Å] distances indicate that these correspond to double bonds. The short C—N bonds at the center of the molecule reveal the effects of resonance in this part of the molecule. The conformation of the molecule with respect to the thiocarbonyl and carbonyl groups is twisted. The 3-methylphenyl and two phenyl rings are also twisted, with dihedral angles of 75.67 (9) and 14.91 (9)°. The phenyl rings are rotated out of the mean plane of the N—C—S—N atoms by 66.87 (8) and 78.40 (9)°. Pairs of molecules are linked into centrosymmetric dimers via intermolecular N—H⋯S interactions and a C—H⋯O link also occurs. The dimers are stacked along the a axis.

4-Bromo-N-(diethyl-carbamothio-yl)-benzamide.

The synthesis of the title compound, C12H15BrN2OS, involves the reaction of 4-bromobenzoyl chloride with potassium thiocyanate in dry acetone, followed by condensation of 4-bromobenzoyl isothiocyanate with diethylamine. The carbonyl and thiocarbonyl bond lengths indicate that these correspond to double bonds. The short C—N bond lengths reveal the effects of resonance in this part of the molecule. The conformation of the molecule with respect to the thiocarbonyl and carbonyl units is twisted, with torsion angles of −5.7 (3) and 87.2 (2)°. The N atom of the diethylamine group is sp 2-hybridized: the sum of the angles around the N atom is 359.97 (14)°. The two diethyl groups are twisted in + and − antiperiplanar conformations with angles of −179.89 and 179.92°. In the crystal structure, the molecules form infinite chains via an intermolecular N—H⋯O interaction.