Nickel(II) complexes of 4-acetamidobenzaldehyde N(4)-substituted thiosemicarbazones

Nickel(II) complexes with five 4-acetamidobenzaldehyde N(4)- substituted thiosemicarbazones have been prepared in EtOH solution and characterized by physical and spectral methods. N.m.r., i.r. and electronic spectra of the thiosemicarbazones and their complexes, along with physical properties of the complexes, have been recorded. These thiosemicarbazones coordinate as anionic ligands via the thiosemicarbazone moiety's azomethine nitrogen and thiolate sulfur [upon loss of the N(2) hydrogen] when reacted with NiCl2 in the presence of Et3N or with Ni(OAc)2.     

Copper(II) complexes of 4-formylantipyrine N(4)-substitutedthiosemicarbazones

Copper(II) complexes between three 4-formylantipyrine N(4)-substituted thiosemicarbazones and four copper(II) salts have been prepared and characterized. I.r., electronic and e.s.r. spectra of the complexes, as well as i.r., electronic and 1H and 13C-n.m.r. spectra of the thiosemicarbazones, have been obtained. Both mononuclear and binuclear complexes have been formed with bridging ligands for the latter, being either chloro or acetato. The stoichiometries of the complexes are dependent on both the steric requirements of the thiosemicarbazone ligands and the electronic effects of their N(4)-substituents.     

Copper(II) complexes of 4-acetamidobenzaldehyde N(4)-substituted thiosemicarbazones

Mononuclear and binuclear copper(II) complexes with four 4-acetamidobenzaldehyde N(4)-substituted thiosemicarbazones have been prepared in EtOH solution and characterized by physical and spectral methods. I.r., electronic, and e.s.r. spectra of the complexes, as well as i.r., electronic, and n.m.r. spectra of the thiosemicarbazones, have been obtained. These thiosemicarbazones coordinate as anionic or neutral ligands via the thiosemicarbazone moiety's imine nitrogen and thiolate/thione sulfur, the former on loss of the hydrazido hydrogen, N(2)H.     

Copper(II) complexes of formylpyrazine N(4)-substituted thiosemicarbazones

Copper(II) complexes of formylpyrazine N(4)-substituted thiosemicarbazones coordinated either as neutral or monoanionic ligands, [M(HL)X2] and [M(L)X], respectively, have been prepared and characterized. I.r., electronic and e.s.r spectra of the complexes, as well as 1H-n.m.r. spectra of the thiosemicarbazones, have been obtained. The N(4)-dialkyl and azacyclothiosemicarbazones and their copper(II) complexes show significant growth inhibitory activity against both Aspergillus niger and Paecilomyces variotii.     

Nickel(II) complexes of 2-aminoacetophenone N(4)-substituted thiosemicarbazones

Mononuclear nickel(II) complexes with 2-aminoacetophenone thiosemicarbazones and three N(4)-substituted thiosemicarbazones have been prepared in EtOH solution and characterized by physical and spectral methods. I.r. and electronic spectra of the thiosemicarbazones and their complexes, along with physical properties of the complexes, have been obtained. The 2-aminoacetophenone thiosemicarbazones coordinate both as neutral and anionic ligands via the thiosemicarbazone moiety's azomethine nitrogen and thione/thiolato sulfur [on loss of the N(2) hydrogen].     

Cobalt(II) complexes with 2-aminoacetophenone N(4)-substituted thiosemicarbazones

Cobalt(II) complexes with 2-aminoacetophenone thiosemicarbazone and three N(4)-substituted thiosemicarbazones have been prepared in EtOH solution and characterized by physical and spectral methods. I.r. and electronic spectra of the thiosemicarbazones and their complexes, along with physical properties of the complexes, have been obtained. The 2-aminoacetophenone thiosemicarbazones coordinate both as neutral and anionic ligands via the thiosemicarbazone moiety's imine nitrogen and thione/thiolato sulfur [on loss of the N(2) hydrogen].     

Copper(II) complexes of 6-methyl-2-acetylpyridine N(4)-substituted thiosemicarbazones

Summary Copper(II) complexes of 6-methyl-2-acetylpyridine N(4)-substituted thiosemicarbazones, coordinated either as a neutral or a monoanionic ligand, have been prepared and characterized. I.r., electronic and e.p.r. spectra of the complexes, as well as¹H- and¹³C-n.m.r. spectra of the thiosemicarbazones, have been recorded. Both the thiosemicarbazones and their copper(II) complexes show either modest or no growth inhibitory activity againstAspergillus niger, but theN(4)-dialkyl- and 3-azacyclo-derivatives, and particularly their copper(II) complexes, have considerable activity againstPaecilomyces variotii.     

Copper(II) complexes of 2-aminoacetophenone N(4)-substituted thiosemicarbazones

Mononuclear copper(II) complexes with 2-aminoacetophenone thiosemicarbazone and three N(4)-substituted thiosemicarbazones have been prepared in ethanolic solution and characterized by physical and spectral methods. I.r., electronic and e.s.r. spectra of the complexes, as well as i.r., electronic, and ¹H- and ¹³C-n.m.r. spectra of the thiosemicarbazones, have been obtained. The 2-aminoacetophenone thiosemicarbazones coordinate as neutral ligands via the thiosemicarbazone moiety's azomethine nitrogen and thione sulfur, except for the piperidylthiosemicarbazone, which undergoes deprotonation and coordinates via the thiolato sulfur, as well as through the azomethine nitrogen. Complexes formed in the presence of triethylamine also form complexes with the anionic form of these thiosemicarbazones.     

Synthesis,magnetic and spectral studies of nickel(II) and zinc(II) complexes of 4-formylantipyrine N(4)-substituted thiosemicarbazones

The synthesis and characterization of nickel(II) and zinc-(II) complexes with 4-formylantipyrine N(4)-methyl-, N(4)-dimethyl- and 3-piperidylthiosemicarbazones are reported. Elemental analyses, molar conductivities, magnetic measurements and spectral (i.r., electronic and n.m.r.) studies have been used to characterize the complexes. The i.r. spectra show that the thiosemicarbazones behave as bidentate or tridentate ligands, either in the thione or thiolato form. Stereochemistries are proposed for the complexes on the basis of spectral and magnetic studies.     

Nickel(II) and copper(II) complexes of 5-substituted-salicylaldehyde thiosemicarbazones

Binuclear nickel(II) and copper(II) complexes with four 5-methoxysalicylaldehyde N(3)-substituted thiosemicarbazones and nickel(II) complexes of four 5-nitro-salicylaldehyde N(3)-substituted thiosemicarbazones have been prepared and characterized. I.r., electronic, and e.s.r. spectra of the complexes, as well as i.r., electronic, and 1H- and 13C-n.m.r spectra of the thiosemicarbazones, have been obtained. None of these compounds show significant growth inhibitory activity against the fungi Aspergillus niger and Paecilomyces variotii.     

Ruthenium(II) 2-hydroxybenzophenone N(4)-substituted thiosemicarbazone complexes

New ruthenium(II) complexes with 2-hydroxybenzophenone N(4)-substituted (Me, Ph and/or piperidyl) thiosemicarbazones have been prepared and characterised by elemental analysis, molar conductivity, thermal analysis, spectroscopy (i.r., ¹H-n.m.r. and u.v.–vis.) and by cyclic voltammetry. The thiosemicarbazones coordinate to ruthenium(II) as mononegative tridentate ligands via the deprotonated hydroxyl group, N¹ nitrogen and thione sulphur centres. The redox properties, nature of the electrode processes and the stability of the complexes towards oxidation in CH₂Cl₂ are discussed. The change in the E _1/2 values of the complexes can be related to the basicity of the N(4)-substituents. All the complexes display an irreversible one-electron charge-transfer couple in the potential range studied. This revised version was published online in June 2006 with corrections to the Cover Date.     

Copper(II) and nickel(II) complexes of pyruvaldehyde bis{N(3)-substituted thiosemicarbazones}

Copper(II) and nickel(II) complexes of pyruvaldehyde bis{N(3)-methyl-, bis{N(3)-ethyl-, bis{N(3)-dimethyl- and bis{piperidylthiosemicarbazone} have been prepared and studied spectroscopically. The four thiosemicarbazones have been characterized by their melting points, as well as i.r., electronic and n.m.r. (1H,13C) spectra. The four coordinate copper(II) complexes have been studied by e.s.r. spectroscopy, and the copper(II) and nickel(II) complexes by several of the spectroscopic techniques mentioned above. Upon formation of these complexes, loss of protons from each thiosemicarbazone moiety occurs, and the bis(thiosemicarbazones) coordinate to the metal centres as dianionic, tetradentate N2S2 ligands.     

Copper(II) and nickel(II) complexes of the bis{N(3)-substituted thiosemicarbazones} of phenylglyoxal and 1-phenylpropane-1,2-dione

Copper(II) and nickel(II) complexes of phenylglyoxal and phenylpropane-1,2-dione bis{N(3)-methyl-, bis{N(3)-dimethyl-, bis{piperidylthiosemicarbazone} have been prepared and studied spectroscopically. The six bis(thiosemicarbazones) have been characterized by their melting points, as well as i.r., electronic and 1H-n.m.r. spectra. The four-coordinate copper(II) complexes have been studied by e.s.r. spectroscopy, and the copper(II) and nickel(II) complexes by spectroscopic techniques mentioned above. Upon formation of these complexes, the loss of protons from each thiosemicarbazone moiety occurs, and the bis(thiosemicarbazones) coordinate to the metal centres as dianionic, tetradentate N2S2 ligands.     

Copper(II) and nickel(II) complexes of glyoxaldehyde bis{N(3)-substituted thiosemicarbazones}

Copper(II) and nickel(II) complexes of glyoxaldehyde bis{N(3)-methyl-, bis{N(3)-ethyl-, bis{N(3)-dimethyl-, bis{piperidyl- and bis{hexamethyleneiminylthiosemicarbazone} have been prepared and studied spectroscopically. The five bis(thiosemicarbazones) have been characterized by their melting points, as well as i.r., electronic and 1H-n.m.r. spectra. The four-coordinate copper(II) complexes have been studied by e.s.r. spectroscopy, and the copper(II) and nickel(II) complexes by a number of the spectroscopic techniques mentioned above. Upon formation of these complexes, loss of protons from each thiosemicarbazone moiety occurs, and the bis(thiosemicarbazones) coordinate to the metal centres as dianionic, tetradentate N2S2 ligands. This revised version was published online in June 2006 with corrections to the Cover Date.     

Structural and spectral studies of copper(II) and nickel(II) complexes of pyruvaldehyde mixed bis{N(4)-substituted thiosemicarbazones}

Pyruvaldehyde mixed bis(thiosemicarbazones) have been prepared in which the two thiosemicarbazone moieties have different N(4)-substituents. The mixed bis(thiosemicarbazones) and their copper(II) and nickel(II) complexes have been characterized with IR, electronic, mass, ¹H NMR (Ni) and EPR (Cu) spectra. Representative crystal structures have been solved of nickel(II) complexes with either a pyruvaldehyde mixed bis(thiosemicarbazone) or a bis(thiosemicarbazone) with identical N(4)-substituents acting as a tetradentate ligand. [Ni(Pu4M4DE)] has an N(4)-methylthiosemicarbazone substituent on the keto “arm” and N(4)-diethylthiosemicarbazone substituent on the aldehyde arm. [Ni(Pu4M)] contains two N(4)-methylthiosemicarbazone moieties. Both bis(thiosemicarbazones) form square-planar N₂S₂ complexes with nickel(II) and copper(II).     

Copper(II) complexes of formyl- and acetylpyrazine N(4)- (2–methylpyridinyl)-, N(4)-(2–ethylpyridinyl)- and N(4)-methyl- (2–ethylpyridinyl)thiosemicarbazones

The title complexes of general formula [Cu(HL)Cl2] or [Cu(L)Cl] were isolated from boiling EtOH. The thiosemicarbazones have been characterized by their 1H- and 13C-n.m.r., i.r. and electronic spectra. The i.r., electronic and e.s.r. spectra of the copper(II) complexes are compared with data on previously studied complexes. The antitumour and antiviral activities of the thiosemicarbazones and their complexes are discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Binuclear copper(II) complexes of 5-nitrosalicylaldehyde N(3)-substituted thiosemicarbazones

Summary Binuclear copper(II) complexes with six 5-nitrosalicylaldehyde N(3)-substituted thiosemicarbazones have been prepared and characterized. I.r., electronic and e.s.r. spectra of the complexes, as well as i.r., electronic, and ¹H-and ¹³C-n.m.r. spectra of the thiosemicarbazones, have been obtained. The crystal structure of a monomeric copper(II) complex of 5-nitrosalicylaldehyde piperidyl-thiosemicarbazone, H₂5NO₂Sapip, grown from DMF solution, has been solved. Neither the thiosemicarbazones or their binuclear copper(II) complexes show growth inhibitory activity against Aspergillus niger, but the copper(II) complexes show some activity against the fungus Paecilomyces variotii.     

Spectral and biological studies of copper(II) complexes of 2-acetyl-pyridine thiosemicarbazones with bulky 4N-substituents

Summary Copper(II) complexes of a large number of 2-acetylpyridine ⁴N-alkyl thiosemicarbazones were prepared and characterized. I.r., electronic and e.s.r. spectra of the complexes, as well as ¹H and ¹³C n.m.r. spectra of the thiosemicarbazones, were obtained. Both the thiosemicarbazones and their complexes show either modest or no growth inhibitory activity against Aspergillus niger, but many have considerable activity against Paecilomyces variotii. There is a relationship between the antifungal activity and size of the ⁴N-substituent for both the thiosemicarbazones and their copper(II) complexes.     

Synthesis,magnetic and spectral studies of iron(III) and cobalt(II,III) complexes of 4-formylantipyrine N(4)-substituted thiosemicarbazones

The synthesis and characterization of complexes of iron(III), cobalt(II) and cobalt(III) with 4-formylantipyrine N(4)-methyl-, N(4)-dimethyl-, and 3-piperidylthiosemicarbazones are reported. Elemental analyses, molar conductivities, magnetic measurements and spectral (i.r., electronic and e.s.r.) studies have been used to elucidate the nature of the metal complexes. The i.r. spectra show that the thiosemicarbazones behave as bidentate or tridentate ligands, either in the thione or thiolato form. Different stereochemistries are proposed for the various cobalt(II) complexes on the basis of spectral and magnetic studies. This revised version was published online in June 2006 with corrections to the Cover Date.     

Synthesis,magnetic and spectral studies of iron(III), cobalt(II,III), nickel(II), copper(II) and zinc(II) complexes of 4–formylantipyrine N(4)-antipyrinylthiosemicarbazone

4–Formylantipyrine N(4)-antipyrinylthiosemicarbazone and its metal complexes have been synthesized and characterized. Elemental analyses, molar conductivities, magnetic measurements and spectral (i.r., electronic, n.m.r., e.s.r.) studies have been used to characterize the complexes. The i.r. spectra show that the thiosemicarbazones behave as bidentate (NS) or tridentate ligands (ONS), either in the thione or thiolato form. Stereochemistries are proposed for the complexes on the basis of both spectral and magnetic studies.