Coordination of cobalt(III), nickel(II), copper(II), palladium(II) and platinum(II) with N-ethyl-N′-(4′-methylthiazol-2′-yl)thiourea (HL)

Thiourea Derivatives in Agrochemical Discovery and Development

Thiourea, represented by the chemical formula (R1R2N)(R3R4N)C═S, is a significant organic sulfur compound characterized by the presence of a sulfur atom and two amino groups. Meanwhile, thiourea and isothiourea are reciprocal isomers. This structure facilitates the formation of a biologically active moiety, which is interconnected through double bonds between the sulfur atom and the nitrogen atoms. As a potent component in pesticide formulations, thiourea demonstrates efficacy in safeguarding crops against a variety of diseases by inhibiting the growth and reproduction of pathogens. This review aims to provide a comprehensive summary of thiourea derivatives exhibiting fungicidal, insecticidal, antiviral, herbicidal, and plant growth regulatory properties, with the objective of offering new perspectives for identifying innovative thiourea-based pesticides and elucidating their mechanisms of action.

Coordination of Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II), Pd(II) and Pt(II) with 2,5-hexanedione bis(thiosemicarbazone), HBTS: crystal structure of cis-[Pd(HBTS)]Cl2 and 1-(2,5-dimethyl-1H-pyrrol-yl)-thiourea

Metal complexes of Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+, Pd2+ or Pt2+ with 2,5-hexanedione bis(thiosemicarbazone), HBTS; have been prepared and spectroscopically investigated. The empirical formulae of the complexes were suggested based on the elemental analysis. Single crystal of Pd(II) has been solved to be cis-form of square-planar geometry by the X-ray crystallography. 1H and 13C NMR spectra have been recorded for HBTS, Zn(II), Cd(II), Hg(II), Pd(II) and Pt(II) complexes, in DMSO-d6, showing the mode of chelation. The ligand acts as a neutral or a binegative tetradentate (N2S2) or neutral bidentate on the basis of FT-IR. The magnetic moments and electronic spectra provide information about the geometry of the complexes which supported by calculating the ligand field parameters for the Co(II) and Fe(III) complexes. The Ni(II) complex has subnormal magnetic moment (0.71 BM) indicative of a mixed stereochemistry of square-planar and tetrahedral structure. [Cu(HBTS-2H)] measured 0.93 BM indicating high interaction between the copper centers. The ligand may be ordered at the top of the spectrochemical series which giving high ligand field splitting energy (10 Dq=17,900 cm(-1) for Co2+ complex). The mass spectra of some complexes proved their stable chemical formulae while the TGA depicts the degradation steps and the final residue. In evaporating the mother liquor during the preparation of HBTS, new compound is obtained naming 1-(2,5-dimethyl-1H-pyrrol-yl)thiourea and its crystal was solved.