New multifunctional heterobinuclear palladium (II) complexes based on organometallic dithiocarbazate ligands

In the research of new compounds with multifunctional applications, heterobinuclear palladium (II) complexes based on organometallic dithiocarbazates (DTCZs) have been isolated. The organometallic DTCZ ligands of the general formula [{(η⁵-C₅H₄)-CH=NNHC(S)SCH₃}]MLn [MLn = Re (CO)₃ ( 2a ); Mn (CO)₃ ( 2b ); FeCp ( 2c )] were prepared by the reaction between formyl organometallic precursors ( 1a−c ) with S-methyldithiocarbazate. Subsequently, a two-step reaction of 2a−c with: (i) K₂[PdCl₄] and (ii) PPh₃ yielded heterobinuclear complexes [Pd{MLn(η⁵-C₅H₄)-CH=NNHC(S)SCH₃}–(Cl)(PPh₃)] [MLn = Re (CO)₃ ( 3a ); Mn (CO)₃ ( 3b ); FeCp ( 3c )]. All compounds were characterized by conventional spectroscopic techniques (infrared spectroscopy, nuclear magnetic resonance spectroscopy, mass spectrometry and elemental analysis). In addition, the molecular structures of 2a , 2c and 3c were determined by single-crystal X-ray diffraction. The new palladium (II) complexes ( 3a−c ) were evaluated as antiproliferative agents against non-small cell lung cancer cells (H1299 cells). Complexes 3a and 3b containing cyrhetrenyl- and cymantrenyl-DTCZ ligands, respectively, were more active than their ferrocenyl analogue 3c . The activity was associated with the electron-withdrawing properties of the (η⁵-C₅H₄)M (CO)₃ moieties and their better lipophilicity than that of the ferrocenyl analogue. In addition, we studied the capacity of metalloligands ( 2a−c ) and palladium (II) complexes ( 3a−c ) to remove methylene blue in water under UV–visible light irradiation. The results established that the complexes showed moderate efficiency and were less active than their corresponding free ligands.     

Synthesis,characterization, X-ray structure,electrochemistry, photocatalytic activity and DFT studies of heterotrinuclear Ni(II), Pd(II) and Zn(II) complexes containing a formylferrocene thiosemicarbazone ligand

Three complexes of the general formula M{CpFe(η⁵-C₅H₄CH=N–N=C(S)NH₂}₂ [where M = Ni^II ( 2a ), Pd^II ( 2b ) and Zn^II ( 2c )] were synthesized with formylferrocene thiosemicarbazone ( 1 ) as a bidentate ligand. All compounds were characterized using conventional spectroscopic and analytical techniques (infrared, ¹H and ¹³C NMR, mass spectrometry and elemental analysis). The molecular structure of 2b was confirmed by single-crystal X-ray analysis. To study the photocatalytic activity of the new complexes ( 2a–c ), methylene blue (MB) was selected as a model pollutant. After 180 min, the degradation efficiency of MB reached 87% for 2a , 76% for 2b and 85% for 2c , and all complexes showed a higher photocatalytic activity than the formylferrocene thiosemicarbazone free ligand 1 . Theoretical studies were used to characterize the geometry and electronic structure of the compounds and to provide a rational explanation for the measured photocatalytic activity.