The ligand, salicylaldehyde Girard-T hydrazonium chloride, [H 2 SalGT]Cl (1), and two complexes [Cu(HSalGT)X 2 ] · H 2 O (X = Br(2); Cl(3)) were synthesized and their crystal structures were determined by singlecrystal X-ray analysis. In the two isostructural complexes, the Cu(II) is located in a square-pyramidal environment, with the chelating ligand and one halogen atom in the basal plane and the second halogen in the apical position. The most apparent structural difference between the 1 and its complexes 2 and 3 is the orientation of the N(CH 3 ) 3 group: in 1, it is practically coplanar to the rest of the molecule, while in 2 and 3 it is oriented to the side of the axially bonded halogen, which can be explained by the C-H. . .X intramolecular interactions. The compounds were characterized by elemental analysis, molar conductivity, magnetic susceptibility and electronic absorption spectra.

Five pentacoordinate copper(II) complexes with 2‐acetylpyridine or di(2‐pyridyl) ketone 1‐adamantoyl hydrazone ligands (Adpy and Addpy, respectively) of the formulae [CuCl2(Adpy)] (1), [Cu2(μ‐Cl)2(Adpy‐H)2] (2), [Cu(NCS)2(Adpy)] (3), [Cu2(μ‐Cl)2(Addpy‐H)2] (4), and [Cu2(NCS)2(μ‐Addpy‐H)2] (5) were synthesized and characterized by spectral, electrochemical, and X‐ray structural analysis. Flow cytometry and morphological analysis confirmed that the copper(II) complexes 2 and 5 induced accumulation of a sub‐G1 phase population, and fluorescence microscopy indicated the presence of large cells in apoptosis. The interaction of the copper(II) complexes with calf thymus DNA (CT‐DNA) was monitored by changes in their UV/Vis spectra. The observed intrinsic binding constants for 2 and 5 (Kb = 1.77 × 106 and 3.58 × 106 M–1, respectively) together with ethidium displacement fluorescence experiments indicate intercalative binding. Complexes 2 and 5 showed nuclease activity against pUC19 plasmid DNA.

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Please cite this article as: L.S. Vojinović-Ješić, M.M. Radanović, M.V. Rodić, V. Živković-Radovanović, L.S. Jovanović, V.M. Leovac, Syntheses and characterization of 2-acetylpyridine-aminoguanidine and its copper(II) complexes: Crystallographical and antimicrobial study, Polyhedron (2016), doi: http://dx. AbstractThe syntheses, physico-chemical and microbiological properties of the ligand, 2acetylpyridine-aminoguanidine dihydrogensulfate monohydrate and its five complexes with Cu(II) are described. The compounds were characterized by single crystal X-ray crystallography. Common fragments encountered in some of the structures were compared by r.m.s. overlay calculations as well as half-normal probability plots. In these complexes the chelate ligand is coordinated in its neutral form in a tridentate N 3 -coordination mode, via pyridine, azomethine and imino nitrogen atoms of the aminoguanidine fragment. In these complexes the Cu(II) ion is situated in moderately or severely distorted square-pyramidal surroundings. The antimicrobial activity of the ligand and the complexes were examined against 6 selected bacterial and 3 fungal strains.structural and antimicrobial properties of the ligand, 2-acetylpyridine-aminoguanidine dihydrogensulfate monohydrate and its Cu(II) complexes. Experimental Materials and physical measurementsAll commercially obtained reagent-grade chemicals were used without further purification. The ligand 2-acetylpyridine-aminoguanidine dihydrogenchloride, L·2HCl, was prepared according to a previously described procedure [18] with a slight modification.Elemental analyses (C, H, N and S) of the air-dried compounds were carried out by standard micro-methods in the Center for Instrumental Analyses, ICTN in Belgrade. The chlorine content was determined by potentiometric titration using AgNO 3 . The compound was combusted using the Schoeniger method [19] and the products were absorbed in a solution of H 2 O 2 and KOH. Molar conductivity measurements of freshly prepared 1 mM solutions were performed on a Jenway 4010 conductivity meter. IR spectra were recorded on a Nicolet Nexus 670 FTIR (Thermo Scientific) spectrophotometer in the range 400-4000 cm -1 by the KBr pellet technique. Electronic spectra of DMF solutions of the ligand and the complexes were recorded on a T80+UV-Vis spectrometer (PG Instruments, Ltd.), in the spectral range 270-1000 nm. Syntheses L·2HCl, 2-acetylpyridine-aminoguanidine dihydrogenchlorideAminoguanidine-hydrogencarbonate (3.4 g, 25 mmol) was dissolved in 25 mL 2N HCl. After the addition of 2-acetylpyridine (2.8 mL, 25 mmol) the reaction mixture was heated for 1 h. The obtained microcrystalline product was evaporated nearly to dryness, using hot air, filtered in vacuo and washed with MeOH. Yield: 4.37 g (70%). Single crystals of the ligand were obtained by recrystallization from warm MeOH. Anal. Calc. for C 8 H 13 N 5 Cl 2 : C, 38.43; H, 5.20; N, 28.01; Cl, 28.34. Found: C, 38.10; H, 5.47; N, 27.76; Cl,27.99%. Conductivity [Λ M /Ω −1 cm 2 mol −1 ]: 170 (in MeOH). Selected IR ba...

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There is a complex interplay between the structural and other physicochemical properties of new compounds and the molecules in living organisms. To understand the mechanism of the interactions at the molecular level, the correlations between the selected properties and their biological responses have to be examined. With this aim, in this paper, density functional theory (DFT) and LMP2 calculations were carried out for the 2-acetylpyridine-aminoguanidine ligand, L, and its copper(II) complexes containing different monoanionic ligands. In addition, several parameters, most frequently used for the prediction of drug-likeness of new compounds, were calculated. The influence of the compounds on the effectiveness of the reference chemotherapeutic drug cisplatin was determined in vitro, by comparison of their combination indices (CIs). The drug interactions between cisplatin and the earlier synthesized ligands L1 (bis(3-chloropyridazine-6-hydrazone)-2,6-diacetylpyridine) and L2 (bis(phthalazine-1-hydrazone)-2,6-diacetylpyridine) and their Co(III), Ni(II), Cu(II) and Zn(II) complexes, respectively, were also measured. The ligands L, L2, and L3, as well as their complexes, showed different interactions in combination with cisplatin from strong antagonism of L to strong synergism of 4-L1 and 4-L2. The experimental results and the calculated parameters were analyzed to evaluate their correlation with the measured interactions. The thermal stability of the LÁ2HCl ligand and its four copper(II) complexes was determined and the thermal stability data were correlated to selected calculated molecular descriptors.

This is the first review dealing with the coordination chemistry of metal complexes with Girard's reagents and their hydrazones. The short introduction points out to chemical properties and significance of these organic compounds. The next section briefly describes synthetic methods for preparing complexes with Girard's reagents, as well as modes of coordination of these ligands. The last two extensive sections review the preparation, stereochemistry and structural characteristics of metal complexes with Girard's hydrazones, including some newer non-hydrazonic derivatives of Girard's reagents, also.[Acknowledgments. Projekat Ministarstva nauke Republike Srbije, br. 172014