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[Zn(L)2] (1) and [(Ph)2Sn(L)(CH3COO)] (2), where HL = 2-benzoylpyridine N(4)-cyclohexylthiosemicarbazone, have been synthesized and characterized. The complexes show different coordination depending on their coordinating preferences. Biological studies carried outin vitroagainst human leukemia K562 cells show that the diorgantin(IV) complex,2, has significant cytotoxicity with IC50 = 3.3 ± 0.5 ?M. [ABSTRACT FROM AUTHOR]

Abstract: Two metal complexes formulated as [Zn(L)2]2·H2O (1) and [Bi(L)(NO3)2(CH3OH)] (2), where HL=2-acetylpyrazine N(4)-phenylthiosemicarbazone, have been synthesized and characterized by elemental analysis, IR, MS, NMR and single-crystal X-ray diffraction studies. Biological studies, carried out in vitro against selected bacteria and the K562 leukemia cell lines, respectively, have shown that the free ligand and its two complexes may be endowed with important biological properties, especially HL with MIC=3.90μg/mL against Pseudomonas aeruginosa, the zinc(II) complex 1 with IC50 =1.0μM against K562 leukemia cell lines, respectively. The compounds HL and 1 may exert their cytotoxicity activity via induced loss of mitochondria membrane potential (MMP). [Copyright &y& Elsevier]

Abstract: 4-Cyclohexyl-1-(1-(pyrazin-2-yl)ethylidene)thiosemicarbazide (HL) and its transition metal complexes formulated as [Mn(L)2] (1) and [Ni(L)2] (2) have been prepared in 55–75% yield and characterized by elemental analysis, IR, MS, NMR and single-crystal X-ray diffraction studies. Biological activities of the synthesized compounds have been evaluated against selected Gram positive bacteria Bacillus subtilis, Gram negative bacteria Pseudomonas aeruginosa and the K562 leukemia cell line, respectively. The cytotoxicity data suggest that these compounds may be endowed with important biological properties, especially the nickel complex 2 with MIC = 31.2 μg/mL and IC50 = 0.53 μM, respectively. Effect of the free ligand and its two complexes on Mitochondria membrane potential (MMP) and PI-associated fluorescence intensity as well as their effect on cell apoptosis in K562 leukemia cell line was also studied. The tested compounds may exert their cytotoxicity activity via induced loss of MMP. [Copyright &y& Elsevier]

Abstract: Four diorganotin(IV) complexes [(Me)2Sn(L1)(CH3COO)]·CH3CH2OH (1), [(Ph)2Sn(L1)(CH3COO)]·CH3CH2OH (2), [(Me)2Sn(L2)Cl] (3) and [(Ph)2Sn(L2)(CH3COO)] (4) where HL1 = 2-benzoylpyridine N(4)-phenylthiosemicarbazone and HL2 = 2-acetylpyrazine N(4)-phenylthiosemicarbazone have been synthesized and characterized by elemental analysis, IR MS, 1H NMR and single-crystal X-ray diffraction studies. Schiff bases in their deprotonated forms coordinate to tin(IV) via pyridine/pyrazine nitrogen atom and the nitrogen atom and sulfur atoms of the thiosemicarbazone moiety. The tin atom is seven-coordinated in 1, 2 and 4 containing one acetato group, respectively, and six-coordinated in 3 containing one chloride ion. Biological studies, carried out in vitro against selected bacteria and K562 leukaemia cells, respectively, have shown that different substituted groups attached at the thiosemicarbazone moieties and different diorganotin(IV) groups showed distinctive differences in the biological property. [Copyright &y& Elsevier]

Abstract: 2-Acetylpyridine N(4)-cyclohexylthiosemicarbazone (HL) and its manganese(II) and nickel(II) complexes formulated as [Mn(L)2] (1) and [Ni(L)2] (2) have been synthesized and characterized by elemental analysis, infrared spectra, mass spectra, and single-crystal X-ray diffraction studies. In the two complexes, the coordination polyhedron approaches an octahedron, where the two ligands coordinate to the metal via the pyridine nitrogen atom and the nitrogen and sulfur donors of the thiosemicarbazide moiety. Biological studies, carried out in vitro against selected bacteria and K562 leukaemia cell line, respectively, have shown that the free ligand and its complexes exhibited distinct differences in the biological activities. [ABSTRACT FROM AUTHOR]

Abstract: 2-Thiophene N(4)-methylthiosemicarbazone (HL) and its Ag(I) complex of formula [Ag6(L)6⋅4DMF] 1 have been synthesized and characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction studies. The silver(I) complex 1 with a 1:1 metal–ligand molar ratio is an unusual hexanuclear cluster with 6 silver atoms in different environments: four silver atoms of them are considered to be 3-coordinate form, which are coordinated by two thiolate sulfur atoms and one imine nitrogen and the other two silver atoms are considered to be 4-coordinate form, which are coordinated by three thiolate sulfur atoms and one imine nitrogen, with four thiolate sulfur bridging two silver atoms and two thiolate sulfur bridging three silver atoms. Biological studies, carried out in vitro against bacteria, fungi and SMMC-7721 liver cancer cell line, respectively, have shown that the free ligand and the title complex show distinct difference in the biological property. [ABSTRACT FROM AUTHOR]

Abstract: Transition metal complexes Mn(L1)2 (1), Mn(L2)2 (2), Co(L3)2Cl 4H2O (3), Zn(L3)2 DMF (4), Co(HL4)2(ClO4)2 3H2O (5) and Zn(L5)2 DMF (6) where HL1 =2-acetylpyridine thiosemicarbazone, HL2 =2-acetylpyridine N(4)-methylthiosemicarbazone, HL3 =2-benzoylpyridine thiosemicarbazone, HL4 =2-benzoylpyridine N(4)-methylthiosemicarbazone and HL5 =2-benzoylpyridine N(4)-phenylthiosemicarbazone, have been synthesized. The complexes 1, 2, 5 and 6 were characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction studies. Preliminary in vitro screening indicated that all the tested compounds showed significant antitumor activity against K562 leucocythemia cancer cell line. [Copyright &y& Elsevier]

Transition metal complexes [Fe(HL)2]Cl3 ⋅ 1.5H2O (1), [Co(L)2] ⋅ ClO4 ⋅ H2O (2), Ni(HL)2(ClO4)2 ⋅ 2H2O (3), Zn(HL)L ⋅ BF4 ⋅ 2H2O (4), and Cd(HL)2(ClO4)2 ⋅ 2H2O (5), where HL = C7H9N5S, 2-acetylpyrazine thiosemicarbazone, have been synthesized. Complex 2 was characterized by elemental analysis, infrared spectra, mass spectra, and single-crystal X-ray diffraction. Preliminary in vitro screening showed that 1, 4, and 5 exhibit higher antitumor activity than 2 and 3 against K562 leucocythemia cancer cell line. [ABSTRACT FROM AUTHOR]

[Fe(HL)2]Cl3 · 1.5H2O (1), where HL = C7H9N5S, 2-acetylpyrazine thiosemicarbazone, was obtained and fully characterized. X-ray diffraction studies show that complex 1 crystallizes in monoclinic lattice, space group P21/n, with a = 11.342(6), b = 12.547(6), c = 17.056(9) Å, β = 103.551(7)°, V = 2360(2) Å3, Z = 2, Mr = 1159.46, DCalcd = 1.632 g cm-3, μ(Mo-Kα) = 1.188 mm-1, F(000) = 1184, the final R1 = 0.0955 and wR2 = 0.2626. The 2-acetylpyrazine thiosemicarbazone is a tridentate ligand and binds to the metal through the pyrazine nitrogen, the imine nitrogen and the sulfur in the neutral thione form yielding an octahedral geometry. The title iron complex showed significant antitumor activity against the Ec9706 human esophagus cancer cell line with an IC50 value (10.50 µM) in a micromolar range similar to cisplatin. [ABSTRACT FROM AUTHOR]

Abstract: A series of thiosemicarbazone ligands, HL1 (2-acetylpyrazine thiosemicarbazone), HL2 (2-acetylpyrazine N(4)-methylthiosemicarbazone), HL3 (2-benzoylpyridine thiosemicarbazone) and HL4 (2-benzoylpyridine N(4)-methylthiosemicarbazone), have been synthesized. The crystal structure of HL1 has been determined by single-crystal X-ray diffraction. Hydrogen bonds link the different components to stabilize the crystal structure. The antitumor activity of the four ligands were tested against K562 leucocythemia and BEL7402 liver cancer cell lines. All the thiosemicarbazones showed significant antitumor activity. Different substituents on the ligands show different levels of antitumor activity. By comparison with the other thiosemicarbazone species studied, HL4 with substitution at N(4) position in thiosemicarbazone along with 2-benzoylpyridine is the most active thiosemicarbazone ligand with IC50 =0.002μm in the K562 leucocythemia cell line and 0.138μm in the BEL7402 liver cancer cell line, respectively. [Copyright &y& Elsevier]

Abstract: 2-Benzoylpyridine N(4)-cyclohexylthiosemicarbazone (HL) and its binuclear copper(II) complex [Cu2(L)2(CH3COO)](ClO4) (1) have been synthesized and structurally characterized. Biological studies, carried out in vitro against human leukemia K562 cells have indicated that 1 indicates significant cytotoxicity with IC50 =0.37±0.028μM comparable to cisplatin. Complex 1 promotes a dose-dependent apoptosis in HepG2 cells and the apoptosis is associated with an increase in intracellular reactive oxygen species (ROS) production and reduction of mitochondrial membrane potential (MMP). [Copyright &y& Elsevier]

Abstract: Up to now, bismuth(III) complexes with thiosemicarbazones have been comparatively rare. Here, a main group seven-coordinated bismuth(III) complex [Bi(L)(NO3)2(CH3CH2OH)] (1) (HL=2-acetylpyridine N(4)-phenylthiosemicarbazone) has been synthesized and characterized by elemental analysis, IR, 1H NMR and single-crystal X-ray diffraction studies. The cytotoxicity data suggest that 1 exhibits higher in vitro antiproliferative activity in four human cancer cells tested. Its possible apoptotic mechanism has been evaluated in HepG2 cells. Compound 1 promotes a dose-dependent apoptosis in HepG2 cells and the apoptosis is associated with an increase in intracellular reactive oxygen species (ROS) production and reduction of mitochondrial membrane potential (MMP). [Copyright &y& Elsevier]

[Display omitted] • Cd (II) and Sb (III) complexes have been synthesized and structurally characterized. • Complexes were characterized by FT-IR, UV-Vis, TGA and SEM. • Excellent antibacterial activity against E. coli and S. aureus. • Effective antiproliferative activity against HepG2 cells. Two cadmium (II) complexes formulated as [Cd(L1)(HL1)]ClO 4 (Cd1) and [Cd(L2) 2 ] (Cd2), also two antimony (III) complexes formulated as [Sb(L1) 2 ] 2 Cl 2 ·CH 3 OH (Sb1) and [Sb(L2)Cl 2 ] (Sb2) (HL1 = 2-acetylpyrazine N4-methylthiosemicarbazone, HL2 = 2-acetylpyrazine N4-dimethylthiosemicarbazone) have been synthesized, and the molecular structure of the four complexes have been determined by single crystal X-ray diffraction. The antimicrobial study has been conducted against E. coli and S. aureus , and the results indicated that the antibacterial activity of Cd1 and Sb1 increased to some extent than their ligand HL1, while Cd2 and Sb2 presented fairly effective antibacterial activity mainly the same as their ligand HL2. The four compounds all exhibited improved cytotoxic activity against the human hepatocellular carcinoma HepG2 cells than the ligands. While Cd2 displayed the most effective antiproliferative activity, and also the preferable selectivity for HepG2 cells versus normal QSG7701 cells. It is noted that there was a strong relationship between the activity of the ligand HL2 and its cadmium (Ⅱ) or antimony (III) complexes. [ABSTRACT FROM AUTHOR]

Graphical abstract Molecular mechanism of 1 inducing apoptosis against human hepatocellular carcinoma HepG2 cells has been discussed in detail. Biological research illustrated that 1 exhibited higher activity against HepG2 cells. Cytotoxicity experiments involving with mitochondria indicated that 1 restrained cells growth in a dose-dependent manner. Protein analysis revealed that 1 restrained Bcl-2 expression and accelerated Bax expression, inducing caspase-3 activation. Abstract In this paper, three bismuth(III) and diorganotin(IV) complexes based on bis(2-acetylpyridine) thiocarbonohydrazone (H 2 L) have been fully designed. The tests of the complexes on inhibiting human hepatocellular carcinoma HepG2 cells growth in vitro revealed that the complexes have higher activity against HepG2 cells but much less toxicity toward normal hepatocyte QSG7701 cells. Particularly, 1 exhibited higher activity with a lower IC 50 value (compound concentration that produces 50% of cell death, 3.42 ± 0.25 µM). Moreover, cytotoxicity experiments involving with mitochondria confirmed that 1 restrained cells growth in a dose-dependent manner. Protein analysis indicated that 1 restrained Bcl-2 expression and accelerated Bax expression, inducing caspase-3 activation. [ABSTRACT FROM AUTHOR]

Two metal complexes [(Me) 2 Sn(L)(OAc)] ( 1 ), and [Pd(L)Cl] ( 2 ) based on 2-benzoylpyridine N (4)-cyclohexylthiosemicarbazone have been synthesized and structurally characterized. X-ray crystallography reveals that in title compounds, each thiosemicarbazone adopts tridentate NNS manner to coordinate with the metal center, and the metal coordination geometry can be described as a distorted pentagonal bipyramid in 1 and a contorted square-planar in 2 , respectively. Growth inhibition assays have indicated that two compounds can effectively inhibit the growth of HepG2 cancer cell lines at micromolar concentrations. In addition, apoptosis mechanisms of 2 on HepG2 cells were further investigated. The results show that 2 can promote the apoptosis of HepG2 cells and the apoptosis is associated with the activation of caspase-3. [ABSTRACT FROM AUTHOR]

Two metal complexes [Cd(L) 2 ]·0.275H 2 O( 1 ) and [In(L) 2 ]NO 3 ( 2 ) (HL = 2-benzoylpyridine N (4)-cyclohexylthiosemicarbazone) have been synthesized and structurally characterized by elemental analysis, a number of spectroscopic methods (IR, UV-vis, NMR), mass spectrometry, and X-ray crystallography. The Schiff’s base ligand forms hexacoordinated complexes having octahedral geometry for Cd(II) and In(III) complexes, respectively. The synthesized compounds were tested for antiproliferative activity and showed the ability to kill HepG2 cells (human hepato cellular carcinoma) significantly, especially 2 with IC 50 = 2.02 ± 0.14 μM. Of particular note is the fact that complex 1 has ca 12-fold lower toxicity in the normal hepatocyte QSG7701 cells than in the hepatocellular carcinoma HepG2 cells. In addition, complex 2 also exhibited excellent luminescent property. Upon the addition of 1 equiv of In 3+ ion, 200-fold fluorescence enhancement of HL at λ em = 504 nm has been observed. Moreover, the fluorescent color change (from transparent to light-green) could be observed by naked eyes under the light of 365 nm. These findings can expand the applications of thiosemicarbazone derivatives in the fields of colorimetric and fluorescent probes. [ABSTRACT FROM AUTHOR]

Abstract: Main group metal complex [Bi(HL)(NO3)3] (1), where HL=2-acetylpyrazine N(4)-pyridylthiosemicarbazone, has been synthesized and characterized by elemental analysis, IR, MS and single-crystal X-ray diffraction studies. The interesting monomeric 8-coordinate bismuth(III) complex 1 is depicted with one electron pair (6s2) of the bismuth(III) atom, one N2S tridentate neutral thiosemicarbazone, two monodentate and one bidentate nitrate ions, respectively. In vitro biological studies have indicated that the bismuth complex 1 has shown effective antibacterial and anticancer activities especially with MIC=15.6μg/mL against Gram positive bacteria Bacillus cereus and IC50 =1.6 μM against K562 leukemia cell lines, respectively, comparable to positive control. [Copyright &y& Elsevier]

Two nickle complexes of 2-acetylpyrazine thiosemicarbazones have been synthesized, Growth inhibition assays indicated complex 2 has the highest tumor cells selectivity. • Two nickel complexes of 2-acetylpyrazine thiosemicarbazone have been synthesized and structurally characterized. • The growth inhibition assays suggested that complex 2 has the highest tumor cells selectivity. In this article, two nickel complexes of 2-acetylpyrazine thiosemicarbazone formulated as [Ni(L1) 2 ]·CH 3 OH (1) and [Ni 2 (L2) 3 ]ClO 4 ·C 2 H 5 OH (2) (HL1 = 2-acetylpyrazine N4-methylthiosemicarbazone, HL2 = 2-acetylpyrazine N4-dimethylthiosemicarbazone), have been synthesized and structurally characterized. The antibacterial activities of the two complexes and ligands were studied. It is found that the ligand HL2 and its corresponding complex displayed effective antimicrobial activity against the tested bacterial. Besides, the growth inhibition assays indicated that complex 2 and the two proligands are capable of showing inhibitory activity against the human hepatocellular carcinoma HepG2 cells, and the subsequent toxicity study on normal QSG7701cells showed that complex 2 has the highest tumor cells selectivity, and its IC 50 values is 7.21 times higher than in HepG2 cells. [ABSTRACT FROM AUTHOR]