Synthesis, characterization and biological activities of 3-methylbenzyl 2-(6-methyl pyridin-2-ylmethylene)hydrazine carbodithioate and its transition metal complexes

A tridentate nitrogen-sulfur Schiff base,3-methylbenzyl 2-(6-methylpyridin-2-ylmethylene)hydrazine carbodithioate (6mpyS3M), was synthesized by condensation of 6 methylpyridine-2-aldehyde with S-3 methylbenzyldithiocarbazate.It crystallized in space group P 21/n. It displayed intermolecular N–HN hydrogen bonding between the a-nitrogen and the pyridyl nitrogen. The thione sulfur is in a trans position with respect to the 6-methylpyridine fragment across the C–N bond but adopts a cis position with the 3-methylbenzyl fragment through the C–S bond. Octahedral complexes containing two 6mpyS3M ligands were prepared with Cu(II), Ni(II), Zn(II) and Cd(II).6mpyS3M and its metal complexes were assayed against selected microbes and two breast cancer cell lines. 6mpyS3M was strongly active against both cancer cell lines. Its metal complexes showed high selectivity with Cu(II), Ni(II) and Zn(II) complexes strongly active against only one of the cancer cell lines, whereas the Cd(II) complex was strongly active only against the other. Only Cu(II) and Cd(II) complexes were active against some of the bacteria

Synthesis, characterisation and structure determination of 3-[(1Z)-{2-[bis({[(2-methylphenyl)methyl]sulfanyl})methylidene]hydrazin-1-ylidene}methyl]benzene-1,2-diol

A light-yellow crystalline product (1), which was isolated after one week from the filtrate of the reaction between S-2-methylbenzyldithiocarbazate and 2,3-dihydroxybenzaldehyde, was characterised by single crystal X-ray diffraction, FTIR and NMR spectroscopic analyses. The experimental molecular structure of 1 has been established by X-ray crystallography and showed, to a first approximation, a planar C2N2S2 + dihydroxyphenyl region that has an almost orthogonal relationship to the rings of the pendant S-bound benzyl groups. This structure has been verified via density functional theory calculations using the B3LYP/6311G(d,p) level of theory. The molecular packing featured linear supramolecular chains along the b-axis sustained by tolyl-C–H…N(imine) and tolyl-C–H…π(tolyl) interactions; the importance of these contacts is indicated by a Hirshfeld surface analysis

Synthesis, characterisation and structure determination of 3-[(1Z)-{2- [bis({[(2-methylphenyl)methyl]sulfanyl})methylidene]hydrazin-1- ylidene}methyl]benzene-1,2-diol

A light-yellow crystalline product (1), which was isolated after one week from the filtrate of the reaction between S-2-methylbenzyldithiocarbazate and 2,3-dihydroxybenzaldehyde, was characterised by single crystal X-ray diffraction, FTIR and NMR spectroscopic analyses. The experimental molecular structure of 1 has been established by X-ray crystallography and showed, to a first approximation, a planar C2N2S2 + dihydroxyphenyl region that has an almost orthogonal relationship to the rings of the pendant S-bound benzyl groups. This structure has been verified via density functional theory calculations using the B3LYP/6311G(d,p) level of theory. The molecular packing featured linear supramolecular chains along the b-axis sustained by tolyl-CH…N(imine) and tolyl-CH … π(tolyl) interactions; the importance of these contacts is indicated by a Hirshfeld surface analysis

o-Vanillin derived Schiff Bases and their Organotin(IV) Compounds: Synthesis, structural characterisation, in-Silico studies and cytotoxicity

Six new organotin(IV) compounds of Schiff bases derived from S-R-dithiocarbazate [R = benzyl (B), 2- or 4-methylbenzyl (2M and 4M, respectively)] condensed with 2-hydroxy-3- methoxybenzaldehyde (oVa) were synthesised and characterised by elemental analysis, various spectroscopic techniques including infrared, UV-vis, multinuclear (1H, 13C, 119Sn) NMR and mass spectrometry, and single crystal X-ray diffraction. The organotin(IV) compounds were synthesised from the reaction of Ph2SnCl2 or Me2SnCl2 with the Schiff bases (S2MoVaH/S4MoVaH/SBoVaH) to form a total of six new organotin(IV) compounds that had a general formula of [R2Sn(L)] (where L = Schiff base; R = Ph or Me). The molecular geometries of Me2Sn(S2MoVa), Me2Sn(S4MoVa) and Me2Sn(SBoVa) were established by X-ray crystallography and verified using density functional theory calculations. Interestingly, each experimental structure contained two independent but chemically similar molecules in the crystallographic asymmetric unit. The coordination geometry for each molecule was defined by thiolate-sulphur, phenoxide-oxygen and imine-nitrogen atoms derived from a dinegative, tridentate dithiocarbazate ligand with the remaining positions occupied by the methyl-carbon atoms of the organo groups. In each case, the resulting five-coordinate C2NOS geometry was almost exactly intermediate between ideal trigonal-bipyramidal and squarepyramidal geometries. The cytotoxic activities of the Schiff bases and organotin(IV) compounds were investigated against EJ-28 and RT-112 (bladder), HT29 (colon), U87 and SJ-G2 (glioblastoma), MCF-7 (breast) A2780 (ovarian), H460 (lung), A431 (skin), DU145 (prostate), BE2-C (neuroblastoma) Int. J. Mol. Sci. 2019, 20, 854 2 of 34 and MIA (pancreatic) cancer cell lines and one normal breast cell line (MCF-10A). Diphenyltin(IV) compounds exhibited greater potency than either the Schiff bases or the respective dimethyltin(IV) compounds. Mechanistic studies on the action of these compounds against bladder cancer cells revealed that they induced the production of reactive oxygen species (ROS). The bladder cancer cells were apoptotic after 24 h post-treatment with the diphenyltin(IV) compounds. The interactions of the organotin(IV) compounds with calf thymus DNA (CT-DNA) were experimentally explored using UV-vis absorption spectroscopy. This study revealed that the organotin(IV) compounds have strong DNA binding affinity, verified via molecular docking simulations, which suggests that these organotin(IV) compounds interact with DNA via groove-binding interactions

Tin(IV) compounds of tridentate thiosemicarbazone Schiff bases: synthesis, characterization, in-silico analysis and in vitro cytotoxicity

Twelve tin(IV) compounds ( 5 - 16 ) derived from four tridentate thiosemicarbazone Schiff bases of 4-methyl-3-thiosemicarbazide with 2-hydroxy-3-methoxybenzaldehyde ( 1, 2 ) and 4-phenyl-3-thiosemicarbazide with 2,3-dihydroxybenzaldehyde ( 3, 4 ) of general formulae of [R 2 Sn(L n )] and [Sn(L n ) 2 ] (where R = Ph or Me; L n = 1 , 2 , 3 and 4 ) were synthesized and characterized by elemental analysis, IR, UVvis, mass spectrometry and multinuclear NMR ( 1 H, 13 C and 119 Sn) spectroscopy. X-ray crystallographic data was obtained for 11′ , a 2:1 co-crystal between Ph 2 Sn(L 2 ) ( 11 ) and 3-methoxysalicylaldehyde azine, and Me 2 Sn(L 2 ) ( 12 ); L 2 H 2 is 2-(2-hydroxy-3-methoxybenzylidene)-Nphenylhydrazinecarbothioamide. The analysis revealed distinct coordination geometries with 11 and 12 approaching trigonal-bipyramidal. In the crystal of 11′ , supramolecular dimers arising from amine-N–H … S(thiolate) hydrogen bonding and {… HNCS} 2 synthons are evident; π(chelate ring) … π(oxidobenzylidene) stacking is also apparent. In the crystal of 12 , supramolecular, helical chains are generated by a combination of amine-N–H … O(phenoxide) hydrogen bonding and Sn … S secondary bonding. The cytotoxic activity of the compounds against a panel of ten cancer cell lines, [HT29 (colon), U87 and SJ-G2 (glioblastoma), MCF-7 (breast), A2780 (ovarian), H460 (lung), A431 (skin), DU145 (prostate), BE2-C (neuroblastoma), and MIA (pancreas) and one normal cell line, MCF-10A (normal breast)] were investigated. The thiosemicarbazone Schiff bases 1 and 4 as well as the diphenyltin(IV) compounds showed a strong ability to inhibit the growth of cancer cells, with particular selectivity against HT29, MCF-7, A2780, A431, BE2-C, SJ-G2, and MIA cell lines. The structure-activity relationship of all these compounds were studied by evaluating the effect of alkyl and aryl groups attached at the thiosemicarbazone backbone, the methoxy/hydroxyl groups present at the meta -position of the phenyl ring and alkyl or aryl groups bound to the tin center