Copper(I) and silver(I) complexes of anthraldehyde thiosemicarbazone: synthesis, structure elucidation, in vitro anti-tuberculosis/cytotoxic activity and interactions with DNA/HSA.

A reaction of copper(i) halides (X = I, Br, Cl) and silver(i) halides with 9-anthraldehyde thiosemicarbazone (9-Hanttsc, H1L) and triphenylphosphine produced halogen-bridged dinuclear complexes, [M2(µ2-X)2(η1-S-9-Hanttsc)2(Ph3P)2] (M = Cu, X = Cl, 1; Br, 2; I, 3; M = Ag, X = Cl, 4; Br, 5). A similar reaction of 9-anthraldehyde-N1-methyl thiosemicarbazone (9-Hanttsc-N1-Me, H2L) with Ph3P and silver(i) halides yielded sulfur-bridged dimers, [Ag2X2(µ2-S-9-Hanttsc-N1-Me)2(Ph3P)2] (X = Cl, 9; Br, 10), however with copper(i) halides insoluble compounds were formed, which upon the addition of one extra mole of Ph3P gave mononuclear complexes of the formula [CuX(η1-S-9-Hanttsc-N1-Me)(Ph3P)2] (X = Cl, 6; Br, 7; I, 8). All of the complexes have been characterized by elemental analysis, NMR (1H, 13C) spectroscopy and single crystal X-ray crystallography (2, 5, 6, and 9). Both the ligands (H1L and H2L) and their complexes (1-10) were tested for their anti-tubercular and anticancer activities. The interactions of the ligands and their complexes (copper and silver) with calf thymus DNA (ct-DNA) and human serum albumin (HSA) were examined through UV-visible and fluorescence spectroscopy. Results showed that copper complex 2 displayed strong interactions with ct-DNA and HSA having binding constant values of 6.66 × 104 M-1 and 3.28 × 104 M-1, respectively, followed by silver complex 10 which gave binding constant values of 4.60 × 104 M-1 and 3.06 × 104 M-1, respectively. All of the complexes also showed good interactions with DNA in docking studies.

Enhancement in anti-tubercular activity of indole based thiosemicarbazones on complexation with copper(I) and silver(I) halides: Structure elucidation, evaluation and molecular modelling.

A series of monomeric tetrahedral complexes of stoichiometry, [MX(HL)(Ph3P)2] (In case of M = Cu, H1L, X = I, 1; Br, 2; Cl, 3; H3L, X = I, 4; Br, 5; Cl, 6; H4L, X = I, 7; Br, 8; Cl, 9 and in case of M = Ag, H1L, X = Cl, 13; Br, 14; H2L, X = Cl, 15, Br 16; H3L, X = Cl, 17, Br, 18) were synthesized by the reaction of copper (I) or silver (I) halides with indole-3-thiosemicarbazone (H1L) or 5-methoxy indole-3-thiosemicarbazone (H2L) or 5-methoxy indole-N1-methyl-3-thiosemicarbazone (H3L), whereas dimers of stoichiometry, [Cu2(µ-X)2(η1-S-H2L)2(Ph3P)2] (X = I, 10; Br, 11; Cl, 12) were obtained by the reaction of copper (I) halides with indole-N1-methyl-3-thiosemicarbazone (HIntsc-N1-Me, H2L). The synthesized complexes were characterized using NMR (1H and 13C) and single crystal X-ray diffraction (H2L, 3, 7, 8, 10, 11 and 13) as well as elemental analysis. Anti- M. tuberculosis activity of ligands (H1L-H4L) and their metal complexes (1-18) were evaluated against M. tuberculosis H37RV strain ATCC 27294. It has been observed that there is unusual enhancement in anti TB activity of these ligands on complexation with copper (I) and silver (I). Molecular modelling studies in the active binding site are also giving complementary theoretical support for the experimental biological data acquired.

Correction: Variable coordination and C-S bond cleavage activity of N-substituted imidazolidine-2-thiones towards copper: synthesis, spectroscopy, structures, ESI-mass and antimicrobial studies.

Correction for 'Variable coordination and C-S bond cleavage activity of N-substituted imidazolidine-2-thiones towards copper: synthesis, spectroscopy, structures, ESI-mass and antimicrobial studies' by Jaspreet K. Aulakh, et al., Dalton Trans., 2017, 46, 1324-1339.

Variable coordination and C-S bond cleavage activity of N-substituted imidazolidine-2-thiones towards copper: synthesis, spectroscopy, structures, ESI-mass and antimicrobial studies.

An equimolar reaction of copper(i) iodide with N-ethyl-imidazolidine-2-thione (l-Et) in acetonitrile formed black prismatic crystals over a period of three weeks. The X-ray structure determination of black crystals revealed that the thio-ligand l-Et has transformed into a new thio-ligand, 1-ethyl-3-(1-ethyl-4,5-dihydro-1H-imidazol-2-yl)imidazolidine-2-thione (l-NEt), through C-S rupture/C-N bond formation which was coordinated in the unusual 2D polymer, {(CuII(κ2-N,S-l-NEt)2)·(CuI4)·(CuI2)}n1. An ESR spectrum supported the presence of divalent CuII in the polymer. In contrast, reaction of copper(i) iodide with N-phenyl-imidazolidine-2-thione (l-Ph) in 1 : 1 molar ratio yielded a polymer, [-Cu(µ-I)2Cu(µ-S-l-Ph)2Cu-]n2, with alternate Cu2I2 and Cu2S2 cores. Further, a series of reactions of copper(i) halides with N-substituted imidazolidine-2-thiones, namely, l-R in 1 : 2 metal to ligand molar ratio (M : L) in acetonitrile have yielded different type of complexes: trigonal planar {CuX(κ1-S-l-R)2, R, X : Et, I, 4; Me, I, 5; Bun, I,6; Me, Br,7; Bun, Br, 8; Me, Cl, 9; Prn, Cl, 10; Ph, Cl, 11}, dinuclear [Cu2Br2(µ-S-l-Ph)2(κ1-S-l-Ph)2] 12, tetranuclear, [Cu4I2(µ-I)2(µ-S-l-Ph)4(κ1-S-l-Ph)2] 3 and hexanuclear [Cu6Cl6(µ-S-l-Bun)6] 13. All these complexes have been characterized using analytical data, IR and proton NMR spectroscopy, ESI-mass studies and single crystal X-ray crystallography. The antimicrobial activity of these complexes has been investigated against Gram positive bacteria, namely, Staphylococcus aureus (MTCC740), methicillin resistant Staphylococcus aureus (MRSA), Gram negative bacteria, Klebsiella pneumoniae (MTCC109), Salmonella typhimurium (MTCC741) and Candida albicans (MTCC227)- a yeast. It is significant to add that among various complexes tested for cytotoxicity toward living cells, 4, 5, 8, 9 and 10 complexes were toxic, while complex 12 was non-toxic.

Crystal structure of methyl (2Z)-2-[(2Z)-2-(2-cyclo-pentyl-idenehydrazin-1-yl-idene)-4-oxo-3-phenyl-1,3-thia-zolidin-5-yl-idene]ethano-ate.

In the title compound, C17H17N3O3S, the cyclo-pentane ring is disordered over two sets of sites with an occupancy ratio of 0.775 (8):0.225 (8) for the affected atoms. The thia-zolidinyl ring is planar (r.m.s. deviation = 0.024 Å) and forms a dihedral angle of 65.13 (8)° with the attached phenyl ring. The mol-ecular packing is stabilized by C-H⋯O and C-H⋯π inter-actions, forming a three-dimensional structure.

Crystal structure of 2-[2-(hy-droxy-imino)-1-phenyl-propyl-idene]-N-phen-ylhydrazinecarbo-thio-amide.

In the title compound, C16H16N4OS, an intra-molecular C-H⋯S hydrogen bond is observed. With the exception of the phenyl ring of the phenyl-propyl-idene unit, the remainder of the mol-ecule has an almost planar skeleton with an r.m.s. deviation of 0.121 (5) Šfrom the plane through the remaining 16 atoms. In the crystal O-H⋯N hydrogen bonds are observed between the terminal hy-droxy-imino groups, forming inverson dimers with R 2 (2)(6) graph-set motifs. Additional C-H⋯N contacts stack the dimers along [100]. While no π-π inter-actions are present, weak C-H⋯O and O-H⋯Cg inter-actions are also observed and help stabilize the crystal packing.

The crystal structure of 1-(2-hydroxy-5-meth-oxy-phen-yl)ethanone 4,4-di-methyl-thio-semicarbazone.

The asymmetric unit of the title compound, C12H17N3O2S, contains two independent mol-ecules, A and B. Both mol-ecules are nearly planar with the dihedral angle between the mean planes of the thio-amide group and benzene ring being 7.5 (1)° in A and 4.3 (2)° in B. In each mol-ecule, the hy-droxy group participates in intra-molecular O-H⋯N hydrogen bonding, while the amino H atom is not involved in hydrogen bonding because of the steric hinderence caused by two neighboring methyl groups. In the crystal, the individual molecules are linked by weak C-H⋯O hydrogen bonds, forming A-A and B-B inversion dimers. The dimers are linked via C-H⋯π inter-actions which help stabilize the packing.

Crystal structure of ethyl 2-phenyl-4-(prop-2-yn-1-yl-oxy)-5,6,7,8-tetra-hydro-pyrido[4',3':4,5]thieno[2,3-d]pyrimidine-7-carboxyl-ate.

In the title compound, C21H19N3O3S, the 5,6,7,8-tetra-hydro-pyridine ring adopts a half-chair conformation. The fused-thieno[2,3-d]pyrimidine ring system is essentially planar (r.m.s. deviation = 0.001 Å) and forms a dihedral angle of 2.66 (6)° with the attached phenyl ring. The three-dimensional crystal packing is stabilized by C-H⋯O and C-H⋯N hydrogen bonds and C-H⋯π inter-actions.

The crystal structures of six (2E)-3-aryl-1-(5-halogeno-thio-phen-2-yl)prop-2-en-1-ones.

The structures of six chalcones containing 5-halogeno-thio-phen-2-yl substituents are reported: (2E)-1-(5-chloro-thio-phen-2-yl)-3-(4-ethyl-phen-yl)prop-2-en-1-one, C15H13ClOS, (I), and (2E)-1-(5-bromo-thio-phen-2-yl)-3-(4-ethyl-phen-yl)prop-2-en-1-one, C15H13BrOS, (II), are isostructural in space group P-1, while (2E)-1-(5-chloro-thio-phen-2-yl)-3-(4-eth-oxy-phen-yl)prop-2-en-1-one, C15H13ClO2S, (III), and (2E)-1-(5-bromo-thio-phen-2-yl)-3-(4-eth-oxy-phen-yl)prop-2-en-1-one C15H13BrO2S, (IV), are isostructural in space group P21/c. There are no hydrogen bonds of any kind in the structures of compounds (I) and (II), but in the structures of compounds (III) and (IV), the mol-ecules are linked into C(7) chains by means of C-H⋯O hydrogen bonds. In the structure of (2E)-3-(4-bromo-phen-yl)-1-(5-chloro-thio-phen-2-yl)prop-2-en-1-one, C13H8BrClOS, (V), there are again no hydrogen bonds nor π-π stacking inter-actions but in that of (2E)-1-(5-bromo-thio-phen-2-yl)-3-(3-meth-oxy-phen-yl)prop-2-en-1-one, C14H11BrO2S, (VI), the mol-ecules are linked into C(5) chains by C-H⋯O hydrogen bonds. In each of compounds (I)-(VI), the mol-ecular skeletons are close to planarity, and there are short halogen⋯halogen contacts in the structures of compounds (II) and (V) and a short Br⋯O contact in the structure of compound (VI). Comparisons are made with the structures of some similar compounds.