Synthesis, characterization and biological activity of Cu(II), Zn(II) and Re(I) complexes derived from S-benzyldithiocarbazate and 3-acetylcoumarin.

Cu(II), Zn(II) and Re(I) complexes have been synthesized with the Schiff base, N'-[1-(2-oxo-2H-chromen-3-yl)-ethylidene]-hydrazinecarbodithioic acid benzyl ester (SBCM-H) which was prepared by condensation of S-benzyldithiocarbazate and 3-acetylcoumarin. The metal complexes were characterized on the basis of various physico-chemical and spectroscopic techniques including elemental analysis and electrochemical studies, and FT-IR, UV-Vis, NMR, EPR and mass spectroscopy. The Schiff base was found to behave as a bidentate ligand coordinating with Cu(II) and Zn(II) in the thiolate form with 1:2 metal to ligand stoichiometry. Crystals suitable for X-ray diffractometry (XRD) were obtained from the reaction of ReCl(CO)5 with SBCM-H forming a centrosymmetric dimeric complex Re2L2(CO)6 linked by Re-S-Re bridges, where S is the thiolate sulfur of the N,S-bidentate ligand. This Re(I) complex is the first metal carbonyl complex with a bidentate dithiocarbazate ligand to have been characterized by XRD. Cytotoxicity assays revealed enhancement of the bioactivity of SBCM-H upon complexation. Both Cu(II) and Re(I) complexes are found to be active against human breast adenocarcinoma cancer cell lines MDA-MB-231 and MCF-7. TOC diagram.

Synthesis, characterization and biological evaluation of transition metal complexes derived from N, S bidentate ligands.

Two bidentate NS ligands were synthesized by the condensation reaction of S-2-methylbenzyldithiocarbazate (S2MBDTC) with 2-methoxybenzaldehyde (2MB) and 3-methoxybenzaldehyde (3MB). The ligands were reacted separately with acetates of Cu(II), Ni(II) and Zn(II) yielding 1:2 (metal:ligand) complexes. The metal complexes formed were expected to have a general formula of [M(NS)2] where M = Cu2+, Ni2+, and Zn2+. These compounds were characterized by elemental analysis, molar conductivity, magnetic susceptibility and various spectroscopic techniques. The magnetic susceptibility measurements and spectral results supported the predicted coordination geometry in which the Schiff bases behaved as bidentate NS donor ligands coordinating via the azomethine nitrogen and thiolate sulfur. The molecular structures of the isomeric S2M2MBH (1) and S2M3MBH (2) were established by X-ray crystallography to have very similar l-shaped structures. The Schiff bases and their metal complexes were evaluated for their biological activities against estrogen receptor-positive (MCF-7) and estrogen receptor-negative (MDA-MB-231) breast cancer cell lines. Only the Cu(II) complexes showed marked cytotoxicity against the cancer cell lines. Both Schiff bases and other metal complexes were found to be inactive. In concordance with the cytotoxicity studies, the DNA binding studies indicated that Cu(II) complexes have a strong DNA binding affinity.

Conjugation of a new series of dithiocarbazate Schiff base Copper(II) complexes with vectors selected to enhance antibacterial activity.

A new series of six Schiff bases derived from S-methyldithiocarbazate (SMDTC) and S-benzyldithiocarbazate (SBDTC) with methyl levulinate (SMML, SBML), levulinic acid (SMLA, SBLA), and 4-carboxybenzaldehyde (SM4CB, SB4CB) were reacted with copper(II), producing complexes of general formula ML2 (M = Cu(II), L = ligand). All compounds were characterized using established physicochemical and spectroscopic methods. Crystal structures were determined for three Schiff bases (SMML, SBML, SBLA) and two Cu(II) complexes (Cu(SMML)2 and Cu(SMLA)2). In order to provide more insight into the behavior of the complexes in solution, electron paramagnetic resonance (EPR) and electrochemical experiments were performed. The parent ligands and their respective copper(II) complexes exhibited moderate antibacterial activity against both Gram-negative and Gram-positive bacteria. The most active ligand (SB4CB) and its analogous S-methyl derivative (SM4CB) were conjugated with various vector moieties: polyarginines (R1, R4, R9, and RW9), oligoethylene glycol (OEG), and an efflux pump blocker, phenylalanine-arginine-ß-naphthylamide (PAßN). Nonaarginine (R9) derivatives showed the most encouraging synergistic effects upon conjugation and complexation with copper ion including enhanced water solubility, bacteria cell membrane permeability, and bioactivity. These Cu(II)-R9 derivatives display remarkable antibacterial activity against a wide spectrum of bacteria and, in particular, are highly efficacious against Staphylococcus aureus with minimum inhibitory concentration (MIC) values of 0.5-1 µM. This pioneer study clearly indicates that the conjugation of cell-penetrating peptides (CPPs) to dithiocarbazate compounds greatly enhances their therapeutic potential.

Crystal structure of 2-{[2-(3-phenyl-allyl-idene)hydrazin-1-yl]thio-carbonyl-sulfanylmeth-yl}pyridinium chloride.

In the title salt of an S-substituted di-thio-carbazate, C16H16N3S2 (+)·Cl(-), the dihedral angles between the almost planar (r.m.s deviation = 0.005 Å) central CN2S2 residue and the terminal pyridinium and phenyl rings are 80.09 (11) and 3.82 (11)°, respectively, indicating the cation has an L-shape; the amine H and thione S atoms are syn. The conformation about each of the imine [1.376 (3) Å] and ethene [1.333 (4) Å] bonds is E. The shortened C-C bond [1.444 (4) Å] linking the double bonds is consistent with conjugation in this part of the mol-ecule. In the crystal, supra-molecular layers with a jagged topology are formed by charged-assisted amine-H⋯Cl(-) and pyridinium-N(+)-H⋯Cl(-) hydrogen bonds. The layers stack along the a axis with no specific directional inter-actions between them.

Benzyl N-[(Z)-(1-methyl-2-sulfanyl-propyl-idene)amino]-carbamodithio-ate.

The title compound, C(12)H(16)N(2)S(3), was obtained by the condensation reaction of S-benzyl dithio-carbazate and 3-mercaptobutan-2-one. The phenyl ring and thiol (SH) group are approximately perpendicular [S-C-C-C and N-C-C-S torsion angles = 67.8 (3) and 116.9 (2)°, respectively] to the rest of the mol-ecule. In the crystal, mol-ecules are linked by weak S-H⋯S and N-H⋯S hydrogen bonds, π-π inter-actions between the benzene rings [centroid-centroid distance = 3.823 (2) Å] and C-H⋯π inter-actions.

2,2-Dibenzyl-hydrazin-1-ium chloride.

In the title salt, C14H17N2(+)·Cl(-), the central N atom is pyramidal (sum of bond angles = 330.9°) and there is a near orthogonal relationship between the benzene rings [dihedral angle = 89.95 (10)°]. The crystal packing features N-H⋯Cl hydrogen bonds, which lead to a supra-molecular undulating ribbon along the a axis comprising edge-shared eight-membered {⋯HNH⋯Cl}2 synthons. The chains are connected into layers in the ab plane by C-H⋯π inter-actions.

(Pyridin-4-yl)methyl N'-(3-phenyl-allyl-idene)hydrazinecarbodithio-ate.

In the title compound, C(16)H(15)N(3)S(2), the central C(2)N(2)S(2) residue is planar (r.m.s. deviation = 0.045 Å) and the pyridyl and benzene rings are inclined and approximately coplanar to this plane, respectively [dihedral angles = 72.85 (9) and 10.73 (9)°], so that, overall, the mol-ecule adopts an L-shape. The conformation about each of the N=C [1.290 (3) Å] and C=C [1.340 (3) Å] bonds is E. Supra-molecular chains along [1-10] are stabilized by N-H⋯N(pyridine) hydrogen bonding and these are connected into a double layer that stacks along the c-axis direction by C-H⋯π(pyridine) inter-actions.

Screening for Mycobacterium tuberculosis using an interferon-gamma release assay.

CONTEXT: The Centers for Disease Control and Prevention recommend analyzing characteristics of populations screened for Mycobacterium tuberculosis infection using interferon-gamma release assays (IGRAs). OBJECTIVE: We characterized requests for IGRA analyses submitted to the first laboratory in Washington State that began to offer IGRAs as a tuberculosis screening test. In addition, we chronicled the process by which this program was launched. DESIGN: Through a retrospective record review we recorded the IGRA results, source of the request, and reason(s) for each request along with demographic information, risk factors, and prior exposure for each subject. Through dissemination and quality control measures, IGRA analyses began within the health district but quickly spread throughout the state and the West. SETTING AND PARTICIPANTS: A regional health district clinical laboratory in the Pacific Northwest received 4422 IGRA requests for 4218 unique subjects from January 2, 2008, through June 5, 2009. RESULTS: Most (96%) requests originated from public health clinics or centers, hospitals, private laboratories or practitioners, and Indian Health Centers. Community and migrant health centers had the highest rates of positive IGRA results (28%, Φc = 0.159, P = .000). About one-half of all requests were for employment or high-risk surveillance. Persons with a positive IGRA had a larger TST induration (M = 16.66 mm, 95% CI: 15.18-18.14) than those with a negative IGRA (M = 13.53 mm, 95% CI: 12.92-14.15) but did not differ for those with an indeterminate IGRA (M = 13.29 mm, 95% CI: 5.95-20.62). CONCLUSIONS: Public and private agencies use IGRAs for surveillance of persons employed, routinely screened, at high risk, or foreign-born. The TST induration varies widely for persons with an indeterminate IGRA. The process for implementing IGRA analyses serves as a model for other programs seeking to conduct similar reviews of test use and results.

Bis{S-benzyl 3-[(phen-yl)(pyridin-2-yl)methyl-idene]dithio-carbazato}zinc acetonitrile monosolvate.

In the title compound, [Zn(C(20)H(16)N(3)S(2))(2)]·CH(3)CN, two different Schiff base moieties coordinate to the central Zn(II) ion as tridentate N,N',S-chelating ligands, creating a distorted octa-hedral environment [the smallest angle being 73.24 (6)° and the widest angle being 155.73 (7)°], with the two S atoms in cis positions. The dihedral angle between the mean planes of the two coordinating ligands is 83.65 (5)°. The crystal packing is consolidated by weak C-H⋯N hydrogen-bonding inter-actions.

{S-Benzyl 3-[(6-methyl-pyridin-2-yl-κN)methyl-idene]dithio-carbazato-κ(2)N(3),S}zinc.

The title compound, [Zn(C(15)H(14)N(3)S(2))(2)], contains two chemically equivalent Schiff base anions that are coordinated to the Zn(II) ion as tridentate N,N',S-chelating ligands, creating a distorted octa-hedral environment [the smallest angle being 75.40 (6)° and the widest angle being 162.87 (6)°], with the two S atoms in cis positions. The dihedral angle between the mean planes of the two coordinating ligands is 85.65 (5)°. Weak C-H⋯S hydrogen bonds are also observed.

Bis{S-benzyl 3-[(6-methyl-pyridin-2-yl)methyl-idene]dithio-carbazato}nickel(II).

The asymmetric unit of the title compound, [Ni(C(15)H(14)N(3)S(2))(2)], consists of two independent mol-ecules with similar configurations. Each Ni(2+) cation is coordinated in a cis-mode by two tridentate N,N',S-chelating Schiff base ligands, creating a distorted octa-hedron [the smallest angle being 77.57 (7)° and the widest being 168.97 (7)° for one mol-ecule, and 78.04 (7) and 167.55 (7)° for the second mol-ecule]. The dihedral angle between the mean coordination planes of the two ligands is 86.76 (7)° for one and 89.99 (7)° for the second mol-ecule. π-π inter-actions between neighbouring pyridine rings with plane-to-plane distances of 3.540 (1) and 3.704 (1) Šare observed.

{S-Benzyl 3-[(6-methyl-pyridin-2-yl)-methyl-idene]dithio-carbazato}nickel(II) monohydrate.

The structure of the title compound, [Ni(C(15)H(14)N(3)S(2))(2)]·H(2)O, has one mol-ecule in the asymmetric unit, along with a solvent water mol-ecule. The two different Schiff base moieties coordinate to the central Ni(II) ion as tridentate N,N',S-chelating ligands, creating a six-coordinate distorted octa-hedral environment [the smallest angle being 77.43 (7)° and the widest angle being 169.99 (7)°]. The mean planes of the two ligands are nearly orthogonal to each other with an angle of 89.53 (6)°. The packing of the complex is supported by O-H⋯N and O-H⋯S hydrogen bonding between the solvent water mol-ecule and the uncoordinated N and S atoms of neighbouring ligands.

Bis{benzyl 2-[4-(4-meth-oxy-phen-yl)butan-2-yl-idene]hydrazinecarbodithio-ato-κ(2)N(2),S}nickel(II).

The complete mol-ecule of the title complex, [Ni(C(19)H(21)N(2)OS(2))(2)], is generated by the application of twofold symmetry. The Ni(II) atom is N,S-chelated by two hydrazinecarbodithio-ate ligands, which provide an N(2)S(2) donor set that defines a distorted square-planar geometry, the S atoms being approximately cis. The conformation of the chelate ring is an envelope with the Ni(II) atom being the flap atom. The dihedral angle between the least-squares planes through the chelate rings = 30.10 (6)°. Supra-molecular chains propagated by glide symmetry along the c axis and mediated by C-H⋯N contacts feature in the crystal packing.

N'-[Bis(benzyl-sulfan-yl)methyl-idene]benzohydrazide.

In the title hydrazonodithio-ate, C(21)H(19)N(3)OS(2), the amide group is twisted out of the plane through the S(2)C=N atoms: the C-N-N-C torsion angle is 139.71 (13)°. The pyridine ring forms dihedral angles of 52.96 (8) and 86.46 (8)° with the phenyl rings, and the latter are approximately orthogonal [dihedral angle = 76.42 (9)°]. Supra-molecular chains sustained by N-H⋯O hydrogen bonds and propagated by glide symmetry along the c axis are found in the crystal structure. The chains are consolidated into a three-dimensional architecture by C-H⋯O and C-H⋯N inter-actions.

1-Methyl-2-({[(2-methyl-phen-yl)meth-yl]disulfan-yl}meth-yl)benzene.

In the title disulfide, C(16)H(18)S(2), the mol-ecule is twisted about the central S-S bond [the C-S-S-C torsion angle = 93.24 (7)°] and the dihedral angle between the benzene rings is 72.84 (7)°, indicating an almost orthogonal relationship; the methyl groups are orientated to the same side of the mol-ecule. The crystal packing features C-H⋯.π inter-actions which consolidate a three-dimensional architecture.

Benzyl 3-(2-methyl-phen-yl)dithio-carbazate.

In the title compound, C(15)H(16)N(2)S(2), the central C(2)N(2)S(2) unit is essentially planar (r.m.s. deviation = 0.047 Å) and forms dihedral angles of 68.26 (4) and 65.99 (4)° with the phenyl and benzene rings, respectively, indicating a twisted mol-ecule. Supra-molecular chains with a step topology and propagating along [100] feature in the crystal packing, mediated through N-H⋯S hydrogen bonds. The chains are consolidated into a three-dimensional architecture by C-H⋯π inter-actions.

1-{(E)-[4-(4-Meth-oxy-phen-yl)butan-2-yl-idene]amino}-3-methyl-thio-urea.

Two independent mol-ecules comprise the asymmetric unit of the title compound, C(13)H(19)N(3)OS, which differ in the conformations of the residues linking the thio-urea and the terminal benzene ring, as manifested in the C(m)-C(m)-C(a)-C(a) torsion angles [78.03 (16) and -93.64 (16)°, respectively; m = methyl-ene and a = aromatic]. The dihedral angles [84.40 (4) and 88.28 (5)°] formed between the thio-urea residue and the benzene ring indicate an almost orthogonal relationship. In each thio-urea residue, the N-H hydrogen atoms are anti, and the terminal N-H hydrogen atom forms an intra-molecular N-H⋯N hydrogen bond with the imine-N atom. In each case, the conformation about the imine C=N double bond [1.2812 (17) and 1.2801 (17) Å] is E. In the crystal, the mol-ecules are connected by N-H⋯S hydrogen bonds and these are connected into four mol-ecule aggregates via N-H⋯O hydrogen bonds, which are assembled into a two-dimensional array parallel to (011) via C-H⋯π and π-π inter-actions [ring centroid-centroid distance = 3.8344 (9) Å].

2-Cyclo-hexyl-idene-N-methyl-hydrazine-carbothio-amide.

The title compound C(8)H(15)N(3)S has two mol-ecules in the asymmetric unit in which cis-trans isomerism is exhibited around the N(NH)C=S bonds. The cyclo-hexyl rings in both mol-ecules adopt a chair conformation. In the crystal, N-H⋯S hydrogen bonding produces dimers, which are inter-connected through further N-H⋯S hydrogen bonds, forming chains along the b-axis direction.

(E)-[({[(3-Methyl-phen-yl)meth-yl]sulfan-yl}methane-thio-yl)amino](1-phenyl-pentyl-idene)amine.

In the structure of the title compound, C(20)H(24)N(2)S(2), the central CN(2)S(2) atoms are planar (r.m.s. deviation = 0.0205 Å) but both benzene rings are twisted out of this plane forming dihedral angles of 23.03 (6) and 84.75 (4)° (tol-yl); the n-butyl group occupies a position normal to the plane [N-C-C-C torsion angle = -84.33 (16)°]. The conformation of the imine bond [1.2888 (18) Å] is E. The syn arrangement of the thione S and amino H atoms enables the formation of N-H⋯S hydrogen bonds between centrosymmetrically related mol-ecules. These lead to eight-membered {⋯HNC=S}(2) synthons which are further stabilized by proximate C-H⋯S interactions. The resulting dimeric aggregates are connected into a supra-molecular chain along the c axis by C-H⋯π(tol-yl) inter-actions.

1-{(E)-[4-(4-Hy-droxy-phen-yl)butan-2-yl-idene]amino}-3-phenyl-thio-urea: crystal structure, Hirshfeld surface analysis and computational study.

The title thio-urea derivative, C17H19N3OS, adopts a U-shaped conformation with the dihedral angle between the terminal aromatic rings being 73.64 (5)°. The major twist in the mol-ecule occurs about the ethane bond with the Ci-Ce-Ce-Cb torsion angle being -78.12 (18)°; i = imine, e = ethane and b = benzene. The configuration about the imine bond is E, the N-bound H atoms lie on opposite sides of the mol-ecule and an intra-molecular amine-N-H⋯N(imine) hydrogen bond is evident. In the mol-ecular packing, hydroxyl-O-H⋯S(thione) and amine-N-H⋯O hydrogen bonding feature within a linear, supra-molecular chain. The chains are connected into a layer in the ab plane by a combination of methyl-ene-C-H⋯S(thione), methyl-ene-C-H⋯O(hydrox-yl), methyl-C-H⋯π(phen-yl) and phenyl-C-H⋯π(hy-droxy-benzene) inter-actions. The layers stack without directional inter-actions between them. The analysis of the calculated Hirshfeld surface highlights the presence of weak methyl-C-H⋯O(hydrox-yl) and H⋯H inter-actions in the inter-layer region. Computational chemistry indicates that dispersion energy is the major contributor to the overall stabilization of the mol-ecular packing.