Fiona Ni Foong How

Synthesis, Characterization and Antibacterial Activity of Schiff Base Derived from S-Methyldithiocarbazate and Methylisatin

New tridentate nitrogen–oxygen–sulfur Schiff base has been prepared from the condensation reaction of S-methyldithiocarbazate and methylisatin. The compound crystallized in triclinic crystal system with space group Pxa0−xa01, Zxa0=xa02, Vxa0=xa0612.92(3)xa0Å3 and unit cell parameters axa0=xa06.8540(2)xa0Å, bxa0=xa08.3022(2)xa0Å, cxa0=xa011.5243(4)xa0Å, α xa0=xa079.8186(13)°, xa0βxa0=xa090.5224(14)° and xa0γxa0=xa072.1362(13)°. Crystal structure reveals that the compound exists in the thione form with the methylisatin moiety is trans with respect to the C3–N2 and C3–S4 bonds whereas the methyl group of the dithiocarbazate moiety is cis with respect to the C3–N2 and C3–S5 bonds. The Schiff base was found to be selectively active against the selected Gram positive bacterial strains (Bacillus subtilis and Staphylococcus aureus) with the inhibition zones of 16 and 12xa0mm, respectively.Graphical AbstractCrystal structure of S-methyl 2-(1-methyl-2-oxoindolin-3-ylidene)hydrazinecarbodithioate (SMMeISA).

Benzyl N′-[1-(3-pyridyl)ethylidene]hydrazinecarbodithioate

The title compound, C15H5N2S2, crystallizes as a trans–cis nconformer. The thione sulfur is in a trans position with the nmethyl pyridyl fragment with respect to the C—N bond but nadopts a cis position with the benzyl ring across the C—S nbond. The dihedral angle between the planar quinoline ring nand the dithiocarbazate unit is 103.70 (1). The inclination of the dithiocarbazate unit with the benzyl group is 17.20 (1).There are strong – stacking interactions between pairs of dithiocarbazate units and also pairs of pyridine rings [3.27 (5)and 3.28 (5) A ° , respectively]. A long-distance intermolecular N—H N hydrogen bond [3.171 (2) A ° ] also stabilizes the structure.

2-Naphthylmethyl N-(3-pyridylmethylene) hydrazinecarbodithioate.

The title molecule, C18H15N3S2, is a trans-cis conformer. The thione S atom is in a trans configuration with respect to the pyridine ring but adopts a cis configuration with respect to the napthylmethyl substituent. In the crystal structure, molecules are linked by intermolecular N-H...N hydrogen bonds via[alpha]-N donor atoms and pyridyl N acceptor atoms into one-dimensional chains along the a axis. In addition, pairs of inversion-related dithiocarbazate groups and the attached pyridine groups are arranged with an interplanar distance 3.30 A, leading to [pi]-[pi] stacking interactions. The crystal used for the structure determination was twinned.

2,5-Bis(2-naphthylmethylsulfanyl)-1-thia-3,4-diazacyclopenta-2,5-diene

The title molecule, C24H18N2S3, consists of three essentially planar fragments viz. two methylnaphthalene groups and a five-membered thiadiazole ring. The dihedral angles between the two methylnaphthalene groups and the central 1-thia-3,4-diazacyclopenta-2,5-diene group are 78.9 (1) and 68.8 (1)°. In the crystal structure, - stacking interactions exist between pairs of symmetry-related naphthalene fragments with an interplanar separation of 3.35 A. All bond lengths and angles are comparable with previous reports except that both C-S bond lengths are slightly longer than normal. In addition, the C-S-C and S-C-C bond angles appear to be smaller than normal and this could be due to the steric hindrance of the methylnaphthalene fragments.

2-Quinolylmethyl N′-[1-(m-tol­yl)ethyl­idene]hydrazinecarbodithio­ate

The title compound, C20H19N3S2, crystallized as a cis–trans nconformer in which the quinoline ring system is cis across the C—S bond but adopts a trans geometry with respect to the nC—N bond. The compound exists in the thione form with the npresence of a C S bond.

2-Naphthyl­methyl N-[1-(4-pyrid­yl)ethyl­idene]hydrazinecarbodithio­ate

The molxadecules in the crystal structure of the title compound, C19H17N3S2, are linked by an interxadmolecular N—H⋯N [2.839u2005(5)u2005A] hydrogen bond via the α-N and the pyridyl N atoms. The thione S atom is in a trans position with respect to the methylxadpyridine fragment across the C—N bond but adopts a cis position with respect to the naphthalene ring across the C—S bond. There is a π–π stacking interxadaction between the naphthalene rings, with a centroid–centroid distance of 3.397u2005(2)u2005A.

S-Quinolin-2-ylmethyldithiocarbazate

In the title compound, C11H11N2S2, there is an intramolecular N-H...N [2.778 (2) A] hydrogen bond linking the quinoline N atom and the imino N atom. The planar quinoline ring system forms an angle of 67.7 (1)° with the dithiocarbazate group. Bond angles for both S-C-S [115.66 (8)°] and N-C-S [119.05 (11)°] are comparable with cis-trans S-methyldithiocarbazate but differ from those found in trans-cis S-methyldithiocarbazate and trans-cis S-benzyldithiocarbazate. This is due to the N-H...N hydrogen bond that exists only in the cis-trans conformation found for the title compound.