Fate, distribution, and bioconcentration of pesticides impact on the organic farms of Cameron Highlands, Malaysia.

Occurrence and distribution of organochlorine pesticides (OCPs), organophosphate pesticides (OPPs), and pyrethroid pesticides (PYRs) residues in the leafy vegetables were analyzed together with the soil samples using gas chromatography-electron capture detector. Edible tissues of vegetables showed detectable residues of these compounds indicating the influence of the conventional farms and nearby organic farms. In the vegetables, the OCPs concentrations were recorded as nd-133.

Determination of pesticide residues in leafy vegetables at parts per billion levels by a chemometric study using GC-ECD in Cameron Highlands, Malaysia.

A simple and sensitive analytical method has been developed employing gas chromatography coupled with electron capture detector (GC-ECD), and validated for screening and quantification of 15 pesticide residues at trace levels in cabbage, broccoli, cauliflower, lettuce, celery, spinach, and mustard. The method consists of two steps, first, to determine the significance of each factor by Pareto chart followed by optimization of these significant factors using central composite design (CCD). Minitab statistical software was used for these multivariate experiments for the generation of 2 design and CCD matrices.

Diorganotin(IV) derivatives of N-methyl p-fluorobenzo-hydroxamic acid: preparation, spectral characterization, X-ray diffraction studies and antitumor activity.

Three diorganotin(IV) complexes of the general formula R2Sn[RcC(O)N(RN)O] (Rc = aryl, RN = Alkyl) have been synthesized by refluxing in toluene the corresponding diorganotin(IV) oxides with the free ligand N-methyl p-fluorobenzohydroxamic acid, using a Dean and Stark water separator. The ligand was derived from the reaction of the corresponding p-fluorobenzoyl chloride and N-methylhydroxylamine hydrochloride in the presence of sodium hydrogen carbonate. The isolated free ligand and its respective diorganotin compounds have been characterized by elemental analysis, IR and 1H-, 13C-, 119Sn-NMR spectroscopies.

(E)-2-[1-(1-Benzothio-phen-2-yl)ethyl-idene]-N-phenyl-hydrazinecarboxamide.

The title compound, C(17)H(15)N(3)OS, crystallizes with two unique mol-ecules, denoted 1 and 2, in the asymmetric unit. The two mol-ecules are closely similar and overlay with an r.m.

3-(2-Hy-droxy-phen-yl)-1-{(E)-[1-(pyrazin-2-yl)ethyl-idene]amino}-thio-urea monohydrate.

In the title compound, C(13)H(13)N(5)OS·H(2)O, the thio-urea mol-ecules closely resemble each other and are approximately planar; the dihedral angles formed between the terminal benzene rings are 7.88 (8) and 7.20 (8)°, respectively.

3-[(E)-(4-Chloro-benzyl-idene)amino]-1-phenyl-thio-urea.

In the title compound, C(14)H(12)ClN(3)S, the dihedral angle between the terminal benzene rings is 56.6 (2)°; the benzene rings lie to the same side of the mol-ecule. The major twist in the mol-ecule occurs around the C(ar)-N bond (ar is aromatic) [C-N-C-C = 49.

Bis(N-isopropyl-N-methyl-dithio-carbamato-κS,S')diphenyl-tin(IV).

The dithio-carbamate anions in the title compound, [Sn(C(6)H(5))(2)(C(5)H(10)NS(2))(2)], chelate to the Sn(IV) atom, which is six-coordinated in a skew-trapezoidal-bipyramidal geometry. The mol-ecule lies across a twofold rotation axis.

Bis(N-butyl-N-ethyl-dithio-carbamato-κS,S')nickel(II).

The dithio-carbamate anions in the title compound, [Ni(C(7)H(14)NS(2))(2)], chelate to the Ni(II) atom, which is four-coordinate in a square-planar geometry. The Ni(II) atom lies on a center of inversion.

n-Butyl-dichlorido{4-cyclo-hexyl-1-[phenyl(2-pyridyl-κN)methyl-ene]-thiosemicarbazidato-κN,S}tin(IV) chloro-form monosolvate.

The monodeprotonated Schiff base ligand in the title com-pound, [Sn(C(4)H(9))(C(19)H(21)N(4)S)Cl(2)]·CHCl(3), N,N',S-chelates to the Sn atom, which is six-coordinated in an octa-hedral environment. The three coordinating atoms along with the butyl C atom comprise a square plane, above and below which are positioned the Cl atoms. The amino group is a hydrogen-bond donor to a Cl atom of an adjacent mol-ecule, the hydrogen bond giving rise to a helical chain propagating in [010].

1-Benzothio-phene-2-carbaldehyde 4-ethyl-thio-semicarbazone.

The title compound, C(13)H(15)N(3)S(2), crystallizes with two unique mol-ecules, A and B, in the asymmetric unit. These differ principally in that the methyl group of the 4-ethyl-thio-semicarbazone moiety is ordered in mol-ecule A but disordered over two positions with equal occupancies in mol-ecule B. The benzothio-phene group and the semicarbazone unit are inclined at dihedral angles of 11.

(E)-3,4-Dihydroxy-benzaldehyde 4-methyl-thio-semicarbazone.

The title compound, C(9)H(11)N(3)O(2)S, adopts an E configuration with respect to the C=N bond. The mol-ecule is approximately planar, with an r.m.

3,4-Dihydroxy-benzaldehyde thio-semi-carbazone.

The asymmetric unit of the title compound, C(8)H(9)N(3)O(2)S, contains three independent mol-ecules which are stacked approximately over each other. In the crystal structure, centrosymmetric pairs of mol-ecules are formed through inter-molecular hydr-oxy-hydr-oxy O-H⋯O and hydr-oxy-sulfur O-H⋯S hydrogen bonds which are, in turn, linked into a two-dimensional network by N-H⋯O(hydr-oxy) hydrogen bonds.

3,4-Dihydroxy-benzaldehyde 4-phenyl-thio-semicarbazone.

Mol-ecules of the title compound, C(14)H(13)N(3)O(2)S, are linked by inter-molecular O-H⋯O hydrogen bonds into centrosymmetric dimers forming R(2) (2)(4) rings which are further linked by O-H⋯S hydrogen bonds and weaker N-H⋯S and N-H⋯O hydrogen bonds to form a three-dimensional network.

(E)-2-[1-(1-Benzothio-phen-3-yl)ethyl-idene]hydrazinecarbothio-amide methanol hemisolvate.

The asymmetric unit of the title compound, C(11)H(11)N(3)S(2)·0.5CH(4)O, contains four thio-semicarbazone mol-ecules and two methanol solvent mol-ecules. Each hydrazinecarbothio-amide mol-ecule adopts an E configuration with respect to the C=N double bond and is stabilized by an intra-molecular N-H⋯N hydrogen bond, resulting in an S(5) ring motif.

(E)-3,4-Dihydroxy-benzaldehyde 4-ethyl-thio-semicarbazone.

The title compound, C(10)H(13)N(3)O(2)S, was prepared by condensation of 3,4-dihydroxy-benzaldehyde with 4-ethyl-3-thio-semicarbazide. The mol-ecule adopts an E configuration with respect to the C=N bond. One of the OH substituents on the dihydroxy-benzene ring is disordered over the two possible 3-positions on either side of the ordered 4-hydr-oxy group.

3-Meth-oxy-N-p-tolyl-benzohydroxamic acid.

Two mol-ecules of the title compound, C(15)H(15)NO(3), are linked by a pair of O-H⋯O(carbon-yl) hydrogen bonds over a centre of inversion to form a hydrogen-bonded dimer. With respect to the -C(=O)-N(OH)- unit, the methoxy-substituted ring is twisted by 42.2 (1)°, whereas the methyl-substituted ring is twisted by 52.

Bis[N,N-bis(2-hydroxyethyl)dithiocarbamato]dimethyltin(IV).

The title compound, [Sn(CH(3))(2)(C(5)H(10)NO(2)S(2))(2)], has crystallographic mirror symmetry (C-Sn-C on mirror plane) and the coordination polyhedron around the Sn atom is a tetrahedron [C-Sn-C 139.3 (2) degrees and S-Sn-S 82.3 (1) degrees ] distorted towards a skew-trapezoidal bipyramid owing to an intramolecular Sn.