Poly[di-µ-aqua-[µ6-N-(4-bromophenylsulfonyl)dithiocarbimato]dipotassium] and poly[di-µ-aqua-[µ4-N-(4-iodophenylsulfonyl)dithiocarbimato]dipotassium].

The rigid organic linkers N-(4-bromophenylsulfonyl)dithiocarbimate(2-) and N-(4-iodophenylsulfonyl)dithiocarbimate(2-) crystallize with two potassium cations and two water molecules in their asymmetric units, forming the title coordination polymers, [K(2)(C(7)H(4)BrNO(2)S(3))(H(2)O)(2)](n) and [K(2)(C(7)H(4)INO(2)S(3))(H(2)O)(2)](n). The anions and the water molecules link the potassium cations into broad two-dimensional networks, which are further linked by K···halide interactions.

Bis(tetra-phenyl-phospho-nium) bis-[N-(trifluoro-methyl-sulfon-yl)dithio-carbimato(2-)-κS,S']zincate(II).

The title salt, (C(24)H(20)P)(2)[Zn(C(2)F(3)NO(2)S(3))(2)], consists of a complex dianion and two tetra-phenyl-phospho-nium cations. The Zn(II) ion displays a distorted tetra-hedral coordination environment with four S atoms from two S,S'-chelated N-(trifluoro-methyl-sulfonyl-)dithio-carbimate anions. In the crystal, besides the ionic inter-action of the oppositely charged ions, inter-molecular C-H⋯O inter-actions between cations and anions are observed. One of the cations inter-acts with an inversion-related equivalent by π-π stacking between phenyl rings, with a centroid-centroid distance of 3.932 (4) Å.

Syntheses, crystal structure, spectroscopic characterization and antifungal activity of new N-R-sulfonyldithiocarbimate metal complexes.

Five new compounds with the general formula of (Bu(4)N)(2)[M(RSO(2)NCS(2))(2)], where Bu(4)N=tetrabutylammonium cation, (M=Ni, R=4-FC(6)H(4)) (1), (M=Zn, R=4-FC(6)H(4), 4-ClC(6)H(4), 4-BrC(6)H(4), 4-IC(6)H(4)), (2), (3), (4) and (5), respectively, were obtained by the reaction of the appropriate potassium N-R-sulfonyldithiocarbimate (RSO(2)N=CS(2)K(2)) with nickel(II) chloride hexahydrate or zinc(II) acetate dihydrate in metanol:water 1:1. The elemental analyses and the IR data are consistent with the formation of the expected bis(dithiocarbimato)metal(II) complexes. The (1)H and (13)C NMR spectra showed the signals for the tetrabutylammonium cation and the dithiocarbimate moieties. The compounds 1, 2 and 5 were also characterized by X-ray diffraction techniques. The nickel(II) is coordinated by two N-4-fluorophenylsulphonyldithiocarbimato(2-) ligands forming a planar coordination. The zinc(II) exhibits distorted tetrahedral configuration in compounds 2 and 5 due to the chelation effect of two sulfur atoms of the N-R-sulfonyldithiocarbimate ligands. The antifungal activities of the compounds were tested in vitro against Colletotrichum gloeosporioides, an important fungus that causes the plant disease known as anthracnose in fruit trees. All the complexes were active.

Synthesis, characterization, absolute structural determination and antifungal activity of a new chlorinated aromatic avenaciolide analogue.

BACKGROUND: Avenaciolide, a natural product isolated from Aspergillus avenaceus H. Smith, possesses several interesting biological properties, such as antifungal and antibacterial activities and inhibition of glutamate transport in mitochondria. In a study aiming to discover new compounds with antifungal activity, a bis-gamma-lactone analogous to avenaciolide was prepared and characterized by elemental analysis, mass spectrometry, and infrared and NMR spectroscopy. RESULTS: The absolute structures of this compound and of the synthetic precursor (also a bis-gamma-lactone) were determined by X-ray diffraction analysis. The bis-gamma-lactones synthesized crystallize in the orthorhombic space group P2(1)2(1)2(1), and the crystal packings are supported by C--H...O hydrogen bonds. The compound showed antifungal activity against Colletotrichum gloeosporioides (Penz.) Penz. & Sacc., while the synthetic precursor was inactive under the in vitro test conditions employed. CONCLUSION: The results indicate that it is not only the bis-gamma-lactone skeleton that is important to antifungal activity. The latter also depends on the presence of the exocyclic double bond possibly due to a Michael addition type reaction with the fungal enzymes.

Inhibition and uncoupling of photosynthetic electron transport by diterpene lactone amide derivatives.

Nine diterpene lactone amide derivatives 1-9 were synthesized from 6-oxovouacapan-7beta,17beta-lactone, which was obtained from 6alpha,7beta-dihydroxyvouacapan-17beta-oic acid isolated from Pterodon polygalaeflorus Benth., and tested for their activity on photosynthetic electron transport. Amide derivatives 3-5 behaved as electron transport chain inhibitors; they inhibited the photophosphorylation and uncoupled non-cyclic electron transport from water to methylviologen (MV). Furthermore, 4 and 5 enhanced the basal electron rate acting as uncouplers. Compound 6 behaved as an uncoupler; it enhanced the light-activated Mg2+-ATPase and basal electron flow, without affecting the uncoupled non-cyclic electron transport. Compounds 1-2 and 7-9 were less active or inactive. Compounds 3-5 did not affect photosystem I (PSI); they inhibited photosystem II (PSII) from water to 2,6-dichlorophenol indophenol (DCPIP). Compound 4 inhibited PSII from water to silicomolybdate (SiMo), but it had no effect on the reaction from diphenylcarbazide (DPC) to DCPIP indicating that its inhibition site was at the water splitting enzyme complex (OEC). Compounds 3 and 5 inhibited PSII from water to DCPIP without any effect from water to SiMo, therefore they inhibited the acceptor site of PSII. Chlorophyll a fluorescence kinetics confirmed the behaviour of 3-5.

Synthesis and antifungal activity of aromatic bis-gamma-lactones analogous to avenaciolide.

Avenaciolide is a bis-gamma-lactone isolated from Aspergillus avenaceus and possesses antifungal activity. Here, we describe the total syntheses and characterization by elemental analyses, and IR and NMR spectroscopy of three new bis-gamma-lactones analogous to avenaciolide, where the octyl group of the natural product was replaced by aromatic groups. The effects of the avenaciolide, the novel compounds, and their synthetic precursors on the mycelia development and conidia germination of Colletotrichum gloeosporioides were evaluated in vitro. The new compounds were as active as avenaciolide in the tested conditions, while the synthetic precursors were inactive. The preparation and characterization of 15 new synthetic intermediates are also described.

Bis(tetra-phenyl-phospho-nium) bis-[N-(octyl-sulfon-yl)dithio-carbimato(2-)-κS,S']-nickelate(II).

The Ni atom in the title complex, (C(24)H(20)P)(2)[Ni(C(9)H(17)NO(2)S(3))(2)], lies on a twofold axis within a square-planar geometry defined by four S atoms derived from two dithio-carbimate dianions, each forming a four-membered chelate ring. A small distortion, described by a deviation of the Ni(II) atom by 0.083 (1) Šfrom the plane through the four S atoms, and also by the torsion angles about the Ni-S bonds, implies a folded conformation for the chelate ring.

A diterpene gamma-lactone derivative from Pterodon polygalaeflorus Benth. as a photosystem II inhibitor and uncoupler of photosynthesis.

6alpha,7beta-Dihydroxyvouacapan-17beta-oic acid (1) was isolated from Pterodon polygalaeflorus Benth. Modification of 1 yielded 6alpha-hydroxyvouacapan-7beta,17beta-lactone (2) and then 6-oxovouacapan-7beta,17beta-lactone (3). Photosynthesis inhibition by 3 was evaluated in spinach chloroplasts. The uncoupled non-cyclic electron transport rate and ATP synthesis were inhibited by 3, which behaved as a Hill reaction inhibitor. Furthermore, 3 acted as an uncoupler because it enhanced the basal and phosphorylating electron transport rate on thylakoids. This last property of 3 was corroborated when it was observed that it enhances the Mg2+-ATPase activity. In contrast, 3 did not affect photosystem I (PSI) activity. Analysis of the partial photosystem II (PSII) reactions from water to DCPIPOX and water to silicomolybdate allowed to locate the inhibition sites at the redox components of PSII. The OJIP test of the chlorophyll a fluorescence transient confirmed that the inhibition sites were 1.) the oxygen-evolving complex (OEC) and 2.) by the formation of silent centers in the non-QA reducing centers.