Aedes aegypti is the main vector of three neglected tropical diseases: dengue, zika and chikungunya. Dengue is under surveillance by health organizations worldwide due to the risk of epidemics. Since there is no specific treatment for dengue, most studies have focused on preventing the reproduction and/or development of the mosquitoes. We studied the larvicidal activity of five phosphates and phosphorothioates derived from cardol, one of the four main components of cashew nut shell liquid (Anacardium occidentale L.), at different concentrations. The organophosphorothioate derivatives were tested for their in vitro inhibitory potential against acetylcholinesterase (AChE). One compound, Cdl.i-dPS (median lethal concentration (LC50) = 0.8 ppm), was four times more efficient compared to an important commercial larvicide, Temephos (LC50 = 3.2 ppm), and showed greater AChE inhibition than its monosubstituted analogue and Temephos.

New asymmetric cardanol-based porphyrins, free-base and coordinated with Ni, Co and Cu, were synthesized and completely characterized as A3B type. Such porphyrins were obtained aiming improved solubility in polar solvents due insertion of an -OH phenolic group. Their thermal and dielectric properties were also evaluated. Changes in the synthetic route reduced the reaction time and improved the yields of the aldehyde precursor obtainment. Electronic absorption spectra of the new porphyrins in CH2Cl2, EtOH and acetone, indicated a decrease in the ε (molar absorptivity) values with increasing solvent polarity, except for the nickel complex which, in acetone, showed a slight increase of 2% in the ε value. The dielectric measurements showed that the conductivity (σ) and the loss tangent (tan δ) increased with frequency, but the permittivity (ε') decreased. The results showed that the coordination of the porphyrin promoted a significant change in thermal and dielectric properties, specially for to the Ni-complex compound, which presented the best dielectric properties with interesting values of permittivity and loss tangent at 100 MHz (19.46 and 0.011 a.u., respectively).

As reações diretas entre [Ru(NH3)5(H2O)](PF6) 2 (1) e P(m-tol)3 (a), P(p-tol)3 (b) e P(OC5H11)3 (c) forneceram os complexos [Ru(NH3)5P(m-tol)3](PF 6)2 (2a), trans-[Ru(NH3)4{P(p- tol)3}2](PF6)2 (3b) e trans-[Ru(NH3)4{P(OC5H 11)3}2](PF6)2 (3c), respectivamente. A constante de velocidade específica de substituição da amônia em (2a) foi de 4,3 x 10-3 s-1 (25 ºC, μ = 0,10 mol L-1). Os aquo complexos trans-[Ru(NH3)4(L)(H2O)]2+ (L = P(p-tol)3, 4b; L = P(OC5H11)3, 4c) foram gerados pela aquação térmica de uma das moléculas de L, dos respectivos complexos trans-[Ru(NH3)4L2 ]2+ (L = P(p-tol)3, 3b; L = P(OC5H11)3, 3c) e os valores das constantes foram: k-1 = 2,7 x 10-3 s-1 e k-1 = 3,5 x 10-3 s-1, respectivamente. Os valores dos potenciais formais de redução para 3b, 3c e 2a foram 0,50 ± 0,01V; 0,48 ± 0,01V e 0,50 ± 0,02V, respectivamente (vs SCE) [μ = 0,10 mol L-1; NaCF3COO; C H+ = 1,0 x 10-3 CF3COOH]. As reações: <IMG SRC="http:/img/fbpe/jbchs/v13n5/12819x1.gif" > foram estudadas e os valores de k1, k-1 e Keq foram 0,28 mol-1 L s-1, 0,06 s-1, 4,67 mol-1 L [para L = P(m-tol)3, 4a]; 0,25 mol-1 L s-1, 0,04 s-1, 6,25 mol-1 L [para L = P(p-tol)3, 4b] e 12,4 mol-1 L s-1, 5,8 x 10-1 s-1, 21 mol-1 L [para L = P(OC5H11)3, 4c] [25ºC; μ = 0,10 mol L-1; NaCF3COO; C H+ = 1,0 x 10-3 CF3COOH].

Direct reactions between [Ru(NH3)5(H2O)](PF6) 2 (1) and P(m-tol)3 (a), P(p-tol)3 (b) and P(OC5H11)3 (c) lead the complexes [Ru(NH3)5P(m-tol)3](PF 6)2 (2a), trans-[Ru(NH3)4{P(p -tol)3}2](PF6)2 (3b) and trans-[Ru(NH3)4{P(OC5H 11)3}2](PF6)2 (3c) respectively. These complexes have been isolated as hexafluorophosphate salts and characterized by elemental analysis, cyclic voltammetry and UV-VIS spectra measurements. One ammonia ligand in 2a is displaced at the a specific rate of 4.3 x 10-3 s-1 (25 ºC, μ = 0.10 mol L-1). The aquo species trans-[Ru(NH3)4(L)H2O]2+ (L = P(p-tol)3, 4b; L = P(OC5H11)3, 4c) are generated by the substitution of one L ligand with H2O, from trans-[Ru(NH3)4(L)2]2+ with k-1 = 2.7 x 10-3 s-1 [L = P(p-tol)3, 3b] and 3.5 x 10-3 s-1 [L = P(OC5H11)3 3c] (25 ºC, μ = 0.10 mol L-1) (NaCF3COO/CF3COOH; C H+ = 1.0 x 10-3 mol L-1). The formal reduction potentials for the species 3b, 3c and 2a are 0.50 ± 0.01V, 0.48 ± 0.01V and 0.50 ± 0.02V, respectively (vs SCE) [μ = 0.10 mol L-1 ; NaCF3COO; C H+ = 1.0 x 10-3 CF3COOH]. The following reactions: <IMG SRC="http:/img/fbpe/jbchs/v13n5/12819x2.gif"> [L = P(m-tol)3, P(p-tol)3 and P(OC5H11)3] were studied and the calculated values for k1, k-1 and Keq are 0.28 mol-1 L s-1, 0.06 s-1, 4.67 mol-1 L [L = P(m-tol)3, 4a]; 0.25 mol-1 L s-1, 0.04 s-1, 6.25 mol-1 L [L = P(p-tol)3, 4b]; 12.4 mol-1 L s-1, 5.8x10-1 s-1, and 21 mol-1 L [L = P(OC5H11)3, 4c], [25.0 ± 0.2 ºC; m = 0.10 mol L-1; NaCF3COO; C H+ = 1.0 x 10-3 CF3COOH].