NOVEL FLUORINATED METAL COMPLEXES

The present invention relates to novel fluorinated metal complexes effective as charge transfer photosensitizers, with utility as components of dye-sensitized solar cells (DSSC) and similar devices

Fluorinated imidazolium salts having liquid crystal characteristics

A family of fluorinated imidazolium salts showing liquid–crystalline properties in a wide temperature range was developed. These fluorinated ionic liquid crystals, due to their intrinsic hydrophobicity, high thermal stability and good conductivity, are suitable candidates to be used as electrolytes in electrochemical devices such as Dye Sensitized Solar Cell (DSSC) or lithium batteries

Microencapsulation and PBO: a tool in resistance management of the green peach aphid

Insecticide resistance can be a serious threat to the application of Integrated Pest Management. The Green Peach-Potato Aphid, Myzus persicae (Sulzer) is a serious pest in peach orchard. Insecticide treatments have selected many populations that have different degrees of insecticide resistance due to different resistance mechanisms. These resistance mechanisms can interfere with many classical insecticide classes, but, fortunately, till now, there is no clear evidence for resistance to neonicotinoids. The severity of this problem is also increased by the reduction of the available active ingredients that can lead to an abuse of a single group of insecticides. Many populations of M. persicae, both in Italy and in Europe, over-express a carboxylesterase (E4/FE4) that reduces in various degrees the efficacy of several insecticides by hydrolysis and/or by sequestering. Recently, many authors have demonstrated that piperonylbutoxide (PBO) can efficiently interfere with esterase activity overcoming insecticide resistance. Several microencapsulated products (in polyurea or cyclodextrin) with PBO and various active ingredients have been tested in laboratory bioassays against a susceptible and against an esterase resistant population of M. persicae. A comparison was done with the commercial formulated products alone or mixed with PBO. The results achieved with the different formulation are discussed in term of increased mortality, application rate as well as offsprings reduction. According to the results, the use of these types of microencapsulation together with PBO could be an interesting tool to be included in resistance management strategies against the green peachpotato aphid

DSSC anode: tailoring crystal shape/phase stability of anatase nanopowders and their use in paste formulation

Among these, anatase nano-rods are used as photo-anode in the Dye Sensitized Solar Cells (DSSC) which have been demonstrated to be a promising, cost-effective alternative to conventional solid semiconducting solar cells for production of electrical energy [2]. Parameters such as shape, size and phase type of titania nanocrystals, that can be optimized recurring to different synthesis methods [3], influence the surface area of the nanoTiO2 and therefore the amount of sensitizing dye absorbed [4,5] that is strictly connected to the DSSC performance. Anyhow, despite the large number of studies on the anatase-to-rutile transformation (A-R) [6] and ab-initio calculations of the effects of crystal shape on anatase stability relative to rutile [7] the role of nanoparticle shape in DSSC are still to be clarified. The present study reports the synthesis of shape- and size-controlled anatase nanorods, their characterization as a function of thermal treatment and their use for preparation of a photo-anode paste. Anatase nanorods (Figure 1) were synthesized by a procedure encompassing hydrolysis of a TiO2 precursor, dispersion in high boiling organic solvent and suitable workup. By only changing the hydrolysis of titanium dioxide precursor, anatase nanorods with two different aspect ratios were obtained. These samples were then subjected to stepwise heating in the range form RT to 1000°C, and the variation of crystal shape, size and titania phase were monitored by powder X-ray diffraction and Rietveld refinements. A paste was made starting from a sample of anatase powder (labeled “SF”) having a surface area higher than the commercial nanotitania products (e.g. Degussa P25®). Each paste was prepared with an amount of TiO2 content of about 10-20% wt/wt. The starting raw material was obtained from a nanosuspension washed with a controlled pH value aqueous solution dried by spray drying. The powder was then mixed with a solvent (terpineol), a co-solvent (2-ethyl-1-hexanol), a binder and a dispersant, under mechanical stirring at room temperature. Such a prepared material was further added with ethanol and mixed for a time needed to ensure the best homogeneity. The paste so obtained was then dried under vacuum to eliminate the low boiling solvents. A strong milling of the paste by a three roll mill (EXAKT) was performed to ensure the grip of the TiO2 thick layer to the conductive glass (FTO) even after heat treatment in the sintering furnace. The adhesion of the fired paste to the support glass was checked by scanning electron microscopy. The paste applied in DSSC devices has been irradiated with solar lamp to allow the calculation of current values of the closed circuit. The values compared with paste made with the commercial nanotitania powder, show an improvement from 20% to 50% in terms of photo-current generated by the cell. Reference: [1] U. Diebold, Surface Science Reports, 2003, 48, 53-229. [2] B. O’Regan, M. Grätzel, Nature, 1991, 353, 737. [3] M. Fernandez-Garcıa, X. Wang, C. Belver, J.C. Hanson, J.A. Rodriguez, J. Phys. Chem. C, 2007, 111, 674-682. [4] Md. K. Nazeeruddin, S. M. Zakeeruddin, R. Humphry-Baker, M. Jirousek, P. Liska, N. Vlachopoulos, V. Shklover, C.-H. Fischer, and M. Grätzel, Inorg. Chem, 1999, 38, 6298-6305. [5] S. Ito, P. Chen, P. Comte, M. K. Nazeeruddin, P. Liska, P. Péchy, and M. Grätzel, Progress in Photovoltaics, 2007, 15, 603- 612. [6] H. Zhang, J.F. Banfield, Chem. Mater., 2005, 17, 3421-3425. [7] A. S. Barnard, L. A. Curtiss, NanoLetters, 2005, 5, 1261-126

The interactions between piperonyl butoxide and analogues with the metabolic enzymes FE4 and CYP6CY3 of the green peach aphid Myzus persicae (Hemiptera: Aphididae)

BACKGROUND: Piperonyl butoxide (PBO) is a well-known insecticide synergist capable of interacting with phase 1 metabolic enzymes, specifically esterases and cytochrome P450s. In this study, structure activity relationship (SAR) analyses were used to characterise the interaction of around 30 analogues of PBO with the esterase FE4 and the P450 CYP6CY3 from insecticide resistant Myzus persicae (Sulzer), in order to predict the synthesis of more potent inhibitors. RESULTS: Enzyme inhibition studies were performed against esterase and oxidase activities and together with in silico modelling, key activity determinants of the analogues were identified and optimised. Novel analogues were then designed and synthesised, some of which showed greater inhibition against both enzymatic systems: specifically, dihydrobenzofuran moieties containing an alkynyl side chain and a butyl side chain against FE4, and benzodioxole derivatives with a propyl/butyl side chain and an alkynyl ether moiety for CYP6CY3. CONCLUSIONS: In vitro assays identified potential candidate synergists with high inhibitory potency. The in vivo confirmation of such results will allow consideration for a possible use in agriculture

EcoSyn: The potential for overcoming insecticide-resistance in arable crop pests using synergists

Insect pests cause significant damage to agricultural crops and transmit several important diseases of humans and animals. Chemical insecticides have been used to control insect pests for many decades and remain essential to ensure a supply of affordable food and as part of disease vector control for the foreseeable future. Unfortunately, the world-wide use of insecticides over many years has led to increased resistance to insecticides and contributed to environmental contamination. One possible way to reduce insecticide use without compromising control is to use a synergist in combination with an insecticide. Synergists are themselves non-toxic at doses applied but increase efficacy of the co-applied insecticides by inhibiting the metabolic defence systems in insects that detoxify insecticides. The goal of this project is to develop ecofriendly synergists for use in formulations with insecticides, both in agriculture and in public health

Ecofriendly synergists for insecticide formulations (EcoSyn)

EcoSyn consists of a consortium of experts to optimise the use of synergists in agriculture and public health by elucidating the relationship between synergist chemical structure and activity on a variety of target insect metabolic enzymes: this will enhance the efficacy of insecticides against resistant and susceptible pest insects in both laboratory and field environments. Repeated use of synthetic insecticides has resulted in the development of insecticide resistance; inhibition of insect defence enzymes by synergists would allow increased kill of resistant pests and control of susceptible pests with reduced insecticidal rates. EcoSyn has characterised interactions of novel synergists based on PBO (piperonyl butoxide) against known resistance-conferring P450/esterase proteins by both in vitro and in vivo assays. Candidate synergists have also been tested against pollinators and in long-term selection experiments to investigate changes in insect pest transcriptom