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Novel NIR-emitting organic dyes with aggregation-induced emission (AIE) properties are described. The thienopyrazine-based donor-acceptor-donor structure allows for easy tuning of the photophysical properties. The intense light absorption ability and the emission in the red/NIR region, both in solution and in the aggregate phase, make them attractive for potential use as functional organic materials in the development of luminescent devices.

In Chile, apple chemical thinning uses primarily carbaryl, which is expected to be banned in the future. New thinning chemicals are needed. During the 2013-14 season, two trials were conducted in a 'Brookfield Gala'/Pajam 2 orchard. Metamitron (Goltix Compact(MR) 90% WG, 450 g ai ha-1) or BA (Exilis®, 180 g ai ha-1) plus NAA (NAA 800®, 18 g ai ha-1) were evaluated at different timings beginning at 4 mm up to 28 mm fruit diameter at 3 to 8 day intervals. Control treatments included, one without any spray and a sprayed control that included NAA at full bloom, carbaryl (Carbaryl 85 WP, 1368 g ai ha-1) at petal fall and BA (180 g ai ha-1) plus carbaryl (1368 g ai ha-1) at 12 mm fruit. All sprays were done when no carbohydrate deficit was predicted by Malusim Model (Cornell University). Thinning was evaluated on two branches tree-1, fifty days after full bloom, as fruits per cluster (F/C). All treatments differed from the control (2.3 F/C). Metamitron treatments were more effective when applied between 8 and 16 mm fruit (1.0 F/C). NAA+BA treatments were more effective when applied right after petal fall (4 mm fruit; 1.3 F/C). After removing the effect of crop load, average fruit weight was increased with BA+NAA spray at 4 and 12 mm fruit. All treatments of metamitron were different from the control.

Dye-sensitized photocatalysis (DSP) is a relatively new approach to convert sunlight into a fuel such as H2. The required optical and electrochemical properties of the dyes employed in DSP are very similar to those necessary for dye-sensitized solar cells (DSC). As a result, the classes of compounds most commonly employed in DSP belong to those classes that have shown the highest efficiencies in DSC. Nevertheless, it's still not clear how the dye structure affects the efficiency of catalysis in H2 production experiments. Thus, the aim of this work is to find reliable guidelines for the synthesis of D-?-A dyes with optimized structures for hydrogen production using different Sacrificial Electron Donors (SED). To date, there are only a few reports concerning the use in DSP of compounds containing the 2,1,3-benzothiadiazole moiety, a scaffold that has already shown impressive power conversion efficiencies in DSC, but no systematic study on their structural optimization. Here, the preparation and application in photocatalytic H2 production of several D-?-A benzothiadiazole-based dyes will be reported. Their photophysical and chemical properties were tuned by a proper choice of terminal groups, ?-spacers and side chains, leading to s in terms of H2 production rate and TON.

The production of H2 from sunlight and water is playing an increasingly important role in the production of clean fuels from sustainable and abundant energy sources. In this process, commonly referred as artificial photosynthesis, the role of the sensitizer, is critical for optimizing the harvesting of visible light and triggering the reduction reaction at the catalytic active site. Organometallic sensitizers have mainly been studied so far, however, thanks to recent advances and lower manufacturing costs, metal-free organic sensitizers have recently received increasing importance. On the basis of recent studies, concerning organic molecules applied on photoactivated H2 production, appeared that those dyes well performing in DSSC are in most cases suitable for hydrogen production. For this reason, we selected a family of organic dyes having a dithienosilole core which are known to lead to high efficiencies in DSSC (10%, 7%) as starting point to synthesize three new dyes (OB1-3) to study the influence of structural changes in the photoactivated H2 evolution process. More in detail, the efficiency of some new organic D-?-A dyes in the H2 production process has been investigated using the commercially available benchmark TiO2 (P25) and the best performing dye was also used to sensitize a catalyst based on a different TiO2 crystalline form, namely brookite/Pt. The aim of this work is to understand the possible correlation between structure and activity of such dyes, in particular the effect of introducing alkyl chains on the scaffold in order to affect several properties such as solubility, aggregation, shielding and wettability of the semiconductor and also the changes induced by the use of a different crystalline form of TiO2.

In light of the ever-growing demand of modern electronics for wearable integrated optoelectronic devices, Fiber-shaped Dye-Sensitized Solar Cells (FDSSCs) have gained increasing interest over the last years as suitable energy production systems for the development of the next generation of smart products. To fulfill the wearable concept, it is important to design long and flexible thin-film FDSSCs capable of adapting to curved surfaces such as the human body. In this study, for the first time, several key parameters towards the optimization of long and flexible FDSSCs based on inexpensive TiO2 as photoanode material and a fully organic thiazolo [5,4-d]thiazole-based sensitizer (TTZ5) were studied. First, the influence of photoanode thickness on photovoltaic performance was evaluated in 3.5 cm-long devices, for which an optimal thickness of 10 μm was identified, obtaining a maximum PCE of 1.57 ± 0.15%. Long (10 cm) complete FDSSCs were then fabricated, using thin layer photoanodes of about 5 μm which were instead found to be the optimal choice for such devices. The as-obtained FDSSCs based on TTZ5 possess dimensions appealing for future applications while also delivering a remarkable PCE of 1.23 ± 0.04%, thus paving the way for further optimization of thin-film flexible long FDSSCs based on organic sensitizers.

Fiber-shaped Dye-Sensitized Solar Cells (DSSFs) represent one of the most interesting technologies aimed at the light harvesting and the production of electricity for wearable applications. In order to boost DSSFs commercialization, their production costs and environmental impact must be reduced. To this end, a suitable strategy could be to build thin film-based devices endowed with metal-free organic sensitizers, exploiting their higher molar extinction coefficients compared to typical ruthenium-containing organometallic dyes. In this work, three thiazolo[5,4-d]thiazole-based organic dyes, TTZ3, TTZ5 and TTZ7, capable of strongly absorb visible light, were used for the first time to manufacture titanium wire-based DSSFs. DSSFs based on a thin TiO2 layer (5 μm) sensitized with the three organic dyes were prepared and tested and the obtained results show that power conversion efficiencies for the organic dyes (0.80%) are higher than that obtained with the reference N719 dye (0.45%). An efficiency of 0.99% with short circuit current density equal to 3 mA/cm2 was achieved when the TTZ7-based DSSFs were tested in diffuse illumination condition, highlighting the supremacy of these dyes compared to the metal-organic reference. The excellent photovoltaic performances of TTZ dyes were attributed to their better light harvesting properties, resulting in the production of higher photocurrent densities, which was confirmed by the electrochemical impedance spectroscopy (EIS) analysis. The superiority of organic dyes on DSSFs performances compared to N719, shown for the first time in this work, support the real possibility to apply these molecules for the preparation of efficient light-harvesting devices based on thin film photoanodes.

A synthetic sequence for the preparation of fully conjugated, 2,7-disubstituted fluorazone (9H-pyrrolo[1,2-a]indol-9-one) derivatives was developed, comprising Elming-Clauson-Kaas type pyrrole formation, POCl3-mediated ring closure, selective halogenation and elongation of the conjugate backbone via cross-coupling reactions. As a proof of principle, such methodology was used to prepare for the first time two organic D-?-A dyes containing the fluorazone moiety. The new compounds displayed broad absorption of visible light when adsorbed on nanocrystalline TiO2 and electrochemical properties compatible with their employment as photosensitizers in dye-sensitized solar cells. Small-scale photovoltaic devices fabricated with the fluorazone dyes yielded power conversion efficiencies in the 2.1-2.4% range, corresponding to approx. 70% of the efficiency obtained with reference organic dye DF15 under the same conditions.

The mechanisation of various vineyard operations reduces production costs and labour requirements, thus allowing for the more efficient management of larger vineyards. However, pruning mechanisation has been associated with yield decline (a decrease in fruit production due to the elongation of the fruiting positions out of the trellis system area), over cropping and unstable yields. Furthermore, manual followup has been a common practice for most vineyards subjected to mechanised pruning. A Merlot vineyard was studied for three consecutive seasons in terms of its vegetative and productive aspects, and hand pruning was compared with mechanised alternating pruning strategies. Bud burst was more successful in hand-pruned vines compared to mechanically pruned vines. However, hand pruning took longer and produced a lower yield compared to mechanical pruning. Traditional high (25 cm above the cordon wire) mechanical pruning showed deteriorating characteristics over time in vegetative and yield parameters. Vines pruned at a lower height (12 cm above the cordon wire) in one of the three seasons maintained high production. Despite higher yields, fruit soluble solids, pH and titratable acidity were not altered. The quantity of second-crop fruit from lateral shoots was small and was very similar among treatments. Mechanical pruning at a lower height in one season in general reduces the annual potential yield, but the average and cumulative effects over the years improve compared to using just traditional high mechanical pruning. These long-term effects make it feasible to fully mechanise vineyard pruning and maintain high yields.

The study was conducted on two consecutive seasons (2007-2008 and 2008-2009) to determine if crop load adjustment and cluster tipping in relation to cluster shape can allow an increase in cluster weight and yield per plant in ‘Thompson Seedless’ table grapes. During the first season the feasibility to classify clusters – prior to cluster thinning – as cylindrical, spherical or conical, was evaluated. Once feasibility was validated a crop load experiment was conducted, regulating crop load depending on the percentage of cylindrical clusters. Additionally, a cluster-tipping trial combining crop load with cluster shape and berry number was carried out. Results indicated that ‘Thompson Seedless’ plants with higher percentage of cylindrical clusters have lower yields; increasing cluster number per plant and berry number per cluster increase yield; and spherical and conical clusters on ‘Thompson Seedless’ present greater berry weight and size. These results can benefit ‘Thompson Seedless’ table grape vineyards management to optimize crop load adjustment in relation to yield and grape quality.

This study tested the relationship between stem water potential (ψstem) and vapor pressure deficit (VPD) in order to evaluate its use as reference for irrigation control of table grape (Vitis vinifera ) cvs. Thompson Seedless and Redglobe. Two trials were carried out on consecutive seasons. In the first season the treatments consisted of four different irrigation regimes: T1, plants irrigated at 100% of ETc; T2, irrigated until fruit set the same as T1 but after fruit set every other time T1; T3, plants with no irrigation from fruit set to harvest; and T4, plants irrigated at 50% of ETc throughout the growing season. Vines from T1 always showed a higher ψstem for a wide VPD range, therefore the ψstem and VPD relationship was established using T1 vines, obtaining a logarithmic function with a high determination coefficient (R2=0.85). The following season this relationship was used to control irrigation frequency on two table grape cvs. Irrigation started when vines had 20 cm shoots and then the irrigation amount was set to replenish 10% of soil available water. Trial 1 was conducted on cv. Thompson Seedless and consisted of two treatments: T1 plants irrigated to satisfy 100% ETc and T2 plants irrigated according to the previously obtained ψstem-VPD reference line. Trial 2 was established with Redglobe cv. plants using three treatments: T1 plants irrigated to satisfy 100% Etc; T2, plants irrigated the same as T1 but after fruit set every other time T1; and T3, plants irrigated according to the ψstem-VPD reference line previously obtained. Irrigation frequency determined using the ψstem-VPD relationship reduced total water volume compared to T1 on both trials, with no effects on yield or quality, showing the feasibility of using this relationship to control irrigation frequency.

Gold nanorods (GNRs) were investigated to enhance light absorptionin co-sentitized dye solar cells (c-DSSC), thanks to their plasmonic characteristics. Pastes were obtained by directly mixing GNRs with titania. The resulting thin films differ for sintering conditions and GNRs concentration. The reported study is based on the absorbance spectra of the different samples, together with SEM and TEM to corroborate the results of the spectroscopic analysis on the transformation of GNRs morphology consequent to the different conditions utilized for TiO2 sintering. We tested these cells with organic dyes that could substitute the more expensive and toxic Ru complexes.

Dye-­sensitized solar cells (DSSC) in which photon-­to-­electron conversion is carried out by a dye molecule adsorbed on nanocrystalline TiO2, have long been considered a potential alternative to silicon­ based PV devices,[1] but their industrial development has been so far hampered by their lower efficiency compared to other technologies, as well their limited lifetime, often due to partial dye desorption from the semiconductor layer.[2] The aim of this study was to design, synthesize and characterize a small library of new DSSC sensitizers bearing innovative, pyridine-­based anchoring groups, and to compare their performances (cell efficiency and stability) with those of similar dyes having a traditional cyanoacrylic acceptor unit. During the work, we focused on purely organic compounds characterized by the well-­known donor­-acceptor architecture (D­-p-­A),[3] aiming to improve the anchoring moiety first. The common D­-p scaffold of the new dyes was built using palladium­-catalyzed cross-­coupling reactions as key synthetic steps. After suitable optimization, another Pd-catalyzed reaction, namely a Stille coupling, was used to introduce the novel anchoring units. Following such strategy, we managed to prepare the target dyes having tree regioisomeric carboxypyridines as acceptor groups. The new compounds underwent full spectroscopic, electrochemical and computational characterization, and their properties where compared with those of a reference compound endowed with a classic cyanoacrylic acid acceptor. Test devices prepared with these new dyes as sensitizers, provided power conversion efficiencies corresponding to 54-63% of those obtained with the reference compound. More significantly, device stability tests carried out on transparent, larger area cells and determination of desorption pseudo-­first order rate constants showed that some of these new compounds were removed from TiO2 more slowly than the reference dye, suggesting, in the case of isomers having the nitrogen atom close to the carboxylic moiety, a possible cooperative effect of the two functional groups on semiconductor binding.[4] At this point, we wondered if a higher photovoltaic efficiency could be obtained by increasing the electron-withdrawing character of the terminal pyridine rings. To this end, we selected two of the three isomers and prepared the corresponding N­-methylpyridinium salts. Despite more favorable photophysical properties, however, the cells built with the cationic sensitizers provided lower efficiencies than their neutral counterparts. Further investigations concerning the anchoring stability of the new N-­methylpyridinium salts on TiO2 substrates are currently underway to confirm the "double binding" theory initially proposed for the original carboxypyridine compounds. References: [1] Hagfeldt, A.; Boschloo, G.; Sun, L.; Kloo, L.; Pettersson, H., Chem. Rev. 2010, 110, 6595-6663. [2] Uam, H.-S.; Jung, Y.-S.; Jun, Y.; Kim, K.-J., J. Photochem. Photobiol. A 2010, 212, 122-128. [3] Ooyama, Y.; Harima, Y., ChemPhysChem. 2012, 13, 4032-4080. [4] Franchi, D.; Calamante, M.; Reginato, G.; Zani, L.; Peruzzini, M.; Taddei, M.; Fabrizi de Biani, F.; Basosi, R.; Sinicropi, A.; Colonna, D.; Di Carlo, A.; Mordini, A., Tetrahedron 2014, 70, 6285-6295.

Several attempts were performed to use efficient organic dyes for DSSCs as building integrated (BIPV) windows, that could substitute the more expensive Ru complexes. For this particular application, transparency in the 500 - 600 nm region is a stringent demand that in most cases implied the use a co-sensitizing NIR dye in addition to a dye sensitizer in the visible region. We employed also gold nanorods (GNRs) to enhance the absorption of the two dyes, with the aim of improving also cell efficiency, which was expected to be lower with respect to those obtained in panchromatic applications.

Since their discovery in 1991,[1] Dye-Sensitized Solar Cells (DSSC) have been considered a very promising technology to convert solar energy in electric current because of their low cost of production and their easy integration in buildings and objects.[2] The photoactive material inside a DSSC is the dye.[3] Totally organic dyes have recently found great interest in this field, thus we decided to study the synthesis of new organic D-p-A dyes with broad light absorption and high extinction molar coefficients: molecules with these features were expected to give good photovoltaic performances within thin-layer, transparent DSSCs. With this aim and aided by theoretical calculations, we designed a class of thiazolo[5,4-d]thiazole-based dyes (TTZ3-7) having different donor and acceptor groups.[4] The dyes were synthesized and subjected to a complete spectroscopic and electrochemical characterization. Thin-layer transparent test DSSCs were built with our dyes, achieving power conversion efficiencies up to 7.71%. References: 1. O'Reagan, B.; Grätzel, M. Nature 1991, 353, 737-740. 2. Dye-sensitized solar cells (Ed.: K. Kalyanasundaram), EPFL Press, Lausanne 2010. 3. Hagfeldt, A.; Boschloo, G.; Sun. L.; Kloo, L.; Petterson, H. Chem. Rev. 2010, 110, 6595-6663. 4. Dessì, A.; Calamante, M.; Mordini, A.; Peruzzini, M.; Sinicropi, A., Basosi, R.; Fabrizi de Biani, F.; Taddei, M.; Colonna, D.; Di Carlo, A.; Reginato, G.; Zani, L. Chem. Commun. 2014, 50, 13952-13955.

Two artificial pollination field trials were carried out in Central Chile (32°S. Lat.) during the 1999-2000 season with ‘Hay-ward’ kiwifruit plants (Actinidia deliciosa (Chev.) Liang et Ferguson). The treatments for both trials used pollen collected from ‘Matua’ and included: flower to flower hand pollination; hand pollination using a velvet pad attached to a handle; and mechanical pollination using a portable pollen (1:1, pollen: licopodium) dusting machine; and a control treatment without artificial pollination. Trial 1 did not include bee hives as did Trial 2. In Trial 2, half of the selected shoots in each plant were isolated from bee pollination by means of a light fabric bag. A block design with 5 replications of one plant each was used in Trial 1, while in Trial 2 a fully random split plot (with and without isolation) with 5 replications was used. In both trials, flower to flower and pad pollination increased fruit set, fruit size, seeds and fertilized locules per fruit. Mechanical pollina...

This chapter provides an overview of the most recent advances in the preparation of polar organometallic compounds (containing alkali metals, magnesium, and zinc), characterized by little if no stabilization, and their reactivity with alkylating agents. After a general introduction on the direct alkylation of alkyl and alkenyl polar organometallics, the chapter focuses on allylation and carbometalation reactions, including diastereo- and enantioselective processes, and finally discusses some of the most updated examples of cross-coupling transformations employing magnesium and zinc organometallics.