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Detailed electrochemical studies have been undertaken on molecular aggregation of the organic semiconductor 7,14-bis((triisopropylsilyl)-ethynyl)dibenzo[b,def]chrysene (TIPS-DBC), which is used as an electron donor material in organic solar cells. Intermolecular association of neutral TIPS-DBC molecules was established by using (1)H NMR spectroscopy as well as by the pronounced dependence of the color of TIPS-DBC solutions on concentration. Diffusion limited current data provided by near steady-state voltammetry also reveal aggregation. Furthermore, variation of concentration produces large changes in shapes of transient DC and Fourier transformed AC (FTAC) voltammograms for oxidation of TIPS-DBC in dichloromethane. Subtle effects of molecular aggregation on the reduction of TIPS-DBC are also revealed by the highly sensitive FTAC voltammetric method. Simulations of FTAC voltammetric data provide estimates of the kinetic and thermodynamic parameters associated with oxidation and reduction of TIPS-DBC. Significantly, aggregation of TIPS-DBC facilitates both one-electron oxidation and reduction by shifting the reversible potentials to less and more positive values, respectively. EPR spectroscopy is used to establish the identity of one-electron oxidized and reduced forms of TIPS-DBC. Implications of molecular aggregation on the HOMO energy level in solution are considered with respect to efficiency of organic photovoltaic devices utilizing TIPS-DBC as an electron donor material.

A family of barbituric and thiobarbituric acid end capped small molecule semiconductors were synthesized, characterized and shown to exhibit n-channel organic thin film transistor properties. By changing the N-alkyl substituent from methyl to ethyl, a dramatic increase in electron mobilities was observed with values nearing 0.3 cm2 V−1 s−1.

A comprehensive study of the effect of intraphase microstructure on organic photovoltaic (OPV) device performance is undertaken. Utilizing a bilayer device architecture, a small molecule donor (TIPS-DBC) is deposited by both spin-coating and by thermal evaporation in vacuum. The devices are then completed by thermal evaporation of C, an exciton blocking layer and the cathode. This bilayer approach enables a direct comparison of device performance for donor layers in which the same material exhibits subtle differences in microstructure. The electrical performance is shown to differ considerably for the two devices. The bulk and interfacial properties of the donor layers are compared by examination with photoelectron spectroscopy in air (PESA), optical absorption spectroscopy, charge extraction of photo-generated charge carriers by linearly increasing voltage (photo-CELIV), time-resolved photoluminescence measurements, X-ray reflectometry (XR), and analysis of dark current behavior. The observed differences in device performance are shown to be influenced by changes to energy levels and charge transport properties resulting from differences in the microstructure of the donor layers. Importantly, this work demonstrates that in addition to the donor/acceptor microstructure, the intraphase microstructure can influence critical parameters and can therefore have a significant impact on OPV performance. The influence of intraphase microstructure on the performance of organic photovoltaics (OPVs) is studied utilizing a bilayer (planar heterojunction) device architecture. Devices in which the donor layer exhibits subtle differences in microstructure are compared, and these differences are shown to affect critical parameters (energy levels, charge transport properties) having a significant impact on performance. Copyright

Charge extraction properties of various binary and ternary blends of organic photovoltaic devices covering both polymers and small molecules are studied. Due to their bipolar nature, both slow and fast carrier mobilities are identified from the extraction current transient. The equilibrium carrier concentration is also estimated for each of the blend films. The product of the slow carrier mobility and equilibrium concentration spreading two orders of magnitude can be used to estimate the short circuit current density. A good agreement between the estimated and measured short circuit current density is obtained with the accuracy reliant on the estimation of the slowest carrier mobility. This simplistic approach will be very useful to predict the short circuit current density for devices based on new materials.

Vertically aligned arrays of single walled carbon nanotubes (SWNTs) were chemically attached to an optically transparent electrode of fluorine doped tin oxide (FTO) for use as a working electrode in a photoelectrochemical solar cell. 7,14-Bis[2-[tris(1-methylethyl)silyl]ethynyl]dibenzo[b,def]chrysene (TIPS-DBC) layers were deposited onto the SWNT/FTO electrodes via spin coating. The photovoltaic properties of these new TIPS-DBC/SWNT/FTO electrodes were then investigated. The presence of the additional TIPS-DBC layer was found to increase the open circuit voltage, short circuit current density and power conversion efficiency of the cells compared to those cells made using nanotube only electrodes. In addition, the spin speed at which the TIPS-DBC layer was deposited was found to have an effect on the photovoltaic performance of the cells. These results show much promise for the further development of photovoltaics in which the photoactive elements are carbon based, rather than transition metal based.

A series of 2-phenylimidazo[1,2-b]pyridazine derivatives were synthesized and evaluated for their in vitro anthelmintic activity against Haemonchus contortus. The most active compounds had in vitro LD99 values of 30 nM, which is comparable to that of the benchmark commercial nematocide, Ivermectin.

The synthesis of a series of novel, unsymmetrically substituted benzothiadiazole-containing vinyl monomers and their free radical polymerization with and without the control of a reversible addition−fragmentation chain transfer (RAFT) agent is reported. The resulting polymers with electroactive pendants show tunable absorption and emission spectra depending on their molecular architecture. Using RAFT allows the synthesis of block copolymers using a hole-transporting vinyl-triarylamine as a second monomer. Efficient energy transfer between the two pendants has been detected. Cyclic voltammetry and photoelectron spectroscopy in air measurements have been employed to reveal the location of the HOMO and LUMO of the block copolymers. The block copolymers also influence the morphology of spin-casted films and show rectifying behavior in organic photovoltaic devices.

A series of novel 2-alkoxy- and 2-aryloxyiminoalkyl trifluoromethanesulfonanilide derivatives have shown significant in vitro parasiticidal activity against the ectoparasites Ctenocephalides felis and Rhipicephalus sanguineus. A number of these compounds also displayed significant in vitro endoparasite activity against the nematode Haemonchus contortus.

A series of 2-phenyl-3-(1H-pyrrol-2-yl)acrylonitrile derivatives were synthesized and evaluated for in vitro activity against the endoparasite Haemonchus contortus and the ectoparasite Ctenocephalides felis. Some compounds had significant in vitro activity against these parasites.

A new evaporable electron acceptor material for organic photovoltaics based on N-ethyl barbituric acid bithiophene (EBB) has been demonstrated. Bilayer devices fabricated with this non-fullerene acceptor and boron subphthalocyanine chloride (SubPc) donor produce power conversion efficiencies as high as 2.6% with an extremely large open-circuit voltage approaching 1.4 V.

Rice Blast Disease, caused by the fungus Pyricularia oryzae, is one of the most important diseases of rice. Several enzymes in the melanin biosynthetic pathway have proven to be valuable targets for development of rice blast fungicides. In particular, inhibitors of trihydroxynaphthalene reductase (3HNR), which catalyzes the conversion of trihydroxynaphthalene to vermelone, have yielded commercially useful rice fungicides. The X-ray structure of 3HNR has been published recently, presenting an opportunity to use this information in the de novo design of novel 3HNR inhibitors that may exhibit useful rice blast activity. We used the LeapFrog program to develop a docking model for interaction of ligands with the active site of THNR. The final model gave a good correlation between calculated binding energy and log Ki and was used to design novel ligands and score compounds for synthesis. Using this as a tool, we synthesized inhibitors in the nanomolar range and also developed several inhibitors that did not conform to the properties of the THNR active site. Leapfrog was able to locate a previously unrecognized binding pocket that could accommodate these otherwise anomalous regions of structure.

Soluble, electroactive derivatives based upon dibenzo[b,def]chrysene are introduced. These compounds do not chemically react with fullerenes, enabling the preparation of solution-processed solar cells based on small molecule blends. Device power conversion efficiencies of 2.25% are described and a correlation between processing conditions, film morphology, and device efficiencies is demonstrated.

A structure-device performance correlation in bulk heterojunction solar cells for new indandione-derived small molecule electron acceptors, FEHIDT and F8IDT, is presented. Devices based on the former exhibit higher power conversion efficiency (2.4%) and higher open circuit voltage, a finding consistent with reduced intermolecular interactions.

A variety of the title imidazopyridazine derivatives are synthesized and evaluated for their in vitro anthelmintic activity.

Reductive alkylation of methyl 3,5-dimethoxybenzoate with the dibromoalkane and the bromochloroalkane derivatives (4a-d) and (4e-g) afforded, after acid hydrolysis, the corresponding methyl 1-( haloalkyl )-3-methoxy-5-oxocyclohex-3-ene-1-carboxylate derivatives (6a-g). Reaction of (6a-c) with lithium diisopropylamide afforded methyl 3-methoxy-5-oxobicyclo[4.2.0]oct-3-ene- 1-carboxylate (2a), methyl 5-methoxy-7-oxo-1,2,3,4,7,7a-hexahydro-3aH-indene-3a-carboxylate (2b) and methyl 6-methoxy-8-oxo-1,3,4,5,8,8a-hexahydronaphtha1ene-4a(2 H)- carboxylate (2c), respectively. Compounds (2b) and (2c) were also obtained from the reaction of (6f) and (6g) with lithium diisopropylamide . Compounds (2a) and (2b) were each obtained as a single bridgehead isomer, the relative stereochemistry of ring fusion of which was assigned as cis on the basis of semiempirical molecular orbital calculations. Compound (2c) was obtained as a mixture of cis-and trans-fused bridgehead isomers. The ester (2b) was converted into the herbicide methyl 5,7-dioxo-6-[1-[(prop-2-enyloxy) imino ] butyl]octahydro-3aH-indene-3a-carboxylate (3a).

Reaction of pyridine-3-carbaldehyde methylhydrazone with 1,1'-carbonylbis-1H-imidazole afforded (E)-1'-methyl-2'-(3"-pyridyl) methylidene ]-1H-imidazole-1-carbohydrazide (2). Reaction of (2) with ethylamine, ethanol, ethanethiol, hydrazine monohydrate and methoxyamine afforded the corresponding semicarbazide, carbazate, thiocarbazate, carbonohydrazide and 4-methoxysemicarbazide derivatives (3a-d,g). Reaction of (2) with methylhydrazine gave the carbonohydrazide derivative (3f) together with 2,4-dimethyl-6-(3'-pyridyl)-1,4,5,6-tetrahydro-1,2,4,5-tetrazin-3(2H)-one (4a). The preparation of (E)-3-[(3'-pyridyl) methylideneamino ]oxazolidin-2-one (5a) and (E)-3-[(3'-pyridyl) methylideneamino ]tetrahydro-2H-1,3-oxazin-2-one (5b) is described.

Reaction of the methyl 2-(phenylmethylidene)hydrazinecarboximidothioate derivatives (3a–d) and (6a,b) with iron(III) chloride afforded the 5-methylsulfanyl-3-phenyl-4H-1,2,4-triazole derivatives (4a–d) and the 5-methylsulfanyl-3-phenyl-1H-1,2,4-triazole derivatives (7a,b). This reaction was extended to the synthesis of the 3-phenyl-5,6-dihydrothiazolo[2,3-c]-1,2,4-triazole derivatives (10a,b) and the 3-phenyl-6,7-dihydro-5H-1,2,4-triazolo[3,4-b][1,3]thiazine derivatives (10c,d). Reaction of 5-(3-chlorophenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione (12a) with 1,2-dibromoethane gave (10a) together with the isomeric 2-(3-chlorophenyl)-5,6-dihydrothiazolo[3,2-b][1,2,4]triazole (13a); similarly, reaction of (12a) with 1,3-dibromopropane afforded (10c) along with 2-(3-chlorophenyl)-6,7-dihydro-5H-[1,2,4]triazolo[5,1-b][1,3]thiazine (13b). The use of nickel peroxide and lead tetraacetate in place of iron(III) chloride was investigated for some of these oxidative cyclization reactions.

A series of hydrazonotrifluorosulfonanilide derivatives were synthesized and evaluated for in vitro activity against the ectoparasites Ctenocephalides felis and Rhipicephalus sanguineus. Some compounds with excellent activity against tick were identified.

A series of tetrahedrally capped acetylene dibenzochrysene derivatives were modelled and then synthesised resulting in compounds with very similar electronic properties, but differing physical properties depending on the capping group. By varying the size of the tetrahedral capping group we have undertaken a study on the relationship between the molecular structure and charge mobility in organic transistors. Thin film characterisation techniques (near-edge X-ray absorption fine structure spectroscopy, scanning electron microscopy, atomic force microscopy and X-ray diffraction) were coupled with organic field effect transistor (OFET) hole mobility data to explore the interplay between molecular structure, molecular packing, substrate dielectrics and transistor hole mobility. Using this strategy we identified a lead compound, TMS-DBC 2b, that has a one-dimensional slipped stack packing motif with a high degree of π–π overlap that produces hole mobilities as high as 0.012 cm2 V−1 s−1 when deposited on SiO2-ODTS substrates. Further refinement of the substrate temperature and deposition rate results in TMS-DBC 2b achieving hole mobilities as high as 1.17 cm2 V−1 s−1. These results show that subtle modification of the tetrahedral capping groups can alter the crystal packing and thin film microstructure of these angular dibenzochrysene materials, which dramatically influences the hole mobility in transistors. Further refinement of the device processing conditions on the lead compound results in a significant increase in transistor mobility.

Solution-processable derivatives 4a–d of the novel diindeno[1,2-g:1′,2′-s]rubicene ring system have been prepared in three steps from 1,5-dichloroanthraquinone. Charge extraction by linearly increasing voltage measurements indicates that 4a–d have bulk mobilities

Reaction of 3-trifluoromethylaniline with the 1,3-diketones 1a–1c and 5a–5d affords the N-[(3-trifluoromethyl)phenyl]-substituted enaminones 2a–2c and 6a–6d. Reaction of 2a with the acryloyl chloride derivatives 3a–3c gives the 1-[(3-trifluoromethyl)phenyl]-3,4-dihydro-2(1H)-pyridinones 4a, 4c, 4d; in a similar manner the 2(1H)-pyridinone 4b is obtained from 2b. Reaction of 6c, 6d with acryloyl chloride affords the 2,5(1H,3H)-quinolinedione derivatives 7 and 9 together with the acrylamides 8a, 8b. The 2(1H)-pyridinones 12a, 12b and the 3,4-dihydro-2(1H)-pyridinone 13 are prepared using routes involving the reaction of 2a with ethyl propiolate, dimethyl acetylenedicarboxylate, and maleic anhydride.

Reaction of the methyl 2-(phenylmethylidene)hydrazinecarboximidothioate derivatives (3a–d) and (6a,b) with iron(III) chloride afforded the 5-methylsulfanyl-3-phenyl-4H-1,2,4-triazole derivatives (4a–d) and the 5-methylsulfanyl-3-phenyl-1H-1,2,4-triazole derivatives (7a,b). This reaction was extended to the synthesis of the 3-phenyl-5,6-dihydrothiazolo[2,3-c]-1,2,4-triazole derivatives (10a,b) and the 3-phenyl-6,7-dihydro-5H-1,2,4-triazolo[3,4-b][1,3]thiazine derivatives (10c,d). Reaction of 5-(3-chlorophenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione (12a) with 1,2-dibromoethane gave (10a) together with the isomeric 2-(3-chlorophenyl)-5,6-dihydrothiazolo[3,2-b][1,2,4]triazole (13a); similarly, reaction of (12a) with 1,3-dibromopropane afforded (10c) along with 2-(3-chlorophenyl)-6,7-dihydro-5H-[1,2,4]triazolo[5,1-b][1,3]thiazine (13b). The use of nickel peroxide and lead tetraacetate in place of iron(III) chloride was investigated for some of these oxidative cyclization reactions.

Reaction of pyridine-3-carbaldehyde methylhydrazone with 1,1'-carbonylbis-1H-imidazole afforded (E)-1'-methyl-2'-(3"-pyridyl) methylidene ]-1H-imidazole-1-carbohydrazide (2). Reaction of (2) with ethylamine, ethanol, ethanethiol, hydrazine monohydrate and methoxyamine afforded the corresponding semicarbazide, carbazate, thiocarbazate, carbonohydrazide and 4-methoxysemicarbazide derivatives (3a-d,g). Reaction of (2) with methylhydrazine gave the carbonohydrazide derivative (3f) together with 2,4-dimethyl-6-(3'-pyridyl)-1,4,5,6-tetrahydro-1,2,4,5-tetrazin-3(2H)-one (4a). The preparation of (E)-3-[(3'-pyridyl) methylideneamino ]oxazolidin-2-one (5a) and (E)-3-[(3'-pyridyl) methylideneamino ]tetrahydro-2H-1,3-oxazin-2-one (5b) is described.

Birch reduction of the silane derivatives (3a-d), prepared from Grignard cross-coupling reactions, afforded the cyclohexane-1,3-dione derivatives (5a-d) after acid hydrolysis. Compounds (5a-d) are precursors to silicon-containing herbicides of the general structure (8).

Reductive alkylation of 3,5-dimethoxybenzoic acid with haloalkanes afforded the 1-alkyl- 3,5-dimethoxycyclohexa-2,5-diene-1-carboxylic acid derivatives (3a-e) which, upon esterification and hydrolysis, furnished methyl 1-alkyl-3-hydroxy-5-oxocyclohex-3-ene-l-carboxylate derivatives (4f-j). Reaction of (4f-j) with butyric anhydride gave methyl 1-alkyl-4-butyryl- 3-hydroxy-5-oxocyclohex-3-ene-1-carboxylate derivatives (6a-e) which were converted into methyl 1-alkyl-4-[1-( ethoxyimino )butyl]-3-hydroxy-5-oxocyclohex-3-ene-1-carbo xyate derivatives (2a-e). Similarly, the oxime O-ether derivative (2f) was prepared from the amide (41), obtained from reaction of (3b) with N,N′- carbonyldiimidazole and dimethylamine followed by hydrolysis.

Synthese en 12 etapes avec un rendement de 6% a partir du pyrrolidino-1 cyclopentene. L'addition Diels Alder a haute pression permet d'obtenir la configuration absolue des jatropholones

The title compounds are 3-aza[6](1,7)-naphthalenophanes with 3-Me and 3-CO2Me substituents, C18H23NO2 and C19H23NO4; in the former the chemical shift of the naphthalene hydrogen enclosed by the medium nitrogen-containing ring is the highest yet observed in a derivative of this type ( σ 9.33). In order to examine the environment of this hydrogen atom and the expected associated naphthalene ring distortions in both compounds, single-crystal X-ray structure determinations have been carried out at 295 K showing the transannular H…N distance in the methyl derivative to be remarkably short at 2.08(2) � . Crystals are triclinic, P1, a 11.683(3), b 10.846(3), c 6.729(2) �, α 90.08(2), β 93.33(2), γ 112.88 Z 2; R was 0.041 for 1378 'observed' reflections. Crystals of the 3-CO2Me derivative are also triclinic, P1, a 12.587(9), b 10.650(4), c 6.758(3) � , a 91.91(3), β 100.51(4), γ 104.74(5)° Z 2; R 0.067 for 1267 'observed' reflections.

Reaction of the reduced pyrrolo [2,1-a] isoquinoline amine (1a) with cyanogen bromide in the presence of methanol gave the medium-ring cyanamide derivative 7,9,10-trimethoxy-2,3,4,5,6,7-hexahydro-1H-3- benzazonine-3-carbonitrile (2a). Analogous products were also obtained from reaction of the reduced 5H-oxazolo[2,3-a] isoquinoline , 2H- benzo [a] quinolizine , 2H,6H-[1,3] oxazino [2,3-a] isoquinoline and [1,4] oxazino [3,4-a] isoquinoline derivatives (1b-e), whereas the reduced 3H-oxazolo[4,3-a] isoquinoline and 5H-oxazolo[2,3-a] isoquinoline derivatives (1f) and (8) gave 1-(2,4-dioxapentyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline-2-carbonitrile (5a) and N-[2-(2-benzoyl-4,5-dimethoxyphenyl)ethyl]-N- methylcyanamide (9) respectively, the latter in low yield. The medium-sized heterocyclic derivatives (2f-h) were also obtained from cyanogen -bromide-mediated water solvolysis reactions of (1a), (1c) and (1e). The cyanamides (2a-h), (5a) and (9) have been converted into the respective tertiary amine derivatives (3a- h), (5c) and (11), with concomitant reduction of the carbonyl group in the last case. The crystal and molecular structure of 1,10,11- trimethoxy-3,4,5,6,7,8-hexahydro-1H-2,6-benzoxazecine-6-carbonitrile (2d) and 1-hydroxy-10,11-dimethoxy-1,4,5,6,7,8-hexahydro-2H-3,6- benzoxazecine-6-carbonitrile (2h) have been determined by single- crystal X-ray methods.