Search results for "Organic P"
showing 10 items of 307 documents
Tackling Performance Challenges in Organic Photovoltaics: An Overview about Compatibilizers
2020
Organic Photovoltaics (OPVs) based on Bulk Heterojunction (BHJ) blends are a mature technology. Having started their intensive development two decades ago, their low cost, processability and flexibility rapidly funneled the interest of the scientific community, searching for new solutions to expand solar photovoltaics market and promote sustainable development. However, their robust implementation is hampered by some issues, concerning the choice of the donor/acceptor materials, the device thermal/photo-stability, and, last but not least, their morphology. Indeed, the morphological profile of BHJs has a strong impact over charge generation, collection, and recombination processes; control o…
Computational determination of the dominant triplet population mechanism in photoexcited benzophenone
2014
In benzophenone, intersystem crossing occurs efficiently between the S-1(n pi(star)) state and the T-1 state of dominant n pi(star) character, leading to excited triplet states after photoexcitation. The transition mechanism between S-1(n pi(star)) and T-1 is still a matter of debate, despite several experimental studies. Quantum mechanical calculations have been performed in order to assess the relative efficiencies of previously proposed mechanisms, in particular, the direct S-1 -> T-1 and indirect S-1 -> T-2(pi pi(star)) -> T-1 ones. Multiconfigurational wave function based methods are used to discuss the nature of the relevant states and also to determine minimum energy paths a…
1-[2-(Benzylamino)-4-pyridyl]-2-(4-fluorophenyl)ethane-1,2-dione
2009
The crystal structure of the title compound, C20H15FN2O2, contains two crystallographically independent molecules, which are related by a pseudo-inversion center and linked into dimersviaintermolecular N—H...N hydrogen bonds. The 4-fluorophenyl ring of moleculeAmakes dihedral angles of 17.17 (16) and 62.25 (15)°, respectively, with the phenyl and pyridine rings. The 4-fluorophenyl ring of moleculeBmakes dihedral angles of 8.50 (16) and 64.59 (15)°, respectively, with the phenyl and pyridine rings. The dihedral angle between the pyridine ring and the phenyl ring of moleculeA[60.97 (15)°] is bigger than in moleculeB[59.49 (15)°]. The dihedral angle between the two pyridine rings is 1.37 (14)°…
Modern Electrochemical Aspects for the Synthesis of Value‐Added Organic Products
2017
The use of electricity instead of stoichiometric amounts of oxidizers or reducing agents in synthesis is very appealing for economic and ecological reasons, and represents a major driving force for research efforts in this area. To use electron transfer at the electrode for a successful transformation in organic synthesis, the intermediate radical (cation/anion) has to be stabilized. Its combination with other approaches in organic chemistry or concepts of contemporary synthesis allows the establishment of powerful synthetic methods. The aim in the 21st Century will be to use as little fossil carbon as possible and, for this reason, the use of renewable sources is becoming increasingly impo…
The Understanding of the Metazoan Skeletal System, Based on the Initial Discoveries with Siliceous and Calcareous Sponges
2017
Initiated by studies on the mechanism of formation of the skeletons of the evolutionary oldest still extant multicellular animals, the sponges (phylum Porifera) have provided new insights into the mechanism of formation of the Ca-phosphate/hydroxyapatite skeleton of vertebrate bone. Studies on the formation of the biomineral skeleton of sponges revealed that both the formation of the inorganic siliceous skeletons (sponges of the class of Hexactinellida and Demospongiae) and of the calcareous skeletons (class of Calcarea) is mediated by enzymes (silicatein: polymerization of biosilica; and carbonic anhydrase: deposition of Ca-carbonate). Detailed studies of the initial mineralization steps i…
Polychlorinated organic compounds in the Arctic cod liver: trends and profiles
2000
Polychlorinated organic compounds (POCs) have been measured in Arctic cod liver from Vestertana Fjord for a period of 1987-1998. Significant decrease was observed for DDD (p = 0.043), alpha-HCH (p = 0.001), and gamma-HCH (lindane; p = 0.001). Contents of DDE, 2,3,7,8-tetrachlorodibenzofuran, PCBs, chlordanes, chloronaphthalenes, hexachlorobenzene and polychlorodiphenyl ethers had no significant trend. Contents of three hexa- and two heptachlorodibenzofurans and octachlorodibenzofuran increased slightly from 1987 to 1994, but then at very high rate from 1994 to 1998. Trends of HCHs, profiles of PCBs and levels of chlordanes are in accordance with atmospheric long range transport. The hexa-, …
[1,2-Bis(diphenyl-phosphan-yl)ethane-κP,P']{2-[(4-nitro-benzoyl-meth-yl)diphenyl-phosphan-yl]phenyl-κC,C'}palladium(II) trifluoro-methane-sulfonate-d…
2011
In the cation of the title compound, [Pd(C(26)H(19)NO(3)P)(C(26)H(24)P(2))]CF(3)O(3)S·CH(2)Cl(2)·0.5C(6)H(14), the Pd(II) atom has a slightly tetra-hedrally distorted square-planar coordination geometry. The PdC(3)P and PdC(2)P(2) five-membered metallacycles adopt envelope and twist conformations, respectively. In the crystal, inter-molecular C-H⋯O hydrogen bonds link cations and anions into a three-dimensional network. The dichloro-methane solvent mol-ecule is disordered over three orientations with a site-occupancy ratio of 0.5/0.3/0.2. The n-hexane solvent mol-ecule has a crystallographically imposed centre of symmetry.
Polycyclic aromatic hydrocarbons (PAHs) and their oxygen-containing derivatives (OPAHs) in soils from the Angren industrial area, Uzbekistan.
2009
We measured the concentrations and depth distribution (0-10, 10-20 cm) of 31 PAHs and 12 OPAHs in soils at eleven equidistant sampling points along a 20-km transect in the Angren industrial region (coal mine, power plant, rubber factory, gold mine), Uzbekistan to gain an insight into their concentrations, sources, and fate. Concentrations of all compounds were mostly much higher in the 0-10 cm than in the 10-20 cm layer except in disturbed soil close to the coal mine. Proximity to one of the industrial emitters was the main determinant of PAH and OPAH concentrations. The Sigma31PAHs concentrations correlated positively with the Sigma7 carbonyl-OPAH (r=0.98, p<0.01), Sigma5 hydroxyl-OPAH (r=…
2,4-Di-tert-butyl-6-({[2-(di-methyl-amino)-eth-yl](2-hy-droxy-benz-yl)amino}-meth-yl)phenol.
2014
The title compound, C26H40N2O2, has both its N atoms in trigonal-pyramidal geometries. The molecular structure is stabilized by O—H...N and C—H...O hydrogen bonds. In the crystal, C—H...π interactions lead to the formation of a supramolecular helical chain along theb-axis direction.
1-{2-[4-(4-Nitrophenyl)piperazin-1-yl]ethyl}-4-aza-1-azoniabicyclo[2.2.2]octane iodide
2012
The title compound, C18H28N5O2+&#183;I&#8722;, was observed as a main product in an intended 1:1 reaction between 4-iodonitrobenzene and 1,4-diazabicyclo[2.2.2]octane (DABCO). In the reaction, DABCO undergoes a ring opening to yield a quaternary salt of DABCO and 1-ethyl-4-(4-nitrophenyl)piperazine with an iodide anion. The crystal structure determination was carried out as no crystal structure had been previously reported in the investigations describing the corresponding reaction with 4-chloronitrobenze. Indeed, the crystal structure of the title compound confirms the molecular composition proposed earlier for the analogous chloride salt. The cation conformation is similar to the …