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showing 10 items of 3516 documents
The C–I･･･⁻O–N⁺ Halogen Bonds with Tetraiodoethylene and Aromatic N-oxides
2020
The nature of C–I⋯⁻O–N⁺ interactions, first of its kind, between non-fluorinated tetraiodoethylene XB-donor and pyridine N-oxides (PyNO) are studied by single-crystal X-ray diffraction (SCXRD) and Density Functional Theory (DFT) calculations. Despite the non-fluorinated nature of the C2I4, the I⋯O halogen bond distances are similar to well-known perfluorohaloalkane/-arene donor-PyNO analogues. With C2I4, oxygens of the N-oxides adopt exclusively 2-XB-coordination in contrast to the versatile bonding modes observed with perfluorinated XB-donors. The C2I4 as the XB donor forms with PyNO’s one-dimensional chain polymer structures in which the C2I4⋯(μ-PyNO)2⋯C2I4 segments manifesting two bondin…
(2-Pyridyl)sulfonyl Groups for ortho -Directing Palladium- Catalyzed Carbon-Halogen Bond Formation at Functionalized Arenes
2017
International audience; We describe an efficient palladium-catalyzed selective C-H ortho-monohalogenation (X=I, Br, Cl, F) of various functionalized (2-pyridyl) aryl-sulfones. ortho-, meta-and para-functionalization is tolerated at the arene group which undergoes C-H halogenation. Some modifications are also possible on the 2-(arylsulfonyl) heteroaryl directing groups. A comparison of the halogenation efficiency suggests that bromination is the practical method of choice, while chlorination and fluorination are possible but more challenging. Under forcing conditions ortho-dihalogenation can also be achieved.
Effects of economic policy uncertainty on stock and bond market integration
2015
Tässä pro gradu – tutkielmassa tarkastellaan sitä , miten talouspoliitti nen epävarmuu s vaikut taa osake - ja korko markkina tuottojen väliseen yhteyteen . Tutkimuksessa saadut e mpiiriset havainnot viittaavat siihen, että kun reaalit alouden kasvu ylittää inflaati o- vauhdin , talouspoliittisen epävarmuuden kasvu on tekijä, joka vähentää osake - ja ko r- ko markkina tuottojen korrelaatiota . Sen sijaan kun inflaatio vauht i ylittää reaalitalouden kasvun, jota tässä tutkielmassa on mitattu S&P 500 i ndeksin osinkojen jaolla, kasvava talouspoliittinen epävarmuus vahvistaa osake - ja korkomarkkinatuottojen korrelaatiota . Tutkimus on toteutettu Yhdysvaltojen rahoitusmarkk inoiden aineistolle…
Self-assembly of square planar rhodium carbonyl complexes with 4,4-disubstituted-2,2′-bipyridine ligands
2020
The impact of non-covalent interactions and reaction conditions on formation and self-assembly of ionic pairs of Rh complexes with 4,4’-disubstituted bipyridine ligands ([Rh(L1)(CO)2][Rh(CO)2Cl2])n (1), [Rh(L1)2Cl2][Rh(CO)2Cl2] (2), ([Rh(L1)(CO)2][Rh(CO)2Cl2][Rh(L1)(CO)2]n([Rh(CO)2(Cl)2])n) (3), ([Rh(L2)CO2] [Rh(CO)2Cl2])n∙EtOH (4), ([Rh(L2)(CO)2])n ([Rh(CO)2Cl2])n (5) (L1 = 4,4’-dimethyl-2,2’-bipyridine, L2 = 4,4’-diamine-2,2’-bipyridine) have been studied. Packing of square planar Rh complexes favor formation of one-dimensional chains. In structure 1, the polymeric chain is formed by the alternating cationic [Rh(L1)(CO)2]+ and the anionic [Rh(CO)2Cl2]- units leading to a neutral pseudo li…
La prise en compte de la stratégie agricole améliore la compréhension de l’effet des pratiques sur les communautés adventices
2019
National audience; Les agriculteurs présents dans une même situation de production peuvent différer dans leurs objectifs et donc leurs pratiques. Afin de tester l’effet d’une pratique particulière (ex. désherbage chimique) sur la communauté adventice, il est donc nécessaire de tenir compte de l’ensemble des autres pratiques, formant une stratégie agricole. Nous avons ainsi développé 14 indicateurs décrivant les pratiques agricoles enquêtées sur la zone de Fénay de 2004 à 2016 auprès des 23 agriculteurs de la zone. L’originalité des indicateurs est qu’ils situent chaque parcelle par rapport aux autres parcelles ayant mis en oeuvre la même culture la même année sur la zone. Ceci nous a permis…
Defying Stereotypes with Nanodiamonds: Stable Primary Diamondoid Phosphines
2016
International audience; Direct unequal C-H bond difunctionalization of phosphorylated diamantane was achieved in high yield from the corresponding phosphonates. Reduction of the functionalized phosphonates provides access to novel primary and secondary alkyl/aryl diamantane phosphines. The prepared primary diamantyl phosphines are quite air stable compared to their adamantyl and especially alkyl or aryl analogues. This finding is corroborated by comparing the singly occupied molecular orbital energy levels of the corresponding phosphine radical cations obtained by density functional theory computations.
Co-crystals of an agrochemical active – A pyridine-amine synthon for a thioamide group
2011
Five novel co-crystals of thiophanate-ethyl (TE), an agrochemical active, with di(2-pyridyl)ketone (1), 2-benzoylpyridine (2), 3-benzoylpyridine (3), 4-phenylpyridine (4) and biphenyl (5) were found and crystal structures of four of them (TE1–TE3, TE5) solved by single crystal X-ray diffraction. Three of the co-crystals (TE1–TE3) form by way of a reliable pyridine-amine hydrogen bond synthon and one (TE5) because of close packing effects. The fifth co-crystal was identified by X-ray powder diffraction. The work demonstrates the usage of a reliable supramolecular synthon for crystal engineering, while concurrently reminds that the close packing of even very similar molecules cannot be fully …
Packing incentives and a reliable N–H⋯N–pyridine synthon in co-crystallization of bipyridines with two agrochemical actives
2011
The co-crystallization of agrochemical actives thiophanate-methyl and thiophanate-ethyl with 2,2′-bipyridine, 4,4′-bipyridine and 1,2-bis(4-pyridyl)ethane was investigated with conventional crystallization, the slurry method and liquid-assisted grinding. Co-crystals of both thiophanates with all bipyridines were found and the structures solved with single crystal X-ray diffraction. Whereas the 2,2′-bipyridine co-crystals seem to form because of a combination of weak interactions, and in the case of the thiophanate-methyl, partly because of close packing incentives, the 4,4′-bipyridine and 1,2-bis(4-pyridyl)ethane co-crystals form mainly because of a favourable N–H···N–pyridine hydrogen bond…
N,N-Dimethyl-N-propylpropan-1-aminium chloride monohydrate
2008
The title compound, C8H20N+·Cl−·H2O, has been prepared by a simple one-pot synthesis route followed by anion exchange using resin. In the crystal structure, the cations are packed in such a way that channels exist parallel to the b axis. These channels are filled by the anions and water molecules, which interact via O—H...Cl hydrogen bonds [O...Cl = 3.285 (3) and 3.239 (3) Å] to form helical chains. The cations are involved in weak intermolecular C—H...Cl and C—H...O hydrogen bonds. The title compound is not isomorphous with the bromo or iodo analogues.
3,4,5-Trimethoxy-4'-methylbiphenyl
2013
In the title compound, C16H18O3, the dihedral angle between the benzene rings is 33.4 (2)°. In the crystal, molecules are packed in a zigzag arrangement along the b-axis and are interconnected via weak C—H⋯O hydrogen bonds, and C—H⋯π interactions involving the methoxy groups and the benzene rings of neighbouring molecules.