66522-06-3Relevant articles and documents
Correlating cobalt redox couples to photovoltage in the dye-sensitized solar cell
Chen, Kitty Y.,Schauer, Phil A.,Patrick, Brian O.,Berlinguette, Curtis P.
, p. 11942 - 11952 (2018)
We report a series of structurally analogous cobalt mediators related to [Co-bpy]Z (bpy = 2,2′-bipyrimidine, Z = 2+ or 3+) to demonstrate a linear relationship between the redox potential of the Co(iii/ii)-based redox couple (Emed) and open-circuit voltage (VOC) of the DSSC. The Emed values vary from 0.42 to 1.07 V vs. NHE depending on the number of nitrogen atoms and the presence of tert-butyl substituents on the ligand. A 64-mV gain in photovoltage was calculated for every +100 mV shift in Emed. Differences in the mediator sizes, diffusion coefficients, light absorption profiles, and spin state configurations for the complexes were not significant and therefore not expected to contribute to changes in the VOC. A decrease in the photocurrent, downward shift in quasi-Fermi level (EF,n) and shorter electron lifetime (Tn) with increasingly positive Emed were instead attributed to enhanced electron recombination from the TiO2 film to oxidized mediator species in the electrolyte.
Mn(II)-catalyzed C-H alkylation of imidazopyridines and N-heteroarenes via decarbonylative and cross-dehydrogenative coupling
Samanta, Sadhanendu,Hajra, Alakananda
, p. 4363 - 4371 (2019/03/26)
A Mn(II)-catalyzed efficient C-H alkylation of imidazoheterocycles and N-heteroarenes with aliphatic aldehydes has been developed via oxidative decarbonylation. Other alkylating agents such as cyclic alkanes, ethers, and alcohols also coupled with N-heteroarenes through cross-dehydrogenative coupling. Regioselectively C5-alkylated imidazoheterocycles were synthesized in good yields. Experimental results show that radical pathway might be involved in this reaction.
2-Amino-1,3,5-triazine chemistry: hydrogen-bond networks, Takemoto thiourea catalyst analogs, and olfactory mapping of a sweet-smelling triazine
Hintermann, Lukas,P?thig, Alexander,Xiao, Li
supporting information, p. 1529 - 1539 (2015/08/18)
Abstract The chemistry of 4,6-dialkyl-2-amino-1,3,5-triazines with bulky alkyl substituents was investigated and their use as building blocks for preparing chiral thiourea organocatalysts explored. Reaction of ammonia with 4,6-di-tert-butyl-2-chloro-1,3,5-triazine gave 4,6-di-tert-butyl-1,3,5-triazin-2-amine which formed extended hydrogen-bond networks in the solid state according to X-ray crystallography. Selected heterocyclic amines were converted to isothiocyanates, and the latter reacted with (S,S)-2-(dimethylamino)cyclohexylamine to give enantiopure 1-hetaryl-3-[2-(dimethylamino)cyclohexyl]thioureas, with hetaryl representing either 4,6-dimethyl-1,3-diazin-2-yl, 4,6-diisopropyl-1,3,5-triazin-2-yl, or 4,6-di-tert-butyl-1,3,5-triazin-2-yl groups. These compounds are structural analogs of Takemotos's chiral thiourea organocatalysts (1-[3,5-bis(trifluoromethyl)phenyl]-3-[(1S,2S)-2-(dimethylamino)cyclohexyl]thiourea) with an aza-aryl instead of the 3,5-bis(trifluoromethyl)phenyl group. They feature a strong intramolecular N-H to N-1 hydrogen bond, as shown by X-ray crystallography of 1-(4,6-di-tert-butyl-1,3,5-triazin-2-yl)-3-[2-(dimethylamino)cyclohexyl]thiourea in the solid state and by 1H NMR spectroscopy of all derivatives in CDCl3 solution, which prevents them from acting as bifunctional organocatalyst. In the reaction of 4,6-di-tert-butyl-2-chloro-1,3,5-triazine with ammonia, 4,6-di-tert-butyl-2-ethoxy-1,3,5-triazine was identified as side-product displaying a mildly sweet, floral odor that is unusual for a 1,3,5-triazine. Analogs (>35) of 4,6-di-tert-butyl-2-ethoxy-1,3,5-triazine were prepared to define the important structural factors of the olfactophore.
