19145-06-3Relevant articles and documents
Light-Activated Sensitive Probes for Amine Detection
Valderrey, Virginia,Bonasera, Aurelio,Fredrich, Sebastian,Hecht, Stefan
, p. 1914 - 1918 (2017)
Our new, simple, and accurate colorimetric method is based on diarylethenes (DAEs) for the rapid detection of a wide range of primary and secondary amines. The probes consist of aldehyde- or ketone-substituted diarylethenes, which undergo an amine-induced decoloration reaction, selectively to give the ring-closed isomer. Thus, these probes can be activated at the desired moment by light irradiation, with a sensitivity that allows the detection of amines at concentrations as low as 10?6m in solution. In addition, the practical immobilization of DAEs on paper makes it possible to detect biogenic amines, such as cadaverine, in the gas phase above a threshold of 12 ppbv within 30 seconds.
Conformation of secondary amides. A predictive algorithm that correlates DFT-calculated structures and experimental proton chemical shifts
Avalos, Martin,Babiano, Reyes,Barneto, Jose L.,Cintas, Pedro,Clemente, Fernando R.,Jimenez, Jose L.,Palacios, Juan C.
, p. 1834 - 1842 (2003)
The magnetic deshielding caused by the amido group on CON-CHα protons of secondary amides can easily be correlated with DFT-based structures at the B3LYP/6-31G* level of theory via a novel algorithm that refines previous models, such as the classical McConnell equation. The shift is given by δ = a + 2.16 cos2(α - 35)/d, where α denotes the virtual dihedral angle resulting from linking the carbonyl and the α-carbons and d is the distance (A) between the shifted proton and the carbonyl oxygen. Notably, in this equation a is a parameter that can be optimized for different solvents, namely, CDCl3, DMSO-d6, and D2O. For the development of these correlations, the preferential conformation of amides is taken from the optimized structures in the gas phase obtained at the DFT level. The deshielding on anti and gauche protons in both rotamers of (Z)-acetamides and E/Z isomers of formamides has been evaluated. This methodology has proved to be highly reliable, allowing us to discard ab initio or DFT conformational arrangements when shifts calculated by the above-mentioned equation differ from the experimental values. Thus, the anti disposition between the CHα proton and the N-H bond appears to be the more stable conformation of simple amides. For amides bearing only one proton at Cα, a local syn minimum can equally be characterized. The rotational barriers around the CON-alkyl bond along with the pyramidalization of the amido group have also been reassessed. As the conformation is taken away from anti or local syn minima, the nonplanarity of the amido group appears to increase.
Concentration-dependent circularly polarized luminescence of chiral cyclometalated platinum(II) complexes for electroluminescence
Guo, Song,Han, Jianmei,Liu, Shujuan,Lu, Hu,Tao, Peng,Xu, Yanan,Zhang, Xinwen,Zhao, Qiang,Zheng, Xiaokang
, (2020/03/30)
Circularly polarized organic light-emitting diodes (CP-OLEDs) have been attracting increasing attention due to the direct generation of CP light, and they show the improved image contrast and luminous efficiency in OLEDs displays. In this work, a pair of chiral Pt(II) complexes with methylbenzylisocyanide and 1,3-bis(2-pyridyl)benzene as a tridentate N∧C∧N ligand were synthesized. Both of them exhibited bright green emission in dilute acetonitrile solution, while strong orange emission in high concentration of acetonitrile solution. However, when the complexes were doped into polymethyl methacrylate, the green emission originated from intrinsic single molecule can be changed to the red emission from excimer by adjusting the doping ratios. More importantly, the amplification of CPL signal can be achieved compared with the solution state. Furthermore, the monochrome devices were fabricated by utilizing these two enantiomers as emitters.
N-formylation of amine using graphene oxide as a sole recyclable metal-free carbocatalyst
Ma, Juan,Zhang, Jingyu,Zhou, Xiao,Wang, Jiawei,Gong, Hang
, p. 2851 - 2860 (2018/10/31)
Abstract: Graphene oxide (GO), an inexpensive, environment-friendly, and metal-free carbocatalyst, used for the N-formylation of amines is developed. In this reaction, GO shows good activity, selectivity, and recyclability. This strategy has an array of advantages, such as being metal free, without additive, wide-scope protocol, scalable with a low catalyst loading of 3?wt%, use of readily available and recyclable carbocatalyst, and DMF as a readily available formyl source. Furthermore, this strategy provides an avenue for the convenient hydroformylation of various amines. Graphical abstract: [Figure not available: see fulltext.].
