24131-31-5Relevant articles and documents
A Cd(ii) and Zn(ii) selective naphthyl based [2]rotaxane acts as an exclusive Zn(ii) sensor upon further functionalization with pyrene
Bej, Somnath,Nandi, Mandira,Ghosh, Pradyut
, p. 294 - 303 (2021)
A new multi-functional [2]rotaxane, ROTX, has been synthesized via a Cu(i) catalysed azide-alkyne cycloaddition reaction between Ni(ii) templated azide terminated pseudorotaxane composed of a naphthalene based heteroditopic wheel, NaphMC, and an alkyne terminated stopper. Subsequently, ROTX has been functionalized with pyrene moieties to develop a bifluorophoric [2]rotaxane, PYROTX, having naphthalene and pyrene moieties. Detailed characterization of these two rotaxanes is performed by utilizing several techniques such as ESI-MS, (1D and 2D) NMR, UV/Vis and PL studies. Comparative metal ion sensing studies of NaphMC (a fluorophoric cyclic receptor), ROTX ([2]rotaxane with a naphthyl fluorophore) and PYROTX ([2]rotaxane having naphthyl and pyrene fluorophores) have been performed to determine the effect of dimensionality/functionalization on the metal ion selectivity. Although NaphMC fails to discriminate between metal ions, ROTX serves as a selective sensor for Zn(ii) and Cd(ii). Importantly, PYROTX shows exclusive selectivity towards Zn(ii) over various transition, alkali and alkaline earth metal ions including Cd(ii).
Electrochemical Dimerization of Phenylpropenoids and the Surprising Antioxidant Activity of the Resultant Quinone Methide Dimers
Romero, Kevin J.,Galliher, Matthew S.,Raycroft, Mark A. R.,Chauvin, Jean-Philippe R.,Bosque, Irene,Pratt, Derek A.,Stephenson, Corey R. J.
, p. 17125 - 17129 (2018/12/04)
A simple method for the dimerization of phenylpropenoid derivatives is reported. It leverages electrochemical oxidation of p-unsaturated phenols to access the dimeric materials in a biomimetic fashion. The mild nature of the transformation provides excellent functional group tolerance, resulting in a unified approach for the synthesis of a range of natural products and related analogues with excellent regiocontrol. The operational simplicity of the method allows for greater efficiency in the synthesis of complex natural products. Interestingly, the quinone methide dimer intermediates are potent radical-trapping antioxidants; more so than the phenols from which they are derived—or transformed to—despite the fact that they do not possess a labile H-atom for transfer to the peroxyl radicals that propagate autoxidation.
Improved Catalytic Activity and Stability of a Palladium Pincer Complex by Incorporation into a Metal-Organic Framework
Burgess, Samantha A.,Kassie, Abebu,Baranowski, Sarah A.,Fritzsching, Keith J.,Schmidt-Rohr, Klaus,Brown, Craig M.,Wade, Casey R.
supporting information, p. 1780 - 1783 (2016/03/01)
A porous metal-organic framework Zr6O4(OH)4(L-PdX)3 (1-X) has been constructed from Pd diphosphinite pincer complexes ([L-PdX]4- = [(2,6-(OPAr2)2C6H3)PdX]4-, Ar = p-C6H4CO2-, X = Cl, I). Reaction of 1-X with PhI(O2CCF3)2 facilitates I-/CF3CO2- ligand exchange to generate 1-TFA and I2 as a soluble byproduct. 1-TFA is an active and recyclable catalyst for transfer hydrogenation of benzaldehydes using formic acid as a hydrogen source. In contrast, the homogeneous analogue tBu(L-PdTFA) is an ineffective catalyst owing to decomposition under the catalytic conditions, highlighting the beneficial effects of immobilization.
