29018-19-7Relevant academic research and scientific papers
Effect of molecular weight on the ion transport mechanism in polymerized ionic liquids
Fan, Fei,Wang, Weiyu,Holt, Adam P.,Feng, Hongbo,Uhrig, David,Lu, Xinyi,Hong, Tao,Wang, Yangyang,Kang, Nam-Goo,Mays, Jimmy,Sokolov, Alexei P.
, p. 4557 - 4570 (2016)
The unique properties of ionic liquids (ILs) have made them promising candidates for electrochemical applications. Polymerization of the corresponding ILs results in a new class of materials called polymerized ionic liquids (PolyILs). Though PolyILs offer the possibility to combine the high conductivity of ILs and the high mechanical strength of polymers, their conductivities are typically much lower than that of the corresponding small molecule ILs. In the present work, seven PolyILs were synthesized having degrees of polymerization ranging from 1 to 333, corresponding to molecular weights (MW) from 482 to 160 400 g/mol. Depolarized dynamic light scattering, broadband dielectric spectroscopy, rheology, and differential scanning calorimetry were employed to systematically study the influence of MW on the mechanism of ionic transport and segmental dynamics in these materials. The modified Walden plot analysis reveals that the ion conductivity transforms from being closely coupled with structural relaxation to being strongly decoupled from it as MW increases.
Metal-Free Catalytic Reduction of α,β-Unsaturated Esters by 1,3,2-Diazaphospholene and Subsequent C-C Coupling with Nitriles
Chong, Che Chang,Rao, Bin,Kinjo, Rei
, p. 5814 - 5819 (2017/09/15)
1,3,2-Diazaphospholene 1 catalyzes the conjugate transfer hydrogenation as well as the 1,4-hydroboration of α,β-unsaturated esters. The initial step for both processes involves a 1,4-hydrophosphination of the α,β-unsaturated esters to afford a phosphinyl enol ether. Subsequent cleavage of the P-O bond in the phosphinyl enol ether by ammonia-borane (AB) generates an enol intermediate which tautomerizes to saturated esters, while the P-O bond cleavage by HBpin via a formal σ-bond metathesis affords boryl enolate intermediate. The latter could undergo a further coupling reaction with nitriles to form substituted amino diesters or 1,3-imino esters, depending on α,β-unsaturated ester substrates. These catalytic reactions can also be performed in a one-pot manner, illustrating a protocol for metal-free catalytic C-C bond construction.
Syntheses, structures and reactivities of rhodium 4,5-diazafluorene derivatives
Jiang, Huiling,Stepowska, Elzbieta,Song, Datong
experimental part, p. 2083 - 2089 (2009/07/10)
Four rhodium 4,5-diazafluorene derivatives, [RhL(PPh3) 2] (1), [Rh(H)2(LH)(PPh3)2]Cl (2), [Rh(H)2L(PPh3)2] (3) and [Rh(H) 2-(LH)(PPh3)2]OTf (4), have been synthesized and fully characterized by NMR spectroscopy, elemental analysis and single-crystal X-ray diffraction. Compound 1 can be converted into 3 when treated with hydrogen gas. Compound 2 can be converted into 3 when treated with NaH, and the reverse reaction can be achieved by treating 3 with aqueous HCl. The air- and moisture-stable compound 2 is an active catalyst for the hydrogenation of a variety of olefins, including non-terminal ones; the chloride counterion in 2 appears to play a role in the catalytic system. Thus, compound 4, the triflate analogue of 2, is inactive towards olefin hydrogenation.
