Coupling of organic halides electrocatalyzed by the Ni^II/Ni^I/Ni⁰–PPh₃system. A mechanistic study based on an electroanalytical approach

Carbon−Carbon Bond Formation with Electrogenerated Nickel and Palladium Complexes

“…[62] The electroreductive dimerisation with [NiBr 2 (PPh 3 ) 2 ] at low temperature (Ϫ20°C ) gave 90% of the coupling product. [63] The dimerisation of benzal chloride catalysed by [Ni(salen)] {salen ϭ 2,2Ј-[1,2-ethanediylbis(nitrilomethylidyne)]bis[phenolato]} in DMF also has been studied. [64] The electropolymerisation of 1,4-bis(chloromethyl)benzene, in the presence of catalytic amounts of [NiCl 2 L] (L ϭ dppe or dppp), afforded poly-p-xylylenes in yields of 81Ϫ98% (Scheme 6).…”

“…[66,67] Using [NiBr 2 (PPh 3 ) 2 ] as the catalyst, the dimerisation of alkyl and allyl halides gave RϪR species and 1,5-hexadienes, respectively, in yields of up to 92%. [63,68] The reductive coupling of alkyl halides has been reported with the use of electrogenerated nickel() complexes derived from [Ni II (cyclam)] (cyclam ϭ 1,4,8,11-tetraazzacyclotetradecane) [69] [70] as well as that of other alkyl bromides and iodides. [71] The kinetics and the mechanisms of these reactions have been examined, and radical intermediates have been proposed.…”

Sulfonated fluorinated-aromatic polymers as proton exchange membranes

“…The SPAEK-35 membrane with high IEC (1.81 mequiv/g) exhibited a relatively low water uptake (23.5%) and was hydrolytically stable since the swelling ratio (inplane direction) was only 5.1% at 80°C, which the authors attributed to the greater length of the fluorinated hydrophobic segment. SPAEK-xx showed good oxidative stability with almost no weight loss after 1 h, and mechanical properties were retained even at 80% RH (tensile strength of [44][45][46][47][48][49][50][51][52][53] MPa and elongation at break of 38-110%, with the trend decreasing with an increase in DS). The SPAEK-35 membrane (DS 1.4) showed a proton conductivity value of 84 mS/cm at 100°C, which was comparable to the proton conductivity of Nafion 117 (proton conductivity 100 mS/cm at 100°C).…”

“…Copolymerization with the sulfonated monomer 2,5-dichloro-3′-sulfobenzophenone (DCSB) and 2,2′-bis[4-(4-chlorobenzoyl)]phenoxyl perfluoropropane (BCPPF) was carried out by varying the molar ratio of DCSB/BCPPF. Here aryl chloride with the electron-withdrawing group was chosen, which the authors attributed to the higher reactivity of such monomer reported previously (45,46). The structure of SPP-co-PAEKs is shown in Scheme 2.…”

Preparation and properties of novel sulfonated poly(p-phenylene-co-aryl ether ketone)s for polymer electrolyte fuel cell applications

“…Based on the study of Colon [21] and Bontempelli [22], the aryl chloride with electron-withdrawing substituent groups, such as carbonyl group, nitrile group and acetophenone group, exhibited higher activity and yields. In accordance with the requirement of solubility, the incorporation of ether linkage and/ or perfluoroisopropyl groups in the polymer backbone could largely enhance the solubility.…”