59945-34-5Relevant articles and documents
Electrochemical CO2 Reduction-The Effect of Chalcogenide Exchange in Ni-Isocyclam Complexes
Apfel, Ulf-Peter,Battistella, Beatrice,Gerschel, Philipp,Ray, Kallol,Siegmund, Daniel
, p. 1497 - 1510 (2020)
Among the numerous homogeneous electrochemical CO2 reduction catalysts, [Ni(cyclam)]2+ is known as one of the most potent catalysts. Likewise, [Ni(isocyclam)]2+ was reported to enable electrochemical CO2 conversion but has received significantly less attention. However, for both catalysts, a purposeful substitution of a single nitrogen donor group by chalcogen atoms was never reported. In this work, we report a series of isocyclam-based Ni complexes with {ON3}, {SN3}, {SeN3}, and {N4} moieties and investigated the influence of nitrogen/chalcogen substitution on electrochemical CO2 reduction. While [Ni(isocyclam)]2+ showed the highest selectivity toward CO2 reduction within this series with a Faradaic efficiency of 86% for the generation of CO at an overpotential of-1.20 V and acts as a homogeneous catalyst, the O-and S-containing Ni complexes revealed comparable catalytic activities at ca. 0.3 V milder overpotential but tend to form deposits on the electrode, acting as precursors for a heterogeneous catalysis. Moreover, the heterogeneous species generated from the O-and S-containing complexes enable a catalytic hydride transfer to acetonitrile, resulting in the generation of acetaldehyde. The incorporation of selenium, however, resulted in loss of CO2 reduction activity, mainly leading to hydrogen generation that is also catalyzed by a heterogeneous electrodeposit.
"Bidentate" and "tridentate" sulfonamide ligands for titanium complexes: Crystal structures and solution dynamics elucidating an η2 or η3-coordination mode
Hamura, Satoshi,Oda, Takashi,Shimizu, Yasuaki,Matsubara, Kouki,Nagashima, Hideo
, p. 1521 - 1527 (2007/10/03)
Highly air- and moisture-sensitive complexes having sulfonamide ligands, (TsNR)2Ti(NMe2)2 (Ts = p-MeC6H4SO2), were prepared by treatment of two equivalents of TsNHR with Ti(NMe2)4 at room temperature. One of the compounds, where R = i-Pr (1), was studied in detail; the crystal structure of 1 revealed that both of the TsNi-Pr ligands were bound to the metal in an η2-coordination mode. Solution dynamics of 1 showed that an η1/η2 interconversion occurred above 60°C with an activation energy of 15.8 kcal mol-1. Treatment of Ti(NMe2)4 with the sulfonamide TsHN(CH2)2O(CH2)2NHTs (3), led to the formation of [TsN(CH2)2O(CH2)2NTs]Ti(NMe 2)2 (2) in high yield, in which the sulfonamide moiety was coordinated to the titanium center in an η3 (NON) mode. No sign of η1/η2 interconversion of the sulfonamide ligands was seen in solution. Treatment of 2 with Me3SiCl resulted in the formation of [{TsN(CH2)2O(CH2)2NTs}Ti(NMe 2)Cl]2 (4) and [{TsN(CH2)2O(CH2)2NTs}TiCl 2]2 (5). An X-ray structure determination of 4 revealed that sulfonyl oxygen bridging resulted in the formation of an eight membered ring.
MACROHETEROCYCES. XXXVI. A CONVENIENT METHOD FOR SYNTHESIS OF DI- AND POLYAZACROWN ETHERS
Luk'yanenko, N.G.,Basok, S.S.,Filonova, L.K.
, p. 1562 - 1571 (2007/10/02)
A method is proposed for the production of di- and polyazacrown ethers by the condensation of bissulfonamides with dibromides or ditosyloxy derivatives in a two-phase aqueous alkali-toluene (benzene) system.The optimum concentration range for the substrate and the alkylating agent is 0.017-0.1 M.The catalytic activity of the quaternary ammonium salts decreases in the order (Bu)4NI > (Bu4)NBr > (Bu4)NCl > (Bu4)NHSO4 > (C2H5)3C6H5CH2NCl >> (Et)4NI > (Et)4NBr.The highest yields of te 12-membered azacrown ethers are obtained in the presence of lithium hyroxide, and the largest yields of the crown ethers with larger ring sizes are obtained in the presence of sodium or potassium hydroxide, and this is probably due to the matrix effects of the cation.