75321-10-7Relevant 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 (2020/04/30)
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.
Synthesis and Complexation Properties of Suitcase-Shaped Macrotricyclic and Butterfly-Shaped Macrobicyclic Polyether Ligands
An, Haoyun,Bradshaw, Jerald S.,Krakowiak, Krzysztof E.,Zhu, Chengyue,Dalley, N. Kent,Izatt, Reed M.
, p. 4998 - 5005 (2007/10/02)
Ten suitcase-shaped macrotricyclic polyethers (1-10) containing nitrogen and carbon bridgehead atoms have been synthesized.These new cage compounds were prepared by connecting together two hydroxymethyl-substituted or two secondary amine-containing butterfly-shaped macrobicyclic polyethers by means of linear bifunctional connecting groups.Intermediate bis(hydroxymethyl)-substituted butterfly-shaped macrobicyclic polyether 14 was prepared by treating N,N'-bis(2-hydroxyethyl)ethylenediaamine with 5-methylene-3,7-dioxane-1,9-diyl ditosylate to give bislariat 1,4-diaza-13-crown-4 (11) which was cyclized with 3-chloro-2-(chloromethyl)-1-propene followed by hydroboration.Intermediate bissecondary amine-containing butterfly-shaped macrobicyclic polyethers 18 and 19 were prepared by treating N,N'-bis(2-hydroxyethyl)ethylenediamine with 6-tosyl-3,9-dioxa-6-aza-1,11-undecanediyl ditosylate (33) to give N-tosyl-N',N"-bis(2-Hydroxyethyl)triaza-15-crown-5 (12).Lariat crown ether 12 was cyclized with 33 followed by reduction with LiAlH4 to give 18, or with 4-tosyl-4-aza-1,7-heptanediyl ditosylate (36 to give 19.Some of the suitcase-shaped macrotricycles interacted with various cations.One was selective for Pb(2+) ions and another interacted strongly with Hg(2+).A crystal structure for the 13-NaClO4 complex also is reported.
Synthesis and characterization of the branched azacage 12-methyl-17-pentyl-1,5,9,12,17-pentaazabicyclononadecane. Basicity and Copper(II) complex
Micheloni, Mauro,Nardi, Nicoletta,Valtancoli, Barbara
, p. 29 - 31 (2007/10/02)
The synthesis and characterization of the new branched azacage 12-methyl-17-pentyl-1,5,9,12,17-pentaazabicyclononadecane, L, is reported.The basicity behaviour in aqueous solution (I=0.15, NaCl; 25 deg C) has been investigated by potentiometry.The cage (L) can take up three protons.It behaves as a strong base 1=11.40(4)> in the first protonation step, as a moderate base in the second step 2=7.67(4)>, and as weak base in the third protonation step 3=3.3(1)>.The influence of the lateral hydrocarbon chain on the proton-transfer properties is discussed.The solid complex (ClO4)2 has been isolated whose electronic spectrum is diagnostic of a distorted square pyramidal structure both in the solid state and in solution.The copper complex shows a great inertness toward dissociation in strong acid solutions, which proves the incapsulation of the copper(II) ion in the cage cavity
