Use of Hydrophobic Ligands for the Stabilization of Low-Valent Transition Metal Complexes. 1. The Effect of N-Methylation of Linear Tetraazaalkane Ligands on the Properties of Their Copper Complexes

Fine‐Tuning the Electronic Properties of Highly Stable Organometallic CuIII Complexes Containing Monoanionic Macrocyclic Ligands

“…This is especially acute for complexes 5 and 6 which contain the macrocyclic ligands L 5 and L 6 with the methylated central amine. This phenomenon has been described in detail previously mainly by Meyerstein and co-workers [16] and by Bernhardt; [17] the MÀN bond strength of tertiary amines is weaker than that of secondary amines under comparable conditions. Herein this phenomenon will from now on be termed the "N-methylation effect".…”

“…This is further supported by the E 1/2 redox potentials of the Cu III /Cu II couple bearing the methylated tertiary amines since they are anodically shifted relative to those of the non-methylated secondary amine (vide infra). This effect has previously been observed in aqueous solutions of non-organometallic Cu II complexes [16,17] and was attributed to a number of factors including the formation of hydrogen bonds between the secondary amines and solvent molecules and less metal-ligand orbital overlap as a result of the steric effects generated by the methylated tertiary amine which displace the nitrogen bonding electron pair out of the main plane in which the metal center is located. Indeed, the latter effect can also be observed in the complexes described in this paper since the methylated complexes 5 and 6 have the highest angles between the planes defined by the carbon atoms of the aromatic ring and the C1, Cu1, N1, and N3 atoms (vide supra).…”

The Redox Chemistry of (N1‐[3‐(2‐aminoethylimino)‐1,1‐dimethylbutyl]ethane‐1,2‐diamine)nickel(II) Perchlorate, NiIIL1(ClO4)2, in Aqueous Solutions –A Pulse Radiolytic and an Electrochemical Study

“…N 2 O-saturated solutions containing 0.01-0.1  NaBr, (0. Figure 7 and 4, and therefore it is proposed that Ni III LBr 2+ is formed in this reaction, see (8).…”

Trifluoromethylation of a Well‐Defined Square‐Planar Aryl‐NiII Complex involving NiIII/CF3. and NiIV−CF3 Intermediate Species

“…[9] The slower reactivity observed with 5 OTf suggests a lower stability of the high oxidation state on the metal when tertiary amines are used. [23] However, the putative aryl-Ni IV intermediated species could not be detected by 1 H NMR spectroscopy even at -40ºC, suggesting that this putative intermediate is highly reactive ( Figure S6). Therefore, DFT calculations at B3LYP-GD3BJ/cc-pVTZ//B3LYP-GD3BJ/TZPV level (see Experimental section below for more computational details) were employed to further elucidate the reaction mechanism.…”