Effect of Ligand Constraints upon the Stabilities and Potentials of Macrocyclic Polythiaether Complexes. Copper(II) and Copper(I) Complexes with Cyclohexyl and Phenyl Derivatives of [14]aneS4 in Water, 80% Methanol, and Acetonitrile

Electron-transfer kinetics and equilibria of copper(ii/i) complexes with 1,4,7-trithiacyclononane. A square scheme mechanism involving ligand additionBased on the presentation given at Dalton Discussion No. 4, 10–13th January 2002, Kloster Banz, Germany.

“…26 For studies in acetonitrile, the hydrated salts were recrystallized twice from acetonitrile before use and Cu(CH 3 CN) 4 ؒClO 4 was prepared by a modification of the method of Hathaway et al 27 as described earlier. 28 (CAUTION! Perchlorate salts are potentially explosive and should be handled with care in small quantities.…”

“…The values of K CA and K EC could not be determined by the same methods in acetonitrile, principally due to the fact that these constants are much larger in the nonaqueous solvent. 28 Instead, the relevant acetonitrile values were estimated from other data as noted below.…”

“…The Osteryoung pulsed square-wave voltammetric method 43 was applied to acetonitrile solutions containing Cu() and varying amounts of ligand in an attempt to evaluate the equilibrium constant between the Cu I L and Cu I L 2 species: For this purpose, the current for the peak corresponding to the oxidation of Cu I L 2 can be related to the Cu I L 2 concentration by the relationship: 28 where i p is the peak current, n is the number of electrons transferred in the reaction, F is the Faraday constant, A is the surface area of the working electrode, D 0 is the diffusion coefficient for Cu I L 2 , τ is the pulse period, and ∆Ψ p is the current function at the peak potential. Under conditions where the total ligand concentration is in excess over Cu() (so that the concentration of free Cu() is insignificant), eqns.…”

Oxidative dehydrogenation of an amine group of a macrocyclic ligand in the coordination sphere of a CuII complex

“…Replacement of the H 2 L ligand by acetonitrile was calculated to be strongly exothermic for copper at 144 kJ mol -1 , which is consistent with the known affinity of acetonitrile for Cu I . 40 In comparison, the corresponding reaction for iron was calculated to be only very weakly exothermic at 9 kJ mol -1 . This difference in the coordinating ability of the solvent leads to the stabilisation of the copper products in the IPA reaction compared to those of iron.…”

Zinc(ii) complexes of constrained antiviral macrocycles

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The configurations of metallocyclams are of interest in relation to protein recognition and anti-HIV activity. We have synthesised four novel zinc(II) complexes with hexyl-Me 2 -cyclam (HMC;3,6,13,12 )docosane), 1, and naphthyl-hexyl-Me 2 -cyclam (NHMC; 2,13-bis(1-naphthylmethyl)-5, 16-dimethyl-2,6,13,17-tetraazatricyclo(16.4.0.0 7,12 )docosane), 2, as ligands. X-ray crystallographic data for Zn(II)-HMC diacetate, 3 show that zinc is six-coordinate in a distorted octahedral environment bound to four equatorial N atoms from the macrocycle and two axial acetato O atoms.

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