The copper(1) complex with tripodal tetradentate amine ligand TMPA, [CuI(TMPA)CH3CN]PF6 (I; TMPA = tris[(2-pyridyl)methyl]amine), reacts with dioxygen, resulting in breakdown of the hexafluorophosphate anion and providing two distinct fluoride Cu(II) complexes that have been crystallographically characterized. [CuII(TMPA)F]2(PF6)2 (2) is a fluoride doubly bridged dimer (axial-equatorial), where each copper ion is pseudooctahedrally coordinated [C36H36Cu2F14N8P2, monoclinic P21/n; a = 11.649 (4), b = 12.942 (4), c = 14.654 (4) Å; β = 110.67 (2)°; Z = 4, V = 2067 (1) Å3]. However, [CuII(TMPA)F]•PF6•CH2Cl2 (3a) contains a trigonal-bipyramidal (TBP) coordination environment, with axial fluoride and tertiary amine ligation [C19H20CI2CuF, N4P, orthorhombic Pcab; a = 11.869 (2), b = 15.891 (3), c = 26.116 (6) Å; Z = 8, V = 4926 (2) Å3]. Complex 3a readily loses its dichloromethane to give [CuII(TMPA)PF6•1/2H2O (3b), which has solution properties (i.e. UV-vis, EPR) characteristic of TBP coordination. Compound 2 breaks down in solution to give the same monomeric structure as 3b, and solution UV-vis and EPR studies indicate the 3b structure can also be directly generated by addition of fluoride ion to [CuII-(TMPA)H2O](ClO4) (4).
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry