FLUORIDE AS A TERMINAL AND BRIDGING LIGAND FOR COPPER - ISOLATION AND X-RAY CRYSTALLOGRAPHIC CHARACTERIZATION OF MONOMERIC AND DIMERIC COMPLEXES [CUII(TMPA)F]NN+ (N=1 OR 2-TMPA=TRIS[(2-PYRIDYL)METHYL]AMINE)

The copper(I) complex with tripodal tetradentate amine ligand TMPA, [Cu1(TMPA)CH3CN]PF6 (1; 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. [Cu(II)(TMPA)F]2(PF6)2 (2) is a fluoride doubly bridged dimer (axial-equatorial), where each copper ion is pseudooctahedrally coordinated [C36H36Cu2F14N8P2, monoclinic P2(1)/n; a = 11.649 (4), b = 12.942 (4), c = 14.654 (4) angstrom; beta = 110.67 (2)-degrees; Z = 4, V = 2067 (1) angstrom 3]. However, [Cu(II)(TMPA)F]PF6.CH2Cl2 (3a) contains a trigonal-bipyramidal (TBP) coordination environment, with axial fluoride and tertiary amine ligation [C19H20Cl2CuF7N4P, orthorhombic Pcab; a = 11.869 (2), b = 15.891 (3), c = 26.116 (6) angstrom; Z = 8, V = 4926 (2) angstrom 3]. Complex 3a readily loses its dichloromethane to give [Cu(II)(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 [Cu(II)(TMPA)H2O](ClO4) (4).