TRIGONAL-BIPYRAMIDAL COPPER(II) COMPLEXES WITH SYMMETRICAL AND UNSYMMETRIC TRIPODAL TETRAMINE LIGANDS

The syntheses of the aliphatic tripodal tetramine ligands N(CH2CH2CH2N H2)(3) (1), N[(CH2CH2CH2NH2)(2)(CH2CH2NH2)] (2), and N[(CH2CH2CH2NH2)( CH2CH2NH2)(2)] (3) are reported. The tripodal N-4-ligands 1-3 react wi th Cu(OH)(2) in water to give blue copper(II) complexes. Addition of N H4PF6 to such solutions yields complexes of the type [Cu(N-4)(NH3](PF6 )(2) [4; N-4 = 1, 4a; N-4 = 2, 4b; N-4 = 3, 4c]. The molecular structu res of complexes 4a-c have been determined by X-ray diffraction, All t hree complexes can be crystallized from water. Selected crystallograph ic details are as follows 4a [4b] (4c): formula C9H27CuF12N5P2 [C8H25C uF12N5P2] {C7H23 CuF12N5P2}, M = 558.82 [544.79] {530.76} amu, monocli nic [monoclinic] {orthorhombic}, P2(1)/c [C2/c] {P2(1)2(1)2}, 8.9519(1 4) [30.181(6)] {15.075(5)} Angstrom, b = 16.803(3) [8.914(3)] {12.2939 (14)} Angstrom, c = 13.834(2) [14.253(4)] {10.064(2)} Angstrom, alpha = 90.0 [90.0] {90.0}degrees, beta = 94.183(12) [93.76(2)] {90.0}degree s, gamma = 90.0 [90.0] {90.0}degrees, V = 2075.3(10) [3826(3)] {1865.2 (12)} Angstrom(3), Z = 4 [8] {4}, R = 5.10 [3.42] {4.32}%, R(w) = 6.67 [5.12] {5.23}% for 2480 [2137] {1533} absorption corrected structure factors F-o(2) greater than or equal to 3 sigma(F-o(2)) and 262 [255] {245} refined parameters. The complex dications in 4a-c exhibit a trig onal-bipyramidal geometry with the tertiary nitrogen of the tripodal L igand and the ammonia nitrogen in the axial positions. Complexes with the unsymmetric ligands 2 and 3 possess both five and six membered che late rings. Depending on the ligand, the size of the cavity for the am monia ligand increases from 4a to 4c. This leads to a shortening of th e Cu-NH3 bond length with the shortest bond of this type observed for 4c.