DINUCLEAR COPPER(II) AND POLYMERIC TETRANUCLEAR COPPER(II) AND COPPER(II)-COPPER(I) COMPLEXES OF MACROCYCLIC LIGANDS CAPABLE OF FORMING ENDOGENOUS ALKOXIDE AND PHENOXIDE BRIDGES - STRUCTURAL, MAGNETIC, AND ELECTROCHEMICAL STUDIES

Template condensation of 2,6-diformyl-4-R-phenols with 1,3-diamino-2-hydroxypropane in methanol or ethanol, in the presence of copper(II) salts, produced the 20-membered macrocyclic complexes [CU2(H2L1)(CH3OH)(ClO4)][ClO4] (I), [CU2(H2L1)X2].2H2O (X = NO3 (II); X = Cl (III)), [Cu2(H2L1)(NCS)2] (IV), [CU2(H2L2)(H2O)2][ClO4]2 (VI), and [CU2(H2L2)(NO3)2].H2O (VII) (H4L1, R = Me; H4L2, R = tBu). Template condensation in the presence of copper(II) acetate and excess azide produced the polymeric complexes [CU2(H2L)][Cu2(N3)6] (L = L1 (VIII); L = L2 (IX)), while template condensation in the presence of CuCl produced an unusual, mixed-oxidation-state species [CU2(H2L1)] [Cu2Cl4] containing the unique Cu2Cl42- anion, which has a dinuclear, chloro-bridged triangular structure. The crystal and molecular structures of [CU2(H2L1)(CH3OH)(ClO4)][ClO4] (I), [CU2(H2L1)] [Cu2Cl4] (V), and [CU2(H2L2)] [CU2(N3)6] (IX) are reported. I crystallized in the monoclinic system, space group P2(1)/c, with a = 12.139 (6) angstrom, b = 17.051 (4) angstrom, c = 14.457 (3) angstrom, beta = 93.51 (2)-degrees, and four formula units per unit cell. Refinement by full-matrix least-squares procedures gave final residuals of R = 0.060 and R(w) = 0.050. V crystallized in the triclinic system, space group P1BAR, with a = 8.940 (4) angstrom, b = 10.371 (3) angstrom, c = 8.018 (5) angstrom, alpha = 95.59 (4)-degrees, beta = 106.62 (4)-degrees, gamma = 101.86 (3)-degrees, and one formula unit per unit cell. Refinement by full-matrix least-squares procedures gave final residuals of R = 0.053 and R(w) = 0.049. IX crystallized in the triclinic system, space group P1BAR, with a = 11.064 (3) angstrom, b = 12.154 (4) angstrom, c = 8.439 (4) angstrom, alpha = 108.42 (3)-degrees, beta = 90.85 (3)-degrees, gamma = 109.80 (2)-degrees, and two formula units per unit cell. Refinement by full-matrix least-squares procedures gave final residuals of R = 0.045 and R(w) = 0.036. I involves an almost planar, dinuclear macrocyclic cation with no secondary alkoxide coordination. A similar cation exists in V and IX, but with the bridging anions linking cations in an unusual axial, polymeric structure. Low room-temperature magnetic moments and variable-temperature magnetic studies indicate strong intradimer antiferromagnetic exchange (-2J = 675-902 cm-1) and also extended exchange in the azide anion bridged polymers. Electrochemical properties of the dinuclear cations show sequential one-electron-transfer steps at negative Potentials (E1/2(1) = -0.93 to -0.96 V; E1/2(2) = -1.32 to -1.35 V (vs Fc+/Fc) due to the formation of Cu(II)-Cu(I) and Cu(I)-Cu(I) species.