MACROCYCLIC CATECHOLATE COMPLEXES AS LIGANDS - SYNTHESIS, STRUCTURAL CHARACTERIZATION AND PROPERTIES OF THE [MH(2)ETC] AND ([NI(ETC)]CU)(2-) COMPLEXES (M=CO, NI H(4)ETC EQUALS THE MACROCYCLIC CATECHOL, 2,3-ETHYLENE-5,6 0-(4',5'-DIOLBZO)-[14]-1,4,8,11-[N-4]-7,12-DIENE)/

The syntheses and properties of the Ni(II) and Co(II) complexes, [M(H( 2)ETC)], of the macrocyclic ligand, 2,3-ethylene-5,6: 13,14-di(5'-meth ylbzo)-9, 10-4',5'-diolbzo)-[14]-1,4,8,11-[N-4]-7,12-diene, [H(4)ETC] are reported. The ligand contains a central tetraaza cavity and a peri pheral catecholate function fused to the tetraaza macrocycle. The appe nded catechol function allows the [M(H(2)ETC)I complexes to serve as s ubstituted catecholate ligands for other metal ions. This is demonstra ted in the synthesis of the {[NiETC]Cu-2)(2-) complex which has been s tructurally characterized. The [M(H(2)ETC)] complexes (M = Ni, Co) can be crystallized in two forms: either as monomeric species with two so lvent molecules hydrogen-bonded to the catechol hydroxyl groups or as dimeric species with the catechol hydroxyl groups hydrogen-bonded to e ach other and a single solvent molecule. The complex {[Ni(H(2)ETC)]. 2 THF}, {IV . 2THF}, crystallizes in the triclinic space group P1 with a = 10.908(1), b = 11.391(3), c = 12.727(2), alpha = 84.56(2), beta = 8 0.28(2) and gamma = 73.39(2). The complex {[Co(H(2)ETC)]. THF}2, {(VI) . THF}(2), crystallizes in the triclinic space group P1 with a = 11.13 4(4), b = 13.383(6), c = 17.286(6), alpha = 77.42(3), beta = 76.18(3) and gamma = 88.41(3). The complex {[Co(H(2)ETC)]. DMF)(2), {(VI). DMF} (2) crystallizes in the monoclinic space group P2(1)/n with a = 9.087( 2), b = 7.962(2), c = 34.012(7) and gamma = 94.55(2). The {[NiETC]Cu-2 }(2-) complex, {(VII). 4EDMF} crystallizes in the monoclinic space gro up P2(1)/e with a= 10.26(2), b = 35.21(4), c = 12.541(13) and gamma = 95.54(11). Single crystal X-ray diffraction data for all crystals were collected on an automated diffractometer using MoK alpha radiation an d the structures solved using conventional methods. Full-matrix refine ment of 378 parameters on 3749 data for IV . 2THE, 308 parameters on 2 030 data for {(VI). DMF}(2), 341 parameters on 4244 data for {(VI). TH F}(2), and 290 parameters on 3998 data for {(VII). 4DMF} gave final R values 0.062, 0.066, 0.05O, and 0.062, respectively. The metal coordin ation geometry in the low spin (S = 1/2) [CoH(2)ETC] complex and the d iamagnetic [NiH(2)ETC] complex is square planar and the M-N bonds are 1.865(5) Angstrom and 1.860(5) Angstrom, respectively. The {[NiETC]Cu- 2}(2-) complex is a monomeric species and contains two NiN4 and one Cu O4 planar chromophores. The paramagnetic CuO4 chromophore (S = 1/2) is not subject to intermolecular bonding interactions and shows a Cu-O b ond of 1.917(6) Angstrom. The intramolecular Ni-Cu and Ni-Ni distances in the centrosymmetric molecule are 7.676(2) Angstrom and 15.352(2) A ngstrom, respectively.