TEMPLATE SYNTHESES AND CRYSTAL-STRUCTURES OF NICKEL(II) COMPLEXES OF HEXAAZA MACROCYCLIC LIGANDS WITH PENDANT FUNCTIONAL-GROUPS - FORMATIONOF A COORDINATION POLYMER

The nickel(II) complexes of hexaaza macrocyclic ligands 1-4, which inc orporate functional groups such as -OH and -CN into the pendant arms a ttached at the uncoordinated bridgehead nitrogen atoms, are synthesize d by the simple template condensation of ethylenediamine, formaldehyde , and primary amines with the appropriate functional groups. The hydro xyl pendant groups in the nickel(II) complex of 1 react with acetic an hydride to produce the Ni(II) complex of 5. The Ni(II) complexes of 1- 5 are in a square-planar geometry in solution. Their UV/vis spectra an d electrochemical data are slightly affected by the type of functional ,stoup and the length of the pendant chain. The pendant hydroxyl group s in [Ni(1)](2+) and [Ni(2)](2+) do not coordinate Ni(II) ion in water at pH less than or equal to 13.0 and an ionic strength 1.0 M (NaClO4) or at pH less than or equal to 10.0 and an ionic strength 0.1 M (NaCl O4). The nickel(II) complex with macrocycle 3 forms a coordination pol ymer on crystallization. [Ni(2)](ClO4)(2)(NiC14H34N6Cl2O10) crystalliz es in the monoclinic space group P2(1)/c with a = 8.724(2) Angstrom, b = 14.581(2) Angstrom, c = 9.255(2) Angstrom, beta = 103.84(1)degrees, and Z = 2. The structure was solved by the direct method and refined to R values of R = 0.0335 and wR(F-2) = 0.0785 for 1751 observed refle ctions (F > 4 sigma(F)) measured with Mo K alpha radiation on an Enraf -Nonius CAD-4 diffractometer. The Ni(II) ion forms a square-planar geo metry, coordinated by four secondary nitrogen donors of the macrocycle with the average Ni-N bond distance of 1.929(2) Angstrom. The oxygen atoms of the pendant hydroxyl groups form hydrogen bondings with the s econdary NH's of the neighboring macrocyclic ligands. Coordination pol ymer [Ni(3)](n)(BF4)(2n)(NiC14H28N8B2F8) crystallizes in the monoclini c space group P2(1)/n with a = 8.269(1) Angstrom, b = 8.559(1) Angstro m, c = 15.814(2) Angstrom, beta = 101.27(1)degrees, and Z = 2. The str ucture was solved by the direct method and refined to R values of R = 0.0485 and wR(F-2) = 0.1395 for 1509 observed reflections (F > 6 sigma (F)) measured with Mo K alpha radiation on an Enraf-Nonius CAD-4 diffr actometer. In the Ni(II) coordination polymer, each Ni(II) ion in the macrocyclic unit is coordinated by two nitrile groups of the neighbori ng macrocycles. The Ni(II) atom is virtually in an octahedral geometry with the average Ni-N(macrocycle) bond distance of 2.056(3) Angstrom and the Ni(II)-N(nitrile) bond distance of 2.162(4) Angstrom.