Thermodynamic and kinetic studies on the Cu2+ coordination chemistry of a novel binucleating pyridinophane ligandElectronic supplementary information (ESI) available: Table S1: observed rate constants for the acid-promoted decomposition of Cu2+ complexes with ligand L. Table S2: observed rate constants for the acid-promoted decomposition of Cu2+ complexes with macrocycle L1. Fig. S1: Variation of some selected 13C chemical shifts as a function of pH. See http://www.rsc.org/suppdata/dt/b2/b209013a/

The synthesis and coordination chemistry of the novel pyridine-functionalized ligand 2,6,9,12,16-pentaaza[17]-(2,6)pyridinophane (L1) is described. The compound behaves as a hexaprotic base in aqueous solution. NMR studies indicate a protonation pattern in which the sp2 pyridine nitrogen (N(py)) does not undergo a net protonation although it is involved in formation of hydrogen bonds. L1 forms mono and binuclear hydroxylated complexes. The crystal structure of [CuL1](ClO4)2 shows a square planar coordination for Cu2+ with the pyridine and the three central nitrogens of the chain forming the vertices of the square. The benzylic nitrogens could be occupying the axial positions of a strongly a…