Bazzicalupi, Carla Bencini, Andrea Berni, Emanuela Bianchi, Antonio Danesi, Andrea Giorgi, Claudia Valtancoli, Barbara Lodeiro, Carlos Lima, João Carlos Pina, Fernando Bernardo, M. Alexandra New Terpyridine-Containing Macrocycle for the Assembly of Dimeric Zn(II) and Cu(II) Complexes Coupled by Bridging Hydroxide Anions and π-Stacking Interactions The synthesis of the new terpyridine-containing macrocycle 2,5,8,11,14-pentaaza[15](6,6‘ ‘)cyclo(2,2‘:6‘,2‘ ‘)terpyridinophane (<b>L</b>) is reported. The ligand contains a pentaamine chain linking the 6,6‘ ‘ positions of a terpyridine unit. A potentiometric, <sup>1</sup>H NMR, UV−vis spectrophotometric and fluorescence emission study on the acid−base properties of <b>L</b> in aqueous solutions shows that the first four protonation steps occur on the polyamine chain, whereas the terpyridine nitrogens are involved in proton binding only at strongly acidic pH values. <b>L</b> can form both mono- and dinuclear Cu(II), Zn(II), Cd(II), and Pb(II) complexes in aqueous solution. The crystal structures of the Zn(II) and Cd(II) complexes {[Zn<b>L</b>H]<sub>2</sub>(μ-OH)}(ClO<sub>4</sub>)<sub>5</sub> (<b>6</b>) and {[Cd<b>L</b>H]<sub>2</sub>(μ-Br)}(ClO<sub>4</sub>)<sub>5</sub>·4H<sub>2</sub>O (<b>7</b>) show that two mononuclear [M<b>L</b>H]<sup>3+</sup> units are coupled by a bridging anion (OH<sup>-</sup> in <b>6</b> and Br<sup>-</sup> in <b>7</b>) and π-stacking interactions between the terpyridine moieties. A potentiometric and spectrophotometric study shows that in the case of Cu(II) and Zn(II) the dimeric assemblies are also formed in aqueous solution containing the ligand and the metals in a 1:1 molar ratio. Protonation of the complexes or the addition of a second metal ion leads to the disruption of the dimers due to the increased electrostatic repulsions between the two monomeric units. dimeric assemblies;ligand;polyamine chain;potentiometric;OH;metal ion;fluorescence emission study;solution;1 H NMR;proton binding;protonation steps;monomeric units;pentaamine chain;UV;Bridging Hydroxide Anions;terpyridine unit;Zn;M L H;Cu;acidic pH values;crystal structures;terpyridine moieties;complex;terpyridine nitrogens 2004-08-09
    https://acs.figshare.com/articles/journal_contribution/New_Terpyridine_Containing_Macrocycle_for_the_Assembly_of_Dimeric_Zn_II_and_Cu_II_Complexes_Coupled_by_Bridging_Hydroxide_Anions_and_Stacking_Interactions/3329458
10.1021/ic049660l.s002