Synthesis and Characterization of a Novel 32‐Membered Unsymmetrical Dinucleating [N12] Macrocycle

Synthesis and Characterization of a Novel 32‐Membered Unsymmetrical Dinucleating [N12] Macrocycle: Preparation of Bimetallic Complexes M2LX2(ClO4)2 (M = Zn, Cd, or Hg; X = Cl, NCS, or NO3)

The condensation reaction of N‐acetylaniline with 1,3‐diaminopropane in 2:1 mole ratio under reflux condition generates an intermediate species having C˭N bonds. The in situ reaction of the intermediate with HCHO and 1,3‐diaminopropane in the presence of perchloric acid results in an off‐white solid product. Analytical, FAB mass, IR, 1H NMR and electronic spectral data of this solid are consistent with the formation of the dihydroperchlorate salt of an unsymmetrical 32‐membered [N12] macrocycle [L · 2HClO4] via a capping mechanism of the intermediate species. Reactions of [L · 2HClO4] with Group 12 metal salts, MX2, and their precursors, [M(Ph3P)2Cl2], produce bimetallic complexes with the stoichiometries M2LX2(ClO4)2 (M = Zn, Cd or Hg; X = Cl, NO3, or NCS) and M2LCl2(ClO4)2, respectively, with liberation of 2 mol equiv. of the ancillary ligand, Ph3P, from the precursors. Physico‐chemical and spectroscopic data of the complexes confirm encapsulation of two metal ions in the macrocyclic cavity via coordination through nitrogen atoms of the unsymmetrical aza groups and the counter anions occupy apical positions in the octahedral geometry around the metal ions. The thermodynamic first ionic association constant and related parameters have been determined from conductometric studies using the Fuoss and Edelson method and are discussed.