Formation of Metal-Based 21- and 22-Membered Macrocycles from Dinuclear Organotin Tectons and Ditopic Organic Ligands Carrying Carboxylate or Dithiocarbamate Groups

Four dinuclear organotin halides of composition Xn­Ph(3–n)­Sn­CH2Si­(Me)2–C12H8–Si­(Me)2­CH2­SnPh(3–n)­Xn (X = Cl, I; n = 1, 2) were prepared and combined in 1:1 stoichiometric reactions with potassium 2,5-pyridinedicarboxylate, 3,5-pyridinedicarboxylate, and piperazine bis-dithiocarbamate, respectively. The reactions yielded a total of five [1 + 1] aggregates with either 21- or 22-membered macrocyclic structures that were fully characterized by elemental analysis, mass spectrometry, IR and NMR (1H, 13C, 29Si, and 119Sn) spectroscopy, and, in three cases, additionally by single-crystal X-ray diffraction analysis. In solution, the macrocycles exhibit conformational and configurational equilibria being fast on the NMR time scale, which, for one of the macrocycles, were closer examined by variable temperature NMR spectroscopy and DFT calculations.