Alkali and Alkaline-Earth-Metalated Forms of Calix[4]arenes: Synthons in the Synthesis of Transition Metal Complexes

This is the first coherent report on the metalation of calix[4]arene by alkali and alkaline-earth metals. thus providing a high-yield production of appropriate synthons for the synthesis of transition metal calix[4]arenes. In addition. various facets of the coordination chemistry by calix[4]arene anions of alkali and alkaline-earth metal ions have been singled out. Among them: 1) the exo and endo coordination of metal ions by the calix[4]arene skeleton: 2) the T solvation of the ions by the phenyl rings: 3) the ion-carrier properties of metallacalix[4]arenes: 4) the simulation of the kinetically labile coordination sphere of alkali and alkaline-earth metal ions by a polyoxo rigid skeleton. The peculiarities of the complexation of alkali and alkaline-earth metal ions by calix[4]arenes outlined are deduced from the synthesis and the structural characterization both in solution (H-1 NMR) and in the state (X-ray structure analysis) of the following classes of compounds: 1) [p-tBu-calix[4](OMSeta)(4)](2) (M = Li, Na, K); 2) [p-tBu-calix[4](OR)(2)(O)(2)ML] (M = Mg, L = THF. R-C5H9; M = Ca, L= TMEDA (tetramethylethylenediamine). R, C5H9; M = Ca, L = DME (dimethoxyethane). R = C5H9; M = Ba, L = TMEDA, R = C5H9; M = Ba, L = none. R = C5H9); 3) [p-tBu-calix[4]-(OC5H9)(2)(O)(2)Ca2I2(MeCN)(2)]; 4) [{p-tBu-calix[4](OR)(2)(O)(2)}(2)BaNa2].