Efficient solid-state microwave-promoted complexation of a mixed dioxa-diaza macrocycle with an alkali salt. Synthesis of a sodium ethyl 4-benzeneazophosphonate complex

The first example of microwave-promoted solid-state synthesis of an alkali complex derived from a heteromacrocyclic compound has been described. The 15-membered mixed dioxa-diaza macrocycle 5,6,14,15-dibenzo-1,4-dioxa-8,12-diazacyclopentadeca-5,14-diene (L) by reaction with sodium ethyl [4-alpha-(benzeneazoanilino)-N-benzyl]phosphonate (NaEP center dot 1.5H(2)O) yielded the sodium complex [Na(L)(mu-EP) center dot H(2)O](2), as a diphosphonate-bridged dinuclear species. The new complex was identified and characterized on the basis of elemental and thermal (TG and DTA) analyses as well as by IR, (1)H and (13)C nuclear magnetic resonance, and ESI and LDI mass spectroscopic studies. The results obtained by the reaction carried out under focused microwave conditions are compared with those obtained by conventional thermal reactions, both in the solid-state and in solution.