GALLOPHOSPHONATES CONTAINING ALKALI-METAL IONS - 2 - SYNTHESIS AND STRUCTURE OF GALLOPHOSPHONATES INCORPORATING NA+ AND K+ IONS

The reactions between t-BuP(O)(OH)(2) and equimolar quantities of MGaM e4(M = Na, K) yield ionic and alkali metal containing molecular gallop hosphonates [Na-4(mu(2)-OH2)(2)(THF)(2)][(Me2GaO3PBu-t)(2)](2) . 2THF( 2) and [K(THF)(6)][K-5(THF)(2){(Me2GaO3PBu-t)(2)}(3)] (3), respectivel y. Compounds 2 and 3 are soluble in common organic solvents and have b een characterized by means of analytical and spectroscopic techniques, as well as by single-crystal X-ray diffraction studies. These compoun ds represent the rare examples of molecular ionic phosphonate cages wh ich contain coordinated Na+ or K+ ions. Compound 2 is constructed from -two eight-membered Ga2O4P2 gallium phosphonate rings which sandwich a central Na-4(H2O)(2) unit. In the case of 3, three eight-membered Ga2 O4P2 gallium phosphonate units envelope an aggregated K-5 core which e xists in the form of a trigonal bipyramidal polyhedron. The Na+ and K ions in 2 and 3 are also coordinated by the endocyclic oxygen atoms o f the eight-membered gallophosphonate crowns, apart from the regular e xocyclic P-O coordination. Unlike the lithium gallophosphonate [Li-4(T HF)(4)][{(MeGaO3PBu-t)(3)(mu(3)-O-2)}(2)] (1), compounds 2 and 5 do no t undergo any clean cage conversion reaction in the, presence of 15-cr own-5 and 18-crown-6, respectively.