SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF N-(PARA-SUBSTITUTED-PHENYL)AZA-15-CROWN-5 SODIUM HETEROPOLYMOLYBDOTUNGSTATE

The title complexes of [Na(N-(p-Rph)15C5) (Et2O)](2)Na2WxMo8-xO26 [(1) : R = H, x = 0.26: (2): R = CH3, x = 0.50] were synthesized by the rea ction of N-(p-Rph)15-crown-5 with tetra-n-butylammonium polymolybdotun gstate and a sodium cation and characterized by elemental analysis, IR , H-1 NMR and H,H-COSY NMR spectra and crystal structure determination of complex (2). The complexes can be described as having a two-dimens ional [Na2WxMo8-xO26](infinity)(2-) anion framework in which the sodiu m is coordinated with six terminal O atoms of neighbouring beta-octamo lybdotungstates in octahedral geometry and a [Na(N-(p-Rph)15C5(Et2O)]( +) complex cation in which the sodium cation shows pentahedral pyramid al coordination geometry, which is rarely observed. The packing of the complex cations and the two-dimensional anion framework were in diffe rent layers separately. The N-(para-substituted-phenyl)aza-15-crown-5 combined with the octamolybdotungstate anion with a ratio of W/Mo of 0 .26/7.74 in complex (1) and 0.50/7.50 in complex (2), respectively, ho wever the DB18C6 and DB24C8 chose the hexamolybdotungstate anion with a ratio of W/Mo of 4/2 and 1/5 to form the complexes [Na(DB18C6) (CH3O H)](2)W4Mo2O19 and [Na(DB24C8)](2)W1Mo5O19. (C) 1997 Elsevier Science Ltd.