Ligand substitution in sandwich-type complexes of germanotungstates: Syntheses, crystal structures and magnetic properties

Two new sandwich-type germanotungstates K2H2{Zn(en)2}{Zn(en)2}2{(GeW9O34)2Zn4(Hen)2}·17H2O (1) and K2H2{Ni(en)2}{Ni(en)2}2{(GeW9O34)2Ni4(Hen)2}·12H2O (2) (en = ethylenediamine) have been hydrothermally synthesized. The polyanions of the two compounds are composed of a [Ge2W18M4(Hen)2O68]10− (M = Zn, Ni) group decorated by two [M(en)2(H2O)]2+ units. The luminescence of compound 1 exhibits an intense UV radiation emission maximum at λ ≈ 449 nm upon excitation of 372 nm. The magnetic investigation of compound 2 demonstrates the presence of ferromagnetic interactions between the Ni2+ ions of the Ni4O14(Hen)2 clusters in 2.