Tetra-Transition-Metal Substituted Weakley-Type Sandwich Germanotungstates and their Derivatives Decorated by Transition-Metal Complexes

Four classic discrete Weakley-type sandwich germanotungstates, Na11H[Co4(H2O)2(α-GeW9O34)2]·31H2O (1), [Co(phen)3]4H3[Co3W(H2O)2(α-GeW9O34)2]·4H2O (2), (C6N2H18)4[Co(H2O)6]H2[Co4(H2O)2(α-GeW9O34)2]·5.5H2O (3), Na(H2O)2(C6N2H18)4.75H1.5[Ni4(H2O)2(α-GeW9O34)2]·1.5H2O (4), and two novel germanotungstates decorated by transition-metal complexes (C6N2H18)3H2[{Co(2,2′-bpy)}2Co4(H2O)2(α-GeW9O34)2]·4H2O (5) (2,2′-bpy = 2,2′-bipyridine), [Ag(phen)2]6H2[{Mn(phen)}2Mn4(H2O)2(α-GeW9O34)2]·3H2O (6) (phen = 1,10-phenanthroline) were synthesized hydrothermally and structurally characterized by elemental analyses, IR spectra, and single-crystal X-ray diffraction structural analysis. Compounds 1−4 show the classical tetra-transition-metal substituted Weakley-type sandwich structural frameworks, whereas 5 and 6 represent the new Weakley-type sandwich frameworks decorated by different transition-metal complexes. EPR studies at 110 K and room temperature reveal that the high-spin paramagnetic metal ions (Co2+, Mn2+) reside i...