Step-by-step assembly of 4d–4f–3d complex based on heptamolybdate anion

Four new complexes, (NH4)11.9[Ln4.7(MoO4)(H2O)23(Mo7O24)4]·xH2O (Ln=Pr, x=34 (1); Ln=Nd, x=19 (2)), [NH4]28[Ce8(MoO4)2(H2O)31(Mo7O24)8]·74H2O (3), and (NH4)26[CoPr8(MoO4)2(H2O)33(Mo7O24)8]·54H2O (4) have been synthesized and characterized by single-crystal and powder X-ray diffraction, CHN elemental analyses TGA analyses, IR and UV–Vis spectroscopy. Complex 1–3 are 0D compounds constructed by the connection between LnIII ions and [Mo7O24]6− unit. In complex 4, the existence of CoII connects the polyanion clusters into 1D chain. The introduction of 3d metal (cobalt cation) and 4f metal (Ln=PrIII, NdIII, CeIII) encourages the coordination capability for [Mo7O24]6− unit, which shows interesting coordination modes. The [Mo7O24]6− unit in 1–4 shows three new coordination modes, connecting up to four metal cations. Complexes 1–4 show antiferromagnetic behavior via variable temperature magnetic study. The photoluminescence spectrum indicates the photoluminescence property for 4. Heptamolybdate anion shows extraordinary coordination geometry in the presence of both lanthanide cation (PrIII) and transitional metal cation (CoII), which give rise to a new 4d–4f–3d complex.▪ ► A new 4d–4f–3d complex that containing 1D chain was obtained and discussed. ► New coordination geometry with higher coordination number of heptamolybdate. ► Series of heptamolybdate contained complexes were synthesized and characterized. ► Complexes mentioned above show antiferromagnetic behavior.