On an Unexpected 2D-linked Rare Earth 1,2,4-Triazolate Network: Synthesis, Crystal Structure, Spectroscopic and Thermal Properties of (2)(infinity)[Ho(Tz)(3)(TzH)(2)]TzH

The network compound (2)(infinity)[Ho(Tz)(3)(TzH)(2) (TzH, (Tz(-) = 1,2,4-triazolate anion, C2H2N3-, TzH = 1,2,4-1H-triazole, C2H3N3), was obtained as pink single crystals by the reaction of the holmium metal with a melt of the airline 1,2,4-1H-triazole. No additional solvent was used. The compound is an unexpected example of a 2D-linked network structure as other lanthanides give 3D-frameworks and MOFs with 1,2,4-1H-triazole instead. This illustrates that the series of lanthanides yields very different results in attempts to create MOF structures. In (2)(infinity)[Ho(TZ)(3)(TzH)(2)]TzH the triazolate ligands Tz(-) function both as mu-eta(1):eta(2) linkers as well as ill end on ligands. The latter coordination mode is also round for additional triazole molecules. C.N. is nine for holmium(III). The layers (2)(infinity)[Ho(Tz)(3)(TzH)(2)] exhibit a system of intra and inter layer hydrogen bonding and to triazole molecules from the melt reaction intercalated in-between the layers. The product was investigated by X-ray single crystal analysis, Mid IR, Far IR and Raman spectroscopy, and with DTA/TG regarding its thermal behaviour.