Synthesis, structures, and photoluminescence properties of novel lanthanide tetracyanoplatinates lacking Pt–Pt interactions

The synthesis of a series of lanthanide tetracyanoplatinates all incorporating 2,2′:6′,2″-terpyridine (terpy) have been carried out by reaction of Ln3+ nitrate salts with terpy and potassium tetracyanoplatinate. The incorporation of different Ln3+ cations results in the isolation of [Ln (DMF)2(C15H11N3)(H2O)2(NO3)]Pt(CN)4 (Ln =La–Nd, Sm–Yb) under otherwise identical reaction conditions. These compounds have been isolated as single crystals and X-ray diffraction has been used to investigate their structural features. All of the reported compounds are isostructural. Crystallographic data for the representative Eu3+ compound (EuPt) are (MoK α, λ =0.71073 Å): monoclinic, space group P 21/c , a =10.1234(4) Å, b =18.7060(7) Å, c =17.1642(5) Å, β =97.249(3)°, V =3224.4(2), Z =4, R (F )=2.78% for 426 parameters with 7724 reflections with I >2σ (I ). The structure consists of a zero-dimensional, ionic salt containing complex [Eu(DMF)2(C15H11N3)(H2O)2(NO3)]2+ cations and View the MathML sourcePt(CN)42− anions. The complex cations contain the Eu3+ ions in a tri-capped trigonal prismatic coordination environment with one terdentate 2,2′:6′,2″-terpyridine molecule, one bidentate nitrate anion, two O-bound dimethylformamide molecules, and two coordinated water molecules. Photoluminescence data illustrate that EuPt displays intramolecular energy transfer from the coordinated terpy molecule to the Eu3+ cation. The uncoordinated tetracyanoplatinate anion also exhibits visible emission.