A First and Homoleptic Rare Earth 3D-Bipyrazolate MOF: ³_∞[Eu(Me₄BpzH)₃(Me₄BpzH₂)]

Alexander Zurawski (1) , Joachim Sieler (2) , Klaus Mueller-Buschbaum (3)

1 Department Chemie und Biochemie
2 Institut fuer Anorganische Chemie
3 Department Chemie und Biochemie

Abstract. The homoleptic framework ³_∞[Eu(Me₄BpzH)₃(Me₄BpzH₂)], Me₄BpzH– = 3,3´,5,5´-tetramethyl-4,4´-bipyrazolate anion, C₁₀H₁₃N₄–, Me₄BpzH₂ = 3,3´,5,5´-tetramethyl-4,4´-bipyrazole, C₁₀H₁₄N₄, is obtained by a high-temperature oxidation of the metal europium with a self consuming melt of 3,3´,5,5´-tetramethyl-4,4´-bipyrazole above 300 °C. The framework structure initiates from a three-dimensional linkage of Eu centres and bridging ligands that coordinate with one N atom of each aromatic ring linking η¹:η¹ via front and backside of the bicyclic ring system. The framework has a (4,8) topology and is the first example of a rare earth bipyrazolate. Thus for the trivalent eightfold by nitrogen atoms coordinated europium a sterically rather crowded ligand with four methyl groups is able to yield a 3D-framework. The crystal structure was refined from systematically eight-fold twinned crystals as meroedric fourfold twins with a subsequent racemic twinning of the fourfold twin individuals.

Mots clés: Physical Sciences

Alexander Zurawski, Joachim Sieler, Klaus Mueller-Buschbaum. A First and Homoleptic Rare Earth 3D-Bipyrazolate MOF: ³_∞[Eu(Me₄BpzH)₃(Me₄BpzH₂)]. Journal of Inorganic and General Chemistry / Zeitschrift für anorganische und allgemeine Chemie, 2009, 635 (12), pp.2034. ⟨10.1002/zaac.200900247⟩. ⟨hal-00498928⟩