Low pH hydrothermal synthesis and properties of lanthanide-organic frameworks with (410,65)(49,66) topology constructed from Ln-Hbptc building blocks

Abstract

Two novel lanthanide-organic frameworks (LnOFs) with (4¹⁰,6⁵)(4⁹,6⁶) topology, [Ln(Hbptc)(H₂O)]_n (Ln = Eu(1), Gd(2); H₄bptc = 3,3′,4,4′-biphenyltetracarboxylic acid) were synthesized via the hydrothermal in situ reaction between lanthanide salts and 3,3′,4,4′-biphenyltetracarboxylic dianhydride (bpta) under low pH conditions. In complexes 1 and 2, homohelix bundles with opposite chirality are assembled alternately and result in pillar-like 3D extended networks incorporated with coordinated water molecules, which show high thermal stability. The luminescence properties are illustrated by the Eu^III complex (1) and its Gd-doped compound, which are intensive red emitters. The magnetic properties of complexes 1 and 2 are also investigated.