Melaminium lanthanide oxalate coordination compounds – synthesis and structural varieties

Abstract

A crystal engineering approach affords novel crystalline ionic coordination networks occurring in two different compositions. [C3H7N6]6[Ln(C2O4)4][NO3] (1) (Ln = Dy, Ho), which is isostructural to its ytterbium homologue and [C3H7N6][Ln(C2O4)2(H2O)] (2) (Ln = Ce, Gd). The crystal structure of 1 is based on the interaction between isolated monomeric building-blocks of [Ln(C2O4)4]5– and melaminium cations. The melaminium cations form parallel layers, in which the lanthanide oxalato anion is intercalated. On the other hand, 2 consists of a 2D framework of interconnected lanthanide oxalate units with isolated melaminium cations intercalated between the metal complex layers.