Crystal structures of [Ln(NO3)3(μ2-bpydo)2], where Ln = Ce, Pr or Nd, and bpydo = 4,4′-bipyridine N,N′-dioxide: layered coordination networks containing 44 grids

Three isostructural coordination networks of Ce, Pr, and Nd nitrate with 4,4′-bipyridine N,N′-dioxide (bpydo) are reported, namely poly[[tris(nitrato-κ2O,O′)cerium(III)]-bis(μ2-4,4′-bipyridine N,N′-dioxide-κ2N:N′)], [Ce(NO3)3(C10H8N2O2)2], poly[[tris(nitrato-κ2O,O′)praeseodymium(III)]-bis(μ2-4,4′-bipyridine N,N′-dioxide-κ2N:N′)], [Pr(NO3)3(C10H8N2O2)2], and poly[[tris(nitrato-κ2O,O′)neodymium(III)]-bis(μ2-4,4′-bipyridine N,N′-dioxide-κ2N:N′], [Nd(NO3)3(C10H8N2O2)2]. All three compounds are isostructural to the previously reported La analogue. The asymmetric unit of [Ln(NO3)3(μ2-bpydo)2] contains one lanthanide cation, two bpydo ligands, and three nitrate anions. Both bpydo ligands act as end-to-end μ2-bridges and display nearly ideal cis and gauche conformations, respectively. The bpydo ligands link the ten-coordinate LnIII cations, forming interdigitating 44 grid-like layers extending parallel to (-101), where interdigitation of layers is promoted by C—H...O interactions between nitrate anions and bpydo ligands. The interdigitated layers are linked to sets of neighboring layers via further C—H...O and π–π interactions.