From 1D chain to 2D layer and 3D network: Solvent-free syntheses of new metal oxalates

Four metal oxalates, Hdpa⋅Cr(ox)2 (1), (Hdpa)2⋅ Zn2(ox)3 ⋅ 2H2O (2), Zn(H2O)(ox) (3), and (Hgua)(H3O) ⋅ Cd(C2O4)2 (4), have been synthesized under solvent-free conditions, where dpa = diisopropylamine, ox = oxalate, and gua = guanidine. These compounds have extended structures varying from 1D chain (for 1), to 2D layer (for 2 and 3), and 3D framework network (for 4). The temperature dependence of the magnetic susceptibility of compound 1 indicates the existence of antiferromagnetic interactions between the chromium ions. Upon excitation at 230 nm, compound 3 exhibits an extensive luminescence with a peak centered at 501 nm.