Abstract: | By the solvothermal reaction under acidic conditions of Cu(NO3)2·3H2O, Na2C2O4 and the N,N′‐ditopic organic coligands 1‐(pyridin‐4‐yl)piperazine (ppz) and 1,2‐bis(pyridin‐4‐yl)ethane (bpa), two novel anionic copper(II) coordination compounds were obtained, namely the one‐dimensional coordination polymer catena‐poly4‐(pyridin‐1‐ium‐4‐yl)piperazin‐1‐ium (oxalato‐κ2O1,O2)copper(II)]‐μ‐oxalato‐κ3O1,O2:O1′]], {(C9H15N3)Cu(C2O4)2)]}n or {(H2ppz)Cu(C2O4)2]}n, (I), and the discrete ionic complex 4,4′‐(ethane‐1,2‐diyl)dipyridinium bis(oxalato‐κ2O1,O2)copper(II), (C12H14N2)Cu(C2O4)2] or (H2bpa)Cu(C2O4)2], (II). The products were characterized by single‐crystal X‐ray diffraction, elemental analysis, powder X‐ray diffraction, thermogravimetric analyses and UV and IR spectroscopic techniques. The Cu(C2O4)2]2− units for (I) and (II) are stabilized by H2ppz2+ and H2bpa2+ cations, respectively, via charge‐assisted hydrogen bonds. Also, a study of the pH‐controlled synthesis of this system shows that (I) was obtained at pH values of 2–4. When using bpa, a two‐dimensional square‐grid network of Cu(C2O4)(bpa)]n was obtained at a pH of 4. This indicates that the pH of the reaction also plays a key role in the structural assembly and coordination abilities of oxalate and N,N′‐ditopic coligands. |