Selected copper(II) compounds with oxalate anion are described (H2L = oxalic
acid; C2H2O4); [CuL(3pyOH)2]n 1, {[Cu(L)(2a4mpy)2][Cu(L)(2a4mpy)]·(2a4mpy)}n 2,
{(CN3H6)2[CuL2]}n 3, {(2apyH)2[CuL2]∙3H2O}n 4, [CuL(H2O)(4apy)2]n 5,
{(NH4)4[Cu(L)2(H2O)2][Cu(L)2]∙2H2O}n 6, {[Cu(HL)2(H2O)2][Cu(HL)2]·6H2O}n 7 and
{Na2[CuL2]}n 8. Coordination units are either neutral or anionic. All compounds are polymeric due to the oxalate ligand. The coordination spheres are octahedral, square pyramidal or square planar with the coordination numbers 6, 5 or 4. All as expected for the copper(II) compounds. The oxalate anion is typically double anion (L2-) and only in the compound 7 it is monoanion (HL-). Elemental analysis is in agreement with the determined compounds formulae. The compounds' spsctra show typical strong IR bands fort he oxalate anion at 1650-1600 cm-1 and 1400- 1300 cm-1. Those with guanidinium or ammonium cations, ammine group or water have additional bands above 3000 cm-1 , methyl group at 2900 cm-1.
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