Synthesis, structural isomerism, and magnetism of extended framework compounds of type [Cu(dca)2(pyz)]n, where dca = dicyanamide (N(CN)-2) and pyz = pyrazine

Abstract

Two structural isomers of the dicyanamide (dca, N(CN)-2) complex [Cu(dca)2(pyz)]n (pyz = pyrazine) were prepared from aqueous solution and crystals were grown by slow diffusion and gel techniques. Crystal data: α-[Cu(dca)2(pyz)]n, CuC8H4N8, monoclinic, Pn, Z = 16, a = 24.2549(7) Å, b = 6.8571(2) Å, c = 24.6445(7) Å, β = 91.023(2)°, V = 4098.2(2) Å3, R(F) = 0.0466 (F > 4σ(F)), Rw(F2) = 0.0939 (all data); β-[Cu(dca)2(pyz)]n, CuC8H4N8, monoclinic, C2/m, Z = 2, a = 9.7659(8) Å, b = 6.8787(7) Å, c = 7.3870(5) Å, β = 95.254(7)°, V = 494.15(6) Å3, R(F) = 0.038, Rw(F) = 0.074 (I > 3σ(I)). The α-isomer consists of two interpenetrating α-Po related networks, while the β-isomer contains sheets composed..