The structural transformation from 2D layers to 3D nets by solvent-mediated cation-exchange reaction

When metal–organic coordination polymers [M2(SO4)(TTTMB)2(H2O)4]·H2BTEC·2H2O (M = Cd: 1, Zn: 2; TTTMB = 1,3,5-tris(triazol-1-ylmethyl)-2,4,6-trimethylbenzene, H4BTEC = 1,2,4,5-benzenetetracarboxylate acid) with two dimensional layers were suspended in Cu(NO3)2 aqueous solution, a metal–organic coordination polymer [Cu2(TTTMB)(BTEC)(μ-H2O)(H2O)4]·6H2O (3) with three dimensional nets would be obtained by solvent-mediated cation-exchange reaction. The direct reaction of TTTMB and H4BTEC with CuSO4 in the absence of 1 or 2 affords different crystal [Cu3(TTTMB)2(H2BTEC)3(H2O)3]·3H2O (4).