Two nickel coordination polymers with flexible ligand 1,3,5-tri(1,2,4-triazol-1-ylmethyl)-2,4,6-trimethylbenzene

The reaction of 1,3,5-tri(1,2,4-triazol-1-ylmethyl)-2,4,6-trimethylbenzene (ttmb) with Ni(II) salts yields two coordination polymers [Ni3(ttmb)2(H2O)6Cl6](H2O)3 (1) and [Ni(ttmb)2(H2O)2](NO3)2(H2O)4 (2). The flexible ligand ttmb shows the cis,cis,cis-conformation and a tri-monodentate coordination mode in 1. Each ttmb links three Ni(II) atoms to form an undulated (3, 4)-connected two-dimensional network. Each undulated two-dimensional network polycatenates other two identical networks, thus giving a rare (2D → 3D) parallel polycatenation network in 1. The ttmb ligand exhibits the cis,trans,trans-conformation and a two-monodentate coordination mode in 2. Each ttmb connects two Ni(II) atoms to construct a two-dimensional (4, 4) network in 2. The thermal stability of compounds 1 and 2 was studied.