Assembly of coordination networks: Role of the different M(II)–cysteate chain in structural diversification

In this paper, we have presented the synthesis and crystal structures of five coordination polymers, namely, {[Ni2(cysteate)2(bpy)2(H2O)2]·3H2O}n (1), {[Cu2(cysteate)2(bpy)2(H2O)2]·4H2O}n (2), {[Mn2(cysteate)2(bpy)(H2O)4](bpy)·H2O}n (3), {[Zn2(cysteate)2(bpy)(H2O)4](bpy)·H2O}n (4), {[Cd(cysteate)(bpy)(H2O)]·4H2O}n (5), using homochiral l-cysteate and 4,4′-bipyridine (bpy) as mixed ligands, reacted with Ni(II), Cu(II), Mn(II), Zn(II) and Cd(II) ions, respectively. When different metal centers being used, l-cysteate gave rise to three different architectures based on coordination polymeric chains: (1) a helical chain, which is further connected by bpy pillars to generate a racemic twofold 3D (42.84)-lvt net in 1 and 2; (2) a zigzag chain, which is further linked by bpy pillars into a homochiral 2D brick-wall structure in 3 and 4; (3) a zigzag chain, which is further linked by bpy pillars into a homochiral 2D 44 grid network in 5. These results indicate that the metal-directed M(II)–cysteate chain has an important effect on the structural diversification of such complexes.