Assembled synthesis of luminescent mono/double‐layered 2D and 3D Zn (II)‐based coordination polymers tuned by flexible bis (pyridyl)propane‐1,2‐diamines and diverse organic dicarboxylates

Abstract

Six mono/double‐layered 2D and three 3D coordination polymers were synthesized by a self‐assembly reaction of Zn (II) salts, organic dicarboxylic acids and L1/L2 ligands. These polymeric formulas are named as [Zn(L1)(C4H2O4)0.5 (H2O)]n·0.5n(C4H2O4)·2nH2O (1), [Zn2(L2)(C4H2O4)2]n·2nH2O (2), [Zn(L1)(m‐BDC)]n (3), [Zn2(L2)(m‐BDC)2]n·2nH2O (4), [Zn3(L1)2(p‐BDC)3(H2O)4]n·2nH2O (5), [Zn2(OH)(L2) (p‐BDC)1.5]n (6), [Zn2(L1)(p‐BDC)2]n·5nH2O (7), [Zn2(L2)(p‐BDC)2]n·3nH2O (8) and [Zn2(L1)(C4H4O4)1.5(H2O)]n·n(ClO4)·nH2O (9) [L1 = N,N′‐bis (pyridin‐4‐ylmethyl)propane‐1,2‐diamine, L2 = N,N′‐bis (pyridin‐3‐ylmethyl)propane‐1,2‐ diamine, m‐BDC2− = m‐benzene dicarboxylate, p‐BDC2− = p‐benzene dicarboxylate]. Meanwhile, these polymers have been characterized by elemental analysis, infrared, thermogravimetry (TG), photoluminescence, powder and single‐crystal X‐ray diffraction. Polymers 1–6 present mono‐ and double (4,4)‐layer motifs accomplished by L1/L2 ligands with diverse conformations and organic dicarboxylates, and the layer thickness locates in the range of 5.8–15.0 Å. In three 3D polymers, the L1 and L2 molecules adopt the same cis‐conformations and join adjacent Zn (II) cations together with p‐BDC2− or succinate, giving rise to different binodal (4,4)‐c nets with (4.52.83)(4.53.72) (7), pts (8) topology and twofold interpenetrated binodal (5,5)‐c nets with (32.44.52.62)(3.43.52.64) (9). Therefore, the diverse conformations of the two bis (pyridyl)‐propane‐1,2‐diamines and the feature of different organic dicarboxylate can effectively influence the architectures of these polymers. Powder X‐ray diffraction patterns demonstrate that these bulk solid polymers are pure phase. TG analyses indicate that these polymers have certain thermal stability. Luminescent investigation reveals that the emission maximum of these polymers varies from 402 to 449 nm in the solid state at room temperature. Moreover, 1, 3 and 5–8 show average luminescence lifetimes from 8.81 to 16.30 ns.