(E)-N-(Pyridine-2-ylmethylene)arylamine as an Assembling Ligand for Zn(II)/Cd(II) Complexes: Aryl Substitution and Anion Effects on the Dimensionality and Luminescence Properties of the Supramolecular Metal–Organic Frameworks

Abstract

Using five Schiff base ligands (E)-N-(pyridine-2-yl) (CHNPhR) (where R = 4–CH3, L 1 ; 2,6-(CH3)2, L 2 ; 2,4,6-(CH3)3, L 3 ; 2,6-(C2H5)2, L 4 ; 2,6-(i-C3H7)2, L 5 ), nine Zn­(II)/Cd­(II) complexes, namely, Zn1–Zn3, Cd1, Cd2, Cd3a, Cd3b, Cd4, and Cd5, have been successfully synthesized. The structures of the Zn­(II)/Cd­(II) complexes have been established by single crystal X-ray diffraction and further physically characterized by 1H NMR, FT–IR, and elemental analysis. The crystal structures of these complexes indicate that the structures of ligand and anions can directly influence the formation of 1D → 3D supramolecular metal–organic frameworks (SMOFs) via C–H···O/C–H···Cl hydrogen bonds and π···π interactions. Upon irradiation with UV light, the nine Zn­(II)/Cd­(II) complexes display deep blue emissions of 401–436 nm in acetonitrile solution and light blue or bluish green emissions of 485–575 nm in the solid state, respectively. The photoluminescence properties of nine Zn­(II)/Cd­(II) complexes can be finely and predictably tuned over a wide range of wavelengths by small and easily implemented changes to ligand structure. It is worth noting that Zn1 and Cd1 exhibit obvious aggregation-induced emission enhancement (AIEE) properties in the CH3CN–H2O mixture solutions.

Unusually Flexible Indium(III) Metal–Organic Polyhedra Materials for Detecting Trace Amounts of Water in Organic Solvents and High Proton Conductivity

“…There is one-third of In­(III) ion, one-third of TCPB 3– anion, and one-third of free H 2 O molecule in the asymmetry unit. Using Addison’s model, the coordination geometry around the indiun atom in In1 (τ 4 = 0.126) can be better described as a quadrilateral geometry by four bidentate carboxylic groups from two individual H 3 TCPB ligands (Figure a). The bond distances of In–O are 1.927 and 1.935 Å, all of which are similar to those reported for other In­(III) ion compounds (Table S1 in the Supporting Information).…”

Zinc (II), palladium (II) and cadmium (II) complexes containing 4‐methoxy‐N‐(pyridin‐2‐ylmethylene) aniline derivatives: Synthesis, characterization and methyl methacrylate polymerization

“…In addition, the steric and electronic properties can be easily modified by appropriate variation on N ‐donors of pyridinylmethanimine moiety, and resulted in stable complexes with a variety of transition or inner transition metals . These metal complexes have found a wide range of applications in various fields, such as synthesis and spectroscopic studies, as catalysts for transfer hydrogenation of ketones, oxidation, supramolecular metal–organic frameworks, olefin polymerization, ε‐caprolactone and methyl methacrylate (MMA) polymerization …”

Effect of the Spacer Chain Length of Organic Dicarboxylic Acid on the Supramolecular Assembly of Two Ternary Zinc (II) Coordination Polymers Derived from Mixed Ligands

“…As for Zn2, it is coordinated with two N from two individual L ligands (Zn2–N5 = 2.013(7) Å, Zn2–N4B = 2.040(7) Å; symmetry code: B = – x + 1, – y + 2, – z + 1) and two O atoms from two SA 2– anions (Zn2–O8 = 1.952(8) Å, Zn2–O4A = 1.963(7) Å; symmetrical code: A = x, y –1, z ). The bond angles around the central Zn II atom are in the range of 98.6(3) to 122.4(4)°, and the Zn–O and Zn–N bond lengths are within the normal range …”

“…At the same time, dicarboxylates as O‐donor ligands have been frequently chosen as building blocks in the construction of CPs owing to their diverse coordination modes (monodentate, chelating, bridging and bis‐monodentate) , . Additionally, the supramolecular interactions such as hydrogen bonding and π ··· π stacking interactions play essential roles in the self‐assembly process of supramolecular frameworks , . Thus, the ternary Zn II CPs based L and dicarboxylate coligands may be adopted for the photodegradation of organic dyes.…”