Syntheses, supramolecular architectures and photoluminescence properties of Zn(II) complexes based on 3,5‑dihydroxybenzoic and pyridine/pyrazole derived ligands

Abstract

Five new coordination compounds [Zn(µ-3,5-DHB)2(H2O)2]n (1a), 3) and [Zn(3,5-DHB)2(3-Mepz)2]•H2O (4) (3,5-HDHB = 3,5-dihydroxybenzoic, Isna = isonicotinamide, 4-Acpy = 4-acetylpyridine and 3-Mepz = 3-methylpyrazole) were synthesized in water or water-methanol as solvents. All these compounds have been characterized by elemental analysis, FTIR-ATR and 1H-NMR spectroscopies and Powder X-ray diffraction (PXRD). For compounds 1b-4, X-ray crystal structures have been determined. In these compounds, 3,5-DHB ligand displays different coordination modes. Complex 1b is a coordination polymer, while the addition of the pyridine/pyrazole ligands in the reaction provokes the formation of monomeric compounds (2-4). Moreover, the crystal packing indicates that these complexes expand into 2D/3D network structures mainly by intermolecular hydrogen bond interactions. Finally, the photoluminescent properties of these complexes in solid state have also been investigated. The strong emission observed for 1b indicates that it may be a good candidate for photoluminescent devices.

Synthesis, Crystal Structure and Characterization of Two Cobalt (II) Complexes Based on Pyridine Carboxylic Acid Ligands

“…Each Co(II) ion is coordinated with two oxygen atoms (O1, O3A, symmetric code: A: x–1, y, z) and one nitrogen atom (N1) (two carboxylic acid groups from the ligand (5‐Br‐2,3‐pydc) 2− group), it is also coordinated to three oxygen atoms (O9, O10, O11) (from coordinated water molecules), a six‐coordinate structure is formed. The sum of the bond angles formed by each coordinating atom N1, O9, O10, O11 and the central Co(II) ion is 360.16°, which is close to the ideal 360°, indicating that these four coordinating atoms form the equatorial plane, and and there are relatively good coplanarity [20] . O1 and O3A on the ligand are located in the axial position, and the axial bond angle O1−Co1−O3A (178.81°) shows that Co‐MOF 1 is an octahedral configuration (Figure 1c).…”

“…The sum of the bond angles formed by each coordinating atom N1, O9, O10, O11 and the central Co(II) ion is 360.16°, which is close to the ideal 360°, indicating that these four coordinating atoms form the equatorial plane, and and there are relatively good coplanarity. [20] O1 and O3A on the ligand are located in the axial position, and the axial bond angle O1À Co1À O3A (178.81°) shows that Co-MOF 1 is an octahedral configuration (Figure 1c). The CoÀ O bond length of the coordination bond is between 0.2064 to 0.2143 nm, and the CoÀ N bond length is between 0.2106 to 0.2130 nm, which is the same as the CoÀ X (X=O, N) bond length of the reported complex (between 0.1995 to 0.2148 nm) consistent range.…”

Novel zinc (II) and nickel (II) complexes of a quinazoline‐based ligand with an imidazole ring: Synthesis, spectroscopic property, antibacterial activities, time‐dependent density functional theory calculations and Hirshfeld surface analysis

“…The coordination geometry of Zn 2+ ions is formed by two symmetry chelating ligands through nitrogen oxide atoms and imidazole N donor, that is, O1/N3 for Zn1 and O3/N7 for Zn2, in addition to two methanol molecules in a six‐coordination environment. [ 33 ] Zn–O bond lengths were 2.1631(18)–2.208(2) Å, Zn–N were 2.0283(18) and 2.0314(18) Å, comparable with other Zn (II) coordination circumstances. [ 34 ] Additionally, the dihedral angle between the coordination planes of N3–Zn1–O1 and O2–Zn1–O2 was 86.144° and O4–Zn2–O4 and O3–Zn2–N7 was 87.801°, revealing a slightly distorted octahedral geometry.…”

Benzoate substituents effects on the structure of Zn(II) complexes and 1D 4,4′-bipyridine derived coordination polymers

“…The comparison between 2 and {[Zn(µ-3,5-(HO [18] is remarkable. In the latter case, a polymeric cationic compound was formed, and only half of the carboxylate ligands are coordinated to the Zn(II) cations.…”

“…As part of our research in compounds formed by carboxylate ligands and Zn(II) as metal node, recently we have reported the synthesis of complex [Zn (3,5-(HO) 2 Bz) 2 (H 2 O) 2 ] n (1), which by recrystallization in water gives the coordination polymer {[Zn(µ-3,5-(HO) 2 Bz)(µ-OH 2 )(H 2 O) 2 ]•3,5-(HO) 2 Bz•4H 2 O} n . Moreover, its reaction with monodentate pyridine ligand leads to the formation of monomeric compounds [18]. As a continuation of this study, we first synthesized a Zn complex including a closely related ligand, 3,5-(MeO) 2 Bz.…”