Photoluminescence properties of a cationic trinuclear zinc(II) complex with the tetradentate Schiff base ligand 6-methyl-2-({[(pyridin-2-yl)methyl]imino}methyl)phenolate

Abstract

Metal complexes with Schiff base ligands have been suggested as potential phosphors in electroluminescent devices. In the title complex, tetrakis[6-methyl-2-({[(pyridin-2-yl)methyl]imino}methyl)phenolato-1:2κ(8)N,N',O:O;3:2κ(8)N,N',O:O]trizinc(II) hexafluoridophosphate methanol monosolvate, [Zn3(C14H13N2O)4](PF6)2·CH3OH, the Zn(II) cations adopt both six- and four-coordinate geometries involving the N and O atoms of tetradentate 6-methyl-2-({[(pyridin-2-yl)methyl]imino}methyl)phenolate ligands. Two terminal Zn(II) cations adopt distorted octahedral geometries and the central Zn(II) cation adopts a distorted tetrahedral geometry. The O atoms of the phenolate ligands bridge three Zn(II) cations, forming a dicationic trinuclear metal cluster. The title complex exhibits a strong emission at 469 nm with a quantum yield of 15.5%.

Crystal structure of tetrakis(μ2-(E)-2,4-dibromo-6-{[2-(pyridin-2-yl)ethyl]iminomethyl}phenolato)trizinc bis(perchlorate) acetonitrile disolvate

“…Since all three Zn atoms lie on the twofold axis, the Zn1-Zn2-Zn3 bond angle is exactly 180 . These metrical parameters are similar to those found in the most closely similar complex (Kim et al, 2015) where Zn-O distances for the terminal Zn atoms range from 2.126 (3) to 2.155 (4) Å while those for the central Zn atom range from 1.945 (3) to 1.965 (4) Å with Zn-O-Zn bridging angles ranging from 97.3 (1) to 98.7 (1) . The Zn-N imine and Zn-N py bond lengths range from 2.077 (4) to 2.117 (4) Å and 2.140 (4) to 2.176 (4) Å , respectively.…”

“…The coordination environment of the title compound, illustrated in Fig. 1, has been observed in zinc(II) complexes with tridentate N,N,O ligands (Hens & Rajak, 2015;Kim et al, 2015). Transition metal complexes of the related tridentate ligand, 1,3(2-pyridyliminomethyl)phenylenediamine, have been shown to form a variety of interesting complex structures (Kundu et al, 2015;Kumar et al, 2011;Bluhm et al, 2003;Souza et al, 2011;Sanyal et al, 2014;Okeke et al, 2017a,b;Okeke et al, 2018).…”

“…A search of the Cambridge Structural Database for complexes of zinc coordinated to (E)-2-({[2-(pyridin-2-yl)ethyl]imino}methyl)phenolato type ligands gave 26 hits of which only one was similar to the title compound in that it contained a trinuclear Zn complex where this ligand was acting as a bridging group to the central Zn atom (Diop et al, 2014 (Kim et al, 2015). The major differences between this complex and 1 is a -CH 2 -link between the imine N and pyridine ring in the former instead of a -CH 2 -CH 2 -link in the latter, and different substituents on the phenyl ring.…”

A strongly fluorescent NiII complex with 2-(2-hydroxyethyl)pyridine ligands: synthesis, characterization and theoretical analysis and comparison with a related polymeric CuII complex

“…A wide variety of nitrogen-containing heterocyclic ligands has been used to construct coordination complexes (Lin et al, 2015;Kim et al, 2015;Huang et al, 2015). In particular, pyridine alcohol derivatives and their metal complexes have been studied extensively in recent years, focusing on the rational design and synthesis of coordination monomers and polymers because of their intriguing structural features as well as potential applications in catalysis and fluorescence and as chemical sensors (Ley et al, 2010).…”