Different Zn^IIcation coordination geometries in di-μ-acetato-bis{2-chloro-6-[(pyridine-2-ylmethylimino)methyl]phenol}dizinc(II) chloroform monosolvate

Abstract

In the title compound, di-μ-acetato-κ(2)O:O;κ(2)O:O'-bis[(6-chloro-2-{(E)-[(pyridin-2-yl)methylimino]methyl}phenolato-κ(3)N,N',O)zinc(II)], [Zn2(C13H10ClN2O)2(C2H3O2)2]·CHCl3, the Zn(II) cation adopts a five-coordinate geometry and is coordinated by two N atoms and one O atom of a tridentate 6-chloro-2-{(E)-[(pyridin-2-yl)methylimino]methyl}phenolate ligand and two O atoms of two bridging acetate groups, but their coordination geometries differ. One Zn(II) cation adopts a distorted trigonal bipyramidal geometry and the other a square-pyramidal geometry. The two acetate ligands bridge two Zn(II) cations with mono- and bidentate coordination modes. The title compound exhibits a strong emission at 460 nm upon excitation at 325 nm with a quantum yield of 23.1%.

Influence of Solvent in Solvothermal Syntheses: Change of Nuclearity in Mixed Valence CoII/III Complexes of a O-Donor-rich Schiff Base Ligand

“…However, the asymmetric stretching zone (1540−1580 cm −1 ) is free from ligand stretching peaks. The presence of a unique band at 1575 cm −1 (characteristic of a syn-syn μ 2 -η 1 :η 1 bridging carboxylate) 74,75 in complex 3, which is absent in 1 and 2, indicates the absence of a bridging carboxylate which is in agreement with the crystal structures.…”

“…Complex 3 contains both bridging and chelating carboxylates which is different compared to complexes 1 and 2 . In general IR spectral data provide good indication of this difference in bonding pattern due to the difference arising in the symmetric and asymmetric stretching frequencies of the carboxylate. − However, in our case the ligand has stretching frequencies in the symmetric stretching frequency zone (1430–1465 cm –1 ) for the carboxylates which renders the assignment of the symmetric stretching bands of carboxylate rather inconclusive. However, the asymmetric stretching zone (1540–1580 cm –1 ) is free from ligand stretching peaks.…”

Synthesis and crystal structure of a zinc(II) coordination polymer: N-(2-pyridylmethyl)- L-alanine)isothiocyanate Zn(II)

“…The basal positions are defined by O2, N1 and N2 of the tridentate reduced Schiff base ligand, HL1 and by N3 of the thiocyanate ligand L2; while the apical position is occupied by the bridging O2 of another HL1 ligand as shown in Figure 6 [15]. The calculated trigonality index, τ = 0.15 confirms a non-perfect squarepyramidal geometry, (τ = 1 for a perfect trigonal bipyramidal geometry and τ = 0 for a perfect square-pyramidal geometry [22]. The deviation from ideal geometry may be due to the fact that the amino hydrogen is in an abnormal position.…”