Synthesis, characterization, solvatochromic behavior and crystal structures of complexes [CoIII(salophen)(thioacetamide)2]ClO4 and [CoIII(salophen)(thiobenzamide)2]ClO4

Abstract

Two new cobalt(III) complexes of the Schiff base N,N'-disalicylidene-1,2-phenylendiimine dianion (salophen), trans-[Co III (salophen)(ta) 2 ]ClO 4 , (ta = thioacetamide) (1) and trans-[Co III (salophen)(tb) 2 ]ClO 4 , (tb = thiobenzamide) (2) were synthesized and characterized using single-crystal X-ray diffraction and spectroscopic techniques. Both complexes show solvatochromism in a variety of solvents. Complex (1) crystallized from CHCl 3 as a solvate of orthorhombic symmetry, space group Pca2 1 with a = 17.3480(10) Å, b = 18.7522(10) Å, c = 18.8128(11) Å, D = ȕ = Ȗ = 90°, and Z = 8. The cobalt(III) center lies in a distorted octahedral environment. The crystal structure of (1) consists of two independent [Co III (salophen)(ta) 2 ] + cations and ClO 4 -anions held together essentially via hydrogen bonds and ʌ-ʌ stacking interactions. Complex (2), forming also a CHCl 3 solvate, crystallized in the monoclinic space group P2 1 /n with a = 14.710(3) Å, b = 13.506(3) Å, c = 18.595(4) Å, ȕ = 100.295(4)°, and Z = 4. The geometry around cobalt(III) center is a distorted octahedron. The crystal structure of (2) contains a [Co III (salophen)(tb) 2 ] + complex with a remarkably twisted salophen ligand. Both complexes, (1) and (2), contain approximately one disordered CHCl 3 molecule per Co in the solid state.

Cobalt(III) Complex [CoL3] Derived from an Asymmetric Bidentate Schiff Base Ligand L (L=(5‐Bromo‐2‐hydroxybenzyl‐2‐furylmethyl)‐imine): Synthesis, Characterization and Crystal Structure

“…6 The synthesis and characterization of these complexes have also been playing an important part in the development of coordination chemistry. 7 It is known that variation of the size and the type of Schiff base ligand can be responsible for changes in the coordination geometry around the cobalt(III) center. 1,2,7 Schiff bases derived from salicylaldehyde and various amines have been extensively used to synthesize many transition metal complexes.…”

“…7 It is known that variation of the size and the type of Schiff base ligand can be responsible for changes in the coordination geometry around the cobalt(III) center. 1,2,7 Schiff bases derived from salicylaldehyde and various amines have been extensively used to synthesize many transition metal complexes. [8][9][10] However, reports on the preparation and characterization of transition metal complexes with bidentate Schiff base ligand derived from furfurylamine are very rare.…”

Switching metal complexesviaintramolecular electron transfer: connections with solvatochromism

“…An absorption in the visible region (between around 450 to 600 nm, depending on the complex) shifts to shorter wavelengths as the solvent donor number is increased, due to a reversible equilibrium involving substitution of the axial ligands by coordinated solvent. [95][96][97] For [Co III (saox)(bipy) 2 ] + (22; H 2 saox = salicylaldoxime), specific solvent-solute interactions cause changes in Δ oct that in turn, affect the energies of the 1 A 1g → 3 T 1g and 1 A 1g → 3 T 2g transitions. 98 In this case, the band wavelengths do not correlate with any of the solvatochromic parameters discussed earlier.…”