Cobalt(III) and chromium(III) complexes of N-(2-Aminoethyl)salicylaldimine: Crystal structure and resolution of the racemates

Abstract

The cobalt(III) and chromium(III) complexes of N-(2- aminoethyl)salicylaldimine, M(salen)2+, have been resolved into their optical isomers. The electronic absorption spectra and circular dichroism spectra of the complexes have been measured for solutions in water and ethanol and assignments for the absorption bands proposed. The crystal structure of the racemate, Co(salen)2I,H2O, has been determined from three-dimensional X-ray diffraction data. The crystals are monoclinic, space group P21/c with a 18.386(1), b 10.216(1), c 12.004(1) Ǻ, β 109.87(1)°, Z 4. The structure was solved by the heavy- atom method and refined by least-squares techniques to R 0.098 for 4493 reflections (63.5% observed). The cobalt atom is octahedrally coordinated by two tridentate ligands in the meridional configuration.

Copper(II) Complexes of Tridentate Schiff Bases of 5‐Substituted Salicylaldehydes and Diamines – The Role of the Substituent and the Diamine in the Formation of Mono‐, Di‐ and Trinuclear Species – Crystal Structures and Magnetic Properties

“…Treatment of either the mono-or the dinuclear compounds with NaOH produces the µ 3 -OH trinuclear derivatives according to Equations (9) and (10 (10) Compound 1c requires 2 mol equivalents of NaOH to be transformed into 3c, suggesting a synergic effect of the NO 2 and en bridge that gives special stability to 1c. This reaction gave 3c (and 1d gave 3d) in very low yields, together with some decomposition products.…”

“…[5,6] According to the literature, the half unit species with en or tn and salH are easily obtained by a template synthesis in the presence of metal ions, giving rise to a rich coordination Scheme 2. chemistry. For + , [7] [CrL 2 ] + , [8] [CoL 2 ] + , [9] and [NiL 2 ], [10] whereas in the presence of Cu II , mononuclear Cu II complexes, [CuL(py)] + (1), [11][12][13] can be obtained by performing the reaction in the presence of pyridine or other auxiliary ligands. Compounds X can then be synthesised by reaction of 1 with another salicylaldehyde (Scheme 1).…”

Synthesis, characterization, and thermodynamic studies of cobalt Schiff base complexes with amines

“…They bind to metals in enzymes, classical coordination complexes, and organometallic compounds [33]. Therefore, we tried to investigate the steric and the electronic effects of these bases on their interaction with the newly-synthesized complex, [Co(Salpyr)(PBu 3 …”

“…Many cobalt derivatives have been prepared and investigated, with particular emphasis on the reactivity of the metal ions in the transmethylation reactions and the reversible absorption of molecular oxygen [1][2][3][4][5]. The cobalt complexes with tetradentate Schiff base ligands have been extensively used to mimic cobalamin (B 12 ) coenzymes [6][7][8][9], oxygen carriers and oxygen activators [10][11][12][13], and enantioselective reduction [14].…”

When the Metal Makes the Difference: Template Syntheses of Tridentate and Tetradentate Salen-Type Schiff Base Ligands and Related Complexes

“…Other metal ions that favor an octahedral coordination, such as iron(III) [107][108][109][110], chromium(III) [111][112][113][114][115][116][117], and cobalt(III) [44,85,[116][117][118][119][120][121][122][123][124][125][126], are known to show a reactivity for obtaining [M( G L) 2 ](X) species with various X − anions, similarly to nickel(II). Differently from before, these metals allow to obtaining N 2 O tridentate Schiff base ligands with diamines bearing two carbon atoms connecting the amine groups (en, pn, etc.…”