52279-45-5Relevant articles and documents
Heteronuclear Iron(III)-Schiff Base Complexes with the Hexacyanidocobaltate(III) Anion: On the Quest to Understand the Governing Factors of Spin Crossover
?alitro?, Ivan,Fuhr, Olaf,Masárová, Petra,Nemec, Ivan,Pavlik, Ján,Ruben, Mario
, (2020)
Two heteronuclear compounds (1 and 2) containing three ferric centers linked in facial-like mode with the magnetically silent hexacyanidocobaltate(III) anion were prepared and studied. The structural investigation revealed that both compounds are tetranuclear complexes with molecular formulas of [{Fe(L1)NC}3Co(CN)3]·2CH3OH·2.5CH3CN (1) and [{Fe(L2)NC}3Co(CN)3]·2H2O·1CH3OH (2). The magnetic properties of both complexes are controlled by the molecular design of the corresponding pentadentate Schiff base anions L12- and L22-. While compound 2 with a symmetric ligand prepared from salicylaldehyde shows high-spin state properties, compound 1 containing the asymmetric ligand with naphthalene units either is low-spin in its solvated form or shows a gradual but hysteretic spin crossover event when desolvated. The magnetic behavior was analyzed with respect to the Ising-like model and spin Hamiltonian, respectively, and the results were confronted with ab initio calculations. Additionally, the influence of structural features, lattice solvent molecules, the distribution of electronic terms, and active orbitals on the spin state properties of reported complexes is discussed.
A new polymorph of a cobalt(III) Schiff base complex exhibits a one-dimensional C - H...O hydrogen-bonded extended structure with helical 21 symmetry
Munro, Orde Q.,Govender, Santham
, p. m150-m152 (2007)
In a new polymorph of acetato(2,2′-{imino-bis[(E)-propane-3,1- diylnitrilo-methyl-idyne]}diphenol-ato)-cobalt(III), [Co(C20H23N3O2)(C2H3O2)], in the space group P21/c, the CoIII ion is six-coordinate, with unequal Co - Ophenolate distances that average 1.908 (12) A and more similar Co - Nimine distances averaging 1.937 (4) A. The acetate ion occupies the sixth coordination site and forms an intra-molecular hydrogen bond (H...O = 1.95 A) with the Co-bound NH group of the penta-dentate chelate. The extended structure is a one-dimensional (aryl)C - H...O(carbonyl) hydrogen-bonded polymer with 21 (helical) symmetry and is thus distinct from the simple hydrogen-bonded stack of the P21/n polymorph [Matsumoto, Imaizumi & Ohyoshi (1983). Polyhedron, 2, 137-139]. International Union of Crystallography 2007.
STERIC AND ELECTRONIC EFFECTS OF LIGAND VARIATION ON COBALT DIOXYGEN CATALYSTS
Corden, Barry B.,Drago, Russel S.,Perito, Richard P.
, p. 2903 - 2907 (2007/10/02)
We report herein the observation that electronic and steric factors of cobalt dioxygen complexes with systematically derivatized pentadentate Schiff-base ligands affects their ability to catalyze the oxidation of sustituted phenols and alter the rate of catalyst decomposition.The electronic and steric factors can be separated sufficiently to indicate that the activity of the cobalt dioxygen catalyst roughly parallels the trends in basicity of the bound O2 suggested by EPR cobalt hyperfine coupling constants of the adducts and predicted from the electronic effects of substituents.
