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Spectroscopic and thermodynamic characterization of a cobalt-verdazyl valence tautomeric system. influence of crystal structure, solvent and counterion.
- Source :
- Dalton Transactions: An International Journal of Inorganic Chemistry; 5/7/2024, Vol. 53 Issue 17, p7536-7545, 10p
- Publication Year :
- 2024
-
Abstract
- Crystallization of the verdazyl-based valence tautomeric ion [Co(dipyvd)<subscript>2</subscript>]<superscript>2+</superscript> (where dipyvd is the radical ligand 1-isopropyl-3,5-di(2'-pyridyl)-6-oxoverdazyl) with a variety of different counterions results in materials that show varying degrees of valence tautomeric (VT) transition in the solid state. The X-ray structure of the SbF<subscript>6</subscript> salt at 150 K reveals a localized structure for the S = 1/2 tautomer, with a Co<superscript>3+</superscript> cation and distinct anionic and radical ligands. Comparison with the structure of the same material at 300 K reveals large structural changes in the ligand as a result of the valence tautomeric equilibrium. Data for the S = 3/2 form is less conclusive; X-ray spectroscopy on the PF<subscript>6</subscript> salt suggests a degree of low spin Co<superscript>2+</superscript> character for the S = 3/2 tautomer at very low temperature though this is inconsistent with EPR data at similar temperatures and structural information at 150 K. Magnetic measurements on the [BAr<superscript>F</superscript><subscript>4</subscript>]<superscript>-</superscript> and triflate salts in organic solvents show that the VT equilibrium is dependent on solvent and ion pairing effects. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 14779226
- Volume :
- 53
- Issue :
- 17
- Database :
- Complementary Index
- Journal :
- Dalton Transactions: An International Journal of Inorganic Chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 177140543
- Full Text :
- https://doi.org/10.1039/d4dt00465e