Details

Autor(en) / Beteiligte

• Cioncoloni, Giacomo
• Senn, Hans M
• Sproules, Stephen
• Wilson, Claire
• Symes, Mark D

Titel

The electronic and solvatochromic properties of [Co(L)(bipyridine)2]+ (L = o-catecholato, o-benzenedithiolato) species: a combined experimental and computational studyElectronic supplementary information (ESI) available: 1H NMR spectra of complexes 1-3, additional EPR, PXRD, TGA, computational and UV-vis results and crystallographic data for complex 2. CCDC 1452332. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6dt02807a

Erscheinungsjahr

2016-10

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Complexes of Co( iii ) containing mixed chelating diimine and o -quinone ligand sets are of fundamental interest on account of their fascinating magnetic and electronic properties. Whilst complexes of this type containing one diimine and two o -quinone ligands have been studied extensively, those with the reverse stoichiometry (two diimines and one o -quinone) are much rarer. Herein, we describe a ready route to the synthesis of the complex [Co III ( o -catecholate) (2,2′-bipyridine) 2 ] + ( 1 ), and also report the synthesis of [Co III ( o -catecholate)(5,5′-dimethyl-2,2′-bipyridine) 2 ] + ( 2 ) and [Co III ( o -benezenedithiolate)(5,5′-dimethyl-2,2′-bipyridine) 2 ] + ( 3 ) for the first time. Spectroscopic studies show that complex 2 displays intriguing solvatochromic behaviour as a function of solvent hydrogen bond donation ability, a property of this type of complex which has hitherto not been reported. Time-dependent density function theory (TD-DFT) shows that this effect arises as a result of hydrogen bonding between the solvent and the oxygen atoms of the catecholate ligand. In contrast, the sulfur atoms in the benzenedithiolate analogue 3 are much weaker acceptors of hydrogen bonds from the solvent, meaning that complex 3 is only very weakly solvatochromic. Finally, we show that complex 2 has some potential as a molecular probe that can report on the composition of mixed solvent systems as a function of its absorbance spectrum. Complexes of Co( iii ) containing mixed chelating diimine and o -quinone ligand sets are of fundamental interest on account of their fascinating magnetic and electronic properties.