Premium
Localized Mixed‐Valence and Redox Activity within a Triazole‐Bridged Dinucleating Ligand upon Coordination to Palladium
Author(s) -
Broere Daniël L. J.,
Plessius Raoul,
Tory Joanne,
Demeshko Serhiy,
de Bruin Bas,
Siegler Maxime A.,
Hartl Frantisek,
van der Vlugt Jarl Ivar
Publication year - 2016
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201601900
Subject(s) - chemistry , non innocent ligand , ligand (biochemistry) , bridging ligand , redox , triazole , crystallography , photochemistry , stereochemistry , inorganic chemistry , crystal structure , organic chemistry , biochemistry , receptor
Abstract The new dinucleating redox‐active ligand ( L H4 ), bearing two redox‐active NNO‐binding pockets linked by a 1,2,3‐triazole unit, is synthetically readily accessible. Coordination to two equivalents of Pd II resulted in the formation of paramagnetic ( S = 1 / 2 ) dinuclear Pd complexes with a κ 2 ‐ N , N′ ‐bridging triazole and a single bridging chlorido or azido ligand. A combined spectroscopic, spectroelectrochemical, and computational study confirmed Robin–Day Class II mixed‐valence within the redox‐active ligand, with little influence of the secondary bridging anionic ligand. Intervalence charge transfer was observed between the two ligand binding pockets. Selective one‐electron oxidation allowed for isolation of the corresponding cationic ligand‐based diradical species. SQUID (super‐conducting quantum interference device) measurements of these compounds revealed weak anti‐ferromagnetic spin coupling between the two ligand‐centered radicals and an overall singlet ground state in the solid state, which is supported by DFT calculations. The rigid and conjugated dinucleating redox‐active ligand framework thus allows for efficient electronic communication between the two binding pockets.