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Controlling Second Coordination Sphere Effects in Luminescent Ruthenium Complexes by Means of External Pressure
Author(s) -
Pannwitz Andrea,
Poirier Stéphanie,
BélangerDesmarais Nicolas,
Prescimone Alessandro,
Wenger Oliver S.,
Reber Christian
Publication year - 2018
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.201800703
Subject(s) - luminescence , hydrostatic pressure , deprotonation , coordination sphere , ligand (biochemistry) , adduct , chemistry , ruthenium , photochemistry , coordination complex , crystallography , ion , materials science , crystal structure , organic chemistry , biochemistry , physics , receptor , optoelectronics , metal , thermodynamics , catalysis
Two luminescent heteroleptic Ru II complexes with a 2,2′‐biimidazole (biimH 2 ) ligand form doubly hydrogen‐bonded salt bridges to 4‐sulfobenzoate anions in single crystals. The structure of one of these cation‐anion adducts shows that the biimH 2 ligand is deprotonated. Its 3 MLCT luminescence band does not shift significantly under the influence of an external hydrostatic pressure, a behavior typical for these electronic transitions. In contrast, hydrostatic pressure on the other crystalline cation–anion adduct induces a shift of proton density from the peripheral N−H groups of biimH 2 towards benzoate, leading to a pronounced redshift of the 3 MLCT luminescence band. Such a significant and pressure‐tunable influence from an interaction in the second coordination sphere is unprecedented in artificial small‐molecule‐based systems.