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Multifunctional Ionic Liquids from Rhodium(I) Isocyanide Complexes: Thermochromic, Fluorescence, and Chemochromic Properties Based on Rh−Rh Interaction and Oxidative Addition
Author(s) -
Tominaga Takumi,
Mochida Tomoyuki
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.201800333
Subject(s) - thermochromism , chemistry , isocyanide , rhodium , ionic liquid , dimer , iodide , bathochromic shift , oxidative addition , iodine , photochemistry , fluorescence , inorganic chemistry , medicinal chemistry , organic chemistry , catalysis , physics , quantum mechanics
Square‐planar rhodium(I) isocyanide complexes exhibit unique chemical reactivities such as the formation of Rh−Rh bonds and oxidative addition. This paper details the syntheses and properties of multifunctional ionic liquids containing Rh I isocyanide complexes [Rh( n BuNC) 4 ]X (X=Tf 2 N (=N(SO 2 CF 3 ) 2 − ), Nf 2 N (=N(SO 2 C 4 F 9 ) 2 − ), FSA (=N(SO 2 F) 2 − ), CF 3 BF 3 − ). Salts with Tf 2 N and Nf 2 N were liquids, whereas those with FSA and CF 3 BF 3 were solids at room temperature. The salts exhibited thermochromism in the liquid state, changing from orange at high temperatures to blue‐purple at lower temperatures. This is based on the equilibrium between monomer, dimer, and other oligomers associated with Rh−Rh bond formation. The salts also exhibited fluorescence. Exposure of the Tf 2 N salt to methyl iodide vapor produced ionic liquid mixtures [Rh( n BuNC) 4 ] x [Rh( n BuNC) 4 IMe] (1− x ) [Tf 2 N], concomitant with a color change from purple to red, orange, and yellow, extending the thermochromic color range. The reaction of the Tf 2 N salt and iodine produced mononuclear and polynuclear iodine adducts. Thus, these liquids exhibit thermochromism, fluorescence, vapochromism, chemical reactivities, and characteristic properties of ionic liquids.