The first (ferrocenylmethyl)imidazolium and (ferrocenylmethyl)triazolium room temperature ionic liquids.
N-(Ferrocenylmethyl)imidazole (3a), 1-(ferrocenylmethyl)-1,2,4-triazole (3b), 1,1'-bis[(1H-imidazol-1-yl)methyl]ferrocene (8a), 1,1'-bis([1H-(2-methyl)imidazol-1-yl]methyl]ferrocene (8b), and 1,1'-bis[(1H-1,2,4-triazol-1-yl)methyl]ferrocene (8c) were synthesized in moderate yields. These compounds were quaternized with methyl iodide to form 1-(ferrocenylmethyl)-3-methylimidazolium iodide (4a), 1-(ferrocenylmethyl)-4-methyl-1,2,4-triazolium iodide (4b), 1,1'-bis([1-(2,3-dimethyl)imidazolium]methyl)ferrocene diiodide (9b), and 1,1'-bis([1-(4-methyl)-1,2,4-triazolium]methyl)ferrocene diiodide (9c), respectively, in excellent yields. Compounds 4a, 4b, 9b, and 9c were metathesized with bis(trifluoromethanesulfonyl)amide to give high yields of 5a, 5b, 10b, and 10c. With potassium hexafluorophosphate, 9b forms 10d. Salts 5a, 5b, and 10c are the first room-temperature ionic liquids with cations containing an organometallic moiety that exhibit T(g) values well below room temperature, i.e., -32, -16, and -11 degrees C. The compounds were characterized by (1)H, (19)F, and (13)C NMR, MS, and elemental analyses. T(g) values and melting points were determined by DSC. T(d) values (5% weight loss temperature) were recorded by TGA. X-ray single-crystal structures show that 9c and 10d crystallize in the triclinic space group P.
Gao
Ye
Y
Department of Chemistry, University of Idaho, Moscow, ID 83844-2343, USA.
Twamley
Brendan
B
Shreeve
Jean'ne M
JM