Expedient Synthesis of Symmetric Aryl Ketones and of Ambient-Temperature Molten Salts of Imidazole

Abstract

A short procedure for the synthesis of 2,2-di(3-thienyl)-1,3-dioxolan is described. The route developed is convenient (only two synthetic and one chromatographic steps are required) and efficient (66% overall yield from 3-bromothiophene). This compound was transformed into the ketone, cyclopenta [2,1-b:3',4'-b']dithiophen-4-one by a known process. Optimized syntheses of symmetric aryl ketones, 1-alkyl-3-methylimidazolium and 1-alkyl-2-methyl-3-methylimidazolium liquid salts are also reported.Electrochemical capacitors are energy conversion devices which consist of two active electrode materials that are in contact with an appropriate electrolyte. 1 First, electronically conducting polymers such as polythiophene derivatives, have recently received some attention as electrode materials due to their potentially high power densities which originate from fast redox switching (e.g. fast ionic transport). 2 Second, conventional liquid solvent-salt and polymer-salt were used as electrolyte (to insure ionic conduction between the two polymer electrodes) in these capacitors. 2 Thiophene derivatives are among the most widely investigated model compounds for electrically conducting material since they give rise to polymers which may be both p-and n-type doped. 2-7 Within this family of polymers, poly(cyclopenta[2,1-b:3',4'-b']dithiophen-4-one, (CDT) 5, introduced by Lambert and Ferraris, 8 stands out for its electrochemical properties, high stability in the conducting state and propensity to multiple redox cycling, making it a stable p-and n-dopable conductor suitable for application as supercapacitors composites as we have recently shown. 9 Roncali et al. have also reported that the polymer obtained from the 1,3-dioxolane derivative of the title compound 5 displayed similar electrochemical properties. 10 Since, many of the precursors of small band gap conducting polymers are substituted-4-methylidene derivatives of 5, 4,9-16 ketone 5 is an important intermediate in the synthesis of a variety of low band gap conducting polymers. 17On the other hand, room-temperature ionic liquids have also attracted interest as solvents for synthesis and catalysis applications, which have recently been reviewed. 18 These liquid salts can replace classic organic solvents which may be volatile and/or hazardous. Much of the progress realized to date render these room-temperature molten salts more stable, chemically and thermally. These liquids are entirely composed of ions and in this state, they resemble the ionic melts which are generally produced by heating normal metallic salts such as sodium chloride to high temperature (e.g. NaCl to over 800°C). Some other useful features of these ionic liquid systems include the greater solubilities of organic species, the prevalence of high coulombic forces resulting in the absence of any significant vapor pressure and the availability of air and moisture stable, water immiscible ionic liquids (e.g. imidazolium salts of PF 6 -or BF 4 -). Such systems are able media for the development of completely nove...

Thermally-Induced Spin Crossover and LIESST Effect in the Neutral [FeII(Mebik)2(NCX)2] Complexes: Variable-Temperature Structural, Magnetic, and Optical Studies (X = S, Se; Mebik = bis(1-methylimidazol-2-yl)ketone)

“…The Me bik ligand was synthesized according to a literature procedure (Lucas et al, 2000). Commercially available chemicals including KSCN, KSeCN, and Fe(SO 4 ) .…”

Ferrocenyl compounds possessing protected phenol and thiophenol groups: Synthesis, X-ray structure, and in vitro biological effects against breast cancer

“…(4-Bromo)phenyl-tbutylthioether [30], propionyl ferrocene [31], 4,4 0 -bis (t-butylthio)benzophenone [32], and 4,4 0 -bis(methylthio) benzophenone [32] were synthesized according to procedures found in the literature. Chart …”

β-Amino functionalization of cinnamic Weinreb amides in ionic liquid

“…The ionic liquid [BMIM][NTf 2 ] was readily prepared by reacting 1-methylimidazole with n -butyl bromide [41–43], followed by anion metathesis using N -lithiotrifluoromethanesulfonimide in acetone solution. The resulting ionic liquid, [BMIM][NTf 2 ], was carefully dried by heating at 60 °C in vacuum, then confirmed by 1 H NMR analysis [44]. All aminochlorination reactions were performed in oven-dried vials.…”