Precious particles: Dicyanoargentate(I) and dicyanoaurate(I) salts of an imidazolium cation form both crystalline (see structure and enlargement of the cation and anion) and smectic‐A phases. Electrodeposition from the ionic liquid crystals provides a novel route to silver particles and gold nanoparticles.

The preparation of chloride (1(n)) and bromide (2(n)) derivatives of 1-methyl-3-[3,4-bis(alkoxy)benzyl]-4H-imidazolium with n = 6, 12, 16, 18 is described. The two series of salts possess a rich thermotropic mesomorphism, chain-length dependent. Thus, a lamellar smectic A phase, a bicontinuous cubic Ia3d phase, and a columnar hexagonal liquid crystalline mesophase are induced as a function of increasing chain length. The mesomorphic properties were studied by polarizing optical microscopy, differential scanning calorimetry, and X-ray diffraction, and with the support of dilatometry and molecular dynamics, models for the various supramolecular arrangements of the salts are proposed. Such cationic amphiphiles were expected to be candidate molecules to design a new delivery reagent for nucleic acid transfection, particularly for short interfering RNA (siRNA). The use of an RNA interference mechanism, by introduction into cells by transfection of chemically synthesized siRNAs, is a powerful method for gene silencing studies. To exploit the potential of these amphilic imidazolium salts, these molecules were formulated with cohelper lipids and tested for their efficacy to deliver active siRNAs. Our results show high transfection efficacy of our formulated compounds and high silencing efficiency with more than 80% inhibition of the targeted gene at 10 nM siRNA concentration. Taken together our results show the potency of amphiphilic imidazolium salts as a new generation of transfection reagents for RNA interference.

The new ionic liquid crystal 1-(4-dodecyloxybenzyl)-3-methyl-1H-imidazol-3-ium bromide has been synthesized and its X-ray structure obtained; various salts containing BF 4 À , SCN À , PF 6 À , CF 3 SO 3 À Scheme 2 Synthesis of the bromide 1a. Reaction conditions: (i) DMF, K 2 CO 3 , BrC 12 H 25 , 60 1C, overnight; (ii) LiAlH 4 , THF, 4 h; (iii) SOBr 2 , DCM; dry THF, methylimidazole under inert atmosphere. Scheme 1 1-(4-Dodecyloxybenzyl)-3-methyl-1H-imidazol-3-ium salts.