Microwave-assisted synthesis of novel imidazolium-based ionic liquid crystalline dimers

Microwave promoted synthesis of novel imidazolium-based ionic liquid crystalline dimers containing calamitic-calamitic, calamitic-discotic and discotic-discotic moieties is reported. Classical reactions failed to produce these dimers. The thermotropic liquid crystalline properties of these salts were investigated by polarizing optical microscopy, differential scanning calorimetry and X-ray diffractometry. These salts, except the one having calamitic-discotic units, with bromide as counter ion were found to be mesomorphic over a wide temperature range.