Hydrogen bonded liquid crystalline heterodimers incorporating alkoxystilbazoles and alkoxy-4-pyridones

<div><p>The preparation and characterisation of a series of hydrogen bonded liquid crystalline dimers containing benzoic acid, alkanoic acid and phenol donors and alkoxy-stilbazole or alkoxy-4-pyridone hydrogen bond acceptors are reported. These heterodimers possess strong intermolecular donor–acceptor hydrogen bonding. The heterodimers, as well some of the individual components used in their preparation, possess liquid crystalline phases.</p></div

Synthesis and characterisation of laterally substituted noncentrosymmetric main chain hydrogen-bonded polymers

<div><p>A series of laterally substituted noncentrosymmetric hydrogen-bonded liquid crystalline polymers which incorporate stilbazole acceptor units, alkyl or ethylene glycol linkers units, and benzoic acid or phenol donor units were prepared and investigated for their hydrogen bonding behaviour and phase transitions. Fourier transform infrared (FTIR) indicated that these polymers possess strong intermolecular donor–acceptor hydrogen bonding. These polymers have lower melting points than their non-substituted analogue, and some of the polymers are mesomorphic.</p></div

pH-Dependent Si-Fluorescein Hypochlorous Acid Fluorescent Probe: Spirocycle Ring-Opening and Excess Hypochlorous Acid-Induced Chlorination

We report the synthesis and characterization of a fluorescent probe (Hypo-SiF) designed for the detection of hypochlorous acid (HOCl) using a silicon analogue of fluorescein (SiF). The probe is regulated in an “off–on” fashion by a highly selective thioether spirocyclic nonfluorescent structure that opens to form a mixture of fluorescent products in the presence of HOCl. Over a range of pH values, the probe reacts with a stoichiometric amount of HOCl, resulting in a mixture of two pH-dependent fluorescent species, a SiF disulfide product and a SiF sulfonate product. The unique colorimetric properties of the individual SiF fluorophores were utilized to perform simultaneous detection of HOCl and pH. When an excess of HOCl is present, the SiF fluorophores become chlorinated, via an intermediate halohydrin, resulting in a more pH independent and red-shifted fluorophore