Chemical-stimuli-controllable circularly polarized luminescence from anion-responsive π-conjugated molecules.

Introduction of a BINOL-boron moiety to dipyrrolyldiketones as precursors of anion-responsive π-conjugated molecules results in the formation of a chiral environment in the form of anion-free receptors and anion-binding complexes. Conformation changes by inversion (flipping) of two pyrrole rings as a result of anion binding can control the chiroptical properties of the anion receptors. In particular, appropriate pyrrole ß-substituents induce distorted receptor π-planes and, as a result, give larger circularly polarized luminescence (CPL), which can be tuned by chemical stimuli (anions). This is the first example of chemical-stimuli-responsive CPL properties.

Hydrogen ion beam transport in an energy range lower than 50 eV: Ion beam species.

Low energy beam transport in the energy range below 50 eV is studied using a compact ion source with a high temperature tungsten cathode that can be put into a vacuum system. A 2.6 cm diameter, 5.2 cm long compact ion source successfully produced more than 2.4 nA beam of H2 + ions at 50 eV beam energy. The source also supplied a stable beam of H3 + ions at 2.5 eV energy with more than 100 pA mass-separated current. The inside wall of the ion source was covered by thin sheets of titanium, nickel, and molybdenum to see if the species composition of the ion beam can be controlled by changing the ion source wall material. Usually, the H2 + ion peak was the highest in the mass spectrum, and the H2 + ion ratio (H2 +/Hn +) was measured for a source operation with hydrogen gas. The ion species ratio drifted against time, and Mo showed the most stable ion ratio.

Positive and negative hydrogen ion reflections of low-energy atomic and molecular hydrogen ion beam from HOPG and Mo surfaces.

Positive and negative hydrogen ion reflections from surfaces by injecting singly charged hydrogen ion beams show a clear difference between atomic and molecular ion injections at low energy and grazing incidence. The intensity ratio of reflected negative to positive ions H-/H+ increased as the incident beam energy per nucleon decreased only when molecular ion beams are injected. It implies that negative ions are more produced upon beam-surface interaction when molecules are injected. A possible reason was discussed in terms of difference in the negative ion production processes between atomic and molecular ions.

Charge-based and charge-free molecular assemblies comprising π-extended derivatives of anion-responsive acyclic oligopyrroles.

Assemblies comprising anion complexes of π-extended oligopyrrole derivatives and counter cations, as well as those of anion-free receptor molecules, exhibited the formation of mesophases based on columnar structures using electrostatic and π-π interactions.