Transcription of Chirality from Metal-Organic Framework to Polythiophene.

Here, we report an unprecedented chirality transfer from a metal-organic framework (MOF) to a polymer. In this work, unsubstituted polythiophene (PTh) was prepared in the nanochannels of a chiral MOF. Circular dichroism spectroscopy revealed that nanoconfinement of the polymer chains could endow optically inactive PTh with a chiral nature. The thickness of polymer chain assemblies could be controlled by tuning the loading amount of PTh, which resulted in a drastic change in the chiroptical properties. Note that PTh liberated from the host still exhibited chirality even without the chiral support. Remarkably, the recovered PTh presented high thermal stability of chirality up to 250 °C. Our findings show that the encapsulation of the polymer chains in chiral MOFs is a simple and effective methodology not only to express the chirality of polymers but also to elucidate the inter- and intrachain chirality in polymer assemblies.

Spiral Eu(iii) coordination polymers with circularly polarized luminescence.

A spiral-type chiral Eu(iii) coordination polymer showed strong luminescence (emission quantum yield Φf-f = 57% and photosensitized energy transfer efficiency ηsens = 53%) and effective CD and CPL properties (gCPL = 0.17) when compared with a mono-nuclear chiral Eu(iii) complex in the solid state (Φf-f = 36%, ηsens = 14%, and gCPL = 0.09).

Pulsed laser induced heat transfer from a phthalocyanine-based thin film to a Bi, Al-substituted DyIG substrate: photothermal demagnetization observed by magnetic circular dichroism and numerical analysis.

We have investigated the demagnetization of a ferrimagnetic substrate, Bi, Al-substituted dysprosium iron garnet (Bi0.8Dy2.2Fe4.3Al0.7O12), based on selective pulsed laser irradiation of a molecular thin film consisting of µ-oxo-bis[hydroxyl{2,9(or 10),16(or 17),23(or 24)-tetra-tert-butylphthalocyanato}silicon] ((SiPc)2) and poly(vinylidene fluoride), and succeeded in reproducing photothermal energy transfer from a molecular thin film to an inorganic magnetic substrate in a submicrometer-order and a submicrosecond time scale using numerical analysis. After the instant temperature rise due to nanosecond pulsed laser irradiation of the (SiPc)2-based film, followed by heat transfer from the film to the neighboring magnetic substrate, demagnetization of the magnetic substrate was spectroscopically monitored by the decrease in its magnetic circular dichroism (MCD) intensity. The MCD intensity decreased with increasing pulsed laser energy, which reflects the fact that the submicrometer-order region of the substrate was demagnetized as a result of temperature rise reaching high Curie temperature. This heat transfer phenomenon resulting in the demagnetization of the magnetic substrate was numerically analyzed in a submicrometer-order and a submicrosecond time scale using the finite difference method: the demagnetized regions were calculated to be the same order of magnitude as those experimentally evaluated. These results would provide a more detailed understanding of photothermal energy transfer in organic-inorganic hybrid materials, which would be useful for developing photofunctional materials.