Positive/Negative Phototropism: Controllable Molecular Actuators with Different Bending Behavior

<div>Herein, a series of molecular actuators based on the crystals of (E)‐2‐(4‐fluorostyryl)benzo[d]oxazole (BOAF4),</div><div>(E)‐2‐(2,4‐difluorostyryl)benzo[d]oxazole (BOAF24), (E)‐2‐(4‐fluorostyryl)benzo[d]thiazole (BTAF4) and (E)‐2‐</div><div>(2,4‐difluorostyryl)benzo[d]thiazole (BTAF24) showed unprecedented different bending behavior under UV</div><div>irradiation. BOAF4 and BTAF4 bent towards light, whereas BOAF24 and BTAF24 bent away from light.</div><div>Although the chemical structures of these compounds are similar, we found out the F‒H‒C interaction was</div><div>the main driving force for the different molecular packing in the crystals, which led to the positive/negative</div><div>phototropism of the actuators. Moreover, the theoretical calculation was carried out to reveal the mechanical</div><div>properties of the crystals. Taking advantage of the photo responsive property, we achieved the potential</div><div>application in pushing objects, as well as enriching and removing pollutants. This system not only achieved a</div><div>class of molecular actuators with different bending behavior through introducing different number of F atom,</div><div>but also realized pushing and catching behavior within one molecule, which opens a novel gate for crystal</div><div>engineering</div>

Positive/Negative Phototropism: Controllable Molecular Actuators with Different Bending Behavior

<div>Herein, a series of molecular actuators based on the crystals of (E)‐2‐(4‐fluorostyryl)benzo[d]oxazole (BOAF4),</div><div>(E)‐2‐(2,4‐difluorostyryl)benzo[d]oxazole (BOAF24), (E)‐2‐(4‐fluorostyryl)benzo[d]thiazole (BTAF4) and (E)‐2‐</div><div>(2,4‐difluorostyryl)benzo[d]thiazole (BTAF24) showed unprecedented different bending behavior under UV</div><div>irradiation. BOAF4 and BTAF4 bent towards light, whereas BOAF24 and BTAF24 bent away from light.</div><div>Although the chemical structures of these compounds are similar, we found out the F‒H‒C interaction was</div><div>the main driving force for the different molecular packing in the crystals, which led to the positive/negative</div><div>phototropism of the actuators. Moreover, the theoretical calculation was carried out to reveal the mechanical</div><div>properties of the crystals. Taking advantage of the photo responsive property, we achieved the potential</div><div>application in pushing objects, as well as enriching and removing pollutants. This system not only achieved a</div><div>class of molecular actuators with different bending behavior through introducing different number of F atom,</div><div>but also realized pushing and catching behavior within one molecule, which opens a novel gate for crystal</div><div>engineering</div>

Effects on Pinus densiflora Seedlings as Affected by Different Container Growth Conditions

The purpose of this study was to determine the effects that different container conditions have on Pinus densiflora seedling growth. Under greenhouse cultivation, there were no statistical differences observed in plant height and the number of branches; however, significant differences in root collar diameter and root status were observed. In control container growth conditions, the roots grew in an abnormal spiral shape, while in negative phototropism container growth conditions the roots grew in a vertical shape. In outdoor cultivation, seedlings in various container growth conditions showed significant differences. The seedlings that were grown in negative phototropism container growth conditions showed the greatest increases in height, number of branches, root collar diameter, and root growth. This study determined that seedling roots in negative phototropism container growth conditions grew vertically, thus displaying successful rooting when they were transplanted outdoors. This resulted in favorable measurements in height, number of branches, root collar diameter, and root growth.