RESUMO
Toward photocontrol of anion transport across the bilayer membrane, stiff-stilbene, which has dimethyl substituents in the five-membered rings, is functionalized with amidopyrrole units. UV-vis and 1H NMR studies show high photostability and photoconversion yields. Where the photoaddressable (E)- and (Z)-isomers exhibit comparable binding affinities, as determined by 1H NMR titrations, fluorescence-based transport assays reveal significantly higher transport activity for the (Z)-isomers. Changing the binding affinity is thus not a necessity for modulating transport. Additionally, transport can be triggered in situ by light.
RESUMO
Molecular photoswitches that offer simultaneous precise control over geometrical and electronic changes are rare yet highly sought tools for the development of responsive nanosystems. Here we present such an advantageous combination of property control within a novel multiphotoswitch architecture. Hemithioindigo-based trioxobicyclononadiene (HTI-TOND) offers a rigid three-dimensional molecular structure that undergoes different exotic rearrangement reactions upon photochemical and thermal signaling. Three to four different states with distinct geometric and electronic properties can be accessed reversibly in high yields within this molecular framework. Thus, a highly promising and unique switching tool has become available to instill the next level of addressability at the smallest scales.
RESUMO
Ph3 Laâ 5 LiCl and the related (m-xylyl)3 Laâ 5 LiCl were used as Hal/La exchange reagents (Hal=Br, I) for the preparation of various triaryl- and triheteroaryl-lanthanum derivatives. These new exchange reagents are compatible with isoquinolines and some functional groups such as a nitrile or an ester. The reactivity of the resulting lanthanum compounds towards electrophiles, such as ketones, aldehydes, N,N-dimethylamides, and primary alkyl halides was investigated. Additionally, a Pd-catalyzed cross-coupling procedure with aryl bromides was developed.