Most surfaces are either static or switchable only between “on” and “off” states for a specific application. It is a challenge to develop reconfigurable surfaces that can adapt to rapidly changing environments or applications. Here, we demonstrate fabrication of surfaces that can be reconfigured for user-defined functions using visible-light-controlled Ru–thioether coordination chemistry. We modify substrates with Ru complex Ru-H2O. To endow a Ru-H2O-modified substrate with a certain function, a functional thioether ligand is immobilized on the substrate via Ru–thioether coordination. To change the surface function, the immobilized thioether ligand is cleaved from the substrate by visible-light-induced ligand dissociation, and then another thioether ligand with a distinct function is immobilized on the substrate. Different thioethers endow the surface with different functions. Based on this strategy, we rewrite surface patterns, manipulate protein adsorption, and control surface wettability. This strategy enables the fabrication of reconfigurable surfaces with customizable functions on demand.
δ-Selective compounds 1 and 2 (DS1, compound 22; DS2, compound 16) were introduced as functionally selective modulators of δ-containing GABA type A receptors (GABAR). In our hands, [H]EBOB-binding experiments with recombinant GABAR and compound 22 showed no proof of δ-selectivity, although there was a minimally higher preference for the α4β3δ and α6β2/3δ receptors with respect to potency. In order to delineate the structural determinants of δ preferences, we synthesized 25 derivatives of DS1 and DS2, and investigated their structure-activity relationships (SAR). Four of our derivatives showed selectivity for α6β3δ receptors (29, 38, 39, and 41). For all of them, the major factors that distinguished them from compound 22 were variations at the para-positions of their benzamide groups. However, two compounds (29 and 39), when tested in the presence of GABA, revealed effects at several additional GABAR. The newly synthesized compounds will still serve as useful tools to investigate α6β3δ receptors.
Controlling the structures and functions of gels is important for both fundamental research and technological applications. Introducing photoresponsive units into gels enables remote control of their properties with light. However, existing gels show photoresponsiveness only at room temperature or elevated temperatures. The development of photoresponsive gels that work below 0 °C can expand their usage in cold environments. Here, photoresponsive metallopolymer organohydrogels that function even at −20 °C are reported. The organohydrogels are prepared using photoresponsive Ru–thioether coordination bonds as reversible crosslinks to form polymer networks. A water/glycerol mixture is used as an anti‐freezing solvent. At −20 °C, the Ru–thioether coordination bonds are dissociated under light irradiation and reformed reversibly in the dark, which result in alternating crosslinking densities in the polymer networks. This process enables inducing reversible gel‐to‐sol transitions, healing damaged gels, controlling the mechanical properties and volumes of the gels, and rewriting microstructures on the gels below 0 °C.
An electrocyclic ring closure is the key step of an efficient one-pot method for the synthesis of pyrrole-2-carboxylates and -carboxamides from chalcones and glycine esters or amides. The 3,4-dihydro-2H-pyrrole intermediates generated in situ are oxidized to the corresponding pyrroles by stoichiometric oxidants or by catalytic copper(II) and air in moderate to high yields. A wide range of functional groups are tolerated, and further combination with an in situ bromination gives access to polyfunctional pyrrole scaffolds.
An elegant combination of supramolecular polymers exhibiting nonlinear topological structures results in a series of brand new, nonlinear supramolecular polymers. Recently, these polymers have attracted increased attention in various fields due to their diverse and advantageous properties. Especially in therapeutic applications, one can take advantage of their unique chemical, physical, and biological properties such as degradability and stimuli‐responsiveness. Due to the large number of possible module modifications, such polymers have great potential as platforms in disease treatments. In this review, the structures, properties, and functions of different nonlinear supramolecular polymers are summarized. Current therapeutic applications are presented and the prospective design trends are discussed for promoting the development of nonlinear supramolecular polymers.
One-Pot Synthesis of Pyrrole-2-carboxylates and -carboxamides via an Electrocyclization/Oxidation Sequence. -(IMBRI, D.; NETZ, N.; KUCUKDISLI, M.; KAMMER, L. M.; JUNG, P.; KRETZSCHMANN, A.; OPATZ*, T.; J. Org. Chem. 79 (2014) 23, 11750-11758, http://dx.
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