Carlos

Star-shaped oligophenylenevinylene (OPV) mesogens are shape-persistent and possess formally large void space. A mesogen with three styrene repeating units packs densely in a columnar helical arrangement. Attachment of one fullerene through a short spacer results in an exceptional increase of the mesophase stability. X-ray scattering and modeling evidence a triple-helical arrangement in which the fullerene perfectly fills the void space between the arms of the star mesogen.

Come into my arms: Stilbenoid star-shaped mesogens pack densely, in helical structures that have a short correlation length, in columnar liquid-crystal phases. Attaching a fullerene guest to the interior of the star fills the void space between the arms and considerably increases the mesophase stability by approximately 70 °C. The stabilization is the result of the formation of a fullerene triple helix.

The preparation of highly water-soluble and strongly fluorescent diketopyrrolopyrrole (DPP) dyes using an unusual taurine-like sulfonated linker has been achieved. Exchanging a phenyl for a thienyl substituent shifts the emission wavelength to near λ=600 nm. The free carboxylic acid group present in these new derivatives was readily activated and the dyes were subsequently covalently linked to a model protein (bovine serum albumin; BSA). The bioconjugates were characterized by electronic absorption, fluorescence spectroscopy and MALDI-TOF mass spectrometry, thus enabling precise determination of the labeling density (ratio DPP/BSA about 3 to 8). Outstanding values of fluorescence quantum yield (30 % to 59 %) for these bioconjugates are obtained. The photostability of these DPP dyes is considerably greater than that of fluorescein under the same irradiation conditions. Remarkably low detection limits between 80 and 300 molecules/μm² were found for the BSA bioconjugates by fluorescence imaging with a epifluorescence microscope.

All-in-one solution! A simple but very effective synthetic strategy to make diketopyrrolopyrrole (DPP) dyes water-soluble and highly fluorescent in aqueous media for bioconjugation to proteins is presented. Bovine serum albumin-DPP conjugates with unprecedentedly high quantum yields were obtained, thus enabling detection of minute amounts of fluorescent proteins through epifluorescence microscopy.

Ordered open channels found in two-dimensional covalent organic frameworks (2D COFs) could enable them to adsorb carbon dioxide. However, the frameworks’ dense layer architecture results in low porosity that has thus far restricted their potential for carbon dioxide adsorption. Here we report a strategy for converting a conventional 2D COF into an outstanding platform for carbon dioxide capture through channel-wall functionalization. The dense layer structure enables the dense integration of functional groups on the channel walls, creating a new version of COFs with high capacity, reusability, selectivity, and separation productivity for flue gas. These results suggest that channel-wall functional engineering could be a facile and powerful strategy to develop 2D COFs for high-performance gas storage and separation.

Efficient CO₂ capture is achieved by converting a conventional two-dimensional covalent organic framework (COF) to an outstanding CO₂ capture material with large capacity and high selectively. The nanopore walls are chemically engineered with functional groups in a controlled manner to enhance interactions with CO₂, leading to the development of a new general way to design COFs for gas storage and separation.

An experimental and theoretical study of the first compound featuring a SiP bond to a two-coordinate silicon atom is reported. The NHC-stabilized phosphasilenylidene (IDipp)SiPMes* (IDipp=1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene, Mes*=2,4,6-tBu₃C₆H₂) was prepared by SiMe₃Cl elimination from SiCl₂(IDipp) and LiP(Mes*)SiMe₃ and characterized by X-ray crystallography, NMR spectroscopy, cyclic voltammetry, and UV/Vis spectroscopy. It has a planar trans-bent geometry with a short SiP distance of 2.1188(7) Å and acute bonding angles at Si (96.90(6)°) and P (95.38(6)°). The bonding parameters indicate the presence of a SiP bond with a lone electron pair of high s-character at Si and P, in agreement with natural bond orbital (NBO) analysis. Comparative cyclic voltammetric and UV/Vis spectroscopic experiments of this compound, the disilicon(0) compound (IDipp)SiSi(IDipp), and the diphosphene Mes*PPMes* reveal, in combination with quantum chemical calculations, the isolobal relationship of the three double-bond systems.

An NHC-stabilized phosphasilenylidene was obtained from SiCl₂(IDipp) (IDipp=1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene) and LiP(Mes*)(TMS) (Mes*=2,4,6-tBu₃C₆H₂). The compound was characterized by various experimental and theoretical methods and compared with those of the isolobal congeners (IDipp)SiSi(IDipp) and Mes*PPMes*.