A novel series of blue emitting silylene-spaced diphenylanthracene derivatives have been synthesized and characterized. The rhodium-catalyzed hydrosilylation of bis[4-(dimethylsilyl)phenyl]anthracene 3-4 yielded stable 9,10-disubstituted (E)-divinylsilylene-diphenylanthracene products 7-10 and salt elimination reaction of bis[4-(chlorodimethylsilyl)phenyl]anthracene 5-6 gave 9,10-disubstituted disilyldiphenylanthracene compounds 11-14. They are fluorescent in the blue region with good quantum efficiencies. The rhodium-catalyzed polyaddition including 2-tert-butyl-9,10-bis[4-(dimethylsilyl)phenyl]anthracene (4) afforded the nonconjugated copolymer 15. 相似文献
In the framework of density functional theory(DFT), we have studied the electronic properties of alkene/alkynehydrosilylated silicon nanocrystals(Si NCs) in the size range from 0.8 nm to 1.6 nm. Among the alkenes with all kinds of functional groups considered in this work, only those containing –NH2and –C4H3S lead to significant hydrosilylationinduced changes in the gap between the highest occupied molecular orbital(HOMO) and the lowest unoccupied molecular orbital(LUMO) of an Si NC at the ground state. The quantum confinement effect is dominant for all of the alkenehydrosilylated Si NCs at the ground state. At the excited state, the prevailing effect of surface chemistry only occurs at the smallest(0.8 nm) Si NCs hydrosilylated with alkenes containing –NH2and –C4H3S. Although the alkyne hydrosilylation gives rise to a more significant surface chemistry effect than alkene hydrosilylation, the quantum confinement effect remains dominant for alkyne-hydrosilylated Si NCs at the ground state. However, at the excited state, the effect of surface chemistry induced by the hydrosilylation with conjugated alkynes is strong enough to prevail over that of quantum confinement. 相似文献
Smart surfaces presenting both antifouling molecules with a charged functional group at their distal end, and molecules that are terminated by RGD peptides for cell adhesion, were fabricated and characterized (see picture). By applying potentials of +300 or -300?mV, the surfaces could be dynamically switched to make the peptide accessible or inaccessible to cells. 相似文献
Not copy and paste: Although β-diketiminato ligands have been employed for the stabilization of Ge(II) and Sn(II) hydrides, the corresponding Si(II) hydride is not accessible. However, coordination of silicon(II) to a {Ni(CO)(3)} fragment allowed the isolation of the first Si(II) hydride metal complex 1. This complex was used for the first silicon(II)-based and Ni(0)-mediated, stereoselective hydrosilylation of alkynes. R = phenyl, tolyl. 相似文献
The combination of ZnEt2 and chiral pyridinebisoxazoline (pybox) or pyridinebisimidazoline (pybim) ligands catalyzed the asymmetric hydrosilylation of aryl, alkyl, cyclic, heterocyclic, and aliphatic ketones. Under mild conditions, high yields and good enantioselectivities were achieved. ESI measurements allowed for the characterization of the active catalyst. 相似文献
A facile two‐step synthesis for branched poly(isoprene)s (PI) based on polyaddition of ABn‐type macromonomers is described. The synthesis of the macromonomers was achieved by anionic polymerization of isoprene and subsequent end‐capping of the polymers by addition of chlorodimethylsilane to the living carbanions. This led to PI‐based macromonomers with narrow polydispersity ( / < 1.15) and molecular weights in the range of 1 700 – 22 100 g · mol−1. Synthesis of the branched polymers was carried out by a hydrosilylation‐based polymerization of the macromonomers. Characterization via SEC, SEC‐MALLS, coupled SEC‐viscosimetry and 1H‐NMR‐spectroscopy supported the formation of branched structures. Interestingly, these branched polymers exhibited α‐values that were similar to those reported for hyperbranched polymers based on AB2‐monomers.
The rare-earth metal complexes Ln( L1 )[N(SiHMe2)2](thf) (Ln=La, Ce, Y; L1 =N,N′′-bis(pentafluorophenyl)diethylenetriamine dianion) were synthesized by treating Ln[N(SiHMe2)2]3(thf)2 with L1 H2. The lanthanum and cerium derivatives are active catalysts for the hydrosilylation of benzophenone derivatives with HN(SiHMe2)2. An amine-exchange reaction was revealed as a key step of the catalytic cycle, in which Ln−Si−H β-agostic interactions are proposed to promote insertion of the carbonyl moiety into the Si−H bond. 相似文献