In the tilted smectic phases of terthiophenes, shear alignment macroscopically aligns the tilt direction of the director leading to a substantial in-plane anisotropy of charge carrier mobility in organic field effect transistor (OFET) experiments.

The silyl‐protected allylhydropentalenone derivative 9, derived from the Weiss diketone, was functionalized by enantioselective deprotonation in the presence of lithium bis(1‐phenylethyl)amide/LiCl as the chiral base, which was generated in situ from bis(1‐phenylethyl)ammonium chloride [(R,R)‐ or (S,S)‐14] and BuLi, and trapping of the resulting enolate with alkyl halide electrophiles to give pseudo‐C2 or ‐Cs‐symmetrical bicyclo[3.3.0]octanones 10 and 11. The influence of the chiral base and electrophiles on the regioselectivity and double stereodifferentiation was investigated. Taking the double stereocontrol into account, a matched selectivity for the pseudo‐C2 pair (1R,4R)‐10/(1S,4R)‐10 and a mismatched selectivity for the pseudo‐Cs pair (1S,6R)‐11/(1R,6R)‐11 were observed in the presence of (R,R)‐14. The use of (S,S)‐14, however, produced a mismatched selectivity for (1R,4R)‐10/(1S,4R)‐10 and a matched selectivity for (1S,6R)‐11/(1R,6R)‐11 with complementary diastereoselectivity depending on the electrophile. Furthermore, the hydropentalenone derivative 10a provided an alternative route to the bicyclo[3.3.0]octene core of the macrocyclic tetramic acid lactam, cylindramide (5).

Abstract. We present a novel silicon-organic hybrid modulator based on an integrated dual-mode interferometer. The modulator offers a compact, simplified design and enhanced robustness to on-chip fluctuations of temperature compared to conventional Mach-Zehnder based systems. A prototype modulator showing a voltage dependent transmission spectrum is obtained by cladding a dual-mode waveguide in a 250 nm silicon-on-insulator technology with a customized organic electro-optic layer. Estimated phase shifts and corresponding figures of merit are discussed in this contribution. The used organic layer is based on the guest-host approach with customized donor-π -acceptor chromophore embedded and poled in a poly(methylmethacrylate) matrix. The presented prototype is to the best of the authors' knowledge the first integrated single waveguide silicon-organic hybrid modulator.

This study demonstrates that β-branched thiophenes exhibit improved NLO properties and thermal stability for electro-optic applications compared to 1D linear systems.