Photoefficient 2nd generation molecular motors responsive to visible light.

Molecular motors that operate with high efficiency using visible light are attractive for numerous applications. Here the synthesis and characterisation of three novel visible light switchable 2nd generation molecular motors is presented. Two of them are based on push-pull systems with the third one possessing an extended π-system. With a maximum effective excitation wavelength of 530 nm we designed the most red-shifted artificial rotary motor known to date. All three motors benefit from efficient switching to the metastable isomer, high quantum yields and excellent photostability setting them apart from visible light switchable motors reported previously. The activation barriers of the rate-determining thermal helix inversion could be accurately predicted using DFT calculations and differences between the motors can be explained by distinct transition state structures. Enantiomers of push-pull motors were successfully separated and their helical twisting power in E7 liquid crystals was determined.

Issue framing in online voting advice applications: The effect of left-wing and right-wing headers on reported attitudes.

Voting Advice Applications (VAAs) provide voting recommendations to millions of people. As these voting recommendations are based on users' answers to attitude questions, the framing of these questions can have far-reaching consequences. The current study reports on a field experiment in which the framing of the header above VAA statements (N = 17) was manipulated (condition 1: no header; condition 2: a right-wing header, e.g., finance; condition 3: a left-wing header, e.g., nature and environment). Visitors of a VAA developed for Utrecht, the fourth largest municipality in the Netherlands, were randomly guided to one of the versions of the tool in which the header type was varied. Results (based on Nrespondents = 27,404) show that providing a header (left-wing or right-wing) leads to more left-wing answers as compared a condition where there is no header above the attitude statement. This effect, however, is only observed for respondents with lower levels of political sophistication.

Visible-Light Excitation of a Molecular Motor with an Extended Aromatic Core.

Exploring routes to visible-light-driven rotary motors, the possibility of red-shifting the excitation wavelength of molecular motors by extension of the aromatic core is studied. Introducing a dibenzofluorenyl moiety in a standard molecular motor resulted in red-shifting of the absorption spectrum. UV/vis and 1H NMR spectroscopy showed that these motors could be isomerized with light of wavelengths up to 490 nm and that the structural modification did not impair the anticipated rotary behavior. Extension of the aromatic core is therefore a suitable strategy to apply in pursuit of visible-light-driven molecular motors.

Positive vs. Negative: The Impact of Question Polarity in Voting Advice Applications.

Online Voting Advice Applications (VAAs) are survey-like instruments that help citizens to shape their political preferences and compare them with those of political parties. Especially in multi-party democracies, their increasing popularity indicates that VAAs play an important role in opinion formation for citizens, as well as in the public debate prior to elections. Hence, the objectivity and transparency of VAAs are crucial. In the design of VAAs, many choices have to be made. Extant research in survey methodology shows that the seemingly arbitrary choice to word questions positively (e.g., 'The city council should allow cars into the city centre') or negatively ('The city council should ban cars from the city centre') systematically affects the answers. This asymmetry in answers is in line with work on negativity bias in other areas of linguistics and psychology. Building on these findings, this study investigated whether question polarity also affects the answers to VAA statements. In a field experiment (N = 31,112) during the Dutch municipal elections we analysed the effects of polarity for 16 out of 30 VAA statements with a large variety of linguistic contrasts. Analyses show a significant effect of question wording for questions containing a wide range of implicit negations (such as 'forbid' vs. 'allow'), as well as for questions with explicit negations (e.g., 'not'). These effects of question polarity are found especially for VAA users with lower levels of political sophistication. As these citizens are an important target group for Voting Advice Applications, this stresses the need for VAA builders to be sensitive to wording choices when designing VAAs. This study is the first to show such consistent wording effects not only for political attitude questions with implicit negations in VAAs, but also for political questions containing explicit negations.