Neuartige zweistufige Redoxsysteme basierend auf 4H-Imidazolen

In der vorliegenden Arbeit wurde das Redoxverhalten von 4H-Imidazolen mit Oxalamidin-Substruktur mittels elektrochemischer Methoden wie Cyclovoltammetrie und Square-Wave-Techniken untersucht. Anhand von zwei synthetisierten Reihen von Verbindungen konnte gezeigt werden, dass sich das Redoxpotential mit Hilfe der Hammett-Konstanten abschätzen lässt. Ein Zugang zu einer neuen Verbindungsklasse - abgeleitet von den 4H-Imidazolen - den 1,3,2-Diazaborolidinen wurde geschaffen. Sie sind strukturell sehr interessant und zeigen eine außergewöhnliche Kombination von Eigenschaften, wie intensive Farbigkeit, rote Fluoreszenz und Redoxaktivität mit Semichinonbildungskonstanten um 1014

Syntheses and Properties of Cycloamidines Based on 4H-Imidazoles*

Employing three different syntheses a broad spectrum of 4H-imidazoles 3a -3s has been synthesized. In the course of the two-fold aminolysis reaction leading to derivatives 3q -3s, deeply colored byproducts could be isolated and structural characterized.These novel donor-acceptor derivatives of type 7 consist of an 1H-and 4H-imidazole which are connected by a nitrogen bridge and rearrange via rapid 1,3-/1,5-hydride shifts. Using 1 H NMR experiments the aminolysis product 3p shows prototropic isomers which could be detected in equilibrium for the first time. Cyclovoltammetric measurements of a series of substituted 2-aryl derivatives 3d -3i displayed two reversible single electron transfer steps with relatively small semiquinone formation constants between 10 2 and 4 × 10 3 . The 4H-imidazole 3d was successfully converted into boratetraaza-pentalene 8a, which showed two well separated reduction potentials. The value of semiquinone formation constant of 8a (1.8 × 10 15 ) is even higher than those reported for similar derivatives. 4H-imidazoles can also be employed for the efficient complexation of catalytically important metals as exemplified by copper complexes 11 and 12. Derivative 3m, which possesses an additional chelating pyridine substructure, formed a stable complex of structural composition Zn(3m) 2 with diethyl zinc

Toward a general psychological model of tension and suspense

Tension and suspense are powerful emotional experiences that occur in a wide variety of contexts (e.g., in music, film, literature, and everyday life). The omnipresence of tension and suspense suggests that they build on very basic cognitive and affective mechanisms. However, the psychological underpinnings of tension experiences remain largely unexplained, and tension and suspense are rarely discussed from a general, domain-independent perspective. In this paper, we argue that tension experiences in different contexts (e.g., musical tension or suspense in a movie) build on the same underlying psychological processes. We discuss key components of tension experiences and propose a domain-independent model of tension and suspense. According to this model, tension experiences originate from states of conflict, instability, dissonance, or uncertainty that trigger predictive processes directed at future events of emotional significance. We also discuss possible neural mechanisms underlying tension and suspense. The model provides a theoretical framework that can inform future empirical research on tension phenomena

Connectivity Patterns During Music Listening: Evidence for Action-Based Processing in Musicians

Musical expertise is visible both in the morphology and functionality of the brain. Recent research indicates that functional integration between multi-sensory, somato-motor, default-mode (DMN), and salience (SN) networks of the brain differentiates musicians from non-musicians during resting state. Here, we aimed at determining whether brain networks differentially exchange information in musicians as opposed to non-musicians during naturalistic music listening. Whole-brain graph-theory analyses were performed on participants' fMRI responses. Group-level differences revealed that musicians' primary hubs comprised cerebral and cerebellar sensorimotor regions whereas non-musicians' dominant hubs encompassed DMN-related regions. Community structure analyses of the key hubs revealed greater integration of motor and somatosensory homunculi representing the upper limbs and torso in musicians. Furthermore, musicians who started training at an earlier age exhibited greater centrality in the auditory cortex, and areas related to top-down processes, attention, emotion, somatosensory processing, and non-verbal processing of speech. We here reveal how brain networks organize themselves in a naturalistic music listening situation wherein musicians automatically engage neural networks that are action-based while non-musicians use those that are perception-based to process an incoming auditory stream.peerReviewe