Four Slip-Stacked Arrangements, Three Types of Photophysics: Crystal Structure and Solid-State Fluorescence of 3,6-Diaryl Substituted Furo[3,4-c]furanone Polymorphs and Regioisomers.

Six symmetrical 3,6-diaryl (aryl=phenyl, 2-, 3- and 4-tolyl, 2,4- and 3,5-xylyl) substituted furo[3,4-c]furanones (DFF) were synthesized. The computational analysis, based on density functional theory, found eight possible centrosymmetrical slipped π-stack arrangements, formed according to electron repulsion minimization principle, as for previously reported for π-isoelectronic diketopyrrolopyrroles (DPP). One of these slipped stack arrangements was found to form infinite columns in the crystals of a new polymorph of parent phenyl derivative (with centre-to-centre distance CC=6.975 Å), other three types of stacks were found for 3-tolyl (CC=6.153 Å), 4-tolyl (CC=3.849 Å) and 2,4-xylyl (CC=4.856 Å) derivatives by single crystal X-ray diffractometry. All six derivatives show intense solution fluorescence in blue/green region, with a maximum driven entirely by a number and position of methyl substituents on phenyl rings. On the other hand, the solid-state fluorescence from yellow over orange to red is observed only for four derivatives and its presence/absence, spectral position and vibronic structure is driven exclusively by the slips in π-stacks (with interplanar distance always less than 3.5 Å) of almost planar DFF molecules, resulting in J-type emission, H-type excimer-like emission and H-type quenching.

Behavioural plasticity of motor personality traits in the common vole under three-day continual observation in a test box.

In animals, behavioural personality traits have been well-documented in a wide array of species. However, these traits, different between individuals, are not completely stable in individuals. They show behavioural plasticity like many other phenotypic traits. This plasticity is able to overcome some weak aspects of personality trait behavioural strategy. In the present study, we examined the relationship between motor personality traits and behavioural plasticity in the common vole (Microtus arvalis) using a PhenoTyper (PT) box (Noldus). During a three-day test, four behavioural motor activity parameters were monitored in 47 voles: distance moved, (loco)motion duration, motion change frequency, sprint duration. Consistency repeatability (RC) of the parameters from the PT test was very high, with all values ≥ 0.91. To select the best linear mixed-effect models (LMMs), several predictors (test day, sex, body weight) were tested. Only test day had a significant effect on the dependent variables and other predictors did not improve the LMMs. Further, we found significant effects of random intercepts (motor personality traits) and slopes (behavioural plasticity), as well as significant negative correlations between them for all behavioural parameters. Our results indicate that motor personality traits were connected with behavioural plasticity. Moreover, we revealed a significant positive correlation between the random slopes of (loco)motion duration and motion change frequency. This relationship could indicate some central plasticity of motor personality traits. In conclusion, negative correlations between the motor personality traits and the behavioural plasticity demonstrate expression of convergent tendency from both opposite trait values. This corresponds with different ideas on ability to compensate personality effects or to prepare for potential future conditions. In the laboratory, plasticity of personality traits take place whenever an animal is placed e. g. in a breeding box for the first time or is left for a long time in an experimental apparatus.

Ruthenium-catalyzed α-(hetero)arylation of saturated cyclic amines: reaction scope and mechanism.

Transition-metal-catalyzed sp(3) C-H activation has emerged as a powerful approach to functionalize saturated cyclic amines. Our group recently disclosed a direct catalytic arylation reaction of piperidines at the α position to the nitrogen atom. 1-(Pyridin-2-yl)piperidine could be smoothly α-arylated if treated with an arylboronic ester in the presence of a catalytic amount of [Ru3(CO)12] and one equivalent of 3-ethyl-3-pentanol. A systematic study on the substrate and reagent scope of this transformation is disclosed in this paper. The effect of substitution on both the piperidine ring and the arylboronic ester has been investigated. Smaller (pyrrolidine) and larger (azepane) saturated ring systems, as well as benzoannulated derivatives, were found to be compatible substrates with the α-arylation protocol. The successful use of a variety of heteroarylboronic esters as coupling partners further proved the power of this direct functionalization method. Mechanistic studies have allowed for a better understanding of the catalytic cycle of this remarkable transformation featuring an unprecedented direct transmetalation on a Ru(II)-H species.