Edge modification of PAHs: the effect of embedded heterocycles on the aromaticity pattern

International audienceAromaticity studies carried out on the condensed model system 2 with different heteroatoms showed that the NICS(1) aromaticity in the five-membered ring correlates with that in the parent five-membered ring having the same heteroelement. Although the local aromaticity pattern is clearly determined by the Clar structure, as evidenced by the local aromaticity values in the reference molecules R1-3, the modifying effect of the heteroatom is significant. The correlation between the NICS(1)5 and NICS(1)6 aromaticities of the neighbouring rings is excellent, by modification of the heterocycle, we can engineer the aromaticity of the connecting six-membered ring as well. Geometry based aromaticity indices do not correlate well with NICS values probably due to annellation effects between rings with different aromatic character. Calculations with the different tested basis sets don’t show significant differences, therefore the use of the computationally cheaper methods is envisaged during further investigations of corresponding systems with extended π-framework

PHOTOELECTRON SPECTROSCOPIC INVESTIGATIONS AT THE TECHNICAL UNIVERSITY OF BUDAPEST. POSSIBLE APPLICATIONS IN PHYSICAL CHEMISTRY

Four different physical-chemical applications of UV photoelectron spectroscopy have been presented in this work. In the first example the interpretation of electronic transitions of some five membered heterocycles have been studied. The second part gives an example for clarifying the mechanism of the tertiary butylation reaction of furan. The geometry of silyl pseudo-halides is considered in the third example, while the last topic is concerned by proving the aromaticity of cyclic molecules containing heteroatoms

1,4-Additions of tricyclic 1,4-diphosphinines – a novel system to study pi-bond activation and dispersion interactions

The dienic nature of the aromatic π-system in 1,4-diphosphinines remained largely unexplored to this day due to a lack of facile and efficient synthetic protocols. Recently reported stable, tricyclic 1,4-diphosphinines were used to explore the thermal reactivity of the π-system towards an array of dienophiles in [4π+2π]- and, for the first time, in [4π+2σ]-type cycloaddition reactions

A P-Functionalized [3]Ferrocenophane with a Dynamic SPS-Bridge

Ferrocene-1,1 '-dithiol reacts with PCl3 and P(NMe2)(3) to give [3]ferrocenophanes with SPS-ansa-bridges comprising potentially reactive P-Cl and P-N bonds at the central bridge atom. The products were characterized by NMR data and single-crystal XRD studies. The P-chloro-derivative exists both in the solid state and in solution as a mixture of two energetically nearly degenerate conformers with different stereochemical disposition of the ansa-bridge. Activation parameters for the dynamic equilibration between both isomers in solution were determined by dynamic NMR spectroscopy. Computational studies suggest that the isomerization proceeds via a torsional motion of the bridging SPS-unit rather than via configuration inversion at the phosphorus atom.Peer reviewe

Synthesis and electronic properties of polycyclic aromatic hydrocarbons doped with phosphorus and sulfur

International audienc

Selected Method of Diagnosing Aviation Ergatic Systems

Insufficiency in showing errors in aviation ergatic system is understood to be a situation when there is no available information about the system or some of the board information is unreliable. With the use of the method of automatic diagnosis it is possible to analyse the symptoms of analytical redundancy. Residual differences, i.e. residuents, which are the final value expression of the consequences (effects) of function observation, which are measured on obtained mathematical model, are the keystones of this method. The content of the mathematical model application contains generator of residuents, i.e. signals, which carry the information about the incorrectness (errors) and aviation ergatic system (AES) failures

DESIGN OF AN APPLICATION FOR AN EXPERIMENTAL IDENTIFICATION OF A SYSTEM IN MATLAB/SIMULINK ENVIRONMENT

This paper focuses on creating an application in the MATLAB/Simulink environment for experimental identification of a system. It theoretically characterizes the experimental identification of a system and the choice and classification of identification methods. It also describes chosen methods of experimental identification (deterministic methods, neural networks) in details. A proposal of an application consisting of a user interface and a generated model scheme are also mentioned. The testing results on data from a small turbojet engine MPM-20 are shown. Based on the comparison of real measured values and output values of the model the application evaluates the accuracy of each of the identification methods. The main contribution of the proposed application is an automatization and simplification of the experimental identification process in MATLAB

Számításos kémiai módszerekkel támogatott foszfor- és szilíciumkémia = Computationally assisted of organophosphorus and organosilicon chemistry

A kutatás során a 14-es (C, Si, Ge, Sn) illetve a 15-ös (N,P) főcsoport elemeit tartalmazó molekulák vizsgálatával foglalkoztunk. Eredményeinket részben különleges kötésszerkezetek (karbének, foszfinidének) illetve hipervalens vegyületek előállíthatósága és stabilizációjuk lehetséges módjainak vizsgálatában értük el. Külön kiemelendő a konjugált foszfortartalmú rendszerek vizsgálata, melyeket szintetikus kutatócsoportokkal együttműködve végeztünk. Optoelektronikai alkalmazásokra felhasználható különböző konjugált/kondenzált foszfolszármazékok vizsgálatával Regis Reau és Thomas Baumgartner csoportjaival együttműködve születtek eredmények, míg a kationos, semleges és anionos diazafoszfol alapvázat Dietrich Gudat csoportjával együttműködve vizsgáltuk. Proazafoszfatrán szuperbázis és származékainak (John Verkade-val együttműködve) vizsgálata stabilizációjában megállapítottuk a transzannulláció szerepét és mértékét. Vizsgáltuk sziloxánláncok kialakulásának mechanizmusát és e láncok stabilitását. | The target molecules of our research contain group 14 (C, Si, Ge, Sn) and group 15 (N,P) elements. The most important results are related to unusual bonded molecules including carbenes, phosphinidenes, and hypervalent molecules, including their stabilization and synthesizability. Especially noteworthy results were obtained in cooperation with synthetic research groups in the field of conjugated organophosphorus compounds. Different cunjugated/annellated phosphole-based ring systems were targeted in cooperations with Regis Reau and Thomas Baumgartner. Cationic, neutral and anionic diazaphosphole systems were investigated with the Group of Dietrich Gudat. Investigating the proazaphosphatrane superbase and its derivatives (in a joint work with John Verkade) we have established the effect and extent of transannullation. The formation and the stability of siloxane chains was also investigated

Pi-extended phosphepines: redox and optically active P-heterocycles with non-planar framework

In this letter, we present the synthesis of a new family of -extended dithieno[b,f]phosphepines. The Pd-catalyzed direct-arylation allows the introduction of various substituents, which tune the absorption/emission in the visible range as well as the redox properties. All those modifications were rationalized through DFT calculations. The physical properties of ambipolar phosphepine with diphenylamino substituents conduct us to use it as a semi-conductor in a p-type organic field-effect transis-tors (OFETs)