Electronic structure significance

Similar to the phenalenyl system, substitution of oxygen atoms at strategic positions of triangulene leads to a series of novel open-shell compounds called trioxytriangulenes, with their electronic structures significantly different from the parent triangulene. The different redox species are shown in Fig. 19 and the neutral... 

This feature of the electronic structure of these inorganic rings is especially dramatic for the six-atom system [SsNs], which is able to accommodate ten r-electrons, cf. six r-electrons for CeHg. The electron-richness of [SsNs] results in a significantly lower r-bond order of 0.17... 

Compare electrostatic potential maps of enolates derived from 2-butanone, 4,4-dimethyl-2-pentanone, 4,4,4-trifluoro-2-butanone and l-phenyl-2-propanone with those of acetone. Which substituents cause significant changes in the electronic structure of these enolates and what are the nature of these changes Justify your answers by making drawings of any important resonance contributors. 

It is possible, on the other hand, to define tautomerism and electronic resonance in a way which gives structural significance to them individually. 

For many years, electron ionization, then more usually known as electron impact, was the only ionization method used in analytical mass spectrometry and the spectra encountered showed exclusively the positively charged species produced during this process. Electron ionization also produces negatively charged ions although these are not usually of interest as they have almost no structural significance. Other ionization techniques, such as Cl, FAB, thermospray, electrospray and APCI, however, can be made to yield negative ions which are of analytical utility. 

The turnover frequency (TOP) based on surface-exposed atoms significantly increases with a decrease in the diameter of the gold particle from 5 nm [66]. This feature is unique to gold, because other noble metals usually show TOFs that decrease or remain the same with a decrease in the diameter [7]. The decrease in particle size gives rise to an increase in corner or edge and perimeter of NPs and change in electronic structure however, the origin of size effects on catalytic activity for CO oxidation is not clear. 

Seemingly, atomic substitutions in this system have little influence on the structural arrangement and do not modify the electronic properties significantly. 

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