Chemically-inert groups’ influence

Ample experimental evidence indicates that the habit of crystallites of the catalyst has a profound influence on the activity and selectivity of the reaction, which results in the appearance of structure sensitivity of the selective oxidation reactions at oxide catalysts (39). However, little is known about the origin of this phenomenon and about the differences of the structure of active sites present at various crystal planes. Even less is known about the role of defects present at the surface of an oxide, in determining the catalytic properties. Only recently studies of the properties of (100) surface of a monocrystal of NiO revealed that an ideal surface is chemically inert and the reactivity of the system increases only if defects are introduced in the surface (40). At such a surface, dissociation of molecular water to form hydroxyl groups is observed in contrast to an ideal surface which is inactive in water dissociation. 

Perfluoropolyethers (PFPEs) are a family of liquid fluoropolymers that have unique properties such as high thermal stability, low volatility, low 7g, chemical inertness, low friction coefficient. PFPEs have the properties of a good lubricant (lower surface energy, low volatility, and good oxidative stability) they are therefore used as lubricants in many applications such as in the aerospace industry [43]. The properties of PFPEs are influenced by their structural characteristics such as MW, MW distribution, type of end-groups, and the structure of the chain [44]. NMR spectroscopy is an ideal technique to study these features of the polymer. 

The electron spin resonance (ESR) spectra of the radical ions of 230 indicate there are no large deviations from the free-electron g value that would have been expected had the 3d orbitals of the sulfur atom played an important part in influencing the spin density of the molecule. Consequently, structure 230 may not be the main contributor to the electronic structure of the compound. Such stability in this compound could be attributed to the inertness of the NSN group and the presence of the aromatic naphthalene ring. However, the H-NMR chemical shifts (8 = 4.45 ppm) suggest the compound is antiaromatic. The compound is therefore referred to as an ambiguous aromatic compound (78JA1235). 

The properties and behavior of p-block metals are less homogenous than those of the s-metals because of their atomic and ionic sizes and other characteristics such as their unusual crystalline structures and the presence of the pair of electrons on the s orbital (s ) of the outermost electron shell. These s orbital electrons do not participate in chemical interactions (covalent or ionic) (inert electron pair). This influence increases with atomic number within a group. 

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