Backbond splitting

Route 2 [206] (Figure 2.43) involves the intermediate formation of pentavalent Si in an Sn2 reaction, resulting in a =Si-H-OH surface species. Then, two scenarios are proposed (see Figure 2.44) (i) solvolytic attack of the remaining Si-H bond or (ii) backbond splitting. In the former process, successive oxidation results in formation of Si(OH)4 and the latter sequence produces an HSi(OH)3 molecule. In process (ii), the intermediate =Si-(OH)2 is formed that reacts with water to Si(OH)4. 

Figure 2.98 Schematic for oxide formation via a kink site (surface state) at which a hole from the Pt levels is injected further oxidation of the radical results in OH termination, which is followed by solvolytic backbond splitting in the subsequent...

The EPR powder spectra of the low-spin complexes [0s(NH3)5L][CF3S03]3 (L = H20 or (5)) have been analyzed the negative sign obtained for the axial splitting when L = (5) has been rationalized in terms of Os L backbonding. Crystal field parameters have also been derived. The spectral and electrochemical properties of [Ru(NH3)5L]" (Ru or Ru L =RC02 R = 4-py-A-Me+ or L = RCONH R = Ph, 4-py-A-Me", 4-py-A-H+) have been studied in detail as a function of pH the carboxamido Ru complexes are weak bases and are deprotonated only in strongly acidic solution. ... 

H-terminated kink site atom on a (111) surface that reacts with water (see Figure 2.42). Models vary depending on whether a Si-H bond on the kink site atom is first attacked or whether solvolytic splitting of a backbonds initiates the dissolution reaction. Figures 2.42 and 2.43 show this situation including the initial attack for... 

As a consequence, several concepts and strategies have been developed for improved stability. They encompass a chemical stability approach, such as surface termination of Si by hydrogen or CH3 [41 6]. However, since even highly ordered single crystal surfaces are characterized by atomic terraces, step edges, and kink sites, solvolytic splitting of backbonds can occur that results in either terrace dissolution or in initiation... 

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