Electrochemical reactions of organosilicon compounds

Abstract

Using the idea of a local hydrodynamical equilibrium in a two-component Coulomb gas, one can prove that the latter possesses a spatially periodic structure. The spatial period calculated is found to be in good agreement with the period experimentally measured for gas plasma.

Electrochemical Oxidation and Radical Cations of Structurally Non‐rigid Hypervalent Silatranes: Theoretical and Experimental Studies

“…The NBO analysis suggests the reason of this to be the intensive (>12 kcal mol −1 ) 4e exchange repulsion between the aromatic π‐orbitals and the oxygen lone electron pair (LEP) in 1 n (or the σ(Si−C) bond in 1 p ), which is absent in 1 k , as well as in the other aryl silatranes 1 l , 1 m , and 1 o . This is perfectly in line with the remarkably easier oxidation of benzyl silatrane compared to phenyl silatrane (Table ); similar trend holds for oxidation of benzyl and phenyl silanes in general …”

“…The NBO analysis suggestst he reason of this to be the intensive (> 12 kcal mol À1 )4 ee xchange repulsion between the aromatic p-orbitalsa nd the oxygen lone electron pair (LEP) in 1n (or the s(SiÀC) bond in 1p), which is absent in 1k,a sw ell as in the other aryl silatranes 1l, 1m,a nd 1o.T his is perfectly in line with the remarkably easier oxidation of benzyls ilatrane compared to phenyls ilatrane (Table 3);s imilart rend holds for oxidation of benzyl and phenylsilanes in general. [19] As mentioned above ( Table 1, footnote [c]), the estimated difference DG s-l for 1p + C was not quite correct because the hS 2 i value for the UMP2 function of 1p + C (s) remains too high even after applying the projection procedure. It was therefore interesting to consider DG s-l at the ROMP2/6-311G(2d,p)l evel of theory.U nfortunately,t he minimum for the 1p + C (l) isomer on PES of 1p + C could not be localized.W ith this, both the expect-ed RCs, 1b + C (s) and 1b + C (l) ,w ere found using the ROPM2 method for methyl silatrane 1b and the datao nt heir geometry and relative stabilityw ere in perfect agreementw ith the UMP2 calculations (DG s-l = 9.40 (UMP2)a nd 9.53 (ROMP2) kcal mol À1 ).…”

Nucleophilic displacement versus electron transfer in the reactions of alkyl chlorosilanes with electrogenerated aromatic anion radicals

“…Since the reduction of chlorosilanes requires very negative potentials [5] and -at least of those with aliphatic substituents-occurs via dissociative ET mechanism [6,7], the ET pathway seems less probable, though in the case of aryl chlorosilanes this possibility cannot be ruled out [7,8]. On the other hand, it is well documented that heterogeneous ET to alkyl chlorosilanes induces cleavage of the Si-Cl bonds leading to the reduction products with Si-Si or Si-H bonds [9].…”

“…Indeed, the reduction of the majority of chlorosilanes is usually observed at -3.2…-2.4 V vs. SCE [9], whereas the E 1/2 of the couple Ph 3 Si  /Ph 3 Si -, estimated by photomodulated voltammetry, is -1.39 V vs SCE [17];…”

Paramagnetic intermediates in the photoinduced reaction between dodecamethylcyclohexasilane and 9,10-phenanthraquinone: Time-resolved CIDNP study

“…In recent decades, many research groups have explored this area, and a vast pool of the experimental data obtained have been summarized and analyzed in the detailed results with the discussion of the possible investigation prospects (see, e.g., [1][2][3][4]). Different methods used to generate and to investigate short-lived silicon-centered radical cations and radical anions include ESR [5], cyclic voltammetry [6], preparative electrolysis [7], electron impact [8], c-irradiation [9], photolysis in highly polar media [10], etc.…”