Electrochemical and Theoretical (DFT) Study of the Complex between 2,2′-Bipyridine and Dichlorodiphenylsilane (bipy·Ph₂SiCl₂) : Structure, Redox Properties, and Reactivity

Abstract

Organosilicon compounds, particularly chlorosilanes, are of significant interest due to their structural versatility and pivotal role as precursors for Si–N, Si–O, and Si–C bond formation in functional materials and coordination systems. Among them, dichlorodiphenylsilane (Ph₂SiCl₂) exhibits strong affinity toward nitrogen-donor ligands such as 2,2′-bipyridine, yet detailed insights into the formation, electronic structure, and reduction behaviour of their complexes remain limited. The study reports the in situ synthesis and reduction of the bipy·Ph₂SiCl₂ complex, combining cyclic voltammetry and DFT calculations (M06-2X/6-31+G(d,p)). The experimental reduction potential (Ep = −1.12 V vs SCE) is in excellent agreement with the theoretical value (−1.20 V vs SCE). The one-electron reduction induces a significant contraction of the N→Si bonds (2.051 → 1.960 Å) and an elongation of the Si–Cl bonds (2.295 → 2.363–2.372 Å). Global reactivity descriptors confirm the high reactivity of the neutral complex (hardness η = 2.030 eV, electrophilicity ω = 19 eV) and the good stability of the resulting radical anion. This work thus makes a significant contribution to the understanding of silicon–nitrogen coordination chemistry and provides new insights into the redox behavior of organosilicon complexes.