Reactions of secondary silanes with biguanide bases: synthesis and characterization of oligomeric 1,4-bis(silyl)biguanides and 1-alkyl-2,5-bis(silyl)biguanides

Abstract

The reactions between diorganosilanes, R¹R²SiH₂ (R¹ = Ph, R² = Ph or Me), and biguanide, 1-propylbiguanide or 1-cyclohexylbiguanide proceed via SiH/NH dehydrocoupling to afford the corresponding oligomeric 1,4-bis(silyl)biguanides (1, 4) and 1-alkyl-2,5-bis(silyl)biguanides (2, 3, 5) with the general formula [R¹R²SiNHC(NH)NC(NHSiR¹R²H)NR³]_n {where R¹ = R² = Ph; R³ = H (1), Prⁿ (2) or Cy (3). R¹ = Me, R² = Ph; R³ = H (4) or Prⁿ (5)}. These have been characterized by GPC, FAB mass, IR, multinuclear (¹H, ¹³C, ²⁹Si) NMR data as well as TGA. The IR and NMR spectra suggest the presence of different conformers in these compounds.