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

The reactions between diorganosilanes, (RRSiH2)-R-1-Si-2 (R-1=Ph, R-2=Ph or Me), and biguanide, 1-propylbiguanide or 1-cyclohexylbiguanide proceed via SiH/NH dehydrocoupling to afford the corresponding oligomeric 1,4-bis(sily l)biguanides (1, 4) and 1-alkyl-2,5-bis(silyl)biguanides (2, 3, 5) with the general formula [(RRSiNHC)-R-1-Si-2(NH)NC((NHSiRRH)-R-1-H-2)NR3](n) {where R-1=R-2=Ph; R-3=H (1), Pr-n (2) or Cy (3). R-1=Me, R-2=Ph; R-3=H (4) or Pr -n (5)}. These have been characterized by GPC, FAB mass, IR, multinuclear ( H-1, C-13, Si-29) NMR data as well as TGA. The IR and NMR spectra suggest t he presence of different conformers in these compounds.