Ferrocene functionalized oligomeric siloxane building blocks as potential linkers for biological active molecules

Despite the fact, that biologically active molecules (e.g., antioxidants, antibiotics and antiviral reagents) were investigated intensively in the last decades, new linker molecules and building blocks, which can enhance the activity and change the polarity of compounds is still a growing field in pharmaceutic research. The application of a ferrocene moiety in combination with a siloxane linker attached to a biological active molecule is realized in the present study for the first time. A method is introduced that uses mono- (FcLi) and dilithioferrocene (FcLi₂) to perform anionic ring opening reactions of hexamethylcyclotrisiloxane (D₃). The formation of lithium silanolate species αDnLi (α = Fc, D₃ = (SiMe₂O)₃) was observed, followed by the termination of the ring opening reactions with chlorosilanes Cl–ω to obtain siloxane oligomers of type αDnω. Approaches were investigated to enable ω = SiMe₂H and ω = SiMe₂Cl functionality. It was shown, that oligomeric siloxanes were able to undergo further hydrosilylation reactions with the introduction of a phenol moiety.