Synthesis and Solution Behaviour of CpFe(CO)(PPh3)[CO(CH2)3N(CH3)2] (FpC3NMe2)

Abstract

Metal carbonyl (MC) colloids in water have a wide range of biomedical applications. The Fp-acyl (Fp: CpFe(CO)2) derivatives are one kind of MC molecules that can be synthesized through migration insertion reaction (MIR). The molecules assemble into colloids stabilized by water carbonyl interaction (WCI) due to the presence of highly polarized carbonyl (CO) groups. In this work, a new MC compound, CpFe(CO)(PPh3)[CO(CH2)3N(CH3)2] (FpC3NMe2) has been synthesized, in which a dimethylamino (-NMe2) group is attached. FpC3NMe2 is non-surface active and hydrophobic, but can be hydrated in neutral water. FpC3NMe2 assembles in THF/water, but the colloids are unstable and aggregate into crystal-like precipitates. This instability is attributed to the weakened hydrophobic interaction resulting from the hydratable -NMe2 groups. In strong acidic solutions, FpC3NMe2 is found to show amphiphilic characteristics due to the high water solubility of the protonated -NMe2 groups.