Herein, we used 4-(dimethylamino)pyridine (dmap) since preliminary works of Krossing and co-workers demonstrated that the pyridine-based ligands are able to stabilize multicationic species. FeC10(HgO2CCF3)10 was dissolved in tetrahydrofuran and an excess of dmap was added (Eq. 3) yielding an orange precipitate. The solid was analysed by NMR and vibrational spectroscopy as well as elemental analysis. While the IR spectrum of the coordination compound exhibits bands which correspond only to the trifluoroacetate (TFA) as well as the nitrogen based ligand , the Raman spectrum features further information especially with respect to the metallocene framework. C Cp -C Cp deformation is found at ṽ = 951 cm -1 and Hg-Cp vibrations at ṽ = 100 cm -1 . Moreover, the Hg-O TFA band (ṽ = 311 cm -1 in FeC10(HgTFA)10) vanished and new bands at ṽ = 193-158 cm appeared, indicating the successful replacement of the carboxylate groups by the dmap ligands. H, F and C NMR signals show the intact ligands and anions but as in the starting material the 199 Hg resonance is not visible. The coordination to the mercury atoms causes a low field shift of Δδ = 6 ppm of the C Cp signals in the C NMR spectrum while all other signals are not significantly affected. The composition was determined by elemental analysis yielding the overall formula FeC10Hg10(dmap)10(TFA)10 (1). Single crystals were obtained by recrystallization from tetrahydrofuran. Compound 1 crystallized in the monoclinic space group P21/n containing one metallocene molecule in the asymmetric unit. All mercury atoms are almost linearly coordinated by one cyclopentadienyl and one dmap ligand with angles of 167.0(3)-178.6(4) ° (Tab. 1), respectively. The distortion from linearity is caused by Hg-O TFA interactions within the sum of van-der-Waals radii of mercury (rvdW = 1.75 Å ) and oxygen (rvdW = 1.52 Å ). The Hg-O distances display a broad range of 2.24(1)-3.28(4) Å and are longer than in FeC10(HgO2CCF3)10 (Tab. 1). The TFA anions serve as bridging ligands between two to three metal centers (Fig. ) similarly to the structure of Hg(TFA)2 ‧ 2 dmap which crystallizes as a dimer bridged by two TFA anions with a distorted octahedral coordination environment around the mercury atoms. This coordination motif causes an eclipsed conformation in 1a (Cp torsion = 3.6(1) ) in contrast to FeC10(HgO2CCF3)10 which exhibits a staggered conformation in solid state. As a result, one intramolecular Hg-Hg contact of 3.440(2) Å is observed. Taking all interactions into account the total coordination number of the mercury atoms is four to six. As only two non-coordinating (distorted) TFA units within the unit cell with an overall occupancy of 1.33 are observed, this metallocene is better described as a "monocation" [FeC10(Hg dmap)10(TFA)8.66][TFA]1.33.