The Triple-Decker Complex [Cp*Fe(µ,η(5):η(5)-P(5))Mo(CO)(3)] as a Building Block in Coordination Chemistry

Although the triple-decker complex [Cp*Fe(µ,η(5):η(5)-P(5))Mo(CO)(3)] (2) was first reported 26 years ago, its reactivity has not yet been explored. Herein, we report a new high-yielding synthesis of 2 and the isolation of its new polymorph (2’). In addition, we study its reactivity towards Ag(I) and Cu(I) ions. The reaction of 2 with Ag[BF(4)] selectively produces the coordination compound [Ag{Cp*Fe(µ,η(5):η(5)-P(5))Mo(CO)(3)}(2)][BF(4)] (3). Its reaction with Ag[TEF] and Cu[TEF] ([TEF](−) = [Al{OC(CF(3))(3)}(4)](−)) leads to the selective formation of the complexes [Ag{Cp*Fe(µ,η(5):η(5)-P(5))Mo(CO)(3)}(2)][TEF] (4) and [Cu{Cp*Fe(µ,η(5):η(5)-P(5))Mo(CO)(3)}(2)][TEF] (5), respectively. The X-ray structures of compounds 3–5 each show an M(I) ion (M(I) = Ag(I), Cu(I)) bridged by two P atoms from two triple-decker complexes (2). Additionally, four short M(I)···CO distances (two to each triple-decker complex 2) participate in stabilizing the coordination sphere of the M(I) ion. Evidently, the X-ray structure for compound 3 shows a weak interaction of the Ag(I) ion with one fluorine atom of the counterion [BF(4)](−). Such an Ag···F interaction does not exist for compound 4. These findings demonstrate the possibility of using triple-decker complex 2 as a ligand in coordination chemistry and opening a new perspective in the field of supramolecular chemistry of transition metal compounds with phosphorus-rich complexes.