The Triple-Decker Complex [Cp*Fe(μ,5:5-P5)Mo(CO)3] as a Building Block in Coordination Chemistry

Although the triple-decker complex [Cp*Fe(mu,eta(5):eta(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[BF4] selectively produces the coordination compound [Ag{Cp*Fe(mu,eta(5):eta(5)-P-5)Mo(CO)(3)}(2)][BF4] (3). Its reaction with Ag[TEF] and Cu[TEF] ([TEF](-) = [Al{OC(CF3)(3)}(4)](-)) leads to the selective formation of the complexes [Ag{Cp*Fe(mu,eta(5):eta(5)-P-5)Mo(CO)(3)}(2)][TEF] (4) and [Cu{Cp*Fe(mu,eta(5):eta(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 (MCO)-C-I<bold> distances </bold>(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 [BF4](-). Such an Ag<bold>F interaction does not exist for compound </bold>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.