One-Dimensional Polymers Based on Silver(I) Cations and Organometallic cyclo-P-3 Ligand Complexes

The synthesis and characterization of the first supramolecular aggregates incorporating the organometallic cyclo-P-3 ligand complexes [(CpMo)-Mo-R(CO)(2)(eta(3)-P-3)] (Cp-R=Cp (C5H5; 1a), Cp* (C-5(CH3)(5); 1b)) as linking units is described. The reaction of the Cp derivative la with AgX (X= CF3SO3, Al(OC(CF3)(3))(4)) yields the one-dimensional (1D) coordination polymers [Ag(CpMo(CO)(2)(mu,eta(3):eta(1):eta(1)-P-3)](2)]n[Al{OC(CF3)(3)}(4)]n (2) and [Ag-CPMo(CO)(2)(mu,eta(3):eta(1):eta(1)-P-3)}(3)](n)[X](n) (X= CF3SO3 (3a), Al{OC(CF3)(3)}(4) (3b)). The solid-state structures of these polymers were revealed by X-ray crystallography and shown to comprise polycationic chains well-separated from the weakly coordinating anions. If AgCF3SO3 is used, polymer 3a is obtained regardless of reactant stoichiometry whereas in the case of Ag[Al{OC(CF3)(3)}(4)], reac-tant stoichiometry plays a decisive role in determining the structure and composition of the resulting product. Moreover, polymers 3a, b are the first examples of homoleptic silver complexes in which Ag-I centers are found octahedrally coordinated to six phosphorus atoms. The Cp* derivative 1b reacts with Ag[Al(OC(CF3)(3)}(4)] to yield the 1D polymer [Ag(Cp*Mo(CO)(2)(mu,eta(3):eta(2):eta(1)-P-3)}(2)](n)[Al{OC- (CF3)(3)}(4)](n) (4), the crystal structure of which differs from that of polymer 2 in the coordination mode of the cyclo-P-3 ligands: in 2, the Ag+ cations are bridged by the cyclo-P-3 ligands in a eta(1):eta(1) (edge bridging) fashion whereas in 4, they are bridged exclusively in a eta(2):eta(1) mode (face bridging). Thus, one third of the phosphorus atoms in 2 are not coordinated to silver while in 4. all phosphorus atoms are engaged in coordination with silver. Comprehensive spectroscopic and analytical measurements revealed that the polymers 2, 3a,b, and 4 depolymerize extensively upon dissolution and display dynamic behavior in solution, as evidenced in particular by variable temperature P-31 NMR spectroscopy. Solid-state P-31 magic angle spinning (MAS) NMR measurements, performed on the polymers 2, 3b, and 4. demonstrated that the polymers 2 and 3b also display dynamic behavior in the solid state at room temperature. The X-ray crystallographic characterisation of 1b is also reported.