Oligonuclear High Spin-Cyclopentadienyl Complexes

• Applicant: Professor Dr. Helmut Sitzmann
• Subject Area: Inorganic Molecular Chemistry - Synthesis and Characterisation
• Term: from 2004 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5430632

Dinuclear Cyclopentadienylmetal halides [CpMX]2 (M = Mn, Fe, Co, Ni; X = Cl, Br, I) with bulky alkylcyclopentadienyl ligands and feature metal-ligand antibonding orbitals with n unpaired elektrons (n = 5,4,1,2). The reduction to even more reactive complexes [CpM]n (M = Fe, Ni; n = 2) enhances their synthetic potential. Goals of the project are: a) Investigation of magnetic properties of the paramagnetic binuclear complexes [CpM(µ-X)]2 (X = N3, OCN, SCN, CN, OH, Alkoxide, Phenolate, Carboxylate have already been screened for feasibility, a variety of other ligands not yet tested will be included). b) For selected metal-ligand combinations the functionality of the bridging ligand will be doubled for generation of complexes of higher nuclearity, e. g. by using µ4-OC6H4O instead of µ-OC6H5. Extension of ferromagnetic coupling from a dinuclear complex to polymeric complexes, possibly through the bulk material, may be achieved this way. c) Bulky alkylcyclopentadienyl complexes [CpLnX2]2 and [Cp2LnX] of the lanthanides will be included into this project much like the transition metal fragments mentioned above. Metallocenes [Cp2Ln] have been shown to eliminate both ligands under the action of TCNE and generate halide-free, polymeric materials with as yet unknown magnetic properties.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1137: Molecular Magnetism