6533b7d6fe1ef96bd1266fd3

RESEARCH PRODUCT

Cubane-Type Mo3CoS4 Molecular Clusters with Three Different Metal Electron Populations: Structure, Reactivity and Their Use in the Synthesis of Hybrid Charge-Transfer Salts

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description

Heterodimetallic cubane-type complexes coordinated to diphosphanes [Mo(3)CoS(4)(dmpe)(3)Cl(4)](+) ([1](+)) (dmpe=1,2-bis(dimethylphosphanyl)ethane), [Mo(3)CoS(4)(dmpe)(3)Cl(4)] (1) and [Mo(3)CoS(4)(dmpe)(3)Cl(3)(CO)] (2) with 14, 15 and 16 metal electrons, respectively, have been prepared from the [Mo(3)S(4)(dmpe)(3)Cl(3)](+) trinuclear precursor using [Co(2)(CO)(8)] or CoCl(2) as cobalt source. Cluster complexes [1](+) and 1 are easily interconverted chemically and electrochemically. The Co-Cl distance increases upon electron addition and substitution of the chlorine atom coordinated to cobalt with CO only takes place in presence of a reducing agent to give complex 2. Structural changes in the intermetallic distances agree with the entering electrons occupying an orbital which is basically Mo-Mo non-bonding and slightly Mo-Co bonding. Magnetic susceptibility measurements for [1](+) and 1 are consistent with the presence of two and one unpaired electrons, respectively and therefore with an "e" character for the HOMO orbital. Oxidation of 1 with TCNQ results in the formation of a charge transfer salt formulated as [1](+)[TCNQ](-) with alternate layers of paramagnetic cluster cations and also paramagnetic organic anions. There is no magnetic interaction between layers and the thermal variation of the magnetic susceptibility has been modelled as a S= 1/2 TCNQ antiferromagnetic chain plus a S=1 cluster monomer with zero field splitting.