Die Reaktion von [Mo6Cl8]X4 mit N-Basen

Reaction of Mo₆Cl₈]X₄ with N-Bases Mo₆Cl₈]X₄ (X = Cl, Br, I) in ethanol solution by titration with Ag⁺ showed 4 labil X atoms. The displacement of X^? especially by F^? accelerates the titration decisively. Conductivity measurements in ethanol or acetone showed that Mo₆Cl₈]X₄ at 25°C behave as weak 1:1-electrolytes. Solutions of Mo₆Cl₈]X₄ in DMF heated up to 60°C and than lowered to 25°C showed that the compounds in this solvent behave as (potential) strong 2:1-valent electrolytes. From the following compounds the labil halides have been determined by titration with Ag⁺: Mo₆Cl₈]X₄(Py)₂ (X = Cl, Br), Mo₆Cl₈]X₄(bipy)₂ (X = Cl, Br, I), Mo₆Cl₈]X₄(Phenpy)₂ (X = Cl, Br, I), (PyH)₂Mo₆Cl₈]X₆ (X = Cl, Br); (bipyH)₂Mo₆Cl₈]I₄Cl₂. Always 4 (respectively 6) labil halides have been observed; exception Mo₆Cl₈]Cl₄(Py)₂ in acetone (2 labil Cl). Lattice constants and mole volumina for the adducts with pyridin and bipyridin have been determined. The adducts with bipyridin and phenylpyridin are isotypic. Conductivity measurements have been made in different solutions. The decomposition on the thermobalance showed that in Mo₆Cl₈]Cl₄(Py)₂ the bond of pyridin is weak. The 2 pyridin molecules are evolved at the same time. However Mo₆Cl₈]I₄(Bipy)₂ loses 1 bipyridin only. (PyH)₂Mo₆Cl₈]X₆ formed during the first decomposition step the novel compounds (PyH) Mo₆Cl₈]X₅ (X = Cl, Br). Both compounds are isotypic. They behave in ethanol solution as strong 1:1-valent electrolytes.