Nucleophilic addition reactions on the electron-deficient cluster dication [H_4Ru_4(C_6H_6)_4]~(2+): synthesis and structural characterisation of the water-soluble cluster cations [H_3Ru_4(C_6H_6)_4(CO)]~+ and [H_3Ru_4(C_6H_6)_4(OH)]~(2+)

摘要

The electron-deficient (58e) cluster cation [H_4Ru_4(C_6H_6)_4]~(2+) 1 was found to react in aqueous solution with simple nucleophiles to give electron-precise (60e) clusters. With carbon monoxide, the cluster cation [H_3Ru_4(C_6H_6)_4(CO)]~+ 3 is formed. The reaction with water needs NaN_3 as catalyst and yields the cluster dication [H_3Ru_4(C_6H_6)_4(OH)]~(2+) 4a; the reaction with alcohols leads to the analogous clusters [H_3Ru_4(C_6H_6)_4(OR)]~(2+) (R = Me:4b, R = Et:4c, R = PhCH_2:4d, R = Ph:4e, R = 4-EtC_6H_4:4f). The single-crystal X-ray structure analyses of the chloroide salts of 3 and 4a reveal a tetrahedral Ru_4 metal core. Each ruthenium atom is coordinated by a #eta#~6-benzene ligand, while the carbonyl or hydroxo ligands are found as #mu#_3 capping ligands over a triangular face of the Ru_4 tetrahedron.