Synthesis, electrochemistry, and crystal and molecular structures of some molybdenum(0) arene derivatives with fluorinated and phenyl-substituted arene ligands

Compounds of general formula Mo(η6-arene)(CO)3, arene=diphenyl, 1; 1,3,5-triphenylbenzene, 2; C6H5F, 3; C6H5CF3, 4, have been prepared in good yields by reacting fac-Mo(CO)3(DMF)3, DMF=N,N-dimethylformamide, with BF3 · OEt2 and the appropriate arene. The crystal and molecular structures of 1, 3, and 4, are reported. The dinuclear derivative Mo2(η6:η6-C6H5-C6H5)(CO)6, 5, was obtained by thermal reaction of Mo(η6-toluene)(CO)3 with Mo(η6-diphenyl)(CO)3. An electrochemical study has been performed on the new complexes, showing that the dimolybdenum complex undergoes a single two-electron reduction at about the same potential as the corresponding dichromium complex, the molybdenum dianion being less stable than the chromium analogue.