Deprotonation of the complex salts {Cp(OC) 3[H 2(2,4,6- tBu 3-C 6H 2)P]M}BF 4 (M=Mo, W) ( 4a, b), obtained from [Cp(OC) 3M]BF 4 ( 2a, b) and (2,4,6- tBu 3-C 6H 2)PH 2 ( 3), yields the metallo-phosphanes Cp(OC) 3MP(H)(2,4,6- tBu 3C 6H 2) ( 5a, b). 5a, b are thermally decarbonylated to the PH-functionalized phosphenium complexes Cp(OC) 2MP(H)(2,4,6- tBu 3C 6H 2) ( 7a, b), which can also be obtained by the base-assisted dehydrohalogenation of the bifunctional complexes Cp(OC) 2[H 2(2,4,6- tBu 3C 6H 2)P]MCl ( 9a, b), prepared by a ligand exchange reaction from Cp(OC) 3MCl ( 8a, b) and 3. The reaction of 7a, b with CCl 4 affords the chloro-substituted phosphenium complex Cp(OC) 2MP(Cl)(2,4,6- tBu 3C 6H 2) ( 10a, b) via H/Cl exchange at the sp 2-phosphorus. Substitution of the P-bonded hydrogen by a methyl group is achieved by in situ deprotonation of 7b and subsequent treatment with methyliodide, yielding the diorgano-phosphenium complex Cp(OC) 2MP(Me)(2,4,6- tBu 3C 6H 2) ( 11).