Ferrocenylalkynes as ligands in transition metal complexes

Several ferrocenylalkynes have been prepared and their reaction with dicobalt octacarbonyl led to the formation of [Co-2(CO)(6)(mu-eta (2):eta (2)-ethynylferrocene)] 1, [Co-2(CO)(6)(mu-eta (2):eta (2)-1,4-bis(ferrocenyl)butadiyne)] 2, [(Co-2(CO)(6))(2)(mu-eta (2):eta (2),mu-eta (2):eta (2)-1,4-bis(ferrocenyl)butadiyne)] 3, [Co-2(CO)(6)(mu-eta (2):eta (2)-1-ferrocenylethynyl-2-hydro-1,2-dihydro-[60]fullerene)] 4, [Co-2(CO)(6)(mu-eta (2):eta (2)-1,1'-bis(phenylethynyl)ferrocene)] 5 and [(Co-2(CO)(6))(2)(mu-eta (2):eta (2),mu-eta (2):eta (2)-1,1'-bis(phenylethynyl)ferrocene)] 6. The [Mo-Co]-alkyne adducts [MoCo(CO)(5)(eta (5)-C5H5)(mu-eta (2):eta (2)-ethynylferrocene)] 7 and [MoCo(CO)(5)(eta (5)-C5H5)(mu-eta (2):eta (2)-1,4-bis(ferrocenyl)butadiyne)] 8 were obtained from complexes 1, 2 and 3. The molecular structures of compounds 2, 3, 6 and 7 were determined by X-ray diffraction, only 6 has the cyclopentadienyl rings of the ferrocene unit eclipsed. The reaction of 1 with bis(diphenylphosphino)methane (dppm) and 1,1'-bis(diphenylphosphino)ferrocene (dppf) resulted in the formation of [Co-2(CO)(4)(mu-eta (1):eta (1)-dppm)(mu-eta (2):eta (2)-ethynylferrocene)] 9 and [(Co-2(CO)(4))(2)(mu-eta (1):eta (1)- dppf)(2)(eta (1)-mu-eta (1)-dppf)(mu-eta (2):eta (2)-ethynylferrocene)(2)] 10, respectively. The reaction of HPPh2 with 7 gave the monosubstituted product [MoCo(CO)(4)(eta (5)-C5H5)(PHPh2)(mu-eta (2),eta (2)-ethynylferrocene)] 11. The bis(phosphido)-bridged complex [Co-2(CO)(6)(mu -PPh2)(2)] undergoes regiospecific insertion with ethynylferrocene to give [Co-2(CO)(4){(mu-eta (4)-PPh2CHCRC(O)}(mu -PPh2)] (R=ferrocene) 12, which was characterized by X-Ray diffraction and contains a five-membered metallacyclic ring.