Kooperative Wirkung in π-Ligand-verbrückten Zweikernkomplexen XX Eine neue Strategie zur Synthese von heterodinuklearen Komplexen mit einem verbrückenden Bis(cyclopentadienyl)-Liganden

Abstract

Abstract The reaction of {M}[ η 5 -C 5 H 4 C(O)OMe]({M} = W(CO) 3 Me: 1a ; {M} = Mn(CO) 3 : 1b ) with tetramethylcyclopentadienyllithium and Me 3 SiCl, subsequently, reveals {M}[ η 5 -C 5 H 4 C(OTMS)(C 5 Me 4 )](OTMS = OSiMe 3 ; {M} = W(CO) 3 Me: 2a ; {M} = Mn(CO) 3 : 2b ) in high yields. Hydrolysis of 2a and 2b results quantitatively in the formation of {M}[ η 5 -C 5 H 4 C(O)(C 5 Me 4 H)] ({M} = W(CO) 3 Me: 3a ; {M} = Mn(CO) 3 : 3b ). 2a,b and 3a,b are versatile precursors for the synthesis of homo- and heterodinuclear complexes containing a bis(cyclopentadienyl) ketone ligand. Deprotonation of 3a and further reaction with [Rh(CO) 2 Cl] 2 yields (Me)(CO) 3 W[ η 5 ( W )-(C 5 H 4 )C(O)- η 5 ( Rh )-(C 5 Me 4 )]Rh(CO) 2 ( 4a ). 4a is also obtained by using 2a instead of 3a . Taking 2a and 2b in corresponding reactions, (CO) 3 Mn[ η 5 ( Mn )-(C 5 H 4 )C(O)- η 5 ( Rh )-(C 5 Me 4 )]Rh(CO) 2 ( 4b ), (Me)(CO) 3 W[ η 5 ( W )-(C 5 H 4 )C(O)- η 5 ( Rh )-(C 5 Me 4 )]Rh(C 7 H 8 ) ( 5 ) (C 7 H 8 = norborna-2,5-diene) and (CO) 3 Mn[ η 5 ( Mn )-(C 5 H 4 )C(O)- η 5 ( Ir )-(C 5 Me 4 )]Ir(C 8 H 12 ) ( 6 ) (C 8 H 12 = cycloocta-1,5-diene) can be synthesized as well. Heating of 3a,b with Co 2 (CO) 8 and 3,3-dimethylbut-l-ene in refluxing THF affords {M}[ η 5 ( M )-(C 5 H 4 )C(O)- η 5 ( Co )-(C 5 Me 4 )]Co(CO) 2 ({M} = W(CO) 3 Me: 7a ; {M} = Mn(CO) 3 : 7b ). The metal-metal bound compounds (CO) 3 W[ η 5 ( W )-(C 5 H 4 )C(O)- η 5 ( M )-(C 5 Me 4 )]M(CO) 2 ( W—M ) (M = Ru: 8 ; M = Fe: 9 ) are formed during the reaction of 3a with the corresponding carbonyl metal complexes in refluxing diglyme. Heating of 3a with a 4.5-fold excess of Fe(CO) 5 yields the homodinuclear complex (CO) 2 Fe[ η 5 -(C 5 H 4 )C(O)- η 5 -(C 5 Me 4 )]Fe(CO) 2 ( Fe-Fe ) ( 10 ) and (CO) 3 W[ η 5 ( W )-(C 5 H 4 )CH 2 - η 5 ( Fe )-(C 5 Me 4 )]Fe(CO) 2 ( W-Fe ) ( 11 ) as unexpected products. 11 contains a completely hydrogenated sp 3 carbon atom as a linker between the two cyclopentadienyl moieties. X-ray diffraction studies of 2b, 5, 7a, 8 and 10 are reported.