C–H Activation in Diiron Bridging Vinyliminium Ligands: Reaction with CS₂ to Form New Zwitterionic Complexes Acting as Organometallic Ligands

Abstract

Abstract The reactions of vinyliminium complexes [Fe 2 {μ‐η 1 :η 3 ‐C(R′)=C(H)C=N(Me)(R)}(μ‐CO)(CO)(Cp) 2 ][SO 3 CF 3 ] (R = Xyl, R′ = Me, 1a ; R = Xyl, R′ = Tol, 1b ; R = Xyl, R′ = COOMe, 1c ; R = Me, R′ = Me, 1d ; R = Me, R′ = n Bu, 1e ; R = p ‐MeOC 6 H 4 , R′ = Me, 1f ; Tol = 4‐C 6 H 4 Me, Xyl = 2,6‐Me 2 C 6 H 3 ) with CS 2 and NaH resulted in the replacement of CH hydrogen (in the bridging frame) with CS 2 to give the corresponding dithiocarboxylate‐vinyliminium complexes [Fe 2 {μ‐η 1 :η 3 ‐C(R′)=C(CS 2 )C=N(Me)(R)}(μ‐CO)(CO)(Cp) 2 ] ( 2a – 2f ). Analogously, 1a and 1d reacted with NaH and SCNPh to afford the complexes[Fe 2 {μ‐η 1 :η 3 ‐C(R′)=C{C(NPh)S}C=N(Me)(R)}(μ‐CO)(CO)(Cp) 2 ](R = Xyl, R′ = Me, 3a ; R = Me, R′ = Me, 3b ), respectively. Complex 2b was methylated at the dithiocarboxylate group upon treatment with CH 3 SO 3 CF 3 to yield [Fe 2 {μ‐η 1 :η 3 ‐C(R′)=C(CS 2 Me)C=N(Me)(Xyl)}(μ‐CO)(CO)(Cp) 2 ][SO 3 CF 3 ] ( 4a ). Likewise, the zwitterionic complexes 2d – f underwent addition of the metal fragment [Fe(CO) 2 Cp] + at the dithiocarboxylate group to yield the corresponding triiron complexes [Fe 2 {μ‐η 1 :η 3 ‐C(R′)=C(CS 2 Fp)C=N(Me)(R)}(μ‐CO)(CO)(Cp) 2 ][SO 3 CF 3 ] [R = R′ = Me, 4b ; R = Me, R′ = n Bu, 4c ; R = p ‐MeOC 6 H 4 , R′ = Me, 4d ; Fp = Fe(CO) 2 Cp]. In a related reaction with [Pd(CH 3 CN) 2 Cl 2 ], 2a binded to Pd through the dithiocarboxylate group as chelating ligand to afford the complex [PdCl 2 {κ 2 ‐( S , S )‐ 2a }] ( 5 ). The X‐ray structures of 2b , 3a and 4d have been determined.