Synthesis and reactivity of #mu#-bis(carbene)dimanganese complexes. X-ray structures of {Cp'(CO)_2Mn}_2{#mu#-=C(OEt)CH_2CH_2(EtO)C=}, (E)-{Cp'(CO)_2Mn}_2{#mu#-=C(OEt)CH=CH(EtO)C=} and {Cp'(CO)_2Mn}_2{#mu#-=CN(Ph)CH(Ph)CHCHCH(Ph)N(Ph)C=}

摘要

The carbene anions resulting from in situ deprotonation of the Fischer-type carbene complexes Cp'(CO)1Mn=C(OEt)CH1R (I; la: R = H; lb: Me) undergo an oxidative coupling in the presence of Cu(I), Cu(II) or Fe(l11) salts to produce the corresponding tl-bis(carbene)dimanganese complexes {Cp'(CO)1Mn}_2{tl-=C(OEt)CH(R)CH(R)(OEt)C",} (2; 2a: R = H; 2b: Me). Double depro- tonation of 2a gives a dianionic species that undergoes an oxidation in the presence of Fe(l11) chloride" to afford the f.l-bis(vinylcarbene)dimanganese complex (E)-{Cp'(CO)1Mn}1{f.l-=C(OEt)CH=CH(OEt)C=} (3). The controlled electro-reduction of the latter gives a radical anion whose ESR spectrum is consistent with a type III MnO(MDI mixed valence complex. When reacted with BC13 followed by benzylideneaniline complex 2 afford a mixture of the mixed f.l-(alkylalkoxy carbene(azetidinylidene)dimanganese complex {Cp'(CO)1Mn}1{f.l-=C(OEt)CH1CHCH(Ph)N(Ph)C=} (4) and the f.l-bis(azetidinylidene)dimanganese complex {Cp'(CO)1Mn}1{f.l-=CN(Ph)CH(Ph)CHtHCH(Ph)N(Ph)C",} (5). Complex 4 is the product of a net [2 + 2] cycloaddition reaction between the mixed f.l-(alkylalkoxy carbene/carbyne)dimanganese complex { Cp'(CO)1Mn} 1{f.l-=C(OEt)CH1CH~C=} + [6]+ and the imine, whereas 5 results from a net 2 x [2 + 2] cycloaddition between the f.l-bis(carbyne)dimanganese complex {Cp'(CO)2Mn}2{f.l-=CCH1CH1C;}~+ [7]1+ and imine. The treatment of complex 4 by BCl_3 followed by ~action ~th ben~lideneaniline afford the mixed f.l-(vinylidene(azetidinylidene)dimanganese complex {Cp'(CO)1Mn}1{f.l-=C-~HCHCH(Ph)N(Ph)C",} (8). Finally, the oxidative coupling-type reaction observed from the alkylalkoxy carbene complex I could be extended to the azetidinylidene complex [Cp'(CO)_2Mn=CN(Ph)CHPhCH1]{lO) to yield 5 in a selective manner.