Synthesis and reactivity of mu-bis(carbene)dimanganese complexes. X-ray structures of {Cp '(CO)(2)Mn}(2){mu-=C(OEt)CH2CH2(EtO)C=}, (E)-{Cp '(CO)(2)Mn}(2){mu-=C(OEt)CH=CH(EtO)C=} and {Cp '(CO)(2)Mn}(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)(2)Mn=C(OEt)CH2R (1; 1a: R = H; 1b: Me) undergo an oxidative coupling in the presence of Cu(I), Cu(II) or Fe(III) salts to produce the corresponding mu -bis(carbene)dimanganese complexes {Cp'(CO)(2)Mn}(2){mu-=C(OEt) CH(R)CH(R)(OEt) C=) (2; 2a: R = H; 2b: Me). Double deprotonation of 2a gives a dianionic species that undergoes an oxidation in the presence of Fe(III) chloride to afford the mu -bis(vinylcarbene)dimanganese complex (E)-(Cp'(CO)(2)Mn}(2)(mu-=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 Mn-0/Mn-I mixed Valence complex. When reacted with BCl3 followed by benzylideneaniline complex 2 afford a mixture of the mixed mu-(alkylalkoxy carbene/azetidinylidene)dimanganese complex {Cp'(CO)(2)Mn}(2){mu-=C(OEt) CH2CHCH(Ph)N(Ph)h=} (4) and the mu -bis(azetidinylidene) dimanganese complex {Cp'(CO)(2)Mn}(2)(mu-=CN(Ph)CH(Ph)CHCHCH(Ph)N(Ph) C=} (5). Complex 4 is the product of a net [2 + 2] cycle addition reaction between the mixed mu-(alkylalkoxy carbenejcarbyne)dimanganese complex (Cp'(CO)(2)Mn}(2){mu-=C(OEt)CH2CH2C drop) (+) [6](+) and the imine, whereas 5 results from a net 2 x [2+2] cycloaddition between the mu -bis(carbyne)dimanganese complex (Cp'(CO)(2)Mn}(2)(mu-drop CCH2CH2C drop}(2 +) [7](2+) and imine. The treatment of complex 4 by BCl3 followed by reaction with benzylideneaniline afford the mixed mu-(vinylidene/azetidinylidene)dimanganese complex {Cp'(CO)(2)Mn}{mu-=C=CHCHCH(Ph)N(Ph)C=} (8). Finally, the oxidative coupling-type reaction observed from the alkylalkoxy carbene complex 1 could be extended to the azetidinylidene complex [Cp'(CO)(2)Mn=CN(Ph)CHPhCH2] (10) to yield 5 in a selective manner. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 70]