Bifunctional Carriers of Organometallic Functionalities: Alkali Metal-Zirconium-Hydrido, -Alkyl, and -Allyl Derivatives of meso-Octaethylporphyrinogen and Their Reaction with Isocyanides

The reaction of alkali-metal organometallics with the meso-octaethylporphyrinogenzirconium complex [(eta(5):eta(1):eta(5):eta(1):-Et(8)N(4))Zr(THF)] (1), acting as a bifunctional carrier, led to the formation of bimetallic K-Zr and Li-Zr organometallics. Such compounds formed from the addition of the nucleophilic fragment to zirconium, while the alkali-metal cation remained bonded to the electron-rich periphery of the porphyrinogen moiety. The addition of ICE to 1 in a 1:1 molar ratio led to the formation of the dinuclear complex [{(eta(5):eta(1):eta(1):eta(1):-Et(8)N(4))Zr}(2)-{mu-KH}(2)] (2), while with a large excess of KH under controlled conditions we obtained a tetranuclear polyhydride species, [{(eta(5):eta(1):eta(1):eta(1)-Et(8)N(4))Zr}(4){KH}(8) .(THF)(10)], (3), having the [Zr4K4H8] skeleton containing both mu(2)- and mu(3)-hydrides. In toluene-THF, the addition of LiR to 1 gave the monomeric dimetallic lithium-zirconium alkyls [{(eta(5):eta(1):eta(1):eta(1)-Et(8)N(4))Zr-R}{Li(THF)(2)}] (R = Me, 4; R = Bu(t), 5). The reaction of 1 with potassium allyl gave a structurally complex, bimetallic, polynuclear compound where the allyl fragment interacts in both an eta(1) and eta(2) fashion, with zirconium and potassium, respectively, to give complex 6, [(eta(5):eta(1):eta(1):eta(1)-Et(8)N(4))Zr(mu-eta(3)-C3H5)K](n) Other potassium-zirconium alkyl derivatives are accessible via: (i) the hydrozirconation of olefins using complex 2 (the reaction of 2 with ethylene gave [{(eta(5):eta(1):eta(1):eta(1)-Et(8)N(4))Zr-CH2CH3}(2)(mu-K)(2)] (7)) and (ii) the exchange of the alkali-metal cation (the reaction of 4 with KH led to the corresponding KMe. derivative supported by 1, [{(eta(5):eta(1):eta(1):eta(1)-Et(8)N(4))Zr-Me}{K(THF)}(2)] (8)). The bimetallic K-Zr alkyl and hydride derivatives are very reactive in insertion reactions. The reaction of 2 and 4 with Bu(t)NC led respectively, to the corresponding eta(2)-iminoformyl [{(eta(5):eta(1):eta(1):eta(1)-Et(8)N(4))Zr(eta(2)-CH=NBu(t))}(2)(mu-K)(2)] (9)), and eta(2)-iminoacetyl ([{eta(5):eta(1):eta(1):eta(1)-Et(8)N(4))Zr(eta(2),C(Me)=NBUt)}{Li(THF)}] (10)), complexes. As such, 9 and 10 should be considered as polar alkali-metal iminoformyl and iminoacetyl derivatives bonded to the bifunctional complex 1.