SYNTHESIS, STRUCTURE, AND REDOX CHEMISTRY OF HETEROPOLYMETALLIC CARBON COMPLEXES WITH MC(2)M', MC(4)M', AND MC(4)M'C(4)M LINKAGES - TRANSMETALATIONS OF LITHIOCARBON COMPLEXES (ETA(5)-C(5)ME(5))RE(NO)(PPH(3))(C-CLI) AND (ETA(5)-C(5)ME(5))RE(NO)(PPH(3))(C-CC-CLI)
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Reactions of (5-C5Me5)Re(NO)(PPh3)(CCLi) and trans-Pd(PEt3)2(Cl)2 or trans-Rh(PPh3)2(CO)(Cl) give heterobimetallic C2 complexes trans-(5-C5Me5)Re(NO)(PPh3)(CC)Pd(PEt3)2(Cl) (3, 66%) or trans-(5-C5Me5)-Re(NO)(PPh3)(CC)Ph(PPh3)2(CO) (4, 72%). Reaction of [5-C5Me5)Re(NO)(PPh3)(ClC6H5)]+ BF4 and HCCCCSiMe3 gives [(5-C5Me5)Re(NO)(PPh3)(HCCCCSiMe3)]+ BF4 (93%; HCC ligated), which with t-BuOK and K2CO3/MeOH yields (5-C5Me5)Re(NO)(PPh3)(CCCCH) (9, 84%). Reaction of 9 and n-BuLi gives (5-C5Me5)Re(NO)(PPh3)(CCCCLi) (10), which is trapped by MeI as (5-C5Me5)Re(NO)(PPh3)(CCCCMe) (85%). Reaction of 10 and trans-Pd(PEt3)2(Cl)2 (2:1) gives trans-(5-C5Me5)Re(NO)(PPh3)(CCCC)Pd-(PEt3)2(CCCC)(Ph3P)(ON)Re(5-C5Me5) (12, 73%). At a 1:1 stoichiometry, trans-(5-C5Me5)Re(NO)(PPh3)-(CCCC)Pd(PEt3)2(Cl) (13) is the major product. Cyclic voltammograms of 3, 12, and 13 show reversible one-electron oxidations. Reactions of 3 and 12 with (5-C5H5)2Fe+ PF6 give the radical cations 3+ PF6 and 12+ PF6. These are unstable at room temperature, but ESR data show the odd electrons to be localized on (one) rhenium. Complexes 3 and 4 (but not 12 and 13) exhibit restricted rotation about the ReCxM moiety, as evidenced by two R3PMPR331P NMR signals at low temperature (G(Tc) = 11.710.9 kcal/mol). The crystal structure of 3 shows eclipsed PEt3 ligands. 1995, American Chemical Society. All rights reserved.
