6533b7d1fe1ef96bd125c07e

RESEARCH PRODUCT

Acid-Promoted Rearrangement of the Metalated Thienyl Rings in Dirhodium(II) Complexes with Thienyl Phosphines as Ligands

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Several mono- and bis-cyclometalated compounds have been prepared and characterized from the thermal reaction of dirhodium(II) tetraacetate and tris(2-thienyl)phosphine, P(2-C4H3S)3 (1), in toluene/acetic acid mixtures. In refluxing acetic acid, the mono-cyclometalated compound Rh2(O2CCH3)3[(2-C4H2S)P(2-C4H3S)2] (CH3CO2H)2 (2A) isomerizes to Rh2(O2CCH3)3[(3-C4H2S)P(2-C4H3S)2](CH3CO2H)2 (2B), which results from the selective rearrangement of the metalated ring from a 2-thienyl to a 3-thienyl structure. In the same conditions, the bis-cyclometalated compounds of formula Rh2(O2CCH3)2[(2-C4H2S)P(2-C4H3S)2]2(CH3CO2H)2 and with head-to-tail (3AA) or head-to-head (4AA) configuration of the phosphines undergo similar rearrangement, yielding compounds Rh2(O2CCH3)2[(3-C4H2S)P(2-C4H3S)2]2(CH3CO2H)2, 3BB and 4BB, respectively. Compounds with only one ring of the thienyl phosphine rearranged, Rh2(O2CCH3)2[(3-C4H2S)P(2-C4H3S)2][(2-C4H2S)P(2-C4H3S)2](CH3CO2H)2, 3AB and 4AB, have also been isolated. The fastest rearrange...