Fritsch, Joseph M. Retka, Noah D. McNeill, Kristopher Synthesis, Structure, and Unusual Reactivity of β-Halovinyl Cobalt Porphyrin Complexes The preparation, structures, and reactivity of tetraphenylporphyrin (TPP) cobalt halovinyl complexes are reported. β-Halovinyl complexes of (TPP)Co(<i>E</i>-CHCHX) (X = Br and I) were prepared from the insertion of acetylene into the cobalt halide bonds of the corresponding halide complexes. The reactivity of these compounds and of the previously reported (TPP)Co(<i>E</i>-CHCHCl), was studied in depth, and it was found that complex reactivity increased with the leaving group ability of the halide. A <i>trans</i>-dichlorovinyl cobalt porphyrin complex, (TPP)Co(<i>Z</i>-CClCHCl), was also prepared through the reaction of (TPP)CoNa and TCE. The structures of (TPP)Co(<i>E</i>-CHCHBr), (TPP)Co(<i>Z</i>-CClCHCl), and (TPP)Co(C<sub>2</sub>H) are reported. The C−C bond length of the vinyl group was found to vary for the β-halovinyl complexes (TPP)Co(<i>E</i>-CHCHX) from 1.211 Å for X = Br to 1.234 Å for X = Cl and 1.320 Å for (TPP)Co(<i>Z</i>-CClCHCl). A comparison of these structures to many chlorovinyl cobalt complexes shows that <i>trans</i>-2-halo substitution results in a dramatically decreased vinyl C−C bond length. The mechanism of halide substitution for the β-halovinyl complexes was investigated with kinetic experiments that indicated a dissociative mechanism and supported the intermediacy of a cobalt acetylene complex. cobalt halovinyl complexes;halide complexes;TCE;1.320 Å;1.211 Å;cobalt halide bonds;TPP;dichlorovinyl cobalt porphyrin;dissociative mechanism;vinyl group;halide substitution;Unusual Reactivity;group ability;CHCHX;chlorovinyl cobalt complexes;1.234 Å;cobalt acetylene 2006-03-06
    https://acs.figshare.com/articles/journal_contribution/Synthesis_Structure_and_Unusual_Reactivity_of_Halovinyl_Cobalt_Porphyrin_Complexes/3234865
10.1021/ic0518834.s004