“Click” Chemistry in Metal Coordination Spheres: Copper(I)-Catalyzed 3+2 Cycloadditions of Benzyl Azide and Platinum Polyynyl Complexes trans -(C 6 F 5 )( p -tol 3 P) 2 Pt(C≡C) n H ( n = 2−6)

Gauthier, Sébastien; Weisbach, Nancy; Bhuvanesh, Nattamai; Gladysz, John A.

doi:10.1021/om900680q

Anions formed by the perhalobenzene series C$$_6$$Cl$$_{n}$$F$$_{6-n}$$ ($n=0-6$) are studied computationally. All members of the series form both stable valence and stable non-valence anions. At the geometry of the neutral parents, only non-valence anions are bound, and the respective vertical electron affinities show values in the $20$ to $60$meV range. Valence anions show distorted non-planar structures, and one can distinguish two types of conformers. A-type conformers show puckered-ring structures and excess electrons delocalized over several C-Cl bonds [in case of C$$_6$$F$$_6^-$$, C-F bonds], while B-type conformers possess excess electrons essentially localized in a single C-Cl bond, which is accordingly strongly stretched and bent out-of-plane. For a specific anion, all conformers are close in energy (relative energies of less than $10$kJ/mol) and are connected by low-lying transition states. Accordingly, A-type and B-type conformers possess similar adiabatic electron affinities, however, their vertical detachment energies exhibit drastically different values, which should ease conformer distinction in photoelectron spectroscopy.

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