Placing Ag+ ion inside penta-indenocorannulene bowl

Theoretical evaluation of potential coordination sites of the large and strained bowl-shaped polyarene, C50H12, towards Ag+ ion binding has been accomplished using the DFT-D level of theory (RI-BP86-D/def2-TZVPP(Ag)//cc-pVDZ(C,H)). Analysis of all possible {Ag-C50H20}+ mono-adducts reveals the preferential metal binding site inside the C50H20 bowl. The most energetically favorable isomer has the Ag+ ion sandwiched between two benzene rings of the adjacent indeno-groups of penta-indenocorannulene in {Ag-endo-Bβ-C50H20}+. Several other stable mono-adducts are found to be notably higher in energy: {Ag-exo-spoke-C50H20}+ (+5.41 kcal/mol), {Ag-exo-rim-C50H20}+ (+7.21 kcal/mol), {Ag-exo-hub-C50H20}+ (+8.10 kcal/mol), and {Ag-endo-hub-C50H20}+ (+8.93 kcal/mol). For the series of bis-adducts {C50H20-Ag-C50H20}+, in addition to the endo-Bβ-site, the exo-rim- and exo-spoke-sites of the second C50H20-bowl provide the next low-energy alternatives for sandwiching a Ag+ ion. This coordination is realized in the two most stable bis-adducts which are energetically equivalent (in the frame of DFT approach), but well separated (with a ∼15 kcal/mol gap) from the next isomer on the energy scale.

Theoretical investigation of adducts of Ag+ with large bowl-shaped polyarene, penta-indenocorannulene (C50H20), revealed a new concave coordination mode of silver(I) cation.Figure optionsDownload as PowerPoint slide