Figure 6: Molecular structure of [(phen)₂In^I−Ag^I(C₆H₅F)]²⁺ (8²⁺).

Selected bond lengths are given in pm and angles in °: av. In−N=233.3(3), In−Ag=256.37(5), Ag−cent=239.4 and In−Ag−cent=173.0 (cent=centroid of the η³-coordinating C₆H₅F; the linearity is in good agreement with earlier reported systems⁷⁰). The [Al(OR^F)₄]^– anions and all of the hydrogen atoms were omitted for clarity. The thermal ellipsoids are set at 50% probability. An alternate formulation as [(phen)₂In^I−In^I(C₆H₅F)]²⁺ diindane is not conceivable, as a [In^I(C₆H₅F)]⁺ complex would be η⁶-coordinated. In addition, the X-ray diffraction refinement of the diindane formulation gave inferior R-factors and the DFT structure refinement did not converge. As an inset, the figure also contains the highest occupied molecular orbital (HOMO) of the converged 8²⁺ structure. The latter features a constructive interaction between the occupied 5 s orbital of the [In^I(phen)₂]⁺ complex and the unoccupied 5 s/4d_z2 hybrid orbital⁷⁰ of the [Ag^I(C₆H₅F)]⁺ complex. The calculated distances are in good agreement with experimental results (bond lengths in pm and angles in °): av. In−N=235.1, In−Ag=262.2, Ag−cent=253.4 and In−Ag−cent=175.0 (B3LYP/SV(P) level, electron density cutoff at 0.06 a.u.).