Probing Donor–Acceptor Interactions in peri-Substituted Diphenylphosphinoacenaphthyl–Element Dichlorides of Group 13 and 15 Elements

Transmetalation reactions of ArLi with ECl₃ (E = Al, P, In, Bi) and ArSnBu₃ with ECl₃ (E = B, Ga, Tl, As, Sb) gave rise to the formation of peri-substituted diphenylphosphinoacenaphthyl–element dichlorides ArECl₂ (Ar = 6-Ph₂P-Ace-5-), which were characterized by multinuclear NMR spectroscopy and X-ray crystallography. DFT calculations were performed on the compounds at relaxed gas-phase molecular geometries. For the series ArECl₂ containing group 13 elements one structure type featuring regular Lewis pairs with short E–P peri distances (E = B, Al, Ga, In, Tl) was observed. For the series ArECl₂ containing group 15 elements two structural types with very different peri distances (E = P, As, Sb, Bi) were found. The computed electron and pair densities were topologically analyzed according to the atoms-in-molecules (AIM) and electron localizability indicator (ELI-D) space-partitioning schemes, which facilitates the characterization of the peri interactions and also allows for monitoring minute electronic effects induced by different substituents and/or spatial arrangements.