Four peri‐substituted acenaphthylphosphinoboranes 5‐Ph2P‐Ace‐6‐BRR′ (R = R′ = H; R = H, R′ = C6F5; R = Cl, R′ = C6F5; R = R′ = C6F5), possessing functionality at the B atoms, were prepared and fully characterized. A quantum‐chemical analysis of these and previously known (ace‐)naphthylaminoboranes and (ace‐)naphthylphosphinoboranes revealed that these compound classes can be divided into three subclasses, namely: regular Lewis pairs (LPs) with predominately attractive peri interactions; frustrated Lewis pairs (FLPs) with predominately repulsive peri interactions; and regular Lewis pairs with predominately repulsive peri interactions. The latter subclass is a straightforward example of the enforced proximity donor concept. A detailed bond analysis showed no principal difference between attractive and enforced B–P bonds in (ace‐)naphthylphosphinoboranes.

In some cases, the antimony atoms not only provide electron density to the transition metal, but also act as acceptor for chloride ions.

The reaction of bis(6‐diphenylphosphinoacenapht‐5yl)mercury, (6‐Ph2P‐Ace‐5‐)2Hg, with [(CO)2RhCl]2 and PtCl2 proceeded with extrusion of mercury / mercury(I) chloride and provided the octahedral rhodium and platinum complexes (6‐Ph2P‐Ace‐5‐)2Rh(CO)Cl and (6‐Ph2P‐Ace‐5‐)2PtCl2, respectively. The reaction of the (6‐diphenylphosphinoacenapht‐5yl)stannane 6‐Ph2P‐Ace‐5‐SnBu3 with PdCl2 gave rise to tributyltin chloride and a dimeric arylpalladium chloride [(6‐Ph2P‐Ace‐5‐)PdCl]2 with a planar Pd2Cl2 core. Together with the previously known gold(III) complex cis‐ and trans‐[R2Au][Cl], the newly prepared compounds were investigated by DFT calculations. The fully optimized gas‐phase structure of [(6‐Ph2P‐Ace‐5‐)PdCl]2 gives rise to a bend Pd2Cl2 core featuring a Pd···Pd palladophilic interaction. The bonding situation was studied using a set of real‐space bonding indicators (RSBIs) derived from the methods Atoms‐In‐Molecules (AIM), Electron Localizability Indicator (ELI‐D) and Non‐Covalent Interaction (NCI) index.

The reaction of (5-Ph 2 P-Ace-6-)Li (I) with InCl 3 provided (6-Ph 2 P-Ace-5-) 3 In (1), which proved to be a remarkably mild transmetalation reagent. The reaction of 1 with NiCl 2 , originally aimed to allow for a Z-type complex, gave (6-Ph 2 P-Ace-5-) 2 InCl (2) and (6-Ph 2 P-Ace-5-) 2 Ni (3), a rare example of a welldefined σ-bonded diorganonickel species. The reaction of (6-Ph 2 P-Ace-5-)X (II, X = F; III, X = Cl; IV, X = Br; V, X = I) with Ni(COD) 2 gave rise to the related dinuclear organonickel halides [(6-Ph 2 P-Ace-5-)NiX] 2 (4, X = F; 5, X = Cl; 6, X = Br; 7, X = I), which upon addition of MeCN yielded the mononuclear complexes (6-Ph 2 P-Ace-5-)Ni(NCMe)X (8, X = Cl; 9, X = Br; 10, X = I). At slightly elevated temperatures, 3−7 undergo a C−C cross-coupling reaction to give 6,6′-bis(diphenylphosphino)-5,5′-biacenaphthyl, (6-Ph 2 P-Ace-5-) 2 (11), having the potential for axial chirality. The electronic structures of 1−10 were investigated by DFT and TD-DFT calculations, including a set of realspace bonding indicators derived from the atoms in molecules (AIM), electron localizability indicator (ELI), and noncovalent interaction (NCI) index schemes.