(6-Diphenylphosphinoacenaphth-5-yl)indium and -nickel Compounds: Synthesis, Structure, Transmetalation, and Cross-Coupling Reactions

The reaction of (5-Ph2P-Ace-6-)Li (I) with
InCl3 provided (6-Ph2P-Ace-5-)3In
(1), which proved to be a remarkably mild transmetalation
reagent. The reaction of 1 with NiCl2, originally
aimed to allow for a Z-type complex, gave (6-Ph2P-Ace-5-)2InCl (2) and (6-Ph2P-Ace-5-)2Ni (3), a rare example of a well-defined σ-bonded
diorganonickel species. The reaction of (6-Ph2P-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-Ph2P-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-Ph2P-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-Ph2P-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 real-space bonding indicators derived
from the atoms in molecules (AIM), electron localizability indicator
(ELI), and noncovalent interaction (NCI) index schemes.