Ir(I)–Bi(III) Donor–Acceptor Adducts Stabilized by Dispersion Interactions between the Metal Pincer Ligands and Their Possible Self-Assembly Forming Molecular 1D Semiconductors

Structure, stability, and electronic properties of the bimetallic {[IrI(terpy)(Me)]-[BiIIINNN]}n monomeric, oligomeric, and polymeric structures (n = 1–3 and ∞; terpy = terpyridine; Me = methyl; BiNNN = bismuth triamide) and their derivatives (designated as (Bi·Ir)n structures) were studied theoretically by DFT cluster and periodic calculations. Stable Bi·Ir adducts (monomers) were formed with short Bi–Ir bonds (2) and electron-withdrawing (NO2, F, CF3) groups, respectively, enhanced the Ir → Bi charge transfer, substantially stabilizing the Bi·Ir monomers. The monomers from the unsubstituted complexes can be considered as dispersion stabilized adducts, and they may form spontaneously (Bi·Ir)n layered oligomers/polymers with semiconducting properties. The self-assembly of monomers into oligomers/polymers is hindered by bulkier protecting groups on the Bi(III) complex, such as tBu and SiMe3.