Tweaking the Charge Transfer: Bonding Analysis of Bismuth(III) Complexes with a Flexidentate Phosphane Ligand

[Image: see text] To account for the charge transfer and covalent character in bonding between P and Bi centers, the electronic structures of [P(C(6)H(4)-o-CH(2)SCH(3))(3)BiCl(n)]((3–n)+) (n = 0–3) model species have been investigated computationally. On the basis of this survey a synthetic target compound with a dative P→Bi bond has been selected. Consecutively, the highly reactive bismuth cage [P(C(6)H(4)-o-CH(2)SCH(3))(3)Bi](3+) has been accessed experimentally and characterized. Importantly, our experiments (single-crystal X-ray diffraction and solid-state NMR spectroscopy) and computations (NBO and AIM analysis) reveal that the P···Bi bonding in this trication can be described as a dative bond. Here we have shown that our accordion-like molecular framework allows for tuning of the interaction between P and Bi centers.