Weak Pnictogen Bond with Bismuth: Experimental Evidence Based on Bi−P Through‐Space Coupling

To study pnictogen bonding involving bismuth, flexible accordion‐like molecular complexes of the composition [P(C(6)H(4)‐o‐CH(2)SCH(3))(3)BiX(3)], (X=Cl, Br, I) have been synthesised and characterised. The strength of the weak and mainly electrostatic interaction between the Bi and P centres strongly depends on the character of the halogen substituent on bismuth, which is confirmed by single‐crystal X‐ray diffraction analyses, DFT and ab initio computations. Significantly, (209)Bi–(31)P through‐space coupling (J=2560 Hz) is observed in solid‐state (31)P NMR spectra, which is so far unprecedented in the literature, delivering direct information on the magnitude of this pnictogen interaction.