On the importance of π-hole spodium bonding in tricoordinated HgII complexes

A new coordination polymer [Hg(L-I)I](n) (1) and a new discrete coordination complex [Hg(HLII)I-2] (2) are synthesized and X-ray characterized. The existence of positive pi-holes at the spodium atoms in both compounds is evidenced by DFT calculations. In 1, a Hg-S semicoordination bond and a Hg center dot center dot center dot I spodium bond are formed at opposite sides of the pi-hole. In 2, two different Hg center dot center dot center dot I spodium bonds are formed at both sides of the pi-hole. This is the first study describing structure-guiding pi-hole spodium bonding.