The structural landscape of ferrocenyl polychalcogenides

• 1,1’-FcSe 3 , Fc 2 Te 2 and FcTe-TeI 2 Fc (Fc = ferrocenyl) co-crystallize with organic HaB donor. • Resulting cocrystals are stabilized by Se•••Se, I•••Se and I•••Te HaBs and Cp•••C 6 F 4 I 2 π-π interactions. • Packing patterns of the cocrystals can be inherited from the parent crystals (FcTeTeI 2 Fc) or governed only by HaB directionality (1,1’-FcSe 3 and Fc 2 Te 2 ). • Crystal and electronic structure of the cocrystals was studied by SC-XRD and in silico (DFT / NBO). Halogen bond (HaB) assisted co-crystallization strategy was used to explore the structural landscape of ferrocenic polychalcogenides varying from a rather compact ferrocenophane triselenide (1,1’-FcSe 3 ) to bulky diferrocenyl ditelluride (Fc 2 Te 2 ) and its mixed-valent derivative (FcTeTeI 2 Fc). Comparison of the supramolecular organization in their native crystals and respective cocrystals with the iconic halogen bond donor, 1,4-diiodotetrafluorobenzene (p-DITFB), demonstrate three different patterns: 1) conservation of the chain structures for FcTeTeI 2 Fc, 2) transformation of single Se···Se intermolecular interaction to double for FcSe 3 , and 3) for Fc 2 Te 2 , in the absence of specific and directed intermolecular interactions, the cocrystal packing of Fc 2 Te 2 is governed only by p-DITFB HaBs directionality. This allows a rough glimpse of ferrocenic polychalcogenides structural landscape and shows the directions and methods for its further detailization.