Halogen vs. ionic bonding: an unusual isomorphism between the neutral (C5Me5)2Fe/C2I2 cocrystal and ionic [(C5Me5)2Fe]Br3 crystal
Yury V. Torubaev, Ivan V. Skabitsky, Georgy A. Saratov, P.Yu. Barzilovich
Abstract
Almost equal molecular sizes of diiodoacetylene (C2I2) and the [Br3]− anion result in isomorphic neutral cocrystal (DMFc–C2I2) and [DMFc]+Br3− salt. This isomorphic pair of neutral and ionic crystals provides a unique example for the analysis of different types of bonding resulting in isotypic solid-state structures. Their energy frameworks visualize the obvious difference between their energetic structures: the lattice of DMFc–C2I2 is built upon the chains stabilized by I···(η5-C5Me5) halogen bonds; at the same time, [DMFc]+Br3− consists of electrostatically assembled layers associated by Br···π(Cp*) XBs interactions.
Topics & Concepts
CocrystalChemistryIonic bondingHalogenCrystallographyHalogen bondCrystal structureIonLattice energySalt (chemistry)Isomorphism (crystallography)MoleculeHydrogen bondPhysical chemistryOrganic chemistryAlkylCrystallography and molecular interactionsInorganic Fluorides and Related CompoundsOrganoboron and organosilicon chemistry