The crystal structure of 6-amino-5-carboxypyridin-1-ium pentaiodide monohydrate C6H9I5N2O3

C6H9I5N2O3, triclinic, P1¯ (no. 2), a = 7.4851(5) Å, b = 9.6056(6) Å, c = 12.4084(7) Å, α = 109.119(3)°, β = 99.341(3)°, γ = 92.334(3)°, V = 827.53(9) Å3, Z = 2, R gt (F) = 0.0234, wR ref (F 2) = 0.0449, T = 150.0 K.

Isolation of unique heterocycles formed from pyridine-thiocarboxamides as diiodine, iodide, or polyiodide salts

The reaction of pyridine-thiocarboxamides with I2 provided a variety of novel heterocyclic products as iodide, triiodide, and/or pentaiodide salts. Bismuth triiodide was incorporated as a crystallization aid to access other structural types.

Words in supramolecular chemistry: the ineffable advances of polyiodide chemistry

Polyiodide chemistry has a rich history deeply intertwined with the development of supramolecular chemistry. Technological and theoretical interest in polyiodides has not diminished in the last decade, quite the contrary; yet the advances this perspective intends to cover are muddled by the involution of supramolecular vocabulary, preventing their unbiased discussion. Herein we discuss the pressing necessity of ordering the current babel of novel - and less so - supramolecular terms. Shared decisions at the community level might be required to shape the field into a harmonious body of knowledge, dominated by concepts rather than words. Secondary, σ-hole and halogen bonding schools of thought are all addressed here, together with their respective impact on the field. Then, on the basis of a shared vocabulary, a discussion of polyiodide chemistry is presented, starting with a revisited view of triiodide. The contemporary fields of supramolecular caging and polyiodide networks are then discussed, with emphasis on how the terms we choose to use deeply affect scientific progress.

Electronic criterion for categorizing the chalcogen and halogen bonds: sulfur–iodine interactions in crystals

Diversity of mutual orientations of Y–S and I–X and covalent bonds in molecular crystals complicate categorizing noncovalent chalcogen and halogen bonds. Here, the different types of S...I interactions with short interatomic distances are analysed. The selection of S...I interactions for the categorization of the chalcogen and halogen bonds has been made using angles that determine the mutual orientation of electron lone pairs and σ-holes interacted S and I atoms. In complicated cases of noncovalent interactions with `hole-to-hole' of S and I orientations, distinguishing the chalcogen and halogen bonds is only possible if the atom is uniquely determined, which also provides the electrophilic site. The electronic criterion for chalcogen/halogen bonds categorizing that is based on analysis of dispositions of electron density and electrostatic potential minima along the interatomic lines has been suggested and its effectiveness has been demonstrated.

I5 – polymers with a layered arrangement: synthesis, spectroscopy, and structure of a new polyiodide salt in the nicotine/HI/I2 system

The reaction of S-nicotine with hydroiodic acid in the presence of iodine gave the new polyiodide-containing salt nicotine-1,1′-diium bis(triiodide)-diiodine (1/1) (C10H16N2) [I3]2·I2 (1). The title compound has been characterised by spectroscopic methods (Raman and IR) and single-crystal X-ray diffraction. The asymmetric unit of the title structure consists of one dication, two triiodide anions, and one iodine molecule, all located in general positions in the non-centrosymmetric space group P1. One of the two crystallographically independent triiodide anions and the doubly protonated nicotinium dication form hydrogen-bonded chains along b, which are arranged parallel to each other in the ½bc plane. The second crystallographically independent triiodide anion and the iodine molecule form an I5 – moiety, which is end-on connected to two symmetry-related anions resulting in polyiode zig–zag chains along the [0 1 1̅] direction. These polyiodide chains are stacked parallel to each other in the 0bc plane. The Raman spectrum of the title compound shows characteristic lines in the 50–200 cm–1 range, which are in excellent agreement with the findings derived from the crystal structure.

Raman spectroscopy study of new thia- and oxazinoquinolinium triodides

New polyiodides of thia- and oxa-zinoquinolinium derivatives were characterized using Raman spectroscopy and periodic 3D calculations of the Raman intensities. Polarized Raman spectra of the oriented crystals revealed the features of spatial organization in the polyiodide-anion chains.