In 2019,Angewandte Chemie, International Edition included an article by Iwasaki, Mitsuhiro; Shichibu, Yukatsu; Konishi, Katsuaki. Quality Control of 4-Iodopyridine. The article was titled 《Unusual Attractive Au-π Interactions in Small Diacetylene-Modified Gold Clusters》. The information in the text is summarized as follows:
It is well known that alkynes act as π-acids in the formation of complexes with metals. Authors found unprecedented attractive Au-π interactions in diacetylene-modified [core+exo]-type [Au8]4+ clusters. The 4-phenyl-1,3-butadiynyl-modified cluster has unusually short Au-Cα distances in the crystal structure, revealing the presence of attractive interactions between the coordinating CC moieties and the neighboring bitetrahedral Au6 core, which is further supported by IR and NMR spectra. Such weak interactions are not found in mono-acetylene-modified clusters, which indicates that they are specific for diacetylenic ligands. The attractive Au-π interactions are likely associated with the low energy of the π* orbital in the diacetylenic moieties, into which the valence electrons of the gold core may be back donated. The [Au8]4+ clusters show clear red-shifts of >10 nm with respect to the corresponding mono-acetylenic clusters in UV/Vis absorption bands, which indicates substantial electronic perturbation effects of the Au-π interactions. The results came from multiple reactions, including the reaction of 4-Iodopyridine(cas: 15854-87-2Quality Control of 4-Iodopyridine)
4-Iodopyridine(cas: 15854-87-2) belongs to pyridine. Pyridine’s structure is isoelectronic with that of benzene, but its properties are quite different. Pyridine is completely miscible with water, whereas benzene is only slightly soluble. Like all hydrocarbons, benzene is neutral (in the acid–base sense), but because of its nitrogen atom, pyridine is a weak base.Quality Control of 4-Iodopyridine
Referemce:
Iodide – Wikipedia,
Iodide – an overview | ScienceDirect Topics – ScienceDirect.com