Protonated Organic Diamines as Templates for Layered and Microporous Structures: Synthesis, Crystal Chemistry, and Structural Trends among the Compounds Formed in Aqueous Systems Transition Metal Halide or Nitrate–Diamine–Selenious Acid

• Published in: International journal of molecular sciences Vol. 24; no. 18; p. 14202
• Main Authors: Charkin, Dmitri O., Nazarchuk, Evgeny V., Dmitriev, Dmitri N., Grishaev, Vasili Yu, Omelchenko, Timofey A., Spiridonova, Darya V., Siidra, Oleg I.
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01-09-2023; MDPI
• Subjects: Acids; Crystals; Hydrogen; Hydrogen bonding; Hydrogen bonds; Magnetism; metal halides; microporous structures; Nitrates; organically templated compounds; selenites; Selenium; synthesis; Transition metal compounds; transition metals; Russia
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms241814202

Systematic studies of crystalline compounds formed in aqueous systems containing aliphatic diamines, divalent transition metal halides, and selenious acid resulted in the discovery of a large family of new complex species corresponding to several new structure types. With ethylenediamine (en), layered (enH2)[M(HSeO3)2X2] compounds are the most commonly formed species which constitute a significant contribution to the family of layered hydrogen selenites containing neutral [M(HSeO3)2] (M = Mg, Mn, Co, Ni, Cu, Zn, Cd) 2D building blocks. In contrast to some previous suggestions, piperazine (pip), as well as its homologue N-methylpiperazine, mostly give rise to quite different, sometimes more complex, structures of varied dimensionality while the (pipH2)[M(HSeO3)2X2] compounds are formed only with M = Cu and Cd. In addition, metal-, halide-, or selenium-free by-product species are observed. The SeIV can be present in a multitude of forms, including H2SeO3, HSeO3−, SeO32−, and Se2O52−, reflecting amazing adaptability to the shape of the templating cations.