Unveiling ammonia’s dual role in the [Zn(NH$_3$)$_4$]SO$_4$$\cdot$H$_2$O synthesis : a Zn(II) ligand and nucleophile in the reaction with nitrile

Modec, Barbara (author), Podjed Rihtaršič, Nina (author)

As a follow-up of the studies on zinc(II) amidine complexes, solvothermal reactions involving zinc(II) sulfate heptahydrate, carboxylic acid (picolinic, pyrazinoic or quinoline-2-carboxylic acid), piperidine, nitrile (acetonitrile or propionitrile) and methanol were investigated. Two novel compounds were obtained and structurally characterized: the tetraamminezinc(II) complex [Zn(NH$_3$)$_4$]SO$_4$$\cdot$H$_2$O (1) and the amidinium salt (propioamH)(pipeH)SO$_4$ (4) (propioamH$^+$ = protonated amidine, pipeH$^+$ = piperidinium cation). Compound 1 formed through coordination of in-situ generated ammonia, arising from the partial hydrolysis of nitrile under harsh reaction conditions, to zinc(II) ions. The double salt 4 consists of protonated propionamidine and piperidinium cations with sulfate counter-anions. The amidine is formed by the nucleophilic addition of ammonia to the triple bond of propionitrile. In addition, two previously known complexes were obtained: pipeamH[Zn(pic)$_3$]·0.5H$_2$O (2) (pipeamH$^+$ = protonated amidine derived from piperidine and acetonitrile, pic$^–$ = anion of picolinic acid) and [Zn(quin)$_2$(NH$_3$)] (3) (quin$^–$ = anionic form of quinoline-2-carboxylic acid). These results expand the understanding of zinc(II)-mediated formation of amidine species and nitrile hydrolysis.

• Language: English
• Keywords: coordination chemistry, zinc(II), ammine complexes, amidine, nitrile hydrolysis
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Publication status: Published
• Publication version: Version of Record
• Year: 2026
• Number of pages: Str. 325-339
• Numbering: Vol. 79, iss. 4
• PID: 20.500.12556/RUL-181505
• UDC: 546.3/.9
• ISSN on article: 0095-8972
• DOI: 10.1080/00958972.2026.2613944
• COBISS.SI-ID: 274635779
• Publication date in RUL: 09.04.2026

Record is a part of a journal

• Title: Journal of coordination chemistry
• Shortened title: J. coord. chem.
• Publisher: Taylor & Francis
• ISSN: 0095-8972
• COBISS.SI-ID: 25726976

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: koordinacijska kemija, cink(II), aminski kompleksi, amidin, hidroliza nitrila

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P1-0134
• Name: Kemija za trajnostni razvoj

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: I0-0022
• Name: Mreža raziskovalnih infrastrukturnih centrov Univerze v Ljubljani (MRIC UL)