Unveiling ammonia’s dual role in the [Zn(NH$_3$)$_4$]SO$_4$$\cdot$H$_2$O synthesisModec, Barbara (Avtor) Podjed Rihtaršič, Nina (Avtor) coordination chemistryzinc(II)ammine complexesamidinenitrile hydrolysisAs a follow-up of the studies on zinc(II) amidine complexes, solvothermal reactions involving zinc(II) sulfate heptahydrate, carboxylic acid (picolinic, pyrazinoic or quinoline-2-carboxylic acid), piperidine, nitrile (acetonitrile or propionitrile) and methanol were investigated. Two novel compounds were obtained and structurally characterized: the tetraamminezinc(II) complex [Zn(NH$_3$)$_4$]SO$_4$$\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.20262026-04-09 10:10:07Članek v reviji181505UDK: 546.3/.9ISSN pri članku: 0095-8972DOI: 10.1080/00958972.2026.2613944COBISS_ID: 274635779sl