Fogaca Lara A, Kováts Éva, Németh Gergely, Kamarás Katalin, Béres Kende A, Németh Péter, Petruševski Vladimir, Bereczki Laura, Holló Berta Barta, Sajó István E, Klébert Szilvia, Farkas Attila, Szilágyi Imre M, Kótai László
Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Müegyetem rakpart 3, Budapest H-1111, Hungary.
Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar Tudósok krt 2, Budapest H-1117, Hungary.
Inorg Chem. 2021 Mar 15;60(6):3749-3760. doi: 10.1021/acs.inorgchem.0c03498. Epub 2021 Mar 1.
Two monoclinic polymorphs of [Ag(NH)]MnO containing a unique coordination mode of permanganate ions were prepared, and the high-temperature polymorph was used as a precursor to synthesize pure AgMnO. The hydrogen bonds between the permanganate ions and the hydrogen atoms of ammonia were detected by IR spectroscopy and single-crystal X-ray diffraction. Under thermal decomposition, these hydrogen bonds induced a solid-phase quasi-intramolecular redox reaction between the [Ag(NH)] cation and MnO anion even before losing the ammonia ligand or permanganate oxygen atom. The polymorphs decomposed into finely dispersed elementary silver, amorphous MnO compounds, and HO, N and NO gases. Annealing the primary decomposition product at 573 K, the metallic silver reacted with the manganese oxides and resulted in the formation of amorphous silver manganese oxides, which started to crystallize only at 773 K and completely transformed into AgMnO at 873 K.
制备了两种含有独特高锰酸根离子配位模式的[Ag(NH)]MnO单斜多晶型物，其中高温多晶型物被用作合成纯AgMnO的前驱体。通过红外光谱和单晶X射线衍射检测到高锰酸根离子与氨的氢原子之间的氢键。在热分解过程中，即使在失去氨配体或高锰酸根氧原子之前，这些氢键也会引发[Ag(NH)]阳离子与MnO阴离子之间的固相机内分子间氧化还原反应。多晶型物分解成细分散的单质银、无定形MnO化合物以及H₂O、N₂和NO气体。在573K下对一次分解产物进行退火处理，金属银与锰氧化物反应，形成无定形银锰氧化物，该氧化物仅在773K开始结晶，并在873K完全转变为AgMnO。
