{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T03:05:20Z","timestamp":1760238320218,"version":"build-2065373602"},"reference-count":80,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2020,8,3]],"date-time":"2020-08-03T00:00:00Z","timestamp":1596412800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>We define a new inversion in a cage isomerism (ic): X@C\u22efY\u20aaicY@C\u22efX, (\u20aa is the isomerism relation) as an isomerism in the three-component system of molecules X, Y, and a cage C, in which one of the molecules is located inside and the other outside the cage. The ic isomerism is similar to the endo-exo one, which occurs only if either the interior or exterior of C is empty. By contrast, ic occurs only if neither the interior nor the exterior of C is empty. We also discuss the other closely related types of isomerisms are also discussed. Calculations of the XH\u22efNH3@C60 and NH3\u22efHX@C60ic isomers were performed at the \u03c9B97XD\/Def2TZVP level. The calculated energies demonstrated that the systems with the HX acid outside (X = F, Cl) and the NH3 base inside the cage, XH\u22efNH3@C60, are more stable than their ic isomers, NH3\u22efHX@C60, by about 4\u20138 kcal\/mol. This is because NH3 is more stabilized inside the cage than HX (a matter of 6.5 kcal\/mol). In the studied systems and subsystems, the HX molecules are Lewis acids and the NH3 molecule is always a Lewis base. The C60 molecule with HX inside or outside the cage is also an acid for the NH3 base positioned outside or inside the cage. On the other hand, the C60 cage is truly amphoteric because it is simultaneously an acid and a base.<\/jats:p>","DOI":"10.3390\/sym12081291","type":"journal-article","created":{"date-parts":[[2020,8,4]],"date-time":"2020-08-04T05:56:46Z","timestamp":1596520606000},"page":"1291","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["The Acid-Base Through-the-Cage Interaction as an Example of an Inversion in a Cage Isomerism"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7301-1590","authenticated-orcid":false,"given":"Jan Cz.","family":"Dobrowolski","sequence":"first","affiliation":[{"name":"Institute of Nuclear Chemistry and Technology, 16 Dorodna Street, 03-195 Warsaw, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"S\u0142awomir","family":"Ostrowski","sequence":"additional","affiliation":[{"name":"Institute of Nuclear Chemistry and Technology, 16 Dorodna Street, 03-195 Warsaw, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,8,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"305","DOI":"10.1002\/andp.18300950702","article-title":"Ueber die Zusmmensetzung der Weins\u00e4ure und Traubens\u00e4ure (John\u2019s S\u00e4ure aus den Vogesen), \u00fcber das Atomengewicht das Bleioxyds, nebst allgemeinen Bemerkungen \u00fcber soche K\u00f6rper, die gleiche Zusammensetzung, aber ungleiche Eigenschaften besitzen","volume":"19","author":"Berzelius","year":"1830","journal-title":"Ann. 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