Todorov P.Petrova R.Naydenova E.Shivachev B.2024-07-102024-07-102024-07-102024-07-102009-01-091895-10661644-362410.2478/s11532-008-0087-3SCOPUS_ID:58149195179https://rlib.uctm.edu/handle/123456789/152The crystal structures of 3-amino-cycloheptanespiro-4′- imidazolidine-2′,5′-dione (I) {systematic name: 3-amino-1,3-diazaspiro[4.6] undecane-2,4-dione} and 3-amino-cyclooctanespiro-4′- imidazolidine-2′,5′-dione (II) {systematic name: 3-amino-1,3-diazaspiro[4.7] dodecane-2,4-dione}, have been determined. In both compounds the polar hydantoin groups cause molecules to aggregate via N-H⋯O and N-H⋯N interactions, forming a layer structure, in which the cycloalkane rings project outwards from the central, more polar, region. The observed molecular structure is compared with that calculated by density functional theory methods. © Versita Warsaw and Springer-Verlag Berlin Heidelberg 2009.enArticle