Epitaxial Retrieval of a Disappearing Polymorph.

ABSTRACT: Recrystallization of [PdCl₂([9]aneS₂O)] ([9]aneS₂O = 1-oxa-4,7-dithiacyclononane), 1, and [PtCl₂([9]aneS₂O)], 2, by diffusion of Et₂O vapor into solutions of the complexes in MeNO₂ yielded three phases of 1 and two phases of 2. The known phase of 1, herein designated ?-1, was obtained under ambient conditions. A second phase, designated ?-1, was initially also obtained by this method; however, following the advent of a third phase, ?-1, all subsequent efforts over a period of a year to crystallize ?-1 yielded either ?-1, obtained by carrying out the recrystallization at elevated temperature, or ?-1, commonly found throughout the study. This persistent absence of a phase which could initially be crystallized with ease led us to the conclusion that ?-1 was an example of a "disappearing polymorph". The first phase obtained of 2, designated ?-2, was obtained by recrystallization under ambient conditions and is isomorphous and isostructural with ?-1. The second phase ?-2 was obtained by slight elevation of the recrystallization temperature and was found to be isomorphous and isostructural with ?-1. Subsequently, ?-2 was used to seed the growth of the disappearing polymorph ?-1. No third phase of 2 (?-2) has been isolated thus far.

SUBMITTER: Tidey JP 

PROVIDER: S-EPMC4291774 | biostudies-literature | 2015 Jan

REPOSITORIES: biostudies-literature