The phenomenon of conglomerate crystallization—XXXIII. Counter-ion effects on crystallization pathway of racemate solutions—IV. The crystal and molecular structure of racemic (H 3O +)[Co(en) 2ox]Cl 2 · H 2O (I)

Abstract

(H 3O +)[Co(en) 2ox]Cl 2 · H 2O( I), CoCl 2O 6N 4C 6H 21, crystallizes as a racemate in the monoclinic space group P2 1/c (No. 14). Infinitely hydrogen-bond spiral strings of homochiral [Co(en) 2ox] + cations are formed which are wrapped about the two-fold screw axis of the crystals. Adjacent spirals are held together by hydrogen bonds between the waters and chlorides and the—NH 2 hydrogens of the cations. Such an arrangement is also present in the conglomerate crystals of the [Co(en) 2ox]Cl · 4H 2O ( II) and [Co(en) 2ox] Br · H 2O ( III) derivatives; however, unlike II and III, which crystallize as conglomerates and all spiral strings are of the same helicity, in I adjacent spirals are of opposite helical chirality and related to one another by the inversion operation of the space group.