The phenomenon of conglomerate crystallization. Part 34. Crystal structures of the conglomerate (–)599-K[cis-α-Λ(δλδ)-Co(edda)(No2)2] and of the racemate K[cis-α-Λ(δλδ)-Co(edda)(NO2)2]·H2O (edda = ethylenediamine-N,N′-diacetate)

Abstract

A racemic solution of K[cis-α-Co(edda)(NO₂)₂]1(edda = ethylenediamine-N,N′-diacetate) was found to crystallize as a conglomerate in the enantiomorphic, orthorhombic space group P2₁2₁2₁. An acidified solution of it produced racemic crystals of K[cis-α-Co(edda)(NO₂)₂]·H₂O 2, space group P, as well as conglomerate crystals of 1. Their crystal structures and the absolute configuration of 1 were determined. In both species the anions form infinite strings which are linked to one another by the potassium cations (and/or waters, where relevant, 2). With 1 the helical strings are homochiral, while with 2 pairs of spiral strings have opposite helical chirality, as expected from the fact that they are related to one another by an inversion centre.