Erdmann’s Anion—An Inexpensive and Useful Species for the Crystallization of Illicit Drugs after Street Confiscations

Abstract

Erdmann’s anion [1,6-diammino tetranitrocobaltate(III)] is useful in the isolation and crystallization of recently confiscated street drugs needing to be identified and catalogued. The protonated form of such drugs forms excellent crystals with that anion; moreover, Erdmann’s salts are considerably less expensive than the classically used AuCl4− anion to isolate them, while preparation of high-quality crystals is equally easy in both cases. We describe the preparation and structures of the K+CoH6N6O8− and NH4+CoH6N7O8−, salts of Erdmann’s. In addition, herein are described the preparations of this anion’s salts with cocaine (C17H28CoN7O12), with methamphetamine (C10H22CoN7O8), and with methylone (C22H34CoN8O14), whose preparation and stereochemistry had been characterized by the old AuCl4− salts methodology. For all species in this report, the space groups and cell constants were determined at 296 and 100 K, looking for possible thermally induced polymorphism—none was found. Since the structures were essentially identical at the two temperatures studied, we discuss only the 100 K results. Complete spheres of data accessible to a Bruker ApexII diffractometer with Cu–Kα radiation, λ = 1.54178 Å, were recorded and used in the refinements. Using the refined single crystal structural data for the street drugs, we computed their X-ray powder diffraction patterns, which are beneficial as quick identification standards in law enforcement work.

Clarifying the complex chemistry of cobalt(II) thiocyanate‐based tests for cocaine using single‐crystal X‐ray diffraction and spectroscopic techniques

“…prepared the green appearing (Hcocaine + ) 2 [Cu(NCS) 4 ], CSD code HAGSEQ, with thiocyanate groups arranged in a distorted square planar geometry around Cu(II) [37]. The third complex of note is the yellow cocaine salt with Erdmann's anion, trans –[Co(NH 3 ) 2 (NO 2 ) 4 ] − , CSD code OSEFIE, which features two cocainium ions and two cobalt(III) containing Erdmann's anions in the asymmetric unit [56]. The paucity of cocainium containing ion pairs in the CSD may, in some part, reflect the commonality of non‐crystalline precipitates such as we observed for samples of cocaine hydrochloride exposed to the classic test.…”

Memorial Issue Dedicated to Dr. Howard D. Flack: The Man behind the Flack Parameter

“…A fascinating illustration of the application of Erdmann's anion, trans-[Co(NH 3 ) 2 (NO 2 ) 4 ] − , in the isolation and crystallization of impounded street drugs is provided by Lalancette and coworkers; using salts of cocaine, methamphetamine and methylone, single-crystal structural data were used to calculate powder X-ray diffraction patterns, giving a means for rapid screening of confiscated materials [17].…”