Self-Assembly of Supramolecular Structures from Palladium Chloride and Guanidinium Salts of Pyridinecarboxylic Acids − A Dramatic Change on Passing from the para- to the meta-Substituted Acid

• Published in: European journal of inorganic chemistry 2003-04, Vol.2003 (8), p.1523-1528
• Main Authors: Bacchi, Alessia, Chiusoli, Gian Paolo, Costa, Mirco, Giacobbi, Emmanuele
• Format: Article
• Language: English
• Subjects: Crystal engineering; Hydrogen bonds; Multicomponent systems; Self-assembly
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.200390198

Supramolecular structures 1 and 2 were obtained in the solid state from the reaction between palladium chloride and guanidinium salts of p‐ and m‐pyridinecarboxylic acid, respectively. The pyridinecarboxylate anions were trans‐coordinated to palladium dichloride through nitrogen, and the carboxylate groups formed hydrogen bonds with guanidinium cations. The present paper describes a remarkable change in the stoichiometry and structural organization of the solid 3 derived from the meta‐substituted acid 2, triggered by the elimination of one guanidine molecule as hydrochloride per molecule of palladium chloride, during crystallization from methanol. The corresponding isonicotinate 1 structure appears to be stable under the same conditions. As shown by the analysis of the crystal structures, the guanidinium nicotinate organic salt 4 turns out to be preorganized to host palladium chloride both in 2 and 3. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)