Crystal Structures and Magnetic Properties of 2D Supramolecular Architectures Assembled from Benzimidazolecarboxylato‐Bridged 1D Double‐Stranded Coordinating Chains Featuring Metallomacrocycles as Subunits

Abstract

AbstractTwo new 2D supramolecular architectures [{Mn2(L1)2(H2O)2}·2CH3OH]n (1) and [{Mn2(L2)2(CH3OH)4}·2CH3OH·4(H2O)]n (2) were assembled from the newly synthesised semi‐rigid ligands H2L1 {2,6‐bis[(6‐carboxy‐2,4‐dimethylbenzimidazol‐1‐yl)methyl]pyridine} and H2L2 {2,6‐bis[(6‐carboxy‐4‐methyl‐2‐propylbenzimidazol‐1‐yl)methyl]pyridine} by reaction with MnII ions. They both contain novel 1D double‐stranded coordinating chains with metallomacrocyclic subunits and dinuclear MnII subrings bridged by benzimidazolecarboxylato ions, the latter derived from the ligands. The differences in the steric hindrance of the methyl and propyl groups attached to the benzimidazole rings in H2L1 and H2L2 led to different coordinating modes of the carboxylato groups and, thus, aesthetically fascinating extended structures with useful magnetic properties. Variable‐temperature susceptibility measurements (2–300 K) revealed antiferromagnetic coupling interactions (J = –0.23 cm–1 for 1 and –0.92 cm–1 for 2) with values being within the reported range but differing from each other due to the distinct bridging modes of the carboxylato ions. The different crystal structures and magnetic properties of 1 and 2 are discussed in detail.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)