Publication Date:
2013-03-29
Description:
Three 3-amino-1, 2, 4-triazole (atz)-based paramagnetic complexes, [Mn(atz)(pa)] n ( 1 ), {[Mn(atz) 1.5 (hip)] · H 2 O} n ( 2 ), and [Mn(H 2 O) 2 (atz) 2 (nb) 2 ] ( 3 ) (H 2 pa = o -phthalic acid, H 2 hip = 5-hydroxylisophthalic acid, and Hnb = p -nitrobenzoic acid) were prepared by introducing different carboxylate-containing aromatic coligands, and structurally and magnetically characterized. Helical Mn II -atz and bent Mn II -pa 2– chains are crosslinked by sharing the same metal sites to generate a honeycomb-shaped framework of 1 . The undulated Mn II -atz layers constructed from 22-member metallomacrocycles are periodically supported by ditopic hip 2– ligands to lead to a pillared-layer structure of 2 . In contrast, complex 3 is a centrosymmetric mononuclear entity, which is assembled into a three-dimensional supramolecular network by abundant hydrogen-bonding interactions. The structural difference of 1 – 3 is significantly due to the combinations of the flexible coordination modes adopted by the mixed atz and carboxylate groups. Weak and comparable antiferromagnetic couplings are observed in the nearest neighbors of 1 – 3 , which are cooperatively transmitted either by short carboxylate and/or atz heterobridges or by weak non-covalent interactions.
Print ISSN:
0044-2313
Electronic ISSN:
1521-3749
Topics:
Chemistry and Pharmacology
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