title: Effect of the apical ligand on the geometry and magnetic properties of copper(ii)/mesoxalate trinuclear units.
abstract: Three new heterometallic metal-organic frameworks, namely, {(Ph4P)2[MnCu3(Hmesox)3Br(H2O)]·H2O}n(1), {(Ph4P)2[CoCu3(Hmesox)3Br]}n(2) and {(Ph4P)2[ZnCu3(Hmesox)3Br]·2.5H2O}n(3) were prepared and their structure and magnetic properties were investigated (H4mesox = mesoxalic acid, Ph4P+= tetraphenylphosphonium). The structure of all the compounds consist of two interpenetrating opposite-chirality supramolecular cationic and polymeric anionic 3-D (10,3)-a networks, which results in chiral compounds. The anionic network is formed from the polymerization of [Cu3(Hmesox)3Br]4-units, working as three connectors, and M(ii) cations, working as three-connecting nodes, M = Mn(ii), Co(ii) and Zn(ii). The Ph4P+cations build the cationic chiral supramolecular network opposite to the anionic one. Compounds 1 and 2 exhibit long-range magnetic ordering with critical temperatures of 7.2 K and 6.9 K, respectively. However, compound 3 does not display long-range order, but shows ferromagnetic and antiferromagnetic coupling among the Cu(ii) ions. The magnetic interactions are studied by DFT calculations and compared with related Cu(ii)-mesoxalate compounds previously reported.
authors.affiliation: Departamento de Química, Facultad de Ciencias, Sección Química, Universidad de la Laguna, 38206 La Laguna, España, Spain. jsanchiz@ull.edu.es.
authors.forename: B
authors.initials: B
authors.lastname: Gil-Hernández
authors.forename: A J
authors.initials: AJ
authors.lastname: Calahorro
authors.forename: P
authors.initials: P
authors.lastname: Gili
authors.forename: J
authors.initials: J
authors.lastname: Sanchiz