A family of [MnIII6LnIII2] rod-like clusters. Issue 13 (2nd March 2015) - Tziotzi, Thomais G.
Abstract : A family of octametallic heteronuclear manganese-lanthanide [Mn III 6 Ln2 ] complexes were isolated and characterized by magnetic measurements. Abstract : Employment of H3 L (= 2-(β-naphthalideneamino)-2-hydroxymethyl-1-propanol) in mixed-metal manganese-lanthanide cluster chemistry has led to the isolation of five new octametallic heteronuclear isostructural [Mn III 6 Ln III 2 ] complexes. More specifically, the reaction of Mn(ClO4 )2 ·6H2 O with H3 L and the corresponding lanthanide nitrate in MeCN in the presence of a base, NEt3, yielded four complexes with the general formula [Mn III 6 Ln III 2 O2 (OH)2 (H2 O)2 (HL)6 (NO3 )6 ]·6MeCN·0.5H2 O (Ln: Gd, 1 ·6MeCN·0.5H2 O; Tb, 2 ·6MeCN·0.5H2 O; Dy, 3 ·6MeCN·0.5H2 O; Er, 4 ·6MeCN·0.5H2 O). Furthermore, the Y III analogue, [Mn III 6 Y III 2 O2 (OH)2 (H2 O)2 (HL)6 (NO3 )6 ]·6MeCN·0.5H2 O (5 ·6MeCN·0.5H2 O), was also synthesized in the same manner. All five clusters describe a central rod-like topology consisting of four face-sharing defective cubane metallic units, forming a planar hexametallic [Mn III 4 Ln III 2 ] core, which is further capped by two Mn III ions. Dc magnetic susceptibility studies in the 5–300 K range for complexes1–5 reveal the presence of dominant antiferromagnetic exchange interactions within the metallic clusters, while ac magnetic susceptibility measurements show temperature and frequency dependent out-of-phase signals for the Dy III analogue (3 ·6MeCN·0.5H2 O), suggesting potential single molecule magnetism character. Furthermore, the Y III analogue yielded a diamagnetic ground-state for the [Mn III 6 ] core, thus proving that the SMM character displayed by3 ·6MeCN·0.5H2 O is due to the presence of the Dy III centres.