A family of [Mn-6(III) Ln(2)(III)] rod-like clusters

作者：Tziotzi Thomais G; Kalofolias Dimitris A; Tzimopoulos Demetrios I; Siczek Milosz; Lis Tadeusz; Inglis Ross^*; Milios Constantinos J

来源：Dalton Transactions, 2015, 44(13): 6082-6088.

DOI：10.1039/c5dt00300h

Employment of H3L (= 2-(beta-naphthalideneamino)-2-hydroxymethyl-1-propanol) in mixed-metal manganese-lanthanide cluster chemistry has led to the isolation of five new octametallic heteronuclear isostructural [Mn(6)(III)Ln(2)(III)] complexes. More specifically, the reaction of Mn(ClO4)(2)center dot 6H(2)O with H3L and the corresponding lanthanide nitrate in MeCN in the presence of a base, NEt3, yielded four complexes with the general formula [Mn(6)(III)Ln(2)(III) O-2(OH)(2)(H2O)(2)(HL)(6)(NO3)(6)]center dot 6MeCN center dot 0.5H(2)O (Ln: Gd, 1 center dot 6MeCN center dot 0.5H(2)O; Tb, 2 center dot 6MeCN center dot 0.5H(2)O; Dy, 3 center dot 6MeCN center dot 0.5H(2)O; Er, 4 center dot 6MeCN center dot 0.5H(2)O). Furthermore, the Y-III analogue, [Mn(6)(III)Ln(2)(III) O-2(OH)(2)(H2O)(2)(HL)(6)(NO3)(6)]center dot 6MeCN center dot 0.5H(2)O (5 center dot 6MeCN center dot 0.5H(2)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(4)(III)Ln(2)(III)] core, which is further capped by two MnIII ions. Dc magnetic susceptibility studies in the 5-300 K range for complexes 1-5 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 DyIII analogue (3 center dot 6MeCN center dot 0.5H(2)O), suggesting potential single molecule magnetism character. Furthermore, the YIII analogue yielded a diamagnetic ground-state for the [Mn-6(III)] core, thus proving that the SMM character displayed by 3 center dot 6MeCN center dot 0.5H(2)O is due to the presence of the DyIII centres.

• 出版日期2015