02332nas a2200217 4500008004100000022001400041245017900055210006900234260007100303300001400374490000700388520144900395100001701844700002601861700002201887700001801909700002601927700001901953700001701972856012501989 2015 eng d a0020-166900aConstruction of polynuclear lanthanide (Ln = Dy-III, Tb-III, and Nd-III) cage complexes using pyridine-pyrazole-based ligands: versatile molecular topologies and smm behavior0 aConstruction of polynuclear lanthanide Ln DyIII TbIII and NdIII a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcSEP a8197-82060 v543 a
Employment of two different pyridyl pyrazolyl-based ligands afforded three octanudear lanthanide(III) (Ln = Dy, Tb) cage compounds and one hexanudear neodymium(III) coordination cage, exhibiting versatile molecular architectures including a butterfly core. Relatively less common semirigid pyridyl pyrazolyl-based asymmetric ligand systems show an interesting trend of forming polynuclear lanthanide cage complexes with different coordination environments around the metal centers. It is noteworthy here that construction of lanthanide complex itself is a challenging task in a ligand system as soft N-donor rich as pyridyl pyrazol. We report herein some lanthanide complexes using ligand containing only one or two O-donors compare to five N-coordinating sites. The resultant multinuclear lanthanide complexes show interesting magnetic and spectroscopic features originating from different spatial arrangements of the metal ions. Alternating current (ac) susceptibility measurements of the two dysprosium complexes display frequency- and temperature-dependent out-of-phase signals in zero and 0.5 T direct current field, a typical characteristic feature of single-molecule magnet (SMM) behavior, indicating different energy reversal barriers due to different molecular topologies. Another aspect of this work is the occurrence of the not-so-common SMM behavior of the terbium complex, further confirmed by ac susceptibility measurement.
1 aBala, Sukhen1 aBishwas, Mousumi, Sen1 aPramanik, Bhaskar1 aKhanra, Sumit1 aFromrn, Katharina, M.1 aPoddar, Pankaj1 aMondal, Raju uhttp://library.ncl.res.in/content/construction-polynuclear-lanthanide-ln-dy-iii-tb-iii-and-nd-iii-cage-complexes-using-0