Lanthanide nonanuclear clusters with sandglass-like topology and the SMM behavior of dysprosium analogue

Twists to the Spin Structure of the Ln9-diabolo Motif Exemplified in Two {Zn2Ln2}[Ln9]{Zn2} Coordination Clusters

“…For 1 , they are tilted at an angle of 0.888° and for 2 at 1.157°. These values lie between those reported for previous examples, which range from 0.290°–0.535° − for the nearly coparallel examples to the significantly tilted Dy 9 example reported by Tang et al where the angle is 1.809° . (B) The two μ 4 -O 2– bridges are placed 0.382 Å (in 1 ) and 0.393 Å (in 2 ) above the Ln 4 plane; these values are significantly higher than those previously reported ranging from 0.147 to0.325 Å.…”

“…The decorated metallic core of compounds 1 and 2 can be enumerated as 1,2,3,4,5,5,5,8M15–1 (Figure ) and this topology has never been seen in polynuclear coordination chemistry before. From the automatic graph based search of TOPOS, a comparison of the topology of the present compounds with previously reported compounds containing the diabolo motif ( 4,8M9–1 graph) ,,− provides very interesting structural data which has not been identified previously in any structural description. These are summarized in Table : (A) In both 1 and 2 , the two Ln 4 planes are not parallel to each other.…”

“…Within the Zn 2 Ln 9 part, the nonanuclear lanthanide unit is held together by two μ 4 -O 2– (O29), eight μ 3 -OH – (O25, O26, O27, O28, and their symmetry-related counterparts), two μ 2 -OH – molecules (O30), and four in situ formed o -vanillin derivatives L3 – (Scheme ). This nonanuclear motif is often referred to as “diabolo” shaped and has been identified in several compounds. ,,− The diabolo description derives from the similarity to the topology of a double spinning top which a player performs tricks with using a two-handled rope. In the compound we describe here, the hands and rope are provided by the “handlebar unit”, corresponding to Zn2 and Gd6 and their symmetry equivalents, respectively; the diabolo is provided by the Ln 9 core, where Gd2, Gd3,Gd4, and Gd5 (and their symmetry related counterparts) form two square planes arranged as a square antiprism with Gd1 in the middle.…”

“…This nonanuclear motif is often referred to as "diabolo" shaped and has been identified in several compounds. 14,16,[30][31][32][33] The diabolo description derives from the similarity to the topology of a double spinning top which a player performs tricks with using a twohandled rope. In the compound we describe here, the hands and rope are provided by the "handlebar unit", corresponding to Zn2 and Ln6 and their symmetry equivalents, respectively, the diabolo is provided by the Ln9 core, where Ln2, Ln3, Ln4 and Ln5 (and their symmetry related counterparts) form two square planes arranged as a square antiprism with Ln1 in the middle.…”

Influence of the Ligand Field on the Slow Relaxation of Magnetization of Unsymmetrical Monomeric Lanthanide Complexes: Synthesis and Theoretical Studies

“…An approximate D 4 d geometry provided by the phthalocyanine ligand stabilizes an easy-axis anisotropy in [Tb­(Pc) 2 ] n −,0, n + complexes showing slow relaxation of magnetization reported by Ishikawa and co-workers in 2003 . Following this discovery, several lanthanide-based SIMs and SMMs flooded the literature. , Among the SIMs and SMMs reported in the literature, the Dy III ion holds an edge over other lanthanide ions because of the Kramers nature of the m j levels coupled with the absence of a nuclear spin moment . In majority of the lanthanide complexes, magnetic bistability arises by a conventional magnetization blockade; however, certain oligomeric lanthanide complexes show magnetic bistability due to spin chirality or single-molecule toroics and an even more fascinating phenomenon called magnetic-chiral dichroism exhibited by certain one-dimensional complexes recently reported by Sessoli and co-workers …”