A Zigzag‐Shaped Yb₄ Cluster Bridged by Pyridine‐2,6‐dimethanol

Abstract

A homometallic lanthanide tetranuclear cluster, namely [Yb 4 (pdmH) 2 (pdm) 4 (PhCO 2 ) 2 (PhCO 2 H) 2 (H 2 O) 2 ]·PhCO 2 H·0.25MeOH (1) (pdmH 2 = pyridine-2,6-dimethanol) was prepared and structurally Symmetry transformations used to generate equivalent atoms: #1 -x, -y, -z+1.

Tetranuclear Lanthanide(III) Complexes with a Zigzag Topology from the Use of Pyridine-2,6-dimethanol: Synthetic, Structural, Spectroscopic, Magnetic and Photoluminescence Studies

“…Complex 4 is the only member of this family of tetranuclear clusters which shows frequency-dependent out-of-phase χ″ M tails of signals at temperatures below ∼5 K (Figure ), indicative of the slow magnetization relaxation of an SMM with a small energy barrier for magnetization reversal. Such behavior most likely arises from predominant single-ion effects of the individual Dy III centers within 4 . ,,− There were no out-of-phase ac signals down to 1.8 K for the remaining compounds (Figure S2, Supporting Information). Thus, it can be tentatively seen that while 4 shows slow magnetization relaxation the isostructural complex 3 does not.…”

“…On the other hand, when the choice of X – is one of the halides, NO 3 – , ClO 4 – , or CF 3 SO 3 – , all with limited bridging affinity, employment of an external organic base which would carry the role of proton acceptor seems necessary to facilitate deprotonation of the organic chelating/bridging ligand and therefore increase the chances of metal cluster formation. The latter route was followed in the present study using as organic chelating/bridging ligand the relatively unexplored in lanthanide metal cluster chemistry pyridine-2,6-dimethanol (pdmH 2 ) . The pyridyl diol ligand pdmH 2 contains two −OH groups which upon deprotonation could bridge up to five metal centers .…”

“…There have been a large number of Ln 4 complexes reported in the literature, and these possess a wide variety of metal topologies such as linear, rectangles, squares and grids, rhombs and butterflies, cubanes, and dimers of dimers . However, complexes 1 – 7 join only a handful of previous Ln 4 compounds with a similar kind of extended, chain-like topology and an [Ln 4 (μ-OR) 6 ] 6+ core. , …”

“…Following our longstanding interest in the coordination ability/affinity of pyridyl alcohols and pyridyl oximes/dioximes for metal cluster synthesis, we decided to employ pyridine-2,6-dimethanol (pdmH 2 , Scheme ), a well-known ligand for synthesis of 3d-metal clusters and SMMs but with scant previous use in homometallic 4f-metal cluster chemistry . Herein we report the syntheses, structures, magnetic, and photoluminescence properties of a family of isostructural tetranuclear [Ln III 4 (NO 3 ) 2 (pdmH) 6 (pdmH 2 ) 2 ](NO 3 ) 4 (Ln III = Eu III , Gd III , Tb III , Dy III , Ho III , Er III , Yb III ) complexes with a rare zigzag topology.…”

Further synthetic investigation of the general lanthanoid(iii) [Ln(iii)]/copper(ii)/pyridine-2,6-dimethanol/carboxylate reaction system: {CuII5LnIII4} coordination clusters (Ln = Dy, Tb, Ho) and their yttrium(iii) analogue

“…[47][48][49][50] We have been using the "assisted self-assembly" variation of the "one-pot" approach by employing pyridine-2,6-dimethanol (H 2 pdm) as the primary organic ligand and simple carboxylate ions (RCO 2 − ) as co-ligands. 51,52 The anionic forms of H 2 pdm are well-explored ligands in transition-metal [53][54][55][56] and lanthanoid(III) [57][58][59] cluster chemistry, having yielded complexes with aesthetically pleasing structures and interesting properties. On the contrary, their use in 3d/4fmetal chemistry has been limited.…”