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Three new polynuclear clusters with the formulae [Mn₁₀O₄(OH)(OMe){(py)₂C(O)₂}₂{(py)₂C(OMe)(O)}₄(MeCO₂)₆](ClO₄)₂(1), Na[Mn₁₂O₂(OH)₃(OMe){(py)₂C(O)₂}₆{(py)₂C(OH)(O)}₂(MeCO₂)₂(H₂O)₁₀](ClO₄)₈(2) and [Mn₁₂O₄(OH)₂{(py)₂C(O)₂}₆{(py)₂C(OMe)(O)}(MeCO₂)₃(NO₃)₃(H₂O)(DMF)₂](NO₃)₂(3) were prepared from the combination of di‐2‐pyridyl ketone, (py)₂CO, with the aliphatic diols (1,3‐propanediol (pdH₂) or 1,4‐butanediol (1,4‐bdH₂)) in Mn carboxylate chemistry. The reported compounds do not include the aliphatic diols employed in this reaction scheme; however, their use is essential for the formation of1–3. The crystal structures of1–3are based on multilayer cores which, to our knowledge, are reported for the first time in Mn cluster chemistry. Direct current (dc) magnetic susceptibility studies showed the presence of dominant antiferromagnetic exchange interactions within1–3. Alternating current (ac) magnetic susceptibility studies revealed the presence of out‐of‐phase signals below 3.0 K for2and3indicating the slow relaxation of the magnetization vector, characteristic of single‐molecule magnets; theU_effvalue of2was found to be 23 K and the preexponential factorτ₀~7.6×10⁻⁹ s.

 

Two new Ce IV /O 2− clusters, (pyH) 8 [Ce 10 O 4 (OH) 4 (O 3 PPh) 12 (NO 3 ) 12 ] (1) and [Ce 6 O 4 (OH) 4 (O 2 PPh 2 ) 4 (O 2 C t Bu) 8 ] (2), have been prepared that contain P-based ligands for the first time. They were obtained from the reaction of (NH 4 ) 2 [Ce(NO 3 ) 6 ], PhPO 3 H 2 or Ph 2 PO 2 H, and t BuCO 2 H in a 2 : 1 : 2 molar ratio in pyridine/MeOH (10 : 1 mL). Both compounds contain a {Ce 6 O 4 (OH) 4 } face-capped octahedral core, with 1 containing an additional four Ce IV on the outside to give a supertetrahedral Ce 10 topology; the {Ce 6 O 8 } unit is the smallest recognizable fragment of the fluorite structure of CeO 2 . The HO˙ radical scavenging activities of 1 and 2 were measured by UV/vis spectral monitoring of methylene blue oxidation by HO˙ radicals in the presence and absence of the Ce/O clusters, and the results compared with those for larger Ce 24 and Ce 38 molecular nanoparticles of CeO 2 prepared in previous work. 1 and 2 are both very poor HO˙ radical scavengers compared with Ce 24 and Ce 38 , a result that is consistent with reports in the literature that PO 4 3− ions inhibit the radical scavenging ability of traditional CeO 2 nanoparticles and putatively assigned to PO 4 3− binding to the surface. 

The simultaneous employment of 1,3-propanediol and di-2-pyridyl ketone in Mn carboxylate chemistry has provided access to three new, structurally-related [Mn 24 ] and [Mn 23 ] clusters. They are based on nanosized supertetrahedal T4 Mn/O structural cores and exhibit slow relaxation of magnetization below 3.5 K. 

A covalently-linked dimer of two single-molecule magnets (SMMs), [Mn 6 O(O 2 CMe) 6 (1,3-ppmd) 3 ](ClO 4 ) 2 , has been synthesized from the reaction of [Mn 3 O(O 2 CMe) 6 (py) 3 ](ClO 4 ) with 1,3-phenylene- bis (pyridin-2-ylmethanone) dioxime (1,3-ppmdH 2 ). It contains two [Mn III 3 O] +7 triangular units linked by three 1,3-ppmd 2− groups into an [Mn 3 ] 2 dimer with D 3 symmetry. Solid-state dc and ac magnetic susceptibility measurements showed that each Mn 3 subunit retains its properties as an SMM with an S = 6 ground state. Magnetization vs. dc field sweeps on a single crystal reveal hysteresis loops below 1.3 K exhibiting exchange-biased quantum tunnelling of magnetization (QTM) steps with a bias field of +0.06 T. This is the first example of a dimer of SMMs showing a positive exchange bias of the QTM steps in the hysteresis loops, and it has therefore been subjected to a detailed analysis. Simulation of the loops determines that each Mn 3 unit is exchange-coupled with its neighbour primarily through the 1,3-ppmd 2− linkers, confirming a weak ferromagnetic inter-Mn 3 interaction of J 12 ≈ +6.5 mK ( Ĥ = −2 JŜ i · Ŝ j convention). High-frequency EPR studies of a microcrystalline powder sample enable accurate determination of the zero-field splitting parameters of the uncoupled Mn 3 SMMs, while also confirming the weak exchange interaction between the two SMMs within each [Mn 3 ] 2 dimer. The combined results emphasize the ability of designed covalent linkers to generate inter-SMM coupling of a particular sign and relative magnitude, and thus the ability of such linkers to modulate the quantum physics. As such, this work supports the feasibility of using designed covalent linkers to develop molecular oligomers of SMMs, or other magnetic molecules, as multi-qubit systems and/or other components of new quantum technologies.