Quantum Monte Carlo simulations of a giant {Ni21Gd20} cage with a S = 91 spin ground state

Abstract

The detailed analysis of magnetic interactions in a giant molecule is difficult both because the synthesis of such compounds is challenging and the number of energy levels increases exponentially with the magnitude and number of spins. Here, we isolated a {Ni21Gd20} nanocage with a large number of energy levels (≈5 × 1030) and used quantum Monte Carlo (QMC) simulations to perform a detailed analysis of magnetic interactions. Based on magnetization measurements above 2 K, the QMC simulations predicted very weak ferromagnetic interactions that would give a record S = 91 spin ground state. Low-temperature measurements confirm the spin ground state but suggest a more complex picture due to the single ion anisotropy; this has also been modeled using the QMC approach. The high spin and large number of low-lying states lead to a large low-field magnetic entropy (14.1 J kg−1 K−1 for ΔH = 1 T at 1.1 K) for this material.

Giant Heterometallic [Mn36Ni4]0/2− and [Mn32Co8] “Loops-of-Loops-and-Supertetrahedra” Molecular Aggregates

“…This behavior could result from the presence of antiferromagnetic exchange interactions between the two [Mn III Ni3II] (in 4 ) or [Mn III Mn3II] (in the [Mn6IIMn2III]) cubane sub-units leading to diamagnetic ground states. The reported S T values for 2 and 3 are among the larger ones for heterometallic aggregates with the S T ≈ 26 being the second highest value reported for a heterometallic cluster (Chen et al, 2018). Clearly the overall magnetic behavior of 2 exhibits remarkable analogies with that of its [Mn6IIIMn4II] building block since they both display ferromagnetic exchange interactions, large S T and small D values and are not SMMs.…”

An Ultrastable Matryoshka [Hf13] Nanocluster as a Luminescent Sensor for Concentrated Alkali and Acid

“…The synthesis of highly stable polynuclear metal clusters is an important goal owing to their unique structures and versatile applications in optoelectronics, luminescence sensing, solar‐energy harvesting, and other areas . Many impressive metal clusters have been reported, with cores such as [Ti 20 ], [Au 32 ] 8+ , [Fe 42 ], [Cu 53 ], [Ag 374 ], [Gd 140 ], and [Ni 21 Gd 20 ], as well as [As@Ni 12 @As 20 ] 3− and inorganic fullerene‐like molecules . These clusters are generally sensitive toward strong acid/alkali or certain solvents, owing to attack by H + , OH − , and/or small molecules, thus tending to decompose or dissolve in water and organic solvents .…”

A Ferromagnetically Coupled, Bell-Shaped [Ni4Gd5] Cage

“…Despite these difficulties, numerous examples of such large cages exist, including an {Fe III 10Gd III 10} cyclic complex with an S = 60 ground-state, 3 a giant {Fe III 18Fe II 24} nanocluster with an S = 45 spin ground-state, 4 a {Mn III 12Mn II 7} cluster with an S = 83/2 ground-state, 5 a {Mn III 11Mn II 6} complex with an S = 37 ground-state, 6 and most recently a [Ni21Gd20] cage displaying a remarkable (field-induced) S = 91 ground state. 7 In this work, the isolation, characterization and investigation of the magnetic behavior of an enneanuclear [Ni II 4Gd III 5] cluster are reported, built by employing the amidoxime ligand 2hydroxy-4-methyl-6-phenyl-pyridine-3-amidoxime, H2L (Scheme 1), which was previously employed succesfully in heterometallic chromium chemistry yielding two Cr III 1In order to fully investigate the synthetic parameters that dictate the formation of 1 (and 2) we performed the reaction upon employing various bases i.e. NMe4OH and NaOH, and also increased the duration of the reaction, but in all cases complex 1 was the product as observed by IR spectroscopy and pXRD.…”