The development and integration of Single-Molecule Magnets (SMMs) into molecular electronic devices continue to be an exciting challenge. In such potential devices, heat generation due to the electric current is a critical issue that has to be considered upon device fabrication. To read out accurately the temperature at the submicrometer spatial range, new multifunctional SMMs need to be developed. Herein, we present the first self-calibrated molecular thermometer with SMM properties, which provides an elegant avenue to address these issues. The employment of 2,2′-bipyrimidine and 1,1,1-trifluoroacetylacetonate ligands results in a dinuclear compound, [Dy 2 (bpm)(tfaa) 6 ], which exhibits slow relaxation of the magnetization along with remarkable photoluminescent properties. This combination allows the gaining of fundamental insight in the electronic properties of the compound and investigation of optomagnetic cross-effects (Zeeman effect). Importantly, spectral variations stemming from two distinct thermal-dependent mechanisms taking place at the molecular level are used to perform luminescence thermometry over the 5–398 K temperature range. Overall, these properties make the proposed system a unique molecular luminescent thermometer bearing SMM properties, which preserves its temperature self-monitoring capability even under applied magnetic fields.

The nature of weak interactions in dimers X3E•••EX3 (E = NBi, X = FI) was investigated by wave function and density functional-based methods. Out of the twenty systems studied, ten are found to be bound at the CP-MP2 and LMP2 levels of theory.Detailed partition of the interaction energy into different components revealed that dispersion is the primary force holding the dimers together but there also exist an important ionic component whose contribution increases with increasing halogen size. As expected, standard density functionals fail to describe bonding in the studied systems.However, the performance of DFT methods can be easily improved via empirical dispersion correction though full agreement with high level ab initio results was not obtained. Total binding energies calculated at the SCS-MP2 and LCCSD(T) levels of theory yield an energy scale of 1015 kJ mol 1 which compares to a weak hydrogen bond and demonstrates that E•••E interactions, and P•••P interactions in particular, can be considered relevant for determining molecular structure in the solid state. In addition to high-level energy estimates, results from detailed bonding analysis showed that group 13 dimetallenes are structural analogues of the studied dimers, and as such contain a slipped -interaction which is anti-bonding in nature.3

Why does cyanide not react destructively with the proximal iron center at the active site of 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase, an enzyme central to the biosynthesis of ethylene in plants? It has long been postulated that the cyanoformate anion, [NCCO2]–, forms and then decomposes to carbon dioxide and cyanide during this process. We have now isolated and crystallographically characterized this elusive anion as its tetraphenylphosphonium salt. Theoretical calculations show that cyanoformate has a very weak C–C bond and that it is thermodynamically stable only in low dielectric media. Solution stability studies have substantiated the latter result. We propose that cyanoformate shuttles the potentially toxic cyanide away from the low dielectric active site of ACC oxidase before breaking down in the higher dielectric medium of the cell.

Lanthanide‐complex‐based luminescence thermometry and single‐molecule magnetism are two effervescent fields of research, owing to the great promise they hold from an application standpoint. The high thermal sensitivity achievable, their contactless nature, along with sub‐micrometric spatial resolution make these luminescent thermometers appealing for accurate temperature probing in miniaturised electronics. To that end, single‐molecule magnets (SMMs) are expected to revolutionise the field of spintronics, thanks to the improvements made in terms of their working temperature—now surpassing that of liquid nitrogen—and manipulation of their spin state. Hence, the combination of such opto‐magnetic properties in a single molecule is desirable in the aim of overcoming, among others, addressability issues. Yet, improvements must be made through design strategies for the realisation of the aforementioned goal. Moving forward from these considerations, we present a thorough investigation of the effect that changes in the ligand scaffold of a family of terbium complexes have on their performance as luminescent thermometers and SMMs. In particular, an increased number of electron‐withdrawing groups yields modifications of the metal coordination environment and a lowering of the triplet state of the ligands. These effects are tightly intertwined, thus, resulting in concomitant variations of the SMM and the luminescence thermometry behaviour of the complexes. Supported by ab initio calculations, we can rationally interpret the observed trends and provide solid foundations for the development of opto‐magnetic lanthanide complexes.

ABSTRACT:The mechanism of the reaction of olefins and hydrogen with dimetallenes ArMMAr (Ar = aromatic group; M = Al or Ga) was studied by density functional theory calculations and experimental methods. The digallenes, for which the most experimental data are available, are extensively dissociated to gallanediyl monomers :GaAr in hydrocarbon solution, but we found that they do not react as the more open dissociated species. Instead, the calculations and experimental data show that they react with simple olefins such as ethylene as intact ArGaGaAr dimers via two stepwise [2 + 2] cycloadditions due to their considerably lower activation barriers vis-à-vis the gallanediyl monomers, :GaAr. This mechanism was preferred over the [2 + 2] cycloaddition of ethylene to a monomeric :GaAr to form a gallacyclopropane ring which could in principle then dimerize to form the 1,2-digallacyclobutane intermediate and, subsequently, the 1,4-digallacyclohexane product. In addition, calculations show that the addition of H2 to digallene proceeds by a different mechanism involving the initial addition of one equivalent of H2 to form a 1,2-dihydride intermediate. This reacts with a second equivalent of H2, to give two ArGaH2 fragments which recombine to give the observed product with terminal and bridging H-atoms, Ar(H)Ga(-H)2Ga(H)Ar.2