Hofmann-type clathrates constitute one of the most versatile families of coordination frameworks displaying spin-crossover (SCO) behaviour, offering unparalleled opportunities for tuning bistability from bulk materials to nanoparticles and thin films. Over the past two decades, significant advances in synthetic methodologies have been achieved, particularly through the use of tetra- and di-cyanometallate building blocks ([M^II(CN)4]^{2 –}, [MI(CN)2]^–) combined with mono- or bidentate bridging organic ligands. These strategies have enabled the construction of structurally diverse FeII-based frameworks exhibiting cooperative and often abrupt spin transitions. This review highlights recent progress in bulk synthesis, structural engineering, and property modulation in Hofmann-type SCO complexes. It emphasizes how dimensionality, ligand design, and metal-metal connectivity govern transition temperatures, hysteresis, and multistep behavior. In this bulk regime, particular attention is devoted to the interplay between spin transition and electron transfer in mixed-valence or redox-active clathrates, which emerges as a powerful handle to encode and expand multifunctional responses. A considerable research effort has also focused on downsizing these materials into nanoparticles while maintaining, or even enhancing, cooperativity. This approach unlocks new prospects for solution processability, surface functionalization, and device integration.Parallel advances in host-guest chemistry demonstrate that these flexible frameworks can encapsulate neutral or charged species, leading to pronounced modulation of SCO behavior, guest-triggered phase transitions, and stimuli-responsive properties. Particular attention is devoted to 2D and 3D host-guest systems and to the emergence of “active” guest molecules capable of mechanical, electronic, or photonic coupling with the SCO matrix. Moreover, advances in the fabrication of thin films, micro-structured architectures, and nanostructured surfaces are increasingly positioning Hofmann-type clathrates at the forefront of applications in molecular electronics, memory devices, spintronics, sensing, and photo-switching. Yet, despite their remarkable functional potential, their practical implementation in devices remains limited. This is likely owing to their intrinsic fragility and the challenges associated with their manipulation, processing, and integration into innovative device architectures. Additional efforts are therefore required, particularly in the development of advanced nanotechnologies, to ultimately translate these materials into genuine societal applications. This review provides a comprehensive account of the field, underscoring key structure-property relationships across multiple length scales. It also outlines current challenges and opportunities for developing high-performance, multifunctional SCO Hofmann frameworks for emerging technologies.

Christelle Hureau-Sabater honored with the CNRS Silver Medal 2024

We are delighted to congratulate Christelle Hureau-Sabater, Research Director at the Laboratory of Coordination Chemistry (LCC), for being awarded the CNRS Silver Medal 2024.

This recognition highlights her remarkable career and outstanding contributions to coordination chemistry and bio-organic chemistry. Her dedication and expertise have been honored with this prestigious distinction from the CNRS Talents.

 

• Read the full article on the CNRS Institute of Chemistry (INC) website

Study published in Chemical Science

As hydrogen emerges as a key energy vector of the 21st century, its large-scale storage and utilization remain major challenges. CNRS chemists propose new, more efficient and durable catalysts for “chemical” storage in organic molecules, from which it could be released on demand and in a controlled manner.
These findings, published in the journal Chemical Science, open new perspectives for the design of effective and durable catalysts for hydrogen storage from amine-borane compounds.

 

• Read the full article on the CNRS Chemistry website  – Editorial: Christophe CARTIER DIT MOULIN

Study published in the Journal of the American Chemical Society.

In order to develop new fluorinated molecules with applications in healthcare, agriculture or even for batteries, it is necessary to split the strong carbon-fluorine bond. This is achieved by using electron-rich metallic species that are difficult to manipulate and are based on scarce and sometimes toxic chemical elements. Scientists have shown that simple phosphorus-based agents are capable of breaking down these carbon-fluorine bonds in a similar way to metals. This work opens the way to more sustainable synthesis of organofluorinated compounds.

 

• Read the full post (in french) on the website of the CNRS Institute of Chemistry (INC) – Editor: Christophe CARTIER DIT MOULIN

Study published as a VIP article in the journal Angewandte Chemie.

The peculiar reactivity of [CpMn(CO)₂(N₂)] (Cp=η⁵-cyclopentadienyl) is revisited to shed light on the proposed nucleophilic attack of PhLi on its N₂ ligand. Our study shows that such reactivity doesn’t happen while the attack of the carbanion on CO is favored, albeit giving rise to a very labile compound. The latter decomposes above −20 °C into a N₂-free phenyl manganate that was erroneously proposed to be an anionic phenyldiazenido complex.

These findings offer new perspectives for the catalytic transformation of diazote into high-value-added compounds.

Application of nanocomposites in daily life requires not only small nanoparticles (NPs) well dispersed in a matrix, but also a manufacturing process that is mindful of the operator and the environment.

Avoiding any exposure to NPs is one such way, and direct liquid reaction-injection (DLRI) aims to fulfill this need. DLRI is based on the controlled in situ synthesis of NPs from the decomposition of suitable organometallic precursors in conditions that are compatible with a pulsed injection mode of an aerosol into a downstream process. Coupled with low-pressure plasma, DLRI produces nanocomposite with homogeneously well-dispersed small nanoparticles that in the particular case of ZnO-DLC nanocomposite exhibit unique properties. DLRI favorably compares with the direct liquid injection of ex situ formed NPs. The exothermic hydrolysis reaction of the organometallic precursor at the droplet-gas interface leads to the injection of small and highly dispersed NPs and, consequently, the deposition of fine and controlled distribution in the nanocomposite. The scope of DLRI nanosynthesis has been extended to several metal oxides such as zinc, tin, tungsten, and copper to generalize the concept. Hence, DLRI is an attractive method to synthesize, inject, and deposit nanoparticles and meets the prevention and atom economy requirements of green chemistry.

This work is the result of a partnership between the laboratories LCC, LAPLACE, IMRCP, and CIRIMAT.

The study was published in the journal Angewandte Chemie International Edition

The study was published in the journal Angewandte Chemie International Edition. The use of light to initiate reactions is one of the most promising method for reducing the carbon footprint of chemistry. Scientists from Strasbourg and Toulouse have developed luminescent copper complexes stabilized by a ligand, allowing them to optimize their properties by forming a molecular corbeille.

These complexes have the potential to replace current photocatalysers based on noble metals.

This article appeared on the magazine’s cover; see opposite image.