Technological challenges for quantum information technologies lead us to consider aspects of molecular magnetism in a radically new perspective. The design of new derivatives and recent experimental results on molecular nanomagnets are covered in this tutorial review through the keyhole of basic concepts of quantum information, such as the control of decoherence and entanglement at the (supra-)molecular level.

The possibility to graft nano-objects directly on its surface makes graphene particularly appealing for device and sensing applications. Here we report the design and the realization of a novel device made by a graphene nanoconstriction decorated with TbPc₂ magnetic molecules (Pc = phthalocyananine), to electrically detect the magnetization reversal of the molecules in proximity with graphene. A magnetoconductivity signal as high as 20% is found for the spin reversal, revealing the uniaxial magnetic anisotropy of the TbPc₂ quantum magnets. These results depict the behavior of multiple-field-effect nanotransistors with sensitivity at the single-molecule level.

The substitution of one metal ion in a Cr-based molecular ring with dominant antiferromagnetic couplings allows the engineering of its level structure and ground-state degeneracy. Here we characterize a ${\mathrm{Cr}}_7\mathrm{Ni}$ molecular ring by means of low-temperature specific-heat and torque-magnetometry measurements, thus determining the microscopic parameters of the corresponding spin Hamiltonian. The energy spectrum and the suppression of the leakage-inducing $S$ mixing render the ${\mathrm{Cr}}_7\mathrm{Ni}$ molecule a suitable candidate for the qubit implementation, as further substantiated by our quantum-gate simulations.

We critically review recent results obtained by studying the low-temperature specific heat of some of the most popular molecule-based materials. After introducing the experimental techniques and basic theoretical framework needed for heat capacity determination and understanding, we report on the magnetothermal properties of molecular antiferromagnetic wheels. For selected molecular high-spin clusters, particular emphasis is devoted to magnetic quantum tunnelling and coherence as well as collective phenomena as probed by heat capacity experiments. We discuss also the possibilities of application of molecule-based materials for magneto-cooling at low temperatures and the limitations in other temperature ranges. Perspectives for future developments are mentioned as well.

Nanomagnets will play a crucial role for the storage and processing of magnetic information in the future, so we may wonder to what extent molecular systems will contribute to this game. In this Feature Article, I'll briefly review the basic requirements for information technology and some of the recent achievements in the field, as well as some ideas that can be further pursued.