Abstracts

Multifunctionality represents a pivotal objective in the realm of smart materials, offering enhanced versatility and performance. Within this context, the field of magneto-luminescent molecular materials has garnered considerable attention and interest due to its potential for a wide array of applications. A significant challenge in this field is the development of single molecule magnets (SMMs) with temperature-dependent luminescence, enabling them to function as in situ thermometers.The ability to continuously monitor temperature in SMMs with temperature-dependent luminescence is invaluable, ensuring the preservation of magnetic behavior across varying thermal conditions. This capability is crucial for applications requiring consistent magnetic properties, such as molecular spintronics and quantum readout systems.Despite recent progress, several challenges remain unresolved. One such challenge is the development of air stable SMMs with high blocking temperatures (T_b). While milestones like the 80 K achieved with metallocenes are noteworthy, their practical utility is hindered by their air instability. Therefore, there is a need for further research to explore air-stable alternatives. In this way, recent efforts have focused on synthesizing air-stable SMMs with improved properties. For instance, a dysprosium azafullerene with a 45 K blocking temperature shows promise. However, the current record for unencapsulated SMMs is 36 K, pointing to the necessity for additional improvements.In this way, we introduce a novel molecular magnet setting a new T_b record of up to 43 K for air-stable unencapsulated SMMs. This material exhibits luminescence thermometry capabilities below the blocking temperature, representing a significant advance in air-stable bifunctional nanomaterials development.Overall, our findings contribute to ongoing efforts to improve multifunctional molecular materials, paving the way for broader applications across various technological and scientific domains. Our air-stable hexagonal bipyramidal complex [DyL(OSiPh₃)₂](BPh₄)·1.5CH₂Cl₂ (1·1.5CH₂Cl₂) serves a dual purpose as both a luminescent thermometer and a single ion magnet (SIM), boasting an impressive energy barrier of 1528 K. However, its robust QTM contributes to a lower T_b. Similarly, our diluted complex [Dy_0.09Y_0.91L(OSiPh₃)₂](BPh₄)·1.5CH₂Cl₂ (1@Y·1.5CH₂Cl₂) functions simultaneously as a magnet and thermometer. It operates as a SIM with a blocking temperature of up to 43 K, the highest reported among air-stable unencapsulated SMMs. Consequently, 1@Y·1.5CH₂Cl₂ stands at the cutting-edge of a dual-role as a model of a bifunctional SMM and luminescent thermometer, facilitating temperature monitoring within its magnetic operational range. Importantly, this material showcases superior magnetic properties (U_eff and T_b) compared to any other documented SMM luminescent thermometer.