Molecular Thermometer

Set of coordination for measuring temperatures and a connected device for performing such measurements which allow to overcome at least partially, the drawbacks of other existing methods.

Title of the patent Use of a coordination compound for the measurement of temperatures
Thematic area Chemistry and biotechnology
Ownership Alma Mater Studiorum - Università di Bologna and Università degli Studi di Parma
Inventors Luca Prodi, Francesco Zerbetto, Sara Bonacchi, Marco Montalti, Nelsi Zaccheroni, Matteo Calvaresi, Daniele Alessandro Cauzzi
Protection Europe, USA
Licensing status Available for licensing agreement
Keywords Thermometer molecular, nanotechnology, metal clusters, copper, luminescence, life time
Filed on Oct 26, 2010

Thermometers come as mercury-in glass thermometers, thermocouples, bi-metallic strips, resistance temperature detectors, thermistors, infrared cameras, and more. With the advent of nanotechnology, several techniques have been developed to measure temperatures at the very small length scales, ranging from Scanning Thermal Microscopy (SthM) to Raman spectroscopy to thermo-reflectance microscopy. They operate at best with 50 nm resolution (SthM) and with acquisition rates of 0.5 points s-1 (Raman) and often involve tedious calibration processes. Fluorescence Thermometry has also a good potential with a range between 25 and 70 ˚C and a relative signal change of 30%. While future developments in nanoscale thermometry may lie with carbon nanotubes filled with liquid metals such as mercury or gallium, a variety of molecules have been proposed for their potential as luminescent molecular thermometers.

The present invention provides a set of coordination for measuring temperatures and a connected device for performing such measurements which allow to overcome at least partially, the drawbacks of other existing methods. These thermometers are, at the same time, easy and economically feasible. The cluster of copper synthesized and shown in the figure has been studied from the perspective of photophysical and, during an in-depth characterization, it was shown that the half-life and intensity of luminescence, both solid state and in various solvents , are very dependent on temperature. This dependence is especially pronounced and used to determine the temperature at which the compound is in a very wide range (from -80 °C to + 80 °C) and sensitivity (0.1 °C) which is the highest between those seen in molecular thermometers.

It has been demonstrated the possibility of using well-characterized nano-systems to measure temperature. The system is general and is based on very simple design principles. It is usable in two different approaches (excitation lifetimes and areas of the emission spectra) that require little or no calibration and very standard instrumentation. It is exploitable in a variety of solvents, water included, in the solid, even in the presence of oxygen, which makes it an important improvement over existing molecular-level thermometers. Ligands variations and/or changes of the metal core with other metals have already been done and can improve the already excellent performance of the system.