Search results for "thermochromism"
showing 10 items of 33 documents
Preparation and Thermochromic Switching between Phosphorescence and Thermally Activated Delayed Fluorescence of Mononuclear Copper(I) Complexes
2020
Instructive, inexpensive, and environmentally friendly laboratory syntheses of two highly luminescent copper(I) complexes CuI(PPh3)2(pyR) (pyR = pyridine, 4-cyanopyridine) are described for second-year/upper-division undergraduate inorganic chemistry students. Both complexes exhibit bright thermally activated delayed fluorescence (TADF) at ambient temperature and phosphorescence at low temperature. The laboratory experiments familiarize the students with mechanochemical syntheses, cluster and complex formation, ligand substituent effects, and the fascinating phenomenon of luminescence thermochromism.
The Two‐Step Spin Conversion in a Supramolecular Triple Helicate Dinuclear Iron(II) Complex Studied by Mössbauer Spectroscopy
2006
The triple helicate dinuclear iron(II) complex, [Fe-2(L)(3)](ClO4)(4)center dot 2H(2)O (1), previously reported by Tuna et al. (Chem. Eur. J. 2004, 10, 5737), was prepared and characterised by detailed SQUID and Fe-57 Mbssbauer measurements. Compound 1 exhibits a thermochromic two-step spin conversion at T-SC((1)) ca. 240 K and T-SC((2)) ca. 120 K, but does not switch its spin state further below 20 K as proven by Mossbauer spectroscopy. The sharp variation of the susceptibility below 20 K is due to zero-field splitting of the remaining iron(II) high-spin species. Applied field Fe-57 Mossbauer spectroscopy experiments at 4.2 K indicate that the gradual thermal spin conversion from [HS-HS] p…
SWEET IONIC LIQUIDS BASED MATERIALS FOR ENVIRONMENTAL APPLICATIONS
Spin-crossover nanocrystals with magnetic, optical, and structural bistability near room temperature.
2008
Templated growth of smart nanocomposite thin films: Hybrid aerosol assisted and atmospheric pressure chemical vapour deposition of vanadyl acetylacet…
2009
Hybrid aerosol assisted and atmospheric pressure chemical vapour deposition methodology has been utilised to produce nanocomposite thin films of gold nanoparticles and vanadium dioxide from vanadyl acetylacetonate and auric acid. The addition of tetraoctyl ammonium bromide (TOAB) to the precursor Solution gave control of the size and distribution of gold nanoparticles in the vanadium oxide matrix. These reactions led to vanadium dioxide films with reduced crystallite sizes and enhanced thermochromic properties. The films were analysed by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. Their optical and thermochromic behaviour was also determined, This h…
A magnetic self-contained thermochromic system with convenient temperature range
2019
A new ionic liquid with sugar-based ligand has been prepared and used to coordinate cobalt(II), at low loading, in an ionic liquid solution. The system obtained reveals magnetic switching and marked thermochromism in solution/polymer films over a convenient temperature range (20–60 °C). This system is self-contained, devoid of any volatile substances, and reproducible over multiple thermal cycles. The colour change can be attributed to a change in the coordination geometry from octahedral (pink) at room temperature to tetrahedral (blue) on warming, monitored by 59Co NMR spectroscopy, which was used for the first time to study the change. This material may find applications in stimuli-respon…
Liquidi ionici biocompatibili come leganti per sistemi termocromici
Reversible solvatomagnetic switching in a single-ion magnet from an entatic state
2016
We have developed a new strategy for the design and synthesis of multifunctional molecular materials showing reversible magnetic and optical switching.
Thermochromic Fluorescence from B18H20(NC5H5)2: An Inorganic–Organic Composite Luminescent Compound with an Unusual Molecular Geometry
2017
BH(NCH) is a rare example of two conjoined boron hydride subclusters of nido and arachno geometrical character. At room temperature, solutions of BH(NCH) emit a 690 nm fluorescence. In the solid state, this emission is shifted to 620 nm and intensifies due to restriction of the rotation of the pyridine ligands. In addition, there is a thermochromicity to the fluorescence of BH(NCH). Cooling to 8 K engenders a further shift in the emission wavelength to 585 nm and a twofold increase in intensity. Immobilization in a polystyrene thin-film matrix results in an efficient absorption of pumping excitation energy at 414 nm and a 609 nm photostable fluorescence. Such fluorescence from polystyrene t…