Kumar K, Stefanczyk O, Chorazy S, Nakabayashi K, Ohkoshi SI. Ratiometric and Colorimetric Optical Thermometers Using Emissive Dimeric and Trimeric {[Au(SCN)
2 ]
- }
n Moieties Generated in d-f Heterometallic Assemblies.
Angew Chem Int Ed Engl 2022;
61:e202201265. [PMID:
35182087 DOI:
10.1002/anie.202201265]
[Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Indexed: 11/09/2022]
Abstract
Gold complexes can generate excimers ([Au2 ]→[Au2 ]*) and exciplexes ([Au3 ]→[Au3 ]*) with light excitation. Four GdIII and YIII complexes were assembled with dimeric {[Au(SCN)2 ]- }2 and trimeric {[Au(SCN)2 ]- }3 bis(thiocyanato)gold(I) counterions. The vibrational signature associated with the Au⋅⋅⋅Au vibrational mode was probed with ultralow frequency (ULF) Raman spectroscopy as a function of temperature. Emission spectroscopy was used to explore photophysical properties. Two broad features in the high- and low-energy regions were associated with the fluorescence and phosphorescence of the gold entities, respectively. Temperature-dependent luminescence measurements showed that the emission color can be tuned from blue to green via cyan and white. Hence, these complexes can act as colorimetric thermometers. Additionally, a ratiometric thermal sensing ability was incorporated with high sensitivity up to 5 % K-1 in the cryogenic temperature range.
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