Construction of eight mixed-valence pentanuclear CuI4Cu^II clusters using ligands with inhomogeneous electron density distribution: synthesis, characterization and photothermal properties

Abstract

In order to enhance the light absorption in the visible region for the utilization of sunlight, eight mixed-valence polynuclear CuI/CuII Clusters have been synthesized for evaluating their Photothermal conversion performance....

Synthesis and Study of Photothermal Properties of a Mixed-Valence Nanocluster CuI/CuII with Strong near-Infrared Optical Absorption Supported by 4-tert-Butylcalix[4]arene Ligand

“…The peak at 286.8 nm and its shoulder peak are assigned to the π→π* transitions of the Calix4 and DMF moiety. The visible band at 462 nm is ascribed to the IVCT . The lower-energy band at 917 nm is assigned to ligand field copper­(II) d–d transitions, which are red-shifted with the reported Cu II complexes. , This may be connected with the multiple Cu II centers with multielectron transfer process .…”

“…These features greatly contribute to the excellent thermo-optical conversion performance of these clusters. Compared with other copper-based photothermal materials, the title cluster shows the best temperature increment under 1 sun known at present. ,− …”

“…In this report, we indicate that there is a significant relationship between the Cu II content of the cluster and its optical absorption ability. The title mixed-valence nanocluster Cu I /Cu II with the highest percentage of Cu II ions demonstrates strong near-infrared absorption in the solid state and the best photothermal conversion capability (the equilibrium temperature ∼78.2 °C) over previous reported pentanucleus Cu I 4 Cu II clusters …”

“…Based on the previous progress, the light absorption ability will be further enhanced both in the visible and the near-infrared range with the higher content of Cu II atoms. 22 However, for producing the multi-nucleus mixedvalence Cu I /Cu II cluster, the following difficulties need to be overcome. First, it is a significant challenge to control the synthesis process of a cluster containing two metal centers with two different oxidation states.…”

“…To increase the efficiency of the opto-electrical properties, some functional groups can be introduced in coordination compounds. − Improving the light absorption is paramount for the usage of sunlight because over 95% solar energy is in the visible and the near-infrared regions. ,, In order to design photothermal molecules with the full light spectrum absorption for achieving better light-harvesting, several optical absorption centers can be introduced by the IVCT process. Based on the previous progress, the light absorption ability will be further enhanced both in the visible and the near-infrared range with the higher content of Cu II atoms . However, for producing the multi-nucleus mixed-valence Cu I /Cu II cluster, the following difficulties need to be overcome.…”