Fe(II)-Pt(II) based metallo-supramolecular macrocycle nanoarchitectonics for high-performance gel-state electrochromic device

Herein, a Pt containing Fe-terpyridine-based square-shaped metallo-supramolecular macrocycle was synthesized, utilizing the advantage of Pt(II)-based complex to form the square macrocycles at room temperature. The step-wise synthesized terpyridine-pyridine containing ligand, its Fe(II)-complex, and the Pt-Fe-TpyN mac-rocycle were fully characterized by different spectroscopic, structural, and morphological characterizations. Incorporating a Pt(II) component can improve the solution processability and the electronic communication between metal centers via conjugated ligands. The solution processable Pt-Fe-TpyN macrocycle was used as an active ECM film to fabricate a gel-state ECD, which demonstrated a reversible purple to transparent dirty white color change during electrochromism with a high optical contrast of 49% in +3/-2 V voltage window utilizing the redox of Fe (II) metal centers. The ECD also showed fast-switching times of 0.58 and 4.4 s for tc and tb, respectively, along with a high coloration efficiency of 227 cm2 C-1 and cycle stability over 1000 cycles. The EC parameters were unaltered in larger sized devices also. The current work may provide a valuable method for synthesizing metallo-macrocycles with improved solubility and film forming ability by incorporating a Pt (II) component into the structure for spectrochemical and optoelectronic devices.

Automated summary

In this study, a Pt-containing Fe-terpyridine-based square-shaped metallo-supramolecular macrocycle was synthesized and characterized. The incorporation of Pt(II) improved the solubility and film forming ability, while maintaining electronic communication between metal centers. The Pt-Fe-TpyN macrocycle was used as a reversible electrochromic device (ECD) and demonstrated high optical contrast, fast-switching times, high coloration efficiency, and cycle stability. This work provides a valuable method for synthesizing metallo-macrocycles for spectrochemical and optoelectronic devices.