Dithienylethene metallodendrimers with high photochromic efficiency

Yuxuan Wang,Qifeng Zhou,Xiaoxiao He,Ying Zhang,Hongwei Tan,Jianhua Xu,Cuihong Wang,Wei Wang,Xiping Luo,Jinquan Chen,Lin Xu

doi:10.1016/j.cclet.2021.09.048

Abstract

It has been challenging to achieve multi-photochromic systems without affecting the individual photoswitching properties of the constituent units. Herein, we present the design and synthesis of a new family of platinum-acetylide dendrimers containing up to twenty-one photochromic dithienylethene (DTE) units that exhibit both high photochromic efficiency and individual switching properties. Upon irradiation with ultraviolet (UV) and visible (vis) light, the resultant metallodendrimers display high conversion yield and good fatigue resistance. More interestingly, cyclization-cycloreversion kinetics revealed that the photochromic property of each DTE unit in these metallodendrimers is unaffected by its neighbor and the full ring-closure of up to twenty-one DTE units in one single dendrimer has been achieved.

Highlights

Photochromic compounds are light-sensitive molecules that can undergo isomerization between at least two forms
Great efforts have been dedicated to resolving this problem over the past few years[20], achieving full photocyclization of all DTE units in a single multiphotochromic system without affecting the individual photoswitching property is still a difficult task
Synthesis and characterization of DTE dendrimers Organometallic complex 1 (Scheme S1, Supplementary Information) was employed as the basic precursor for the divergent dendrimer growth for following two reasons: (i) it contains platinum-acetylide unit that can react with alkyne units as well as two protected alkynes that can be gently exposed for dendrimer growth[29]; (ii) bis(thien-3-yl) derivatives of perfluorocyclopentene usually exhibit high conversion yields and excellent fatigue-resistant properties[30]

Summary

Introduction

Photochromic compounds are light-sensitive molecules that can undergo isomerization between at least two forms. During the past few decades, photochromic systems have attracted more and more attentions since their physicochemical properties can be fine-tuned upon being triggered by light or heat[1]. An increasing effort has been recently devoted to the development of multiphotochromic molecules that are comprised of two or more photochromic because of their wide applications ranging from molecular sensors, molecular motors, energy and information storage devices, photoactuators, and artificial muscles[2]. The construction of multi-photochromic systems without affecting the individual photoswitching property of the constituent units remains a great challenge in this field. Great efforts have been dedicated to resolving this problem over the past few years[20], achieving full photocyclization of all DTE units in a single multiphotochromic system without affecting the individual photoswitching property is still a difficult task

Methods

Results

Conclusion