Photochromism- and Photoluminescence-Tunable Heterobimetallic Supramolecular Hybrid Isomers

Abstract

Supramolecular isomerism in coordination compounds, an ideal platform for understanding the self-assembly and structure–property relationships, has received extensive research interest in the past decades. In this context, we have synthesized five multifunctional three component viologen-based 3d-4f hetereobimetallic supramolecular isomers with tunable properties depending on the synthetic conditions, especially stoichiometric amounts of the components, namely, 2D network {[Tb (BCEbpy) (H2O)4]·[CoIII(CN)6]}·4H2O (1), 1D coordination chain [Tb0.5(BCEbpy)0.5 (H2O)3]·[CoIII(CN)6]0.5 (2), 3D framework {[Tb­(BCEbpy)­(H2O)4]­[CoIII(CN)6)]}·H2O (3), 2D network {[Tb­(BCEbpy)­(H2O)4]­[CoIII(CN)6)]}·2H2O (4), and {[Tb0.5(BCEbpy)0.5 (H2O)2]­[CoIII(CN)6]0.5}·H2O (5) via a self-assembly method. Single-crystal X-ray analyses reveal that the binding mode of [CoIII(CN)6]3– has a dramatic influence on the final structures of the heterometallic frameworks and further results in their distinct photochromic behaviors upon irradiation. Further careful inspection of the structures of these complexes indicates that the different photochromic behaviors could be mainly attributed to their different packing modes and electron-accepting abilities of the bipyridinium unit. In addition, these compounds show multicolored switchable photoluminescence via selective excitation of the green emissive Tb3+, blue luminescent conjugated ligand BCEbpy, and red luminescent Co­(CN)6 3– components.

Viologen Guest-Mediated Luminescence Emission Tuning and Photochromic Behavior by a Series of Viologen@Zn-MOF Materials

“…The shorter distances are more favorable for electron transfer. Additionally, as previously reported, the small dihedral angles between the two pyridinium rings were more conducive to the photoinduced reduction of viologens and the stability of free radicals. , Zn-MOF-3 showed the smallest dihedral angle (the dihedral angles between the two pyridinium rings for Zn-MOFs-1, 2, and 3 are 29.4, 0, and 11.95°, respectively) and showed the strongest π···π stacking interactions. The small dihedral angle and strong π···π stacking interactions between the bipyridinium ring and H 4 pdda ligand lead to fast photochromism of Zn-MOF-3 in the presence of UV light.…”

A Three-Component Donor–Acceptor Hybrid Framework with Low-Power X-ray-Induced Photochromism

“…For the realization of low-power XIP, the D–A hybrid materials must possess strong donor or acceptor moieties and short distances between donor and acceptor moieties. ,,,− Like the multiple electron pair donors, − the cyanometallates make up an excellent class of donor candidates, while the viologen derivatives are electron-deficient π-conjugated species that can capture and stabilize the electrons dissociated from the electron donors upon irradiation and thus form the photoinduced bistable systems. Therefore, a combination of organic viologen acceptors with inorganic donors [Co III (CN) 6 ] 3– are anticipated to provide the favorable electron-transfer pathways under the low-power X-ray stimuli in D–A hybrid systems.…”

Synthesis, structure, photoluminescence and magnetism of a series of cobalt‐lanthanide heterometallic complexes originated from 2,3‐dichlorobenzoate and 1,10‐phenanthroline

“…During the last few decades, the study and development of heterometallic complexes containing 3d and 4f metal ions has attracted considerable attention. The reason why the 3d-4f heterometallic complexes are of interest is their unique structures [1][2][3] and potential applications in catalysis, [4][5][6] photoluminescence, [7,8] adsorption [9][10][11] and magnetism. [12][13][14] Especially, such complexes may be good candidates for functional materials displaying singlemolecule magnet (SMM) behaviors.…”