Controllable multiple-step configuration transformations in a thermal/photoinduced reaction

Abstract

Solid-state photochemical reactions of olefinic compounds have been demonstrated to represent powerful access to organic cyclic molecules with specific configurations. However, the precise control of the stereochemistry in these reactions remains challenging owing to complex and fleeting configuration transformations. Herein, we report a unique approach to control the regiospecific configurations of C = C groups and the intermediates by varying temperatures in multiple-step thermal/photoinduced reactions, thus successfully realizing reversible ring closing/opening changes using a single-crystal coordination polymer platform. All stereochemical transitions are observed by in situ single-crystal X-ray diffraction, powder X-ray diffraction and infrared spectroscopy. Density functional theory calculations allow us to rationalize the mechanism of the synergistic thermal/photoinduced transformations. This approach can be generalized to the analysis of the possible configuration transformations of functional groups and intermediates and unravel the detailed mechanism for any inorganic, organic and macromolecular reactions susceptible to incorporation into single-crystal coordination polymer platforms.

Coordination-Driven Self-Assembly of Complexes Constructed from Two Helical Ligands: Synthesis, Structures, and Selective Gas Adsorption Properties

“…Chirality is considered a fundamental feature in natural processes and plays an integral role in many chemical and biological processes. 1−4 Currently, chiral metal complexes are widely used in asymmetric synthesis and catalysis, 5,6 enantiomeric separation, 7 and supramolecular chemistry due to their ability to create asymmetric environments. 8−10 They are also widely used in chiral liquid crystals, chiral luminescent materials, 11−13 enantioselective sensors, 14,15 magnetic chiral compounds, 16 and chiral reagents.…”

Topological structural transformation of a two-dimensional coordination polymer via single-crystal to single-crystal photoreaction

“…In the past decades, there exists persistent interest in developing crystalline metal–organic coordination compounds with d 10 electron configuration metal ions and conjugated organic ligands. These coordination compounds may be employed as fluorescent materials to manufacture fluorescence sensors or optical memory storage devices.…”

“…4–7 On the other hand, if a [2 + 2] photocycloaddition reaction takes place inside a solid compound, due to the significant changes in the internal organic compositions and intramolecular electronic interactions, the chemical and physical properties of the solid will also display significant differences. 8–10 Therefore, the [2 + 2] photocycloaddition reaction within solid-state compounds is a powerful tool to exploit photocontrolled intelligent materials and molecular/supramolecular devices.…”

“…Therefore, Cd(NO 3 ) 2 ·4H 2 O, phthalic acid (H 2 pha) and an olefinic ligand 1,2-bis(3-pyridyl)ethylene (3,3′-bpe) were selected as the starting materials to construct a coordination polymer. Since the coordination polymers that composed of d 10 metal ions and conjugated organic ligands are potential candidates for applicable fluorescent materials, we anticipated to obtain a photoreactive coordination polymer with photocontrolled fluorescence behavior. Herein, we report the preparation, photoinduced SCSC transformation and photocontrolled fluorescence behavior of a unique coordination polymer [Cd(pha)(3,3′-bpe)] n ( 1 ).…”

Reversible Single-Crystal-to-Single-Crystal Transformation of a Coordination Polymer through Solar-Switchable Cycloaddition and Cycloreversion Reaction

“…As a type of photoreactive compound, olefinic ligands can be used to construct photoreactive CPs. − When the olefins are combined with appropriate metal ions and auxiliary ligands, the olefinic molecules may be closely aligned in parallel to satisfy Schmidt’s topochemical criteria (the distance between two parallelly aligned olefinic bonds should be less than 4.2 Å) for solid-state [2 + 2] cycloaddition reactions . To date, some CPs that can undergo [2 + 2] photocycloaddition reactions have been successfully designed and prepared, and the fast and quantitative [2 + 2] cycloaddition reactions based on most of the reported CPs need to be stimulated by UV light. − Although some UV-light-induced [2 + 2] cycloaddition reactions can also be achieved by using sunlight or visible light, they may take longer periods than the utilization of UV-light sources . Due to the limitation of photoreactivities, it is still a challenge to rapidly and efficiently carry out [2 + 2] cycloaddition reactions within olefin-containing CPs by using sunlight or visible light .…”