Photomechanical effect in Zn(ii) and Cd(ii) 1D coordination polymers: photosalient to non-salient behaviour

Abstract

A Zn(II) based one-dimensional (1D) coordination polymer (CP), [Zn(cis-1,4-chdc)(4-nvp)] (1) {cis-1,4-H2chdc = cis-1,4-cyclohexanedicarboxylic acid and 4-nvp = 4-(1-naphthylvinyl)pyridine} undergoes solid-state photochemical [2+2] cycloaddition reaction acompanied by mechanical motion, wherein crystals...

Recent Advances in Photomechanical Crystals Made from Metal–Organic and Organometallic Complexes

“…(c) SEM image of Zn(II) complex crystal before irradiation, cracking, and collapsed after UV irradiation. Reproduced from ref . Copyright 2022 The Royal Society of Chemistry.…”

“…Mir group has synthesized two one-dimensional complexes utilizing 4-(1-naphthylvinyl) pyridine (4-nvp) as a photoresponsive group with different central atom, namely, Zn(II) and Cd(II). 47 The centroid distance of adjacent C�C bonds in two CPs are less than 4.2 Å, yet Zn(II) and Cd(II) CPs exhibit distinct crystal packing arrangements (Figure 3a,b). The photodimerization was confirmed by the presence of a cyclobutane peak in the 1 H NMR spectra of both CPs.…”

“…The metal centers in metal–organic complexes have a significant influence on the photomechanical properties. Mir group has synthesized two one-dimensional complexes utilizing 4-(1-naphthylvinyl) pyridine (4-nvp) as a photoresponsive group with different central atom, namely, Zn­(II) and Cd­(II) . The centroid distance of adjacent CC bonds in two CPs are less than 4.2 Å, yet Zn­(II) and Cd­(II) CPs exhibit distinct crystal packing arrangements (Figure a,b).…”

Construction of Photoreactive Chiral Metal–Organic Frameworks and Their [2 + 2] Photocycloaddition Reactions

“…Among several approaches for constructing CMOFs, an effective way could rely on the introduction of enantiopure chiral ligands as a chiral source. ,, In this case, less harsh reaction conditions are generally required to avoid ligand racemization. − Without a doubt, the development of extended areas of CMOFs has been highly challenging. On the other hand, solid-state [2 + 2] photocycloadditions established by the pioneering works of Schmidt et al are interesting reactions between olefin compounds that create covalent bonds in organic compounds and inorganic complexes including MOFs. − ,− Moreover, [2 + 2] photocycloaddition reactions in the solid state are ecofriendly and stereospecific because of the nonsolvent conditions yielding side-reaction-free products. , To undergo a [2 + 2] cycloaddition reaction, a pair of olefin (CC) bonds in the ligands should be aligned parallel within a distance of <4.2 Å (Schmidt’s criteria) . Some photoreactive MOFs derived from a bipyridyl olefin ligand, 1,4-bis­[2-(4-pyridyl)­ethenyl]­benzene (bpeb; Figure ), and dicarboxylate coligands with appropriate metal ions give rise elegant and highly organized products via the appearance of cyclobutane rings under UV irradiation because of its CC bonds arranged in close proximity. − Because bpeb has two CC bonds, it allows diverse types of products through the formation of either one or two cyclobutane rings depending on the alignment modes: out-of-phase or in-phase.…”

Photomechanical effects based on a one-dimensional Zn coordination polymer crystal driven by [4 + 4] cycloaddition

“…25,26 Mir et al synthesized three one-dimensional Zn(II)coordination polymers that consist of 4-(1-naphthylvinyl)pyridine, showing popping behaviors. [27][28][29] However, to the best of our knowledge, the photosalient effect driven by [4 + 4] cycloaddition in the crystals formed from metal-organic compounds has rarely been observed due to its dominated coordination bonds rather than π-π interactions. Therefore, it is quite challenging to modulate the actuation properties of a metal-organic compound based on anthracene.…”