Arylazoimidazole Coordinated and Naphthalene-Dicarboxylato Bridged Polymers of Co(II) and Photochromic Zn(II) Complexes

Abstract

Naphtheledicarboxylato ((NDC 2− ) bridged coordination polymers (CPs) along with (E)-1-methyl-2-(p-chlorophenylazo)imidazole (ClPai-Me) coordination to Co(II), [Co(∝-NDC) 0.5 (∝ 4 -NDC) 0.5 (ClPai-Me)]•0.5H 2 O (1), and to Zn(II), [Zn(∝-NDC) 0.5 (∝ 4 -NDC) 0.5 (ClPai-Me)]•0.5H 2 O (2), have been characterized. In the single crystal X-ray structure of 1, ClPai-Me chelates to the Co(II) ion by N(azo) and N(imidazolyl), whereas in compound 2, it acts as a monodentate N(imidazolyl) donor to the Zn(II) ion. The coordination atmosphere around Co(II) in the 1 ion is distorted octahedral CoN 2 O 4 , whereas in the case of 2, it is distorted square pyramidal ZnNO 4 . Compounds 1 and 2 exhibit the righthanded (P) and left-handed (M) one-dimensional helical chain. NDC −2 is serving as a bridge between two M(II) ions to constitute μ-NDC and four M(II) ions to construct μ 4 -NDC to assemble threedimensional polymers. Upon UV light (369 nm) irradiation, compound 2 shows trans-to-cis isomerization of -NN−C 6 H 4 −Clp both in the solid and solution state but 1 remains silent. Prolonged light irradiation in the solid state (film phase) does not change the coordinated ClPai-Me in complexes 1 and 2, whereas the free stage of ClPai-Me undergoes photoreduction of the −NN− bond and forms azo radicals with a concomitant permanent color change. The persistence of the radical has been characterized by electron paramagnetic resonance spectroscopy in the solid state at g = 2.009. The effective magnetic moment of 1 is 4.17 μ B at 300 K, Co(II) ion of S = 3/2.

Unlocking the Remarkable Influence of Intramolecular Group Rotation for Third‐order Nonlinear Optical Properties

“…To investigate whether light‐induced cis‐trans isomerization has occurred, we monitored the linear absorption spectra of 1 and 2 [51,52] . The color of the solution changes from yellow to orange and obviously deepened.…”

“…To investigate whether light-induced cis-trans isomerization has occurred, we monitored the linear absorption spectra of 1 and 2. [51,52] The color of the solution changes from yellow to orange and obviously deepened. As shown in Figure 4, the maximum absorption band (λ max~3 60 nm) in the spectrum comes from the π-π* transition.…”

Biporous Cd(II) Coordination Polymer via in Situ Disulfide Bond Formation: Self-Healing and Application to Photosensitive Optoelectronic Device

“…Over the last few decades, light-induced molecular transformation (physical/ chemical) has attracted attention due to its simple, inexpensive, and environmentally benign method. The photoisomerization and photochromism, 14 light-induced radical generation 46 and polymerization, photoredox reaction and photocyclization, photopolymerization processes, 47 and so on are significant light-induced transformations, 48 and out of them radical generation and subsequent chemical reactions are most outstanding. Interestingly, thiol radicals have been generated by light-induced disulfide cleavage, which undergoes a recombination of disulfide bond formation when exposed to air (Scheme 2).…”

“…Coordination polymers (CPs) are of intriguing interest due to their wide variety of structure building units and their fascinating potential applications. − Smart architecture reversibly changes the molecular structure and the subsequent properties upon exposure to external stimuli such as light, pH, heat, and so on. − The CPs are mainly constructed by the support of metal ion nodes and organic linkers. , Because of their inexpensive availability, easy synthetic methodology, and various coordinating sites, organic linkers are more appropriate for the design of these organic–inorganic composite materials.…”

“…We have designed CPs of various dicarboxylates and mono- or bidented N-donor ligands, and the compounds are used in the field of semiconducting devices and the sorption and adsorption of gases. ,,, In this Article, a Cd­(II)-bonded zigzag 2D coordination polymer undergoes extensive hydrogen bonding like N–H···O, N–H···S, and π···π interactions to form the 3D architecture. The presence of a S–S bond may induce flexibility in the material due to the twisted conformations of the S–S and C–S single bonds in the H 2 DSBA ligand, which further extend the development of self-healed CPs under external stimulus conditions.…”