Synthesis and Characterization of Acid-Responsive Luminescent Fe(II) Metallopolymers of Rigid and Flexible Backbone N-Donor Multidentate Conjugated Ligands

Abstract

In this report we have disclosed the syntheses and properties of two new conjugated organic moieties bearing the same coordination sites but possessing different backbone rigidities and rotational flexibilities. Two new metallopolymers have been synthesized from the corresponding ligands under identical reaction conditions, and they have been thoroughly characterized through different techniques to understand the effect of backbone rigidity on the evolution of different properties in these metallopolymers. A FESEM micrograph of the rigid metallopolymer confirms the formation of a rigid nanorod type structure, while long agglomerated nanofiber strands are visible on the substrate in the case of the flexible analogue. All of the newly synthesized materials are fluorescence active. An Fe(II) metallopolymer of the flexible ligand showed huge changes in emission properties in the presence of different acids and showed a possibility of it being used as a thin film acid vapor sensor. All of the materials showed reversible electrochemical activity, and both of these polymers have shown electroluminescence when an appropriate potential is applied.

Photophysical and Theoretical Interpretation of the Insensitive Emission to Temperature of a Metallopolymer Containing Europium Ions

“…Metallopolymers are considered to be in the forefront of luminescent applications in the fields of electroeletronic devices, nanobiomedical, microelectronics, microfluidics, and luminescent sensors. , The hybrid characteristics of metallopolymers allow the combination between the metallic and the organic parts, giving rise to new properties in optics and electronics applications. − To explore the properties of metallopolymers, lanthanide coordination polymers can assume three main configurations: type I in which the lanthanide is linked to a lateral chain of the polymer, without electronic interaction with the main chain; type II in which the metal is inserted into the polymer as ramification, interacting with its π system; and type III in which the metallic center is directly linked to the polymer backbone. Each type has its own advantages and disadvantages, depending on the envisaged application. − Recently, metallopolymers as ratiometric luminescent probes have attracted great attention because apart from the interest in soluble molecular luminophores showing temperature-dependent luminescence, they can afford more robust signals and can eliminate most of the ambiguities. , …”

From Center-to-Multilayer Chirality: Asymmetric Synthesis of Multilayer Targets with Electron-Rich Bridges

“…The overall structural design was performed by taking advantage of retro-synthetic analysis (RSA) with target 1a as an example . With the aim of facile access to the multilayer three-dimensional (3D) family of compounds, we designed a convergent strategy wherein two fragments (diboronic ester 7 and bromide 8 ) would be joined via a Suzuki–Miyaura coupling as the key asymmetric step . The functional group conversions retro-synthetically involve the Sandmeyer reaction, carbamate hydrolysis, Hoffmann rearrangement, cyanide hydrolysis, and amide dehydration in order as depicted in Figure .…”

“…This multilayer molecular chirality was inadvertently discovered as a consequence of the pursuit of more efficient GAP reagents (GAP: group-assisted purification). , The C–N bond-anchored folding chirality was then constructed via double Buchwald–Hartwig cross-couplings. , Two enantiomers were separated and isolated by preparative chiral high-performance liquid chromatography (HPLC). Afterward, the fully C–C bond-based folding chirality was constructed via double Suzuki–Miyaura cross-couplings . Two diastereoisomers were differentially produced as a result and separated by silica gel column chromatography following the reductive ring opening of the benzothiadiazole ring of the central layer to furnish the diamine, which was then protected using a bulky carbonyl chloride or anhydride.…”

Aggregation-Induced Polarization (AIP): Optical Rotation Amplification and Adjustment of Chiral Aggregates of Folding Oligomers and Polymers

“…In the meanwhile, C series presents were found to display not only AIE characteristics but also reversible redox properties in electrochemical performance. Monomer 4,7-bis(4,4,5,5-tetramethyl-1,3,2 1) was synthesized by reacting bis(pinacolato)diboron with 4,7-bis(8-bromonaphthalen-1-yl) benzo[c][1,2,5]thiadiazole, which was preformed from the treatment of 4,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2yl)benzo[c][1,2,5]thiadiazole with 1,8-dibromonaphthalene under traditional Suzuki-Miyaura cross-coupling conditions followed by treating with bis(pinacolato)diboron (Miyaura and Suzuki, 1995;Kumar et al, 2020). Selenodiazoles (3) was derived from its thiadiazole counterpart through the reductive opening of thiadiazole ring by using an excess amount of sodium borohydride (4.0 equiv) in the presence of CoCl 2 •6H 2 O (10 mol%) (Scheme 1) (Neto et al, 2005;Idris et al, 2018).…”