Development of molecular photoswitch with very fast photoresponse based on asymmetrical bis-azospiropyran

Nourmohammadian, Farahnaz; Abdi, Ali Ashtiani

doi:10.1016/j.saa.2015.07.110

Cited by 10 publications

(5 citation statements)

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“…Salicylaldehyde, aniline, sodium nitrite, sodium hydroxide, hydrochloric acid (35%), N -ethylethylenediamine, and metal salts, Fe(NO 3 ) 3 ·9H 2 O, and Fe(ClO 4 ) 3 ·6H 2 O were purchased from Merck. 2-Hydroxy-5-phenylazobenzaldehyde was prepared by a previously reported procedure . Ligand HL was synthesized by Schiff-base condensation reaction between 2-hydroxy-5-phenylazobenzaldehyde and N -ethylethylenediamine in situ while performing metalation.…”

Section: Methodsmentioning

confidence: 99%

“…2-Hydroxy-5-phenylazobenzaldehyde was prepared by a previously reported procedure. 15 Ligand HL was synthesized by Schiff-base condensation reaction between 2-hydroxy-5-phenylazobenzaldehyde and N-ethylethylenediamine in situ while performing metalation. FT-IR spectra (4000−400 cm −1 ) were recorded on KBr pellets with a PerkinElmer Spectrum BX spectrometer.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

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Above Room Temperature Spin Transition in Thermally Stable Mononuclear Fe(III) Complexes

et al. 2019

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Two solvent-free mononuclear Fe(III) complexes [Fe(L) 2 ]-NO 3 (1) and [Fe(L) 2 ]ClO 4 (2) have been synthesized by employing a new πconjugated azo-phenyl substituted ligand, 2-((E)-((2-(ethylamino)ethyl)imino)methyl)-4-(2-phenyldiazenyl)phenol (HL). The noncoordinated azophenyl part of the ligand adopts two different conformations which can exert a varied local distortion around the metal center affecting the spin crossover behavior. The magnetic data (2−450 K) reveal that complex 1 displays spin crossover above room temperature where the ligand is in linear form, while complex 2 shows an incomplete spin transition where the ligand adopts a skew form in the solid state. These complexes represent rare examples of high-temperature spin transition for mononuclear Fe(III) complexes with T 1/2 > 350 K with very high thermal stability. Presence of strong intermolecular interactions and solvent-free nature of the complexes leads to exceptional thermal stability up to 485 K (for 1) and 496 K (for 2) as revealed by thermogravimetric analysis. The magnetic data for complex 1 have been analyzed by employing an Ising-like model with vibrations yielding the enthalpy change ΔH and entropy change ΔS of the spin transition along with the critical temperature T 1/2 and the solid-state cooperativeness Γ. Spin crossover behavior of complex 1 has also been characterized by differential scanning calorimetry and electron paramagnetic resonance measurements. Ab initio calculations have been performed to analyze the difference in energies of the ground state and excited states of the complexes.

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Section: Methodsmentioning

confidence: 99%

Section: ■ Materials and Methodsmentioning

confidence: 99%

Above Room Temperature Spin Transition in Thermally Stable Mononuclear Fe(III) Complexes

et al. 2019

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“…It is worth noting that, due to the stability of the MC form of azospiropyrans, the spontaneous thermal back reaction in the dark and therefore photochemical bleaching by common low‐energy light sources is not possible. However, the repetition of ON and OFF cycles of an azospiropyran molecule by a laser source was shown elsewhere, and this will be investigated later.…”

Section: Resultsmentioning

confidence: 97%

“…The other possibility for the photochemical process is the well‐known cis–trans isomerization of the azo bonds, which would lead to a decrease in color intensity . However, such isomerization of the azobenzene moieties should have a negligible impact on the resulting immensely increased color intensities resulting from the mero forms spiropyrans.…”

Section: Resultsmentioning

confidence: 99%

“…Recently, we synthesized and studied the photoresponse of bis‐azospiropyrans connected with a conjugated aromatic bridge . These photoswitches showed a high molar absorption coefficient in the MC form . Such a high molar absorption coefficient improves the sensitivity and contradistinction between the two ON (MC) and OFF (SP) levels of finely photoresponsive molecules.…”

Section: Introductionmentioning

confidence: 99%

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Sensitivity and Resolution Development of Spiropyran‐based Molecular Photoswitches

Heydaripour

Nourmohammadian

Saadatjoo

2016

J Chinese Chemical Soc

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The phenylazo moiety and its donor‐ and acceptor‐substituted derivatives are studied as effective auxochromes to improve their sensitivity and resolution for distinguishing between the spiro (SP; OFF) and mero (ON) forms in molecular photoswitching applications. Thus, 13 azospiropyran derivatives were synthesized and their spectroscopic and photokinetic behaviors were studied. The quality of photochromic reactions of the synthesized photochromic compounds were compared using a dose–response model. Interestingly, by replacing the nitro group in 6‐nitrospiropyran (ε = 0.42 × 104 M−1 cm−1) with a simple phenylazo moiety, the SP form is still colorless and the color intensity of the merocyanine (MC) form is improved desirably by extending the conjugation length (1a, ε = 1.35 × 104 M−1 cm−1). The presence of a hydrophilic OH group or a CH3 group at the para position of phenylazo moiety revealed more or less the same photochromic properties as 1a. The OCH3 group substituted at position 6 of the phenylazo moiety at the para position of the azobenzene moiety effectively increased the photochromic properties with the maximum k‐value for SP to MC switching. Meanwhile, Cl, Br, COOH, and NO2 groups at the para position of the azobenzene moiety revealed the reduction in photochromic properties compared to 1a.

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Synthesis, characterization, and photochromism study of two spiropyran molecules with a terminal alkynyl functional group and their new 1,2,3-triazoline-containing derivatives

et al. 2021

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Development of molecular photoswitch with very fast photoresponse based on asymmetrical bis-azospiropyran

Cited by 10 publications

References 50 publications

Above Room Temperature Spin Transition in Thermally Stable Mononuclear Fe(III) Complexes

Above Room Temperature Spin Transition in Thermally Stable Mononuclear Fe(III) Complexes

Sensitivity and Resolution Development of Spiropyran‐based Molecular Photoswitches

Synthesis, characterization, and photochromism study of two spiropyran molecules with a terminal alkynyl functional group and their new 1,2,3-triazoline-containing derivatives

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