4-Amino-1,1'-azobenzene-3,4'-disulfonic acid monosodium salt

• CAS: 74543-21-8
• Catalog Number: ACM74543218
• Category: Main Products
• Molecular Weight: 379.34
• Molecular Formula: C12H10N3NaO6S2
• Synonyms: 2-Amino-5-([4-sulfophenyl]azo)benzenesulfonic acid monosodium salt, Acid Yellow 9 monosodium salt
• Appearance: Powder

Case Study

4-Amino-1,1'-Azobenzene-3,4'-Disulfonic Acid Monosodium Salt as a High-Performance Anolyte for Aqueous Redox Flow Batteries

Shimizu, Takeshi, et al. Angewandte Chemie International Edition 61.36 (2022): e202206093.

Azo-based redox couples can undergo multi-electron transfer and, when rendered water-soluble, become attractive anolytes for aqueous redox flow batteries (RFBs). 4-Amino-1,1'-azobenzene-3,4'-disulfonic acid monosodium salt (AADA) is a high solubility molecule that features reversible redox chemistry that is amenable to flow-cell operation.
An aqueous flow cell was constructed with AADA solution as the anolyte and ferricyanide ([Fe(CN)6]3-) as the catholyte. Cells were tested at a range of fixed current densities to quantify accessible capacity, utilization, and cycling stability as a function of AADA concentration (e.g., 0.1, 0.5 and 0.8 M).
Key Performance
· Charge capacity was calculated for 0.1 M AADA and 10 mA·cm-2 to be 5.1 Ah/L, and is comparable to the theoretical capacity for the AADA redox couple (5.36 Ah/L) under these conditions. Capacity utilization is near 100%, showing that nearly all of the active material in the cell is being used during cycling.
· Increasing AADA to 0.5 M and 0.8 M produced proportional increases in capacity (25.7 Ah/L and 41.5 Ah/L, respectively) at the same current density, demonstrating scalable capacity with concentration.
· Observed capacity fade rates were low for the AADA/ferricyanide cell, at approximately 0.05% per cycle for 0.1 M AADA and 0.16% per cycle for 0.5 M AADA. In the case of a vanadium-based RFB, the capacities did not change when the concentration was doubled, and the capacity retention was lower (0.287%) than in the case of RFBs with the AADA anolyte.

4-Amino-1,1'-Azobenzene-3,4'-Disulfonic Acid Monosodium Salt as a Light-Responsive Additive in Bio-inspired Photomechanical Nanochannels

Chun, Kyoung-Yong, et al. Small 14.17 (2018): 1703618.

Biomimetic sensors that reproduce the rapid, low-power gating behavior of plant stomata are attractive for low-energy photodetection and optofluidic control. A water-soluble azobenzene derivative, 4-amino-1,1'-azobenzene-3,4'-disulfonic acid monosodium salt (AZO), was investigated as the light-responsive component in a composite coating.
AZO acts as the photoswitch in an AZO-PDDA (poly(diallyldimethylammonium chloride)) composite. Under illumination AZO undergoes trans-cis isomerization, producing a photomechanical response in the composite layer that changes the effective pore diameter of the underlying membrane. Those pore changes translate into measurable ionic current modulation through the nanochannels. This AZO-PDDA-based sensor exhibits different current levels in response to light of different wavelengths. The photoreceptor has a response time of approximately 0.2 s and operates with extremely low power consumption (approximately 15 nW) at a bias voltage of 0.1 V.
Materials & Preparation: AZO (950 mg) was dissolved in deionized water and mixed with a diluted PDDA solution so that the AZO:PDDA weight ratio was 1:4.4. Salt was removed from the mixture by dialysis, and the volume was concentrated by heating to about 10% of the original volume to yield a concentrated AZO-PDDA coating solution. The composite was applied to a polycarbonate track-etched (PCTE) membrane (tens-of-nanometer pores) by a dropping-and-brushing method, fixed in a Teflon support, and finalised by 6 h freeze-drying to produce the modified membrane (PCTE/AZO-PDDA).

4-Amino-1,1'-Azobenzene-3,4'-Disulfonic Acid Monosodium Salt: Electropolymerizable Dye for High-Performance Hybrid Electrochemical Sensors

Sharma, Varsha, et al. Applied Surface Science 449 (2018): 558-566.

In this work, the water-soluble azo dye 4-amino-1,1'-azobenzene-3,4'-disulfonic acid monosodium salt (AY) was exploited as the electropolymerizable monomer to form poly(AY) on a graphene nanoplatelet (GNP)/silver nanorod (AgNR) scaffold for electroanalysis of small biomolecules such as dopamine (DA) and ascorbic acid (AA).
AY serves two roles in the hybrid interface: (a) after electrochemical polymerization it provides a stable, conjugated polymer film (poly(AY)) that interacts favorably with the target analytes, and (b) as an azo dye monomer it can be electrografted uniformly onto high-surface-area supports (GNP decorated with AgNRs), producing a composite layer that couples electronic conductivity, catalytic sites and selective surface chemistry.
Fabrication Approach: Graphene nanoplatelets were functionalized with silver nanorods and deposited onto a polished, electrochemically activated glassy carbon electrode by drop-casting and thermal drying. Aqueous AY monomer (in 0.1 M H2SO4) was then electropolymerized onto the GNP/AgNR layer by cyclic voltammetry between -0.4 and +2.0 V for 20 cycles to form a strongly adherent GNP/AgNR/poly(AY) film.
Electroanalytical Performance: The GNP/AgNR/poly(AY) modified electrode exhibited pronounced electrocatalytic activity toward DA and AA in physiological buffer (pH ≈ 7). Well-separated oxidation peaks for the two analytes were obtained, facilitating simultaneous detection. The sensor showed a linear amperometric response from 1 to 200 μM for both DA and AA, with reported detection limits of 0.42 μM for dopamine and 0.88 μM for ascorbic acid.