Supramolecular Control of Photonic Response and Sensing of Nitricoxide using Iron(III) Corrole Monolayers and Their Stacks

Abstract

In this work, we assemble amphiphilic iron(III) corroles at airwater interfaces into well-defined quasi-two-dimensional molecular monolayers and theirs stacks for sensing of nitric oxide (NO). For this purpose, we use the Langmuir-Blodgett (LB) technique, which allows varying the packing density of iron(III) corroles anchored to the aqueous subphase via one molecular side. The stacks of ten down to three molecular monolayers on the front and back sides of the substrates are sufficiently optically dense to detect NO binding to the layers photometrically. This sensing with few layers demonstrates the potential for electronic detection, where very thin surface functionaliza-tions enable efficient electronic communication between the layer and the (semi)conductor. Despite increasing optical densities, the spectral responses to NO exposure become smaller with increasing packing density until the collapse point of the monolayers is reached. This demonstrates that the highest molecular efficiency for binding and detection of NO is achieved at the smallest packing densities. This finding is relevant to all molecular sensor films with axial binding of analytes to the sensor molecules and demonstrates the advantage of sensor molecule assembly into monolayers on water-air interfaces using the LB technique.

Reversible Reactions of Nitric Oxide with a Binuclear Iron(III) Nitrophorin Mimic

“…Changes in both the color and λ max of the main absorption were followed (Figure 5a), confirming robust reversible N O reactivity. As NO binding to solid materials is important in many applications, [40] a solution of ( 1 ‐Fe) 2 in CH 2 Cl 2 was drop‐cast on a platinum surface of the IR device (Figure 5b, black trace). Repeating the same procedure using a freshly prepared NO‐purged solution revealed a new N−O stretching band at 1795 cm −1 (Figure 5b, red trace).…”

Recent Progress in the Applications of Langmuir–Blodgett Film Technology

“…In a study by Graewe et al [ 36 ], the LB technique was employed to assemble amphiphilic iron(III) molecules into well-defined quasi-two-dimensional molecular monolayers and their stacks at the air–water interface for nitric oxide (NO) detection ( Figure 7 ). The thinner surface functionalization facilitates efficient electronic communication between the layers and the (semi-)conductor.…”

“…( b ) Surface pressure area isotherms and compression modulus of 1-Fe and reference amphiphilic stearic acid. The dashed lines indicate the average molecular area and surface pressure at deposition, respectively [ 36 ]. Copyright 2023, Wiley Online Library.…”

“…Furthermore, the effect of ionic concentration on the fluorescence intensity by varying the input of Cr2O7 2-is evaluated and shows a linear relationship in a low concentration region of 0-10 µM (R 2 = 0.989), as shown in Figure 6, LB film-based materials demonstrate higher Ksv values (1.53 × 10 5 M −1 ), lower detection limits, and superior recyclability, underscoring their practical utility. In a study by Graewe et al [36], the LB technique was employed to assemble amphiphilic iron(III) molecules into well-defined quasi-two-dimensional molecular monolayers and their stacks at the air-water interface for nitric oxide (NO) detection (Figure 7). In a study by Graewe et al [36], the LB technique was employed to assemble amphiphilic iron(III) molecules into well-defined quasi-two-dimensional molecular monolayers and their stacks at the air-water interface for nitric oxide (NO) detection (Figure 7).…”

“…In a study by Graewe et al [36], the LB technique was employed to assemble amphiphilic iron(III) molecules into well-defined quasi-two-dimensional molecular monolayers and their stacks at the air-water interface for nitric oxide (NO) detection (Figure 7). In a study by Graewe et al [36], the LB technique was employed to assemble amphiphilic iron(III) molecules into well-defined quasi-two-dimensional molecular monolayers and their stacks at the air-water interface for nitric oxide (NO) detection (Figure 7). The thinner surface functionalization facilitates efficient electronic communication between the layers and the (semi-)conductor.…”