Regulating Copper‐Binding Affinity with Photoisomerizable Azobenzene Ligand by Construction of a Self‐Assembled Monolayer

Abstract

Photoactive molecules have attracted much interest because they allow molecular properties to be changed and switched dramatically. [1][2][3][4][5] For example, functional molecules and systems that both bind and release metal ions have been constructed by reversible structural regulation using photochromic molecules, such as spiropyran and azobenzene. [3, 4] In the case of a spiropyran derivative, one of the isomers bound a transition-metal ion through its negatively charged group, whereas the other isomer did not. This photoregulated metalbinding system was useful both in solution and in a polymer matrix.[3] However, the metal-binding ability was relatively weak since the binding site was singly negatively charged, and binding sites with two or more charged groups are required for a more effectively regulated metal-binding system.It has been reported that an azobenzene derivative containing two iminodiacetic acid moieties (azo-IDA) could strongly bind to a metal ion in aqueous solution, but the difference in the binding constants of the trans and cis isomers with the Cu II ion were relatively small: K Cu = 6.49 10 10

Aromatic and Aliphatic Thiol Self-Assembled Monolayers on Au: Anchoring and Delivering Copper Species

“…Loss of charge in consecutive voltammetric scans of the Cu redox couple has already been shown as an effective method to test the ability to deliver Cu species by photoisomerizable azobenzene ligand in the AuÀSAM interface. 82 On the other hand, the possibility to enhance the capture of CuAc on the SAM-modified NSAu substrates has been shown in the previous section. In Figure 9c we also show that it is possible to electrochemically induce Cu(I) ion delivery from the N donor SAMs on NSAu substrates.…”

Photochromic Materials: More Than Meets The Eye

“…charged nanoparticles and metal ions), both in bulk solution79 and modified surfaces 72b, 74d. Azobenzene, another shining star of photochromic family, also plays an important role in photo‐modulated electro/optic devices,62b, 84a–84b photo‐switchable surface and nanostructures,7a,7c, 84c–84f and photo‐triggered biological applications84g–84j due to its significant steric or geometrical changes by light stimulation. Recently, azobenzene derivatives have been widely reviewed in various research fields 14b, 62a, 85…”

“…Usually, molecular switches act as switching units in various optoelectronic devices and functional materials are addressed by stimulating it with light, electricity or chemical reagents to specifically switch the physical properties between two states 3. So far, photochromic materials are very fascinating in fields such as molecular logic gates,4 data recording and storage,5 multi‐photon devices,6 surface/nanoparticle devices,7 photo‐electronic devices,8 electrochemical wiring,9 etc. Thus, further creation of optoelectronic and photo‐optical devices based on photochromic molecular switches which operate at both molecular and supramolecular levels have recently attracted many attentions.…”

Oligothiophene-derivatized azobenzene as immobilized photoswitchable conjugated systems

“…Azobenzene derivatives have been grafted on surfaces in view of various applications in molecular electronics, 2 molecular machines, 3 photoswitchable wettability, 4 photoinduced magnetization 5 and modulation of interactions of surfaces with biomolecules 6 or metal cations. 7 Azobenzene-based molecular or nano-junctions that exhibit conductance switching with trans/cis photoisomerization have been recently reported. 2a,c,d,3,8 In this context, the development of molecular architectures that could lead to high on/off current ratio between the two configurational states appears as a valuable goal.…”