3-Input AND Molecular Logic Gate with Enhanced Fluorescence Output: The Key Atom for the Accurate Prediction of the Spectra

Abstract

The development of artificial receptors for sensing and recognition of species, as well as for advanced logic functions, is a significant challenge in the field of molecular information technology. Here, we study theoretically, via DFT/TD-DFT calculations, the photophysical properties of a 3-input AND molecular logic gate which presents an enhanced fluorescence spectrum. It was found that the geometry conformation at an N atom of the piperazine group is the key factor for the correct calculation of the absorption spectra of the calculated structures. Its geometry is between tetrahedral and planar, while changes in the corresponding CNCC dihedral angle of about 10 degrees can cause significant shifts of the main peak of the absorption spectra up to 100 nm. Moreover, the unusually enhanced fluorescence of a molecular logic gate (MLG) is explained. Finally, we conclude that molecular systems having N atoms, whose geometry is between planar and tetrahedral, can be ideal molecules as sensors and molecular logic gates. Our calculated absorption and emission spectra are in excellent agreement with available experimental data.

A DFT Study towards the Amide cis‐trans Isomerization Process of the Myc‐Max Inhibitor Mycro 3 and Its Photophysical Properties; Synthesis and NMR Studies of the trans‐Conformation

“…The absorption and the emission spectra of the isomers were obtained via Time Dependent DFT (TD‐DFT) calculations including 20 singlet‐spin excited electronic states. The accuracy of the present methodologies has been confirmed by the fact that theoretical calculations using the functionals employing here can predict the vis‐UV and IR spectra for amides and amines in very good agreement with experimental data [37,38,39,40,41,42,43,44] . All calculations were carried out using the Gaussian16 suite of codes [45]…”

“…The accuracy of the present methodologies has been confirmed by the fact that theoretical calculations using the functionals employing here can predict the vis-UV and IR spectra for amides and amines in very good agreement with experimental data. [37,38,39,40,41,42,43,44] All calculations were carried out using the Gaussian16 suite of codes. [45] Geometry & Energetics: At first, a conformational analysis of mycro 3 was conducted in order to find the lowest in energy trans and cis isomers at the B3LYP/6-31 + G(d,p) level of theory in DMSO solvent.…”

An Efficient Light‐Mediated Protocol for the Direct Amide Bond Formation via a Novel Carboxylic Acid Photoactivation Mode by Pyridine‐CBr4

“…On the contrary, in the case of DMA, the N … Br bond is elongated by 0.6 Å and the CCNC dihedral angle from 145.8 degrees in the S 0 state becomes almost planar at 171.1 degrees in the T 1 state. Note that changes in the dihedral geometry of the N atom are associated with the properties of compounds [21] …”

“…Note that changes in the dihedral geometry of the N atom are associated with the properties of compounds. [21] The strongest binding energy (ΔE bind ) is observed for the DMA-CBr 4 pair at À 4.59 kcal/mol, even though the N atom of DMA is not planar, while the weakest one is found for the pyridine-BrCCl 3 at À 3.78 kcal/mol (Table 3). DMA forms the most stable donor-acceptor pairs, and it presents the lowest adiabatic S 0 !T 1 excitation energy, that is, 24.9 kcal/mol (DMA-CBr 4 ) (Table 4).…”

Celebrating Diversity, Equity, Inclusion, and Respect in Computational and Theoretical Chemistry

“…It was demonstrated that, although the two enzymes share a similar substrate range, they exhibit distinct reaction pathways with the formation of different reaction products. Tzeliou and Tzeli applied density functional theory (DFT) and time-dependent (TD) DFT calculations to characterize the photophysical properties of modular photoelectron transfer molecules that function as three-input and molecular logic gates . It was shown that the correct calculation of absorption spectra associated with these molecules requires the accurate description of the geometry of the piperazine group composing the fluorophore and one of the receptors in the molecular system.…”