Low-Symmetry Phthalocyanines Bearing Carboxy-Groups: Synthesis, Spectroscopic and Quantum-Chemical Characterization

The synthesis and characterization of A3B-type phthalocyanines, ZnPc1–4, bearing bulky 2,6-diisopropylphenoxy-groups or chlorine atoms on isoindoline units “A” and either one or two carboxylic anchors on isoindoline unit “B” are reported. A comparison of molecular modelling with the conventional time dependent—density functional theory (TD-DFT) approach and its simplified sTD-DFT approximation provides further evidence that the latter method accurately reproduces the key trends in the spectral properties, providing colossal savings in computer time for quite large molecules. This demonstrates that it is a valuable tool for guiding the rational design of new phthalocyanines for practical applications.

Demonstration of a Stereospecific Photochemical Meta Effect

A fundamental goal of photochemistry is to understand how structural features of a chromophore can make specific bonds within a molecule prone to cleavage by light, or photolabile. The meta effect is an example of a regiochemical explanation for photolability, in which electron donating groups on an aromatic ring cause photolability selectively at the meta position. Here, we show, using a chromophore containing one ring with a meta-methoxy group and one ring with a para-methoxy group, that two stereoisomers of the same compounds can react with light differently, based simply on the three-dimensional positioning of a meta anisyl ring. The result is that the stereoisomers of the compound with the same configuration at both stereogenic centers are photolabile while the stereoisomers with opposite configuration do not react with light. Furthermore, time-dependent density functional theory (TD-DFT) calculations show distinct excitation pathways for each stereoisomer.

DFT and TD-DFT Studies of 1,3,5-Tris (Dipheny1amino) Benzene Derivatives Based Hole Transport Materials: Application for Perovskite Solar Cells

The current study examined a series of 1,3,5-tris (diphenylamino) benzene derivatives used as hole transport materials in perovskite solar cells (HTM1-HTM9). DFT and TD/DFT with the B3LYP/6-311G basis set used for all calculations. The ground state geometry, frontier molecular orbital (FMO), photoelectric properties and reorganization energies and the absorption spectra were investigated. The energy levels of HOMO and LUMO orbitals were calculated for HTM1-HTM9, compared to all of the compounds under investigation and the spiro-OMeTAD, HTM 8 has the lowest HOMO energy level, indicating a favourable overlap with the MAPbI3 perovskite active layer.

Excited States Computation of Models of Phenylalanine Protein Chains: TD-DFT and Composite CC2/TD-DFT Protocols

The present benchmark calculations testify to the validity of time-dependent density functional theory (TD-DFT) when exploring the low-lying excited states potential energy surfaces of models of phenylalanine protein chains. Among three functionals suitable for systems exhibiting charge-transfer excited states, LC-ωPBE, CAM-B3LYP, and ωB97X-D, which were tested on a reference peptide system, we selected the ωB97X-D functional, which gave the best results compared to the approximate coupled-cluster singles and doubles (CC2) method. A quantitative agreement for both the geometrical parameters and the vibrational frequencies was obtained for the lowest singlet excited state (a ππ* state) of the series of capped peptides. In contrast, only a qualitative agreement was met for the corresponding adiabatic zero-point vibrational energy (ZPVE)-corrected excitation energies. Two composite protocols combining CC2 and DFT/TD-DFT methods were then developed to improve these calculations. Both protocols substantially reduced the error compared to CC2 and experiment, and the best of both even led to results of CC2 quality at a lower cost, thus providing a reliable alternative to this method for very large systems.

DFT and TD-DFT study of adsorption behavior of Zejula drug on surface of the B12N12 nanocluster

The adsorption of the Zejula drug on the surface of B12N12 nanocluster has studied using DFT and TD-DFT. The quantum calculations have performed at the M062X/6–311 + + G(d,p) level of theory in the solvent water. The adsorption of the Zejula from N13 atom on the B12N12 leads to the higher electrical conductivity due to the low Eg rather. The change of DM also displays a charge transfer between Zejula and nanocluster. The UV absorption and IR spectra were calculated. The adsorption of Zejula drug over B12N12 nanocluster in the complexes Zejula/B12N12 can be considered as a bathochromic shift. According to QTAIM analysis, -G(r)/V(r) values for B-O and B-N bonds confirming the electrostatic and partial covalent character. The values of LOL and ELF confirm that the interactions are dominated by electrostatic interaction contributions. The calculated data reveal the B12N12 nanocluster can be appropriate as a biomedical system for the delivery of Zejula drug.

Encapsulation of anticancer drug Ibrance into the CNT(8,8-7) nanotube: A study based on DFT method

In this research, a DFT calculation was performed for study to investigate the encapsulation of the anticancer drug Ibrance into CNT(8,8-7) by using M062X/6-311G * level of theory in the solvent water. TD-DFT method was used to compute the electronic spectra of the Ibrance drug, CNT(8,8-7) and complex CNT(8,8-7)/Ibrance in aqueous medium for the study of non-bonded interaction effect. The non-bonded interaction effects of Ibrance drug with CNT(8,8-7) on the electronic properties and natural charges have been also studied. The results display the change in title parameters after process adsorption. According to NBO results, the molecule Ibrance and CNT(8,8-7) play as both electron donor and acceptor at the complex CNT(8,8-7)/Ibrance. Charge transfer, on the other hand, occurs between the bonding, antibonding, or nonbonding orbitals of Ibrance drug and CNT (8,8-7). According to QTAIM analysis and the LOL and ELF values, all intermolecular bonds in the complex are non-covalent in nature. As a result, CNT(8,8-7) can be thought of as a drug delivery system for transporting Ibrance as an anticancer drug within biological systems.

Accurate predictions of the electronic excited states of BODIPY based dye sensitizers using spin-component-scaled double-hybrid functionals: a TD-DFT benchmark study

The excitation energies of 13 BODIPY dye sensitizers are benchmarked by means of TD-DFT, using 36 functionals. Spin-component-scaled double-hybrid (DSD) functionals are found to show the best performance.

Enantiopure, Luminescent, Cyclometalated Ir(III) Complexes with N-Heterocyclic Carbene-Naphthalimide Chromophore: Design, Vibrational Circular Dichroism and TD-DFT Calculations

A series of chiral cyclometalated iridium complexes of the type [Ir(C^N)2(C^C:)], {(C^N) = ppy (2); dfppy (3)} featuring a naphthalimide N-heterocyclic carbene ligand (C^C:) = (Naphthalimide-NHC) are described and...

A rational design of Carbon Dots via the combination of Nitrogen and Oxygen Functional Groups toward the first NIR window Absorption

Carbon Dots (CDs) that exhibited a First Near Infra-red (NIR) Window absorption was designed by a combination of Nitrogen and Oxygen surface functional groups. The Time-Dependent Density Functional Theory (TD-DFT)...