DFT, TD-DFT and biological activity studies of some maleanilic acid derivatives ligands and their organometallic complexes

1564-1573This study is a complementary study to our previous study that included the synthesis and characterization of some maleanilic acid derivative ligands (L1-4) and their metal carbonyl complexes (2-4)a-d as effective compounds for cancer cell growth inhibition against three cancer cell lines: HCT-116, HepG-2 cells and MCF-7. The activity data has manifested that the p-nitrophenyl maleanilic acid ligand (L2) and its chromium complex (2b) inhibited the tested cancer cells more effectively than the other complexes. Additionally, DFT and TD-DFT studies are performed to investigate their frontier molecular orbital (FMO), optical properties, and the correlation between the structure and biological activity. The calculated optical energy gap (Eg) is in the range of 1.78- 2.13 eV, and electron cloud delocalization of HOMO/LUMO levels revealed that all complexes show effective charge separation. The DFT results show a strong relation between Eg values of the carbonyl complexes and their experimental biological activity, where it is obvious that complex (2b) with the lowest Eg value has the greatest inhibitory potency against cancer cells. In contrast, complex (2d) with the highest Eg value exhibits the lowest inhibition potency. These findings translate the inverse relationship between Eg values of the complexes and the inhibition potency against cancer cells

DFT, TD-DFT and Biological Activity Studies of Some Maleanilic Acid Derivatives Ligands and Their Organometallic Complexes

This study is a complementary study to our previous study that included the synthesis and characterization of some maleanilic acid derivatives ligands (L1-4) and their metal carbonyl complexes (2-4)a-d as effective compounds for cancer cell inhibition against three cancer cell lines: HCT-116 (colon cancer), HepG-2 cells (Hepatocellular cancer) and MCF-7 (breast cancer). The activity data manifested that p-nitrophenyl maleanilic acid ligand (L2) and its chromium complex (2b) showed higher inhibitory than the other complexes against the tested cancer cells. Additionally, DFT and TD-DFT studies were performed to investigate their frontier molecular orbital (FMO), optical properties, and the correlation between the structure and biological activity. The calculated optical energy gap (Eg) was in the range of 1.78- 2.13 eV, and electron cloud delocalization of HOMO/LUMO levels revealed that all complexes show effective charge separation. DFT results show a great relation between Eg values of the carbonyl complexes and their experimental biological activity. Where it was obvious that complex (2b) with the lowest (Eg) value exhibits the highest inhibition potency against cancer cells. In contrast, complex (2d) with the highest (Eg) value exhibits the lowest inhibition potency. These results translate the reverse relationship between Eg values of the complexes and the inhibition potency against cancer cells

Facile and low-cost synthesis of a novel dopant-free hole transporting material that rivals Spiro-OMeTAD for high efficiency perovskite solar cells

A Spiro fluorene-based dopant-free hole-transporting material denoted as Spiro-IA has been designed and developed from inexpensive starting materials with high yield via a simple synthetic approach for application in perovskite solar cells (PSCs). The unit cost of Spiro-IA can be as low as 1/9th that of the conventional Spiro-OMeTAD. Moreover, Spiro-IA shows good solubility in different organic solvents, e.g. CHCl3, acetone, EtOH, and DMF, and showed favorable charge-transport ability and greater photocurrent density compared to Spiro-OMeTAD. The UV absorption/emission spectra of Spiro-IA (lambda(max) = 430 nm, E-max = 601 nm) are red shifted compared to those of Spiro-OMeTAD (lambda(max) = 388 nm, E-max = 414 nm) with larger stokes shift values (171 nm) which helps suppress the loss of incident photons absorbed by the HTM and is more beneficial for improving the performance of PSCs. Optical and electrochemical studies show that Spiro- IA fulfilled the basic requirements of the hole transfer and electron regeneration process in the fabricated devices. PSCs fabricated (surface area = 1.02 cm(2)) with dopant-free Spiro-IA achieved a maximum power conversion efficiency (PCE) of 15.66% (J(SC) = 22.14 mA cm(-2), V-OC = 1.042 V, FF = 0.679%), which was comparable to that of the most commonly used Li-doped Spiro-OMeTAD (PCE = 15.93%, J(SC) = 20.37 mA cm(-2), V-OC = 1.057 V, FF = 0.74%) and surpassed that of the dopant- free Spiro- OMeTAD (PCE = 9.34%). Additionally, the PSCs based on dopant-free Spiro-IA achieved outstanding long-term stability and favorable conductivity (sigma = 2.104 x 10(-4) S cm(-1)) compared to those based on Spiro-OMeTAD (sigma = 9.00 x 10(-8) S cm(-1)). DFT studies were performed using Gaussian 09 at the B3LYP/6-31G (d/p) level to investigate their electron cloud delocalization in HOMO/LUMO levels. These results showed that Spiro-IA could be a promising candidate for low-cost PSC technology and has a great chance to supersede the expensive Spiro-OMeTAD

Synthesis, optical characterization, and TD-DFT studies of novel mero/bis-mero cyanine dyes based on N-Bridgehead heterocycles

Novel mero/bis-mero cyanine dyes based on N-Bridgehead imidazo[1,2-g]quinolino[2,1-a][2,6]naphthyridine have been synthesized and characterized to evaluate intramolecular charge transfer (ICT) effect on the energy gap (E0-0). The UVâ Vis/emission spectral studies revealed that, dyes are absorbed in the region of Îťmax (485-577) nm and emitted at (567-673) nm. Their solvatochromic behavior in solvents of various polarities, viz. (CCl4, C6H6, H2O, CHCl3, acetone, and DMF) was studied to emphasize the effect of solvent polarity on the absorption maxima, molar extinction coefficients of the dyes, and excitation energy of the dyes. Their electron cloud delocalization in HOMO/LUMO levels were studied by DFT using Gaussian 09 software. Time-dependent density functional theory (TD-DFT) was applied to theoretically explore the first excitation energy (E0-0) of these dyes which in well agreement with experimental results.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Novel arylazo nicotinate derivatives as effective antibacterial agents: Green synthesis, molecular modeling, and structure-activity relationship studies

A series of novel arylazo nicotinates compounds, denoted as (3a-k and 5a-d) were synthesized and characterized through the reaction of 3-oxo-arylhydrazonals with various active methylene nitriles using microporous zeolite as a green catalyst. The structure of the newly prepared heterocycles was determined using various spectral techniques such as MS, IR, NMR, and elemental analysis. The antibacterial activity of these compounds against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) was evaluated, and it was found that all arylazo nicotinate compounds were highly effective against both gram-negative (E. coli) and gram-positive (B. subtilis) bacterial strains. The efficacy of the developed arylazo nicotinate derivatives as antimicrobial agents against E. coli and B. subtilis was evaluated using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. Density-functional theory (DFT) was employed to investigate the structure–activity relationships of recently synthesized compounds. Gaussian 09 software was utilized to compute various molecular properties, including the distribution of frontier molecular orbitals (FMO), the energy levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), the energy gap (Eg), as well as several biological activity descriptors such as ionization potential (IP), electron affinity (EA), chemical potential (μ), chemical hardness (η), electronegativity (χ), global softness (S), and electrophilicity index (ω). The results of the FMO calculations revealed that the arylazo nicotinates had effective charge separation and distinct HOMO/LUMO energy levels for each compound, as reflected by the different Eg values. The Eg values were found to have a strong correlation with the antibacterial efficacy against E. coli and B. subtilis. The highest and lowest efficacy among the molecules (3a-k) were observed for compounds 3b (Eg = 3.36 eV) and 3 k (Eg = 2.27 eV), respectively, while the highest and lowest efficacy among the molecules (5a-d) were observed for compounds 5d (Eg = 3.33 eV) and 5c (Eg = 2.94 eV), respectively

Overcoming small-bandgap charge recombination in visible and NIR-light-driven hydrogen evolution by engineering the polymer photocatalyst structure

Abstract Designing an organic polymer photocatalyst for efficient hydrogen evolution with visible and near-infrared (NIR) light activity is still a major challenge. Unlike the common behavior of gradually increasing the charge recombination while shrinking the bandgap, we present here a series of polymer nanoparticles (Pdots) based on ITIC and BTIC units with different π-linkers between the acceptor-donor-acceptor (A-D-A) repeated moieties of the polymer. These polymers act as an efficient single polymer photocatalyst for H2 evolution under both visible and NIR light, without combining or hybridizing with other materials. Importantly, the difluorothiophene (ThF) π-linker facilitates the charge transfer between acceptors of different repeated moieties (A-D-A-(π-Linker)-A-D-A), leading to the enhancement of charge separation between D and A. As a result, the PITIC-ThF Pdots exhibit superior hydrogen evolution rates of 279 µmol/h and 20.5 µmol/h with visible (>420 nm) and NIR (>780 nm) light irradiation, respectively. Furthermore, PITIC-ThF Pdots exhibit a promising apparent quantum yield (AQY) at 700 nm (4.76%)