Electronic Absorption Spectra Research Articles

Synthesis and characterization of new organometallic lanthanides metal complexes for photodynamic therapy

New Schiff base ligand: 4-methoxy salicaldhyde-2-2-phenyl-hydrazono acetaldehíyde prepared by facile method. The molecular structures characterized by elemental analysis and proton magnetic resonance spectra (1H-NMR spectra). This spectra at the chemical shifts (3.5–10.39 ppm) confirmed the types and the numbers of protons. The sharp melting point at the range 110–112 °C confirmed purity. New optically active metal (samarium, terbium and gadolinium) complexes of the Schiff base synthesized in a one pot reaction. Vibrational IR spectra confirmed functional groups. Scanning electron microscopy micrographs confirmed that the modified microstructure of the metal complexes differed in morphology than the ligand. Powder X-ray diffraction patterns confirmed good crystalline structure. The optically activity of the solid metal complexes confirmed from electronic absorption spectra. The UV absorbance band at the wavelength range 280–390 nm and the intense phosphorescence bands up to 830 nm enabled application in photo dynamic therapy for apoptosis cancer cells by conversion triplet oxygen in the tissues into reactive singlet oxygen. Low charge transfer energy: 2.59–2.61 eV, high molar extinction coefficients (ε) at the order of magnitude \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:{10}^{6}$$\\end{document} M− 1 cm− 1 and the intense phosphorescence bands reflected good photodynamic activity. The metal complexes are thermally stable.

Periodic Bonding Behaviors of Actinide Atoms (An = Th-Cm) with Negatively Curved Nanographene.

The nanographene with negative curvature has been extensively studied due to its interesting properties and potential applications. In the present work, we have performed all-electron scalar relativistic density functional theory (DFT) calculations to understand the periodic interaction mechanisms of actinide atoms (An = Th, Cm) with the TB8C nanographene. The encapsulated complexes (An@TB8C) were formed due to the octagonal vacancy in the TB8C nanographene. TB8C shows fairly high affinity toward An atoms, especially for Th and Pa. AIMD simulations further confirmed the effective trapping of An atom with TB8C. The partial covalent characters of An-C bonds in An@TB8C were revealed through various bond analysis methods. The 6d electrons of An play an important role in the participation of chemical bonds. The delocalization index (DI) is proposed as a useful descriptor in the study of bond strength involving the actinides. Electronic absorption spectra were simulated for further identification in the experiments. The current work has expanded the potential molecular properties and applications of nanographene.

Toward a realistic theoretical electronic spectra of metal aqua ions in solution: The case of Ce(H2O)n3+ using statistical methods and quantum chemistry calculations.

Accurately predicting spectra for heavy elements, often open-shell systems, is a significant challenge typically addressed using a single cluster approach with a fixed coordination number. Developing a realistic model that accounts for temperature effects, variable coordination numbers, and interprets experimental data is even more demanding due to the strong solute-solvent interactions present in solutions of heavy metal cations. This study addresses these challenges by combining multiple methodologies to accurately predict realistic spectra for highly charged metal cations in aqueous media, with a focus on the electronic absorption spectrum of Ce3+ in water. Utilizing highly correlated relativistic quantum mechanical (QM) wavefunctions and structures from molecular dynamics (MD) simulations, we show that the convolution of individual vertical transitions yields excellent agreement with experimental results without the introduction of empirical broadening. Good results are obtained for both the normalized spectrum and that of absolute intensity. The study incorporates a statistical machine learning algorithm, Gaussian Mixture Models-Nuclear Ensemble Approach (GMM-NEA), to convolute individual spectra. The microscopic distribution provided by MD simulations allows us to examine the contributions of the octa- and ennea-hydrate of Ce3+ in water to the final spectrum. In addition, the temperature dependence of the spectrum is theoretically captured by observing the changing population of these hydrate forms with temperature. We also explore an alternative method for obtaining statistically representative structures in a less demanding manner than MD simulations, derived from QM Wigner distributions. The combination of Wigner-sampling and GMM-NEA broadening shows promise for wide application in spectroscopic analysis and predictions, offering a computationally efficient alternative to traditional methods.

Synthesis, spectroscopic characterization, DFT analysis, antibacterial, antifungal, antioxidant, molecular docking, and ADME study of 3,4-dihydro-2H-napthalen-1-one tagged chalcone derivatives

Chalcone derivatives were synthesized from 3,4-dihydro-2H-naphthalen-1-one using a base-catalyzed Claisen-Schmidt reaction and characterized by FT-IR, ¹H NMR, and ¹³C NMR spectroscopy. Density functional theory (DFT) with the B3LYP/6-311G(d,p) basis set was employed to explore the structural, electronic, and quantum properties of the compounds. Simulated electronic absorption spectra for compounds 3c and 3e in gas phase, DMSO, and DCM were generated using time-dependent DFT (TD-DFT). Compound 3c's first singlet excited state shifted from 376.10 nm in the gas phase to 390.08 nm in DMSO, while compound 3e shifted from 381.58 nm to 383.54 nm in DMSO. Experimental absorption values matched the theoretical predictions, with higher oscillator strengths in DMSO and DCM indicating solvent-enhanced transition probabilities. The antimicrobial activity of the chalcones was evaluated against four bacterial strains (E. coli, B. subtilis, S. aureus, and Streptococcus spp.) and four fungal strains (R. oryzae, P. chrysogenum, A. niger, and C. albicans). Compounds 3d and 3f showed strong antibacterial activity with MIC values of 3.9 µg/mL and moderate antifungal activity. Antioxidant properties were assessed using DPPH and hydroxyl radical assays, with compound 3d demonstrating 75.8 % and 76.4 % scavenging activity for OH and DPPH radicals, respectively. ADME studies were conducted to evaluate pharmacokinetics, and molecular docking studies revealed strong binding affinities. Compounds 3a and 3e had docking scores of -8.7 kcal/mol with the E. coli protein (PDB ID: 1KZN), while 3d and 3f performed best against B. subtilis (PDB ID: 1BAG) and S. aureus gyrase (PDB ID: 2XCT), with scores of -9.1 and -8.3 kcal/mol, respectively. Molecular dynamics simulation of compound 3d with 1BAG over 100 ns confirmed stable binding. These findings suggest chalcone derivatives have strong potential for pharmaceutical development.

Effect of N-substituted aliphatic glycine presence on bioactivity, cytotoxicity, and selectivity of Pt(II) and Pd(II) complexes in cancer treatment

In this study, four new platinum (II) and palladium(II) complexes were synthesized to develop metallo-drugs that can attach to DNA and prevent the division of cancer cells. The complexes, 1: [Pt(bipy)(LP)]NO3, 2: [Pt(bipy)(LA)]NO3, 3: [Pd(bipy)(LP)]NO3, and 4: [Pd(phen)(LP)]NO3 (where LP is propylglycine, LA is 2-heptyl glycine, bipy is 2,2-bipyridine, and phen is 1,10-phenanthroline), were structurally characterized using computational and experimental analysis. Their stability, solubility, and lipophilicity were evaluated. Single-crystal X-ray and powder X-ray crystallographic analyses were performed for [Pt(bipy)(LA)]NO3. Density functional theory calculations were performed to investigate the reactivity, stability descriptors, and natural bond orbital analysis of these complexes. The in vitro cytotoxicity of these substances was examined against the human colorectal carcinoma (HCT116), A549 (Human Caucasian lung carcinoma), MCF7 (breast cancer), and HFF (Human Freskin Fibroblast) cell lines. According to the findings, complexes 4 and 3 had near oxaliplatin concentrations and more than carboplatin due to lipophilic ligands in their structure. Also, regarding IC50 values on normal HFF cell line, 4 is selectively toxic against the A549 cancer cell line with SI=5.6. Fluorescence, electronic absorption spectroscopy, and CD spectroscopy were used to investigate the binding affinities of compounds to CT-DNA and HSA. The results revealed that they could interact with CT-DNA through groove mode and with HSA via hydrogen bond and van der Waals forces. Electronic absorption and CD spectra indicated that compounds changed the way the HSA folded by increasing the proportion of a-helix. The binding posture of the metal complex to both biomolecules was predicted using docking simulation, which also verified the groove binding for DNA-complex. The findings indicated that complex 4 had a greater negative docking energy and a higher propensity for CT-DNA and HSA interaction.

Insights on the Bonding Mechanism, Electronic and Optical Properties of Diamond Nanothread-Polymer and Cement-Boron Nitride Nanotube Composites.

The success of composite materials is attributed to the nature of bonding at the nanoscale and the resulting structure-related properties. This study reports on the interaction, electronic, and optical properties of diamond nanothread/polymers (cellulose and epoxy) and boron nitride nanotube/calcium silicate hydrate composites using density functional theory modeling. Our findings indicate that the interaction between the nanothread and polymer is due to van der Waals-type bonding. Minor modifications in the electronic structures and absorption spectra are noticed. Conversely, the boron nitride nanotube-calcium silicate hydrate composite displays an electron-shared type of interaction. The electronic structure and optical absorption spectra of the diamond nanothread and boron nitride nanotube in all configurations studied in the aforementioned composite systems are well maintained. Our findings offer an electronic-level perspective into the bonding characteristics and electronic-optical properties of diamond nanothread/polymer and boron nitride nanotube/calcium silicate hydrate composites for developing next-generation materials.

Synthesis and characterization of aniline-based azo molecules: In vitro pharmacological and emission studies.

The present work involves the synthesis of novel dispersed mono-azo dyes using different coupling components and 2-methoxy-5-nitro aniline as amine through a simple and convenient diazo-coupling method. The structures of the newly synthesized mono azo dyes were confirmed by using various spectral techniques such as 1H NMR, Fourier transform infrared, and high-resolution mass spectrometry. At room temperature, the electronic absorption spectra and fluorescence spectra of the synthesized mono azo dyes were recorded with different solvents. The global reactive parameters for the synthesized azo molecules were evaluated by performing density functional theory through the 6-311++G (d, p) basis set. The anti-microbial activities for the synthesized azo compounds were carried out, and the compounds G1 and G2 exhibited good antibacterial and anti-fungal activities. The in silico molecular docking studies of the azo molecules revealed that all the compounds exhibited extraordinary binding affinity as that of the standard drug. Further, the anti-tuberculosis study against the Mycobacterium tuberculosis for the synthesized azo dyes was evaluated, and from the results, it was revealed that the compound G4 showed good sensitivity among the other synthesized azo compounds.

Electronic structure, global reactivity descriptors and nonlinear optical properties of glycine interacted with ZnO, MgO and CaO for bacterial detection

Modern laboratory medicine relies on analytical instruments for bacterial detection, focusing on biosensors and optical sensors for early disease diagnosis and treatment. Thus, Density Functional Theory (DFT) was utilized to study the reactivity of glycine interacted with metal oxides (ZnO, MgO, and CaO) for bacterial detection. Total dipole moment (TDM), frontier molecular orbitals (FMOs), FTIR spectroscopic data, electronic transition states, chemical reactivity descriptors, nonlinear optical (NLO) characteristics, and molecular electrostatic potential (MESP) were all investigated at the B3LYP/6–31G(d, p) level using DFT and Time-Dependent DFT (TD-DFT). The Coulomb-attenuating approach (CAM-B3LYP) was utilized to obtain theoretical electronic absorption spectra with the 6-31G(d, p) basis set to be more accurate than alternative quantum chemical calculation approaches, showing good agreement with the experimental data. The TDM and FMO investigation showed that glycine/CaO model has the highest TDM (10.129Debye) and lowest band gap (1.643 eV). The DFT computed IR and the experimental FTIR are consistent. The calculated UV-vis spectra showed a red shift with an increase in polarity following an increase in the absorption wavelength due to the interaction with ZnO, MgO, and CaO. Among the five solvents of water, methanol, ethanol, DMSO and acetone, the water and DMSO enhances the UV-Vis absorption. Glycine/CaO model showed high linear polarizability (14.629 × 10−24esu) and first hyperpolarizability (23.117 × 10−30esu), indicating its potential for nonlinear optical applications. The results showed that all model molecules, particularly glycine/CaO, contribute significantly to the development of materials with potential NLO features for sensor and optoelectronic applications. Additionally, MESP confirmed the increased electronegativity of the studied structures. Additionally, glycine/ZnO nanocomposite was synthesized and characterized using IR and UV-visible spectroscopy to determine their structural and spectroscopic features. It was discovered that there was good agreement between the DFT computed findings and the related experimental data. The antibacterial activity of glycine/ZnO nanocomposites against Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa were studied in terms of concentration and time. The results showed that increasing the concentration of glycine/ZnO nanocomposite significantly enhanced its antibacterial efficacy by lowering optical density. Notably, Pseudomonas aeruginosa exhibited lower susceptibility to the nanocomposite compared to S. aureus, requiring higher concentrations for effective bactericidal action. In summary, this study contributes novel insights into the dual functionality of glycine-metal oxide complexes, with significant implications as optical biosensor for microbial detection.

Elucidation of DNA binding properties of transition metal ion complexes of curcumin: An In Vitro study

Introduction: The present work aims to synthesize, characterize, and DNA binding properties of copper, nickel, zinc, and iron complexes of a well-known polyphenol drug curcumin. The metal ion complexes of curcumin's synthesized transition metal ion complexes were characterized by UV-vis spectroscopy and FTIR. Method: The complexation of curcumin with transition metal ion complexes changes the color of the curcumin based on the metal incorporated. Moreover, the shift in the absorption maxima of curcumin metal ion complexes may confirm the formation of coordination complexes. Then, FTIR results indicated that the coordination of curcumin with metal ions in the ketone group of curcumin confirms the formation of 1:2 (M: L) complexes. Results: Then, we evaluated the DNA binding properties of synthesized metal ion complexes of curcumin using electronic absorption spectra and agarose gel electrophoresis. The results indicated that the curcumin zinc complex exhibited less DNA binding constant among the four metal ion complexes than all the other compounds tested, confirming its weak interaction. Conclusion: Moreover, all the compounds degrade plasmid DNA, confirming their DNA cleavage activity. From our findings, these compounds will pave the way for developing new anticancer drugs with less toxicity.

Hexa-(2-ethylhexyl)-hexa-peri-hexabenzocoronene as archetypal model compound of asphaltenes and MAONs

Hexa(ethylhexyl)-hexa-(peri)-hexabenzocoronene (HEH-HBC) was selected as model compound of asphaltenes. In fact, in the “island” model the asphaltenes are described with a relatively large aromatic core surrounded by aliphatic chains attached to the edges of the core. In their turn the asphaltenes are considered model compounds of MAONs (Mixed Aromatic-aliphatic Organic Nanoparticles), the possible carriers of the Unidentified Infrared Bands (UIBs), i.e. a set of certain infrared features found in very different astrophysical objects. The differential scanning calorimetric analysis (DSC) shows that HEH-HBC displays a discotic liquid crystal behavior, similar to that observed also in a selected authentic petroleum asphaltene sample. The electronic absorption spectrum of HEH-HBC was recorded for the first time in hydrocarbon solvents fully transparent in the UV, permitting to observe the UV part of HEH-HBC and to compare it with that of unsubstituted HBC. The FT-IR spectrum of HEH-HBC was recorded not only at room temperature but also at higher resolution at the liquid nitrogen temperature. The molar extinction coefficients and integrated molar absorptivity of the main bands were also estimated. The results are briefly discussed from an astrochemical perspective.

Exploring Spectral and Electrochemical Behavior of Hydroxy‐N‐Benzylideneanilines by Integrated Theoretical and Experimental Approaches

ABSTRACTThe present work explored the effect of –OH group substitution (o/p) on the spectral and electrochemical behavior of N‐benzylideneaniline. The geometry optimization of unsubstituted and (o/p)‐OH‐substituted analogs revealed the coplanarity of the molecules. The vibrational spectra of the compounds were computed using density functional theory (DFT) and compared with the experimental data. The observed bands were assigned based on total energy distribution (TED). Predicted electronic absorption spectra from time‐dependent density functional theory (TD‐DFT) calculation were compared with the UV–visible spectra of the molecules. The analysis of the lowest spin‐allowed (singlet‐singlet) excited states divulged possible electronic transition. The o‐substituted benzylideneaniline possessed the lowest highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) energy gap among the substituted and unsubstituted analogs. The intramolecular contacts were interpreted using natural bond orbital and localized molecular orbital analysis. The –CH=N– linkage was investigated as a bridge for the electron delocalization from the donor to acceptor moieties. The manifestation of a reduction peak in the cyclic voltammetric studies confirmed the electrochemical behavior in the –OH‐substituted molecule, which was diffusion‐controlled. The discrepancy in the electrochemical property concerning the position of the –OH substituent of the candidate molecules was put forward.

Влияние цетиламина на спектры поглощения и протолитические свойства люмогаллиона и магнезона ХС

The interaction of monoazo compounds lumogallion (LG) and magnezon HS (MHS) with cetylamine (CA) in a wide pH range has been studied using a spectrophotometric method.It has been shown that the formation of ionic associates of CA under the interaction of its cation with sulfo group of azo compounds in the pH range 1–4 does not change the electronic absorption spectra of the azodyes. The interaction of CA at dissociated OH groups conjugated with the π-system of the azo compounds leads to a bathochromic shift in the maximum of the absorption spectrum of the corresponding ionic form of the reagents by 15 and 30 nm for the doubly and triply charged forms of LG, respectively, and by 50 nm for the doubly charged form of MHS. The shift in the maximum of the absorption spectrum is accompanied by the shift in the apparent pK value of the reagents by 2–4 pH units, caused by the binding of the dissociated form of the reagents. The reason for these changes in the absorption spectra and protolytic properties of both reagents is the formation of hydrophobically hydrated ionic associates of azo compounds with the cetylamine cation.

Optimizing non-fullerene acceptor molecules constituting fluorene core for enhanced performance in organic solar cells: a theoretical methodology.

Looking for novel outstanding performance materials suitable for organic solar cells, we constructed a range of non-fullerene acceptors (NFAs) evolved from the recently synthesized acceptor molecule identified as DICTIF, structured around fluorene core where 2-(2,3-dihydro-3-oxo-1H-inden-1-ylidene) propanedinitrile presented the terminals end-groups. Employing density functional theory (DFT) and time dependent-DFT (TD-DFT) simulations, we have simulated the impact of altering the end groups of DICTIF molecule by five assorted acceptors molecules, for the purpose of exploring their opto-electronic properties and their performance in organic solar cell (OSC) applications. We proved that the designed non-fullerene acceptors provide enhanced efficiency compared to the synthesized molecule, such as planar geometries and narrower energy gap ranging from 1.51 to 1.95 eV. A red shift in absorption was observed for all tailored molecules (λmax = 583.5-711.4 nm) as compared to the reference molecule (λmax = 578 nm).Various decisive factors such as frontier molecular orbitals (FMOs), exciton binding energy (EB), absorption maximum (λmax), open circuit voltage (VOC), reorganization energies (RE), transition density matrix (TDM), reduced density gradient (RDG), and electron-hole overlap have also been computed for analyzing the performance of NFAs. Low reorganizational energy values facilitate charge mobility which improves the conductivity of all the designed molecules. This study showed that our novel tailored molecules might be suitable candidates for the fabrication of highly efficient photovoltaic materials. After testing various hybrid functionals, optimized geometries were assigned using DFT HSEH1PBE/6-31G(d) level of theory. Electronic excitations and absorption spectra were investigated using the TD-DFT MPW1PW91/6-31G(d) level of theory. We ascertained that HSEH1PBE/6-31G(d) level of theory yield the closest calculated highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the DICTIF to the corresponding experimental ones and that TD-MPW1PW91//6-31G(d) was the most suitable level of theory for exploring electronic excitations and finding the maximum of absorption (λmax).

Crystal Structure, Photophysical Properties and Antibacterial Activity of a Cd(II) Complex with Trans-2,3,4-Trimethoxycinnamic Acid and 4,4'-Bipyridine Ligands.

A new coordination polymer {[Cd(C12H13O5)2(4,4'-bpy)(H2O)2]}n (Cd-Tmca-bpy) was constructed with trans-2,3,4-Trimethoxycinnamic acid (HTmca) and 4,4'-Bipyridine (4,4'-bpy) ligands. This complex was structurally characterized on the basis of elemental analysis, infrared (IR) spectroscopy, powder X-ray diffraction and thermogravimetric analyses. X-ray crystallography revealed that the complex was monoclinic, space group C2/c. The Cd(II) ion in the complex was six coordinated, adopting an octahedron geometry. The neighboring Cd(II) ions linked linear ligand 4,4'-bpy molecules to form an infinite 1D chain. The 1D chain was further interlinked by O-H···O and C-H···O hydrogen bonds, resulting in a 3-D supramolecular framework. Meanwhile, the photoluminescence spectrum of the Cd(II) complex at room temperature exhibited an emission maximum at 475 nm. Using the time-dependent density functional theory (TD-DFT) method, the electronic absorption spectra of the Cd(II) complex was predicted. A good agreement was achieved between the predicted spectra and the experimental data. Bioactivity studies showed that the complex exhibited significant inhibition halos against Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus).

Infrared optical spectra of a silicene quantum dot modulated by spin-orbit coupling and uniaxial strain

Abstract We theoretically study the electronic structure and light absorption spectra of a triangular silicene quantum dot (TZSQD) modulated by spin-orbit coupling (SOC) and the uniaxial strain from a symmetry point of view. After considering the SOC, the symmetry of the system decreases and the degenerate energy level split, creating the absorption peaks in the far infrared region and some multimodal structures in the near-infrared region and visible region. In addition, the intensity of the SOC also affects the degree of splitting of the energy levels, which makes the absorption peaks in the far infrared region are blueshifted to the mid-infrared region, and absorption edge in the near infrared region is redshifted to the mid-infrared region. We also find that when a uniaxial strain and SOC coexist at the same time, the symmetry of the system is further reduced, and the number of absorption peaks is increased. Moreover, the uniaxial strain intensity can efficiently regulate the frequency position of the absorption edge in the near-infrared region, and make its spectral range greatly expanded.

Pyridine-2-olato bridged dirhodium(III) acyl organometallics: Synthesis, spectroscopic, structural and theoretical studies

The heterogeneous phase reaction of [Rh(MeLsb)(PPh3)2Cl2] (1) with the sodium salt of three different pyridine-2-olato ligands [Na(R‒Opy), R = H, Me, NO2] in dichloromethane–acetone–water medium afforded the complexes of type [Rh(Lal)(PPh3)(R-Opy)]2 (2(R)) in excellent yield. These are the first examples of dirhodium(III) acyl complexes with the bridging pyridine-2-olato ligand. The penta coordinated dirhodium(III) acyl complexes are formed by the cleavage of the RhCl and RhPPh3 bonds of the precursor complex 1. The two R-Opy ligands bridge the two rhodium centers through their OOpy donor centers. The conversion of 1→2(R) is attended with the concomitant hydrolysis of the aldiminium function in 1. The spectral (UV–vis, IR, NMR) data of the complexes are reported. The identity of 2(Me) has been established by single crystal X–ray structure determination which revealed distorted trigonal bipyramidal RhCNO2P coordination sphere. The Rh, C, N and Ophenolato atoms define the equatorial plane whereas Rh, OOpy and P atoms define the axial plane. The electronic structures and absorption spectra of the complexes are also scrutinized by the density functional theory (DFT) and time–dependent DFT calculations.

UV/Visible Diffusion-Ordered Spectroscopy: A Simultaneous Probe of Molecular Size and Electronic Absorption.

Based on concepts from nuclear magnetic resonance, we have developed UV/vis diffusion-ordered spectroscopy, which simultaneously probes the size and electronic absorption spectrum of molecules and particles. We use simple flow technology to create a step-function concentration profile inside an optical sample cell, and by measuring the time-dependent absorption spectrum in an initially solvent-filled part of the sample volume, we obtain the diffusion coefficients and UV/vis spectra of the species present in the sample solution. From these data, we construct a two-dimensional spectrum with absorption wavelength on one axis and diffusion coefficient (or equivalently, size) on the other, in which the UV/vis spectrum of a mixture with different molecular sizes is separated into the spectra of the different species, sorted by size. We demonstrate this method on mixed solutions of fluorescent dyes, biomolecules, and the UV-absorbing components of coffee, caffeine, and chlorogenic acid, all with concentrations in the μM range.

The investigation on the synthesis, characterization and anticancer activity of Ru-based chelating diphosphine ligand compounds

Compound trans-[RuIII(dmpe)2Cl2]2(PF6)2 (2) (dmpe = 1, 2 - bis (dimethylphosphino) ethane) was obtained by directly reaction of trans-[RuII(dmpe)2Cl2] (1) with [Cp2FeIII(PF6)]. trans-[RuIII(dmpe)2Cl2]2(FeIIIX4)2 (X = Cl, 3; X = Br, 4) were prepared by reaction of compound 1 with FeX3 (X = Cl, Br), respectively. Compounds 2-4 were characterized by IR, electronic absorption spectra, elemental analysis and Single-crystal X-ray diffraction, respectively. Single-crystal X-ray diffraction studies indicate that the ruthenium atoms in compounds 2-4 all define a slightly distorted octahedron with a [RuP4Cl2] coordination core, and the iron atoms in anion FeX4− of compounds 3 and 4 displays the expected tetrahedron with a [FeX4]− coordination core. Both metal-to-ligand charge-transfer (MLCT) and ligand-to-metal charge-transfer (LMCT) transitions exhibit in the lectronic absorption spectra of compounds 2-4. The in vitro activity of compounds 1-4 was evaluated in A549 and HeLa as well as MCF7 cell lines. The relative cell viability of compounds 2-4 on A549, HeLa and MCF7 cancer cells is in the order of 2>3>4 >1 by CCK-8 method. Compounds 2-4 have better activity than that of cisplatin in higher concentration, especially compound 2.

Ab initio electronic absorption spectra of para-nitroaniline in different solvents: Intramolecular charge transfer effects.

Intramolecular charge transfer (ICT) effects of para-nitroaniline (pNA) in eight solvents (cyclohexane, toluene, acetic acid, dichloroethane, acetone, acetonitrile, dimethylsulfoxide, and water) are investigated extensively. The second-order algebraic diagrammatic construction, ADC(2), ab initio wave function is employed with the COSMO implicit and discrete multiscale solvation methods. We found a decreasing amine group torsion angle with increased solvent polarity and a linear correlation between the polarity and ADC(2) transition energies. The first absorption band involves π → π* transitions with ICT from the amine and the benzene ring to the nitro group, increased by 4%-11% for different solvation models of water compared to the vacuum. A second band of pNA is characterized for the first time. This band is primarily a local excitation on the nitro group, including some ICT from the amine group to the benzene ring that decreases with the solvent polarity. For cyclohexane, the COSMO implicit solvent model shows the best agreement with the experiment, while the explicit model has the best agreement for water.

Theoretical exploration of the photophysical properties of two series of iridium(III) complexes with different main ligand

On the basis of the thiophene-containing and furan-containing complexes, we design four complexes by introducing thiazole, isothiazole, oxazole, isoxazole on main ligands. The electronic structure, absorption and emission spectra, charge injection/transport properties, absorption and phosphorescence properties have been investigated by density functional theory (DFT) and time-dependent density functional theory (TDDFT). Introducing S atom to substitute O atom could enhance HOMO energy level, blueshift emission wavelength, decrease ΔES1- T1 value. The introduction of N atom on furan ring and thiophene ring could decrease HOMO and LUMO energy levels and energy gaps, blueshift emission wavelength, decrease ΔES1- T1 value, enhance electron transport ability. Introducing thiazole could decrease hole injection ability and ΔES1- T1, and then may have higher ΦPL. Isoxazole and isothiazole groups could facilitate the electron transition from HOMO to LUMO and enhance hole injection ability. Thiazole and isothiazole groups could increase absorption peak strength and hole transport ability.