A C^N Cycloplatinated(II) Fluorido Complex: Photophysical Studies and Csp3‒F Bond Formation

<div>This work reports the synthesis and characterization of a new C^N-based cycloplatinated(II) fluorido complex [Pt(ppy)PPh3)F] involving a Pt‒F bond. The new complex is highly luminescent in green area with a high quantum yield of 94.6% at 77K. A comparison study of the heavier of halogen derivatives reveals a descending emission quantum yield order of F > Cl > Br > I. Time-dependent density functional theory (TD-DFT) calculations ascribe the decreased emission efficiency to the decreasing trend of ILCT transition from F to I, which accounts for the major radiative pathway.</div>

Download Full-text

Computational Insights on the Mechanism of the Chemiluminescence Reaction of New Group of Chemiluminogens—10-Methyl-9-thiophenoxycarbonylacridinium Cations

International Journal of Molecular Sciences ◽

10.3390/ijms21124417 ◽

2020 ◽

Vol 21 (12) ◽

pp. 4417

Author(s):

Milena Pieńkos ◽

Beata Zadykowicz

Keyword(s):

Quantum Yield ◽

Density Functional ◽

Single Atom ◽

Human Organism ◽

Functional Theory ◽

The Density Functional Theory ◽

Aqueous Environments ◽

Td Dft ◽

Electronically Excited ◽

Potential Applicability

Immunodiagnostics, in which one of the promising procedures is the chemiluminescent labelling, is essential to facilitate the detection of infections in a human organism. One of the standards commonly used in luminometric assays is luminol, which characterized by low quantum yield in aqueous environments. Acridinium esters have better characteristics in this topic. Therefore, the search for new derivatives, especially those characterized by the higher quantum yield of chemiluminescence, is one of the aims of the research undertaken. Using the proposed mechanism of chemiluminescence, we examined the effect of replacing a single atom within a center of reaction on the efficient transformation of substrates into electronically excited products. The density functional theory (DFT) and time dependent (TD) DFT calculated thermodynamic and kinetic data concerning the chemiluminescence and competitive dark pathways suggests that some of the scrutinized derivatives have better characteristics than the chemiluminogens used so far. Synthesis of these candidates for efficient chemiluminogens, followed by studies of their chemiluminescent properties, and ultimately in chemiluminescent labelling, are further steps to confirm their potential applicability in immunodiagnostics.

Download Full-text

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

Molecules ◽

10.3390/molecules27020524 ◽

2022 ◽

Vol 27 (2) ◽

pp. 524

Author(s):

Dmitry A. Bunin ◽

Nobuhle Ndebele ◽

Alexander G. Martynov ◽

John Mack ◽

Yulia G. Gorbunova ◽

...

Keyword(s):

Density Functional ◽

Rational Design ◽

Chemical Characterization ◽

Computer Time ◽

Functional Theory ◽

Practical Applications ◽

Large Molecules ◽

Td Dft ◽

Low Symmetry

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.

Download Full-text

The Nature of S-N Bonding in Sulfonamides and Related Compounds: Insights into π-Bonding Contributions from Sulfur K-Edge XAS

10.26434/chemrxiv.13204985.v1 ◽

2020 ◽

Author(s):

Tulin Okbinoglu ◽

Pierre Kennepohl

Keyword(s):

Density Functional ◽

Chemical Properties ◽

Functional Theory ◽

Rotational Barriers ◽

Td Dft ◽

Nitrogen Bonds ◽

X Ray Absorption ◽

Related Compounds ◽

And Chemical Properties

Molecules containing sulfur-nitrogen bonds, like sulfonamides, have long been of interest due to their many uses and chemical properties. Understanding the factors that cause sulfonamide reactivity is important, yet their continues to be controversy regarding the relevance of S-N π bonding in describing these species. In this paper, we use sulfur K-edge x-ray absorption spectroscopy (XAS) in conjunction with density functional theory (DFT) to explore the role of S<sub>3p</sub> contributions to π-bonding in sulfonamides, sulfinamides and sulfenamides. We explore the nature of electron distribution of the sulfur atom and its nearest neighbors and extend the scope to explore the effects on rotational barriers along the sulfur-nitrogen axis. The experimental XAS data together with TD-DFT calculations confirm that sulfonamides, and the other sulfinated amides in this series, have essentially no S-N π bonding involving S<sub>3p</sub> contributions and that electron repulsion and is the dominant force that affect rotational barriers.

Download Full-text

Exo⇔Endo Isomerism, MEP/DFT, XRD/HSA-Interactions of 2,5-Dimethoxybenzaldehyde: Thermal, 1BNA-Docking, Optical, and TD-DFT Studies

Molecules ◽

10.3390/molecules25245970 ◽

2020 ◽

Vol 25 (24) ◽

pp. 5970

Author(s):

Nabil Al-Zaqri ◽

Mohammed Suleiman ◽

Anas Al-Ali ◽

Khaled Alkanad ◽

Karthik Kumara ◽

...

Keyword(s):

Density Functional ◽

Energy Gap ◽

Structural Parameters ◽

Population Analysis ◽

Xrd Analysis ◽

X Ray Diffraction ◽

Optical Energy Gap ◽

Functional Theory ◽

Reactivity Descriptors ◽

Td Dft

The exo⇔endo isomerization of 2,5-dimethoxybenzaldehyde was theoretically studied by density functional theory (DFT) to examine its favored conformers via sp2–sp2 single rotation. Both isomers were docked against 1BNA DNA to elucidate their binding ability, and the DFT-computed structural parameters results were matched with the X-ray diffraction (XRD) crystallographic parameters. XRD analysis showed that the exo-isomer was structurally favored and was also considered as the kinetically preferred isomer, while several hydrogen-bonding interactions detected in the crystal lattice by XRD were in good agreement with the Hirshfeld surface analysis calculations. The molecular electrostatic potential, Mulliken and natural population analysis charges, frontier molecular orbitals (HOMO/LUMO), and global reactivity descriptors quantum parameters were also determined at the B3LYP/6-311G(d,p) level of theory. The computed electronic calculations, i.e., TD-SCF/DFT, B3LYP-IR, NMR-DB, and GIAO-NMR, were compared to the experimental UV–Vis., optical energy gap, FTIR, and 1H-NMR, respectively. The thermal behavior of 2,5-dimethoxybenzaldehyde was also evaluated in an open atmosphere by a thermogravimetric–derivative thermogravimetric analysis, indicating its stability up to 95 °C.

Download Full-text

Photophysical Properties of N-Methyl and N-Acetyl Substituted Alloxazine: A Theoretical Investigation

Physical Chemistry Chemical Physics ◽

10.1039/d1cp01201k ◽

2021 ◽

Author(s):

Huimin Guo ◽

Xiaolin Ma ◽

Zhiwen Lei ◽

Yang Qiu ◽

Bernhard Dick ◽

...

Keyword(s):

Density Functional Theory ◽

Electronic Structure ◽

Theoretical Investigation ◽

Density Functional ◽

Photophysical Properties ◽

Time Dependent ◽

Functional Theory ◽

Td Dft ◽

Dependent Density

The electronic structure and photophysical properties of a series of N-Methyl and N-Acetyl substituted alloxazine (AZs) were investigated with extensive density functional theory (DFT) and time-dependent density functional theory (TD-DFT)...

Download Full-text

Structural and computational investigation of an imine-based propeller-shaped macrocyclic cage

SN Applied Sciences ◽

10.1007/s42452-021-04255-7 ◽

2021 ◽

Vol 3 (2) ◽

Author(s):

Sriram Srinivasa Raghvan ◽

Suresh Madhu ◽

Velmurugan Devadasan ◽

Gunasekaran Krishnasamy

Keyword(s):

Band Gap ◽

Density Functional ◽

Strain Tensor ◽

Strong Interactions ◽

Soft Condensed Matter ◽

Functional Theory ◽

Self Assembling ◽

Phenyl Rings ◽

Crystal Volume

AbstractIn this study, we present the synthesis, spectroscopic and structural characterization of self-assembling gem-dimethyl imine based molecular cage (IMC). Self-assembling macrocycles and cages have well-defined cavities and have extensive functionalities ranging from energy storage, liquid crystals, and catalysts to water splitting photo absorber. IMC has large voids i.e., 25% of the total crystal volume thus could accommodate wide substrates. The synthesized imine-based molecular cages are stabilized by coaxial π bonded networks and long-range periodic van der Waal and non-bonded contacts as observed from the crystal structure. IMC also has typical properties of soft condensed matter materials, hence theoretical prediction of stress and strain tensor along with thermophysical properties were computed on crystal system and were found to be stable. Molecular dynamics revealed IMC is stabilized by, strong interactions between the interstitial phenyl rings. Density functional theory (DFT) based physicochemical properties were evaluated and has band gap of around 2.38ev (520 nm) similar to various photocatalytic band gap materials.

Download Full-text

Density functional theory investigation of the effect of axial coordination and annelation on the absorption spectroscopy of nickel(II) and vanadyl porphyrins relevant to bitumen and crude oils

Canadian Journal of Chemistry ◽

10.1139/cjc-2012-0532 ◽

2013 ◽

Vol 91 (9) ◽

pp. 872-878 ◽

Cited By ~ 16

Author(s):

Stanislav R. Stoyanov ◽

Cindy-Xing Yin ◽

Murray R. Gray ◽

Jeffrey M. Stryker ◽

Sergey Gusarov ◽

...

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Polyaromatic Hydrocarbons ◽

Geometry Optimization ◽

Soret Band ◽

Heavy Oils ◽

Visible Absorption ◽

Functional Theory ◽

Axial Coordination ◽

Td Dft

The vanadium and nickel components in heavy oils and bitumen are important impurities in catalytic processing and form aggregates with other asphaltene components. Metalloporphyrins are commonly analyzed using the characteristic Soret band in the UV–vis absorption spectrum. However, the Soret band of metalloporphyrins in petroleum is broadened and weaker than expected based on the concentration of Ni and V in heavy oils and the extinction coefficients of isolated porphyrins. We hypothesize that the low intensity and broadening of the Soret band could be due to axial coordination of the metal center or fusion (annelation) of aromatic rings on the porphyrin π-system. This hypothesis is examined using the density functional theory for geometry optimization and time-dependent density functional theory (TD-DFT) for calculation of excited states of nickel(II) and vanadyl porphyrins with axially coordinated ligands and annelated polyaromatic hydrocarbons. Predictions of the excited electronic states performed using the tandem of TD-DFT and conductor-like polarizable continuum model of solvation support this hypothesis and provide insight into the extent of Soret band broadening and intensity decrease due to coordination and annelation. These computational results, validated with respect to visible absorption spectra, are important for understanding asphaltene aggregation and spectroscopic characterization and suggest methods for removal of transition metals from heavy oil.

Download Full-text

A Hybrid Cylindrical Model for Characterization of MCM-41 by Density Functional Theory.

ChemInform ◽

10.1002/chin.200444002 ◽

2004 ◽

Vol 35 (44) ◽

Author(s):

Bei Liu ◽

Wenchuan Wang ◽

Xianren Zhang

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Functional Theory ◽

Cylindrical Model ◽

Mcm 41

Download Full-text

Metal-Rich Metallaboranes: Synthesis, Structures and Bonding of Bi- and Trimetallic Open-Faced Cobaltaboranes

Inorganics ◽

10.3390/inorganics9040028 ◽

2021 ◽

Vol 9 (4) ◽

pp. 28

Author(s):

Kriti Pathak ◽

Chandan Nandi ◽

Jean-François Halet ◽

Sundargopal Ghosh

Keyword(s):

Electronic Structures ◽

Density Functional ◽

Room Temperature ◽

Electron Pair ◽

X Ray Diffraction ◽

Functional Theory ◽

X Ray ◽

Cluster 2 ◽

Cobalt Center

Synthesis, isolation, and structural characterization of unique metal rich diamagnetic cobaltaborane clusters are reported. They were obtained from reactions of monoborane as well as modified borohydride reagents with cobalt sources. For example, the reaction of [Cp*CoCl]2 with [LiBH4·THF] and subsequent photolysis with excess [BH3·THF] (THF = tetrahydrofuran) at room temperature afforded the 11-vertex tricobaltaborane nido-[(Cp*Co)3B8H10] (1, Cp* = η5-C5Me5). The reaction of Li[BH2S3] with the dicobaltaoctaborane(12) [(Cp*Co)2B6H10] yielded the 10-vertex nido-2,4-[(Cp*Co)2B8H12] cluster (2), extending the library of dicobaltadecaborane(14) analogues. Although cluster 1 adopts a classical 11-vertex-nido-geometry with one cobalt center and four boron atoms forming the open pentagonal face, it disobeys the Polyhedral Skeletal Electron Pair Theory (PSEPT). Compound 2 adopts a perfectly symmetrical 10-vertex-nido framework with a plane of symmetry bisecting the basal boron plane resulting in two {CoB3} units bridged at the base by two boron atoms and possesses the expected electron count. Both compounds were characterized in solution by multinuclear NMR and IR spectroscopies and by mass spectrometry. Single-crystal X-ray diffraction analyses confirmed the structures of the compounds. Additionally, density functional theory (DFT) calculations were performed in order to study and interpret the nature of bonding and electronic structures of these complexes.

Download Full-text