Photophysical Properties of Functionalized Double Decker Phenylsilsesquioxane Macromonomers: [PhSiO1.5]8[OSiMe2]2 and [PhSiO1.5]8[O0.5SiMe3]4. Cage-Centered Lowest Unoccupied Molecular Orbitals Form Even When Two Cage Edge Bridges Are Removed, Verified by Modeling and Ultrafast Magnetic Light Scattering Experiments

2019 ◽  
Vol 52 (19) ◽  
pp. 7413-7422 ◽  
Author(s):  
Jun Guan ◽  
Kenji Tomobe ◽  
Ifeanyi Madu ◽  
Theodore Goodson ◽  
Krishnandu Makhal ◽  
...  
Keyword(s):  
Light Scattering ◽  
Photophysical Properties ◽  
Molecular Orbitals ◽  
Double Decker ◽  
Lowest Unoccupied Molecular Orbitals

scholarly journals Molecular Structure Modulated Trap Distribution and Carrier Migration in Fluorinated Epoxy Resin

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 3071 ◽  
Author(s):  
Jin Li ◽  
Yufan Wang ◽  
Zhaoyu Ran ◽  
Hang Yao ◽  
Boxue Du ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Surface Charge ◽  
Epoxy Resin ◽  
Mobility Model ◽  
Molecular Orbitals ◽  
Chemical Calculation ◽  
Dissipation Process ◽  
Highest Occupied Molecular Orbitals ◽  
Lowest Unoccupied Molecular Orbitals ◽  
Positively Charged

Surface charge accumulation on epoxy insulators is one of the most serious problems threatening the operation safety of the direct current gas-insulated transmission line (GIL), and can be efficiently inhibited by the surface modification technology. This paper investigated the mechanisms of fluorination modulated surface charge behaviors of epoxy resin through quantum chemical calculation (QCC) analysis of the molecular structure. The results show that after fluorination, the surface charge dissipation process of the epoxy sample is accelerated by the introduced shallow trap sites, which is further clarified by the carrier mobility model. The electron distribution probability of the highest occupied molecular orbitals (HOMO) under positive charging and the lowest unoccupied molecular orbitals (LUMO) under negative charging shows distinctive patterns. It is illustrated that electrons are likely to aggregate locally around benzenes for the positively charged molecular structure, while electrons tend to distribute all along the epoxy chain under negatively charging. The calculated results verify that fluorination can modulate surface charge behaviors of epoxy resin through redesigning its molecular structure, trap distribution and charging patterns.

Photophysical properties of microencapsulated phthalocyanines

2010 ◽  
Vol 14 (03) ◽  
pp. 278-283 ◽  
Author(s):  
Virginia E. Diz ◽  
Gabriela A. Gauna ◽  
Cristian A. Strassert ◽  
Josefina Awruch ◽  
Lelia E. Dicelio
Keyword(s):  
Differential Scanning Calorimetry ◽  
Light Scattering ◽  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Photophysical Properties ◽  
Oxygen Production ◽  
Electronic Microscopy ◽  
Scanning Calorimetry ◽  
Singlet Molecular Oxygen ◽  
Photophysical Parameters

Lipophilic substituted zinc(II) phthalocyanines: 2,3,9,10,16,17,23,24-octakis[(N,N-dimethylaminoethylsulfanyl)]phthalocyaninatozinc(II) (S1) and tetrakis(N,N-dibutylaminoethoxy)phthalocyaninatozinc(II) (3) were incorporated into soybean L-α-phosphatidylcholine (SPC) liposomes of 100 nm diameter. Liposomes were characterized by static light scattering (SLS), transmission electronic microscopy (TEM), and differential scanning calorimetry. The fluorescence quantum yield and singlet molecular oxygen production of 3 are Φ F = 0.15 and ΦΔ = 0.24, respectively, whereas the same photophysical parameters for S1 are Φ F = 0.13 and ΦΔ = 0.51. Higher values of Φ F and ΦΔ are obtained in organic solvent for both dyes. Synthesis of compound 3 has also been reported.

Observational studies of imperfect carbon cage structures of C 60 by high-resolution scanning tunnelling microscopy

1994 ◽  
Vol 444 (1921) ◽  
pp. 325-332 ◽  
Keyword(s):  
High Resolution ◽  
Molecular Orbitals ◽  
Scanning Tunnelling Microscopy ◽  
Carbon Cage ◽  
Scanning Tunnelling ◽  
Tunnelling Microscopy ◽  
Dynamics Simulations ◽  
First Time ◽  
Highest Occupied Molecular Orbitals ◽  
Lowest Unoccupied Molecular Orbitals

Anomalies in the morphology of the carbon cage of C 60 clusters have been investigated with atomic level resolution using high-resolution scanning tunnelling microscopy. The imperfect carbon cages have been resolved in the finest detail, which, for the first time, provide a remarkable confirmation of a variety of theoretical defect structures recently predicted by molecular dynamics simulations. The observed tunnelling spectra are consistent with the theoretical contention that the gap between the highest occupied molecular orbitals (HOMO) and the lowest unoccupied molecular orbitals (LUMO) for the clusters is decreased with the presence of defects.

C60-modified mixed (phthalocyaninato)(porphyrinato) yttrium(III) double-decker complex: Synthesis, characterization, and photophysical properties

2014 ◽  
Vol 102 ◽  
pp. 257-262 ◽  
Author(s):  
Likun Li ◽  
Xianyao Zhang ◽  
Xiaochuan He ◽  
Wenxin Lu ◽  
Liguo Yang ◽  
...  
Keyword(s):  
Photophysical Properties ◽  
Double Decker

scholarly journals Energy-level alignment at interfaces between manganese phthalocyanine and C60

2017 ◽  
Vol 8 ◽  
pp. 927-932 ◽  
Author(s):  
Daniel Waas ◽  
Florian Rückerl ◽  
Martin Knupfer ◽  
Bernd Büchner
Keyword(s):  
Energy Level ◽  
Photoelectron Spectroscopy ◽  
Energy Difference ◽  
Molecular Orbitals ◽  
Organic Photovoltaic ◽  
Photovoltaic Devices ◽  
Organic Photovoltaic Devices ◽  
Energy Level Alignment ◽  
Organic Heterojunctions ◽  
Lowest Unoccupied Molecular Orbitals

We have used photoelectron spectroscopy to determine the energy-level alignment at organic heterojunctions made of manganese phthalocyanine (MnPc) and the fullerene C60. We show that this energy-level alignment depends upon the preparation sequence, which is explained by different molecular orientations. Moreover, our results demonstrate that MnPc/C60 interfaces are hardly suited for application in organic photovoltaic devices, since the energy difference of the two lowest unoccupied molecular orbitals (LUMOs) is rather small.

scholarly journals Photoactivity of Metal-Phenylporphyrins Adsorbed on TiO2 Under Visible Light Radiation: Influence of Central Metal

2010 ◽  
Vol 4 (1) ◽  
pp. 15-22
Author(s):  
Gilma Granados-Oliveros ◽  
Fernando Martínez Ortega ◽  
Edgar Páez-Mozo ◽  
Corinne Ferronato ◽  
Jean-Marc Chovelon
Keyword(s):  
Visible Light ◽  
Metal Ion ◽  
Photophysical Properties ◽  
Molecular Orbitals ◽  
Frontier Molecular Orbitals ◽  
Central Metal ◽  
Carboxylate Groups ◽  
Quantum Chemical Methods ◽  
Ft Ir ◽  
Good Agreement

A set of Co, Cu, Zn and metal-free phenylporphyrins were studied by spectroscopic (UV-vis, FTIR) and quantum-chemical methods. The Q and Soret bands were identified in the UV-vis spectra of solid samples. In all the complexes the frontier molecular orbitals (OMs) predict that the electronic processes sites are localized on the ligand rather than in the metal atom. Metal ion has a largely influence on energy of OMs. The calculated values of electronic transitions between the OMs are in good agreement with the UV-vis data. Phenyl porphyrins were attached onto TiO2 to be evaluated as photocatalysts, under visible light irradiation. The interaction of porphyrins with TiO2 surface was investigated using UV-vis and FT-IR spectroscopies and it was found that the dyes were adsorbed to the semiconductor by carboxylate groups. Degradation of luminol and photooxidation of terephthalic acid to 2-hydroxyterephthalic acid (TAOH) were employed as probe reactions. Luminol was degraded from 20 – 60% in presence of O2. In the same way, the formation of TAOH values of comprises between 0.12 – 0.17 mM, in presence of H2O2 and O2 was obtained. It was found that superoxide anion radicals (O2•_) are primarily formed and they are the precursor for the hydroxyl radicals (•OH) production when H2O2 is added to suspension. Influence of metal on photoactivity was analyzed, specifically, in terms of: the nature of metal (number of d electrons), photophysical properties and energies of frontier molecular orbitals (OMs). Apparently, energy of OMs is an important factor which could affect photoactivity of sensitizers attached on TiO2

scholarly journals ЦЕЛЕНАПРАВЛЕННЫЙ ПОИСК ВЕЩЕСТВ В РЯДУ ПРОИЗВОДНЫХ 3-АРИЛ(АРАЛКИЛ)КСАНТИНА, ОБЛАДАЮЩИХ АНТИРАДИКАЛЬНОЙ АКТИВНОСТЬЮ В ОТНОШЕНИИ СУПЕРОКСИД-РАДИКАЛА

2016 ◽  
Author(s):  
V. P. Ryzhenko ◽  
O. A. Ryzhov ◽  
S. V. Levich ◽  
I. F. Belenichev ◽  
К. V. Aleksandrova
Keyword(s):  
Linear Dependence ◽  
Quantum Chemical ◽  
Molecular Orbitals ◽  
Frontier Molecular Orbitals ◽  
Chemical Methods ◽  
Quantum Chemical Methods ◽  
Semi Empirical ◽  
Lowest Unoccupied Molecular Orbitals

<p>The aim of the research was to study the basic descriptors of frontier molecular orbitals of 3- aryl (aralkyl) xanthine using semi-empirical quantum- chemical methods and substantiate their impact on the manifestation of anti-radical activity.</p><p>Comparison of received data and calculated descriptors values revealed linear dependence of anti-radical activity on the highest occupied and lowest unoccupied molecular orbitals energy values.</p>

New Quantum Chemical Method for Assessing the Relative Activity of Antioxidants

2019 ◽  
pp. 96-104 ◽  
Author(s):  
T.A. Yarkova ◽  
A.M. Gyulmaliev
Keyword(s):  
Antioxidant Activity ◽  
Quantum Chemical ◽  
Chemical Potential ◽  
Relative Activity ◽  
Molecular Orbitals ◽  
Chemical Hardness ◽  
Test Substance ◽  
Lowest Unoccupied Molecular Orbitals ◽  
Electronic Chemical Potential ◽  
Electronic Chemical

A new method for evaluating the antioxidant activity of organic compounds based on quantum chemical calculations of their electronic structure using the DFT B3LYP/6-31G (d, p) method has been proposed. The geometric parameters of antioxidant molecules were optimized and the reactivity indices were determined from the energy values of the highest occupied and the lowest unoccupied molecular orbitals: absolute electronegativity; electronic chemical potential; absolute "chemical hardness". The found indicators allow us to quantify the antioxidant activity by building their dependence on the energy of the lower vacant molecular orbitals. The correlation of the obtained parameters with the standard, such as trolox, allows determining the relative antioxidant activity of the test substance.

Orbital interactions. VIII. Competition kinetic measurements of the Birch reduction of some compounds having the bicyclo[2,2,1]heptadiene framework as a means of investigating orbital interactions through space in these systems

1980 ◽  
Vol 33 (4) ◽  
pp. 785 ◽  
Author(s):  
MN Paddon-Row ◽  
R Hartcher
Keyword(s):  
Rate Constants ◽  
Relative Rate ◽  
Butyl Alcohol ◽  
Molecular Orbitals ◽  
Kinetic Measurements ◽  
Birch Reduction ◽  
Orbital Interactions ◽  
Relative Rate Constants ◽  
Lowest Unoccupied Molecular Orbitals

Relative rate constants for the Birch reduction (Li/liq. NH3/t-butyl alcohol) of norbornadiene (1),1,4-dihydro-1,4-methanonaphthalene (3), 9-(1-methylethylidene)-1,4-dihydro-1,4-methanonaphthalene(5), 1,4- dihydro-1,4-epoxynaphthalene (7), lithium benzoate, α-methylstyrene, and the hexahydrobenzenomethanoanthracene(20a), were obtained and compared with that obtained for the reduction of norbornene from an earlier study. Compounds (1), (3) and (5) were some 105 times more readily reduced than norbornene. These results are best explained in terms of the presence of through-space interactions operating between the two lowest unoccupied molecular orbitals in these molecules. The Birch reduction of (7) gave mainly 1,4-dihydronaphthalene (17).A mechanism for this reaction is presented.

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