Theoretical Study on the Influence of Iron Mordant in the Optical Properties of Natural Dyes

2008 ◽  
Vol 587-588 ◽  
pp. 608-612
Author(s):  
M. Carreira ◽  
António Estevao Candeias ◽  
A. Manhita ◽  
C.T. Costa ◽  
P.J. Mendes ◽  
...  
Keyword(s):  
Optical Properties ◽  
Energy Band ◽  
Lower Energy ◽  
Theoretical Study ◽  
Geometry Optimization ◽  
Natural Dyes ◽  
Spin Structures ◽  
Lower Energy Band ◽  
B3lyp Level ◽  
Td Dft

Geometry optimization of free alizarin, purpurin and luteolin and coordinated Fe(II) complexes was performed at DFT/B3LYP level. TD-DFT spectra were also calculated for free and coordinated alizarin and luteolin. For the Fe(II) complexes several spin multiplicities have been calculated and quintuplet spin structures were found to be the most stable. In the luteolin-Fe(II) complex, the coordination of the chromophore with the iron leads to a decrease in the lower energy band. In the case of luteolin complex, a new band emerges due to interactions between the delocalized π electrons of the luteolin molecule with the d metal orbitals.

scholarly journals Structural, Spectroscopic and Optical Properties of Monohydrated Adenine: A Theoretical Study

2016 ◽  
Vol 64 (2) ◽  
pp. 157-161
Author(s):  
M Alauddin ◽  
MM Islam ◽  
MA Aziz
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Theoretical Study ◽  
Minimum Energy ◽  
Band Gap Energy ◽  
Gap Energy ◽  
B3lyp Level ◽  
A Minor ◽  
Homo Lumo ◽  
Hydrogen Bonded

The structural, spectroscopic (IR, NMR and UV-Vis), electronic and optical properties of monohydrated adenine (monohydrated 6-aminopurine, C5H5N5.H2O) are investigated theoretically using DFT/B3LYP level of theory. Three minimum energy structures have been identified for monohydrated of adenine where H2O molecule is doubly hydrogen bonded with adenine.1H NMR analysis shows that the protons which are hydrogen bonded become deshielded and chemical shift moves to the higher frequency region.Five IR active mode of vibrations were found at 3108, 3295, 3665, 3676 and 3719 cm-1 which are assigned as bonded -OH vibration of H2O, Bonded -NH vibration of NH2, Free -NH vibration of adenine (9 N), Free -NH vibration of NH2, Free -OH vibration of H2O, respectively and agree well with the available experimental results. The investigation of electronic properties shows that the HOMO-LUMO band gap energy of monohydrated adenine at B3LYP level is 5.15 eV. The major electronic transition (from HOMO to LUMO (83%) (π→π*)) occurs at 258 nm (4.80 eV) with a minor transition at 237 nm (5.23 eV). Theoretically it is observed that the HOMO-LUMO band gap energy is for monohydrated adenine is lower than that of adenine. Dhaka Univ. J. Sci. 64(2): 157-161, 2016 (July)

EFFECT OF SYNTHESIS REACTION TIME AND DOPING ON UV/VIS ABSORPTION OF POLYENE COATING

2017 ◽  
Vol 79 (2) ◽  
Author(s):  
Mohd Nurazzi Norizan ◽  
Rahmah Mohamed
Keyword(s):  
Reaction Time ◽  
Band Gap ◽  
Energy Band ◽  
Lower Energy ◽  
Control Sample ◽  
Reaction Times ◽  
Energy Band Gap ◽  
Lower Energy Band ◽  
Dechlorination Reaction ◽  
Absorbance Spectra

Absorbance spectra and energy band gap of synthesizing polyene from dechlorination of polyvinyl chloride (PVC) with varying synthesizing reaction times and doping percentages were examined in this paper. The reaction time of dechlorination was varied from 30 minutes, 1 hour, 2 hours and 4 hours. Polyene obtained from the dechlorination reaction was doped with potassium iodide (KI). Sample for UV/Vis test was prepared in the form of film. Modified EO film as control sample showed that there is only a single absorption peak around 327nm. The C-Cl adsorption band link from source link polymer was observed at 422nm and all polyene film samples and new bands absorption were observed from 422nm to 590nm, and 683nm upon the increase in reaction time. The lower energy band gap was observed at 683.18nm absorption with 1.08eV.    

Structures and Electronic Spectroscopy of Rhodium-Based Complexes: a Theoretical Study on Promising Optical Materials

2011 ◽  
Vol 284-286 ◽  
pp. 2288-2291
Author(s):  
Yuan Ru Guo ◽  
Qing Jiang Pan
Keyword(s):  
Photocatalytic Activity ◽  
Lower Energy ◽  
Optical Materials ◽  
Theoretical Study ◽  
Electronic Spectroscopy ◽  
Bidentate Ligand ◽  
Structural Description ◽  
Td Dft ◽  
Lower Energy Region ◽  
Fine Tune

A series of rhodium-based complexes were explored theoretically to understand their application in optical materials and potential photocatalytic activity. Better structural description of [RhAu(CNH)2(PH2CH2PH2)2]2+ (1) were achieved with the ab initio MP2, XαVWN, and SVWN methods. To fine-tune the electronic spectroscopy, two analogues of 1 were taken into account by varying its Au metal center and bridging bidentate ligand. The experimental spectra were well reproduced by our TD-DFT calculations. It was shown that the lowest-energy absorption of homobimetallic Rh-Rh complex occurs in lower-energy region than those of heterobimetallic Rh-Au complexes.

The Electronic Single Crystal Spectrum of Binuclear Rhodium(II)acetate Hydrate Rh2(CH3COO)4· 2 H2O

1978 ◽  
Vol 33 (10) ◽  
pp. 1095-1098 ◽  
Author(s):  
G. Bienek ◽  
W. Tuszynski ◽  
G. Gliemann
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Energy Band ◽  
Lower Energy ◽  
Ultraviolet Spectrum ◽  
Temperature Range ◽  
Lower Energy Band ◽  
Near Ultraviolet ◽  
Temperature Dependences ◽  
Acetate Hydrate

Abstract The visible and near-ultraviolet spectrum of rhodium(II)acetate hydrate single crystals has been measured in a temperature range from 10 K to 295 K. Two band systems centered at 17,000 cm-1 and 22,000 cm-1 have been found, both consisting of components polarized parallel to and perpendicular to the rhodium-rhodium z-axis. Polarizations, intensities and temperature dependences are consistent with an assignment of z-polarized a1g →a2u and xy-polarized eg →a2u transitions for the lower energy band. For the higher energy band it could not be determined definitely whether only the b2g →-b1u and eg → b1u transitions give rise to the z-and x,y-polarization directions, respectively, or if b1g → b2u and eg →b2u also make a contribution.

Second-order nonlinear optical properties of two chalcone derivatives: insights from sum-over-states

2021 ◽  
Author(s):  
Jean Custodio ◽  
Giulio Demetrius Creazo d'Oliveira ◽  
Fernando Gotardo ◽  
Leandro Cocca ◽  
Leonardo De Boni ◽  
...  
Keyword(s):  
Optical Properties ◽  
Nonlinear Optical ◽  
Theoretical Study ◽  
Second Order ◽  
Nonlinear Optical Properties ◽  
Chalcone Derivatives

In the following study, a combined experimental and theoretical study of the nonlinear optical properties (NLO) of two chalcone derivatives, (E)-3-(2-methoxyphenyl)-1-(2-(phenylsulfonylamine)phenyl)prop-2-en-1-one (MPSP) and (E)-3-(3-nitrophenyl)-1-(2-(phenylsulfonylamine)phenyl)prop-2-en-1-one (NPSP) in DMSO is reported. Single...

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

2013 ◽  
Vol 91 (9) ◽  
pp. 872-878 ◽  
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.

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