Synthesis, Characterization and Properties of Amphiphilic Copolyfluorenes

2006 ◽  
Vol 11-12 ◽  
pp. 371-374
Author(s):  
Ai Ying Li ◽  
Jie Yun Chang ◽  
Kai Quan Wang ◽  
Lu De Lu
Keyword(s):  
Molecular Weight ◽  
Absorption Maximum ◽  
Amphiphilic Copolymers ◽  
Narrow Molecular Weight Distribution ◽  
Thermal Stabilities ◽  
Visible Absorption ◽  
1H And 13C Nmr ◽  
Good Solubility ◽  
Suzuki Polycondensation ◽  
Uv Visible

One novel fluorene-based amphiphilic copolymers has been synthesized by Suzuki polycondensation (SPC) with monomer 2,7-dibromo-9,9-bis-(3,6-dioxahepyl)fluorene and 9,9-dioctylfluorene-2,7-bis-(trimethyleneboronate). The copolyfluorenes’ molecular structure is characterized by 1H and 13C NMR as well as elemental analysis. The copolyfluorenes have high molecular weight and narrow molecular weight distribution, at the same time, are found to have good solubility and thermal stabilities. The copolyfluorenes exhibit a UV-visible absorption band in the range of 389-393 nm in both toluene solution and the film state. Upon photo-excitation around the absorption maximum wavelength, their PL spectra show a maximum peaks around at 415-427 nm.

UV-Visible Response of Kraft Lignin in Soft Wood Black Liquor

1990 ◽  
Vol 197 ◽  
Author(s):  
Daojie Dong ◽  
Arthur L. Fricke
Keyword(s):  
Molecular Weight ◽  
Analytical Method ◽  
Black Liquor ◽  
Kraft Lignin ◽  
Visible Absorption ◽  
Lignin Concentration ◽  
Refined Method ◽  
Dual Beam ◽  
Uv Visible ◽  
Black Liquors

ABSTRACTUV-visible light absorption is an analytical method that is commonly used to determine the concentration of lignin in solution; however, there are uncertainties with this method, particularly for use in determining lignin concentration in black liquors. To try to resolve these uncertainties, a detailed study of UV-visible absorption by lignin in solution has been made.A dual beam UV-visible instrument capable of repetitive scan was used. The effects of lignin concentration, lignin molecular weight, molecular weight dispersion, and solvent were examined as well as the effect of the reference solvent. Measurements were made for lignin dissolved in dilute caustic, DMF, THF, and DMSO. Measurements for soft wood black liquors were also made. A refined method for determining lignin concentration in soft wood black liquors resulted that is now being used in our research to evaluate lignin concentration in soft wood black liquor.The results of the current work have led to improvements in this analytical method so that it appears to be less affected by lignin characteristics and by solution complexities.

scholarly journals Synthesis of high cis-1,4 polybutadiene with narrow molecular weight distribution via a neodymium-based binary catalyst

RSC Advances ◽  
2018 ◽  
Vol 8 (39) ◽  
pp. 21926-21932 ◽  
Author(s):  
Jie Liu ◽  
Xiaodong Fan ◽  
Xin Min ◽  
Xiuzhong Zhu ◽  
Na Zhao ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Narrow Molecular Weight Distribution ◽  
Good Solubility ◽  
Binary Catalyst

Complex Nd(CF3SO3)3*3TOP with good solubility was synthesized to prepare polybutadiene with high cis-1,4-unit content and narrow molecular weight distribution.

scholarly journals Solvent Effects on the UV-Visible Absorption Spectra of Some New 3-Methyl-5-(Phenylamino)-4-((4-Phenylazo-Phenyl)Azo)-2-Substituted Thiophene Dyes

2021 ◽  
Vol 11 (5) ◽  
pp. 12937-12945
Keyword(s):  
Absorption Spectra ◽  
Absorption Maximum ◽  
Bathochromic Shift ◽  
Thiophene Ring ◽  
Solvent Polarity ◽  
Visible Absorption ◽  
Chemical Structures ◽  
Effect Of Solvent ◽  
Polar Groups ◽  
Uv Visible

The preparation of 3-methyl-5-(phenylamino)-4-((4-phenylazo-phenyl)azo)thiophene dyes 4a-d, having different polar groups at the second position, was described through hetero-cyclization of the precursor 4-mercapto-4-(phenylamino)-3-((4-phenylazo-phenyl)azo)but-3-en-2-one (3) with various α-chlorinated reagents. The absorption spectra of the synthesized thiophene dyes were studied in three solvents (MeOH, CHCl3, and DMF) to correlate the effect of solvent polarity as well as chemical structures on absorption in the UV–vis region. The absorption maximum (λmax) changed from 486 to 502 nm in methanol, from 502 to 512 nm in chloroform, and from 626 to 654 nm in DMF. The benzoyl group's introduction in the second position of the thiophene ring brings the absorption maxima to higher values (bathochromic shift).

Electrochemical, Photophysical and Theoretical Studies of Novel Zinc Phthalocyanines

2020 ◽  
Vol 20 (9) ◽  
pp. 5402-5410
Author(s):  
Rangaraju Satish Kumar ◽  
Naveen Mergu ◽  
Kyeong Su Min ◽  
Young-A Son
Keyword(s):  
Chemical Properties ◽  
Monomethyl Ether ◽  
Color Filter ◽  
Glycol Monomethyl Ether ◽  
Visible Absorption ◽  
Good Solubility ◽  
Zinc Phthalocyanines ◽  
Aggregation Property ◽  
Uv Visible ◽  
Industrial Solvents

In this research, we successfully synthesized three novel zinc phthalocyanines and applied for electrochemical and photo physical properties. These phthalocyanines are naphthoxy derivatives with methyl, benzyl and butyl-benzyl, with halo substitution (PCME, PCBN and PCBBN) and poses very good solubility in all industrial solvents. To check the preliminary results of LCD green color filter properties of these molecules, we taken the UV-Visible absorption and transmittance studies in Propylene glycol monomethyl ether acetate and achieved around 90% of transmittance in the region of 400–550 nm. Further understand the solubility of our phthalocyanines, we checked the aggregation property in PGMEA and we observed no any aggregation. All compounds showed very nice electro chemical properties with nice oxidation and reduction peaks. These phthalocyanines are fit for LCD color filter applications. Finally to get insights of the electronic and UV-Visible properties of the new dyes, the DFT calculations were performed.

SYNTHESIS AND ELECTRO-OPTICAL PROPERTIES OF BLUE EMITTING POLY(BP-alt-BCV) CONJUGATED POLYMERS

2005 ◽  
Vol 14 (04) ◽  
pp. 535-543
Author(s):  
JEONG JU BAEK ◽  
YOUNG CHUL JEONG ◽  
LEE SOON PARK ◽  
JUNG KYUNG LEE ◽  
YOON SOO HAN ◽  
...  
Keyword(s):  
Optical Properties ◽  
Conjugated Polymers ◽  
Double Layer ◽  
Phosphonic Acid ◽  
Conjugated Polymer ◽  
Absorption Maximum ◽  
Blue Emission ◽  
Diethyl Ester ◽  
Visible Absorption ◽  
Uv Visible

A new blue electroluminescent conjugated polymer, poly(BP-alt-BCV), was prepared by Hornor–Emmons polycondensation of [5-carbazol-9-yl-3-(diethoxy-phosphorylmethyl)-2-(2-ethyl-hexyloxy)-benzyl]-phosphonic acid diethyl ester (PHBP) and 4,4′-biphenyldicarboxaldehyde (BPCA) in the presence of tert-BuOK in THF. UV-visible absorption maximum (λmax,UV, π-π* transition) of poly(BP-alt-BCV) was measured at 340 nm. PL maximum (λmax,PL) values of poly(BP-alt-BCV) were obtained at 406 and 430 nm, when excited at its own λmax,UV. It was found that double layer [ITO/poly(BP-alt-BCV)/Alq3 (50 Å)/Al] PLED exhibited maximum EL peak at 440 nm and blue emission (x = 0.1794, y = 0.1878), similar to the NTSC standard blue (x = 0.14, y = 0.08).

scholarly journals Cu (II)-Red Onion Skin Extract-Azo metal Complex - A Potential for Oilfield Applications

2019 ◽  
pp. 1-7
Author(s):  
A. A. Akaho ◽  
U. J. Chukwu ◽  
O. Akaranta
Keyword(s):  
Metal Complex ◽  
Absorption Maximum ◽  
Skin Extract ◽  
Visible Absorption ◽  
Azo Compound ◽  
Onion Skin ◽  
Ft Ir ◽  
Uv Visible ◽  
Visible Absorption Spectroscopy ◽  
Ft Ir Spectroscopy

Red Onion skin extract (ROSE)- azo compound of 2-aminophenol and Cu (II) metal complex of the azo compound (Cu-APmROSE) were formed and characterized using FT-IR spectroscopy, UV-Visible absorption spectroscopy and Scanning electron microscopy. The IR Spectra showed the values of N=N- stretching frequency of 1512.24cm-1 at 1500 cm-1 in APmROSE. This stretching frequency is absent in the Cu-APmROSE. This is an indication of the involvement of the N=N- bond in coordination to the metal. APmROSE shows an absorption maximum at 512 nm. This band was shifted to 334 nm in Cu-APmROSE. This suggests an interaction between the Cu and the azo compound.

Photophysicochemical properties and TD-DFT calculations of a novel terminal alkyne substituted metal free phthalocyanine

2014 ◽  
Vol 18 (03) ◽  
pp. 251-258 ◽  
Author(s):  
Yusuf Yılmaz ◽  
John Mack ◽  
Mehmet Sönmez ◽  
Tebello Nyokong
Keyword(s):  
Triplet State ◽  
Therapeutic Window ◽  
Quantum Yields ◽  
Visible Absorption ◽  
H Nmr ◽  
Good Solubility ◽  
Near Ir ◽  
Wide Range ◽  
Td Dft ◽  
Uv Visible

The synthesis of a novel free base tetrakis(prop-2-ynyloxy)phthalocyanine (2) is described, along with its characterization by IR, UV-visible absorption, and 1 H NMR spectroscopy and mass spectrometry. The compound exhibited good solubility in a wide range of organic solvents and no significant aggregation was observed over a wide concentration range. The values for the singlet oxygen (ΦΔ), photodegradation, fluorescence (ΦF) and triplet state quantum yields and the fluorescence and triplet state lifetimes are reported. A relatively high ΦΔ value of 0.46 was obtained in DMSO. The ability to carry out "click" chemistry at the ligand periphery enhances the potential utility of 2 for use in bioconjugates in photodynamic therapy (PDT). A moderately high ΦF value of 0.18 is observed for emission in the therapeutic window in the near-IR region, which suggests that it may also be possible to determine the level of localization of 2 in tumor cells through bioimaging.

Peculiarities of flow and viscoelastic properties of solutions of polymers with a narrow molecular-weight distribution

1973 ◽  
Vol 9 (11) ◽  
pp. 1231-1249 ◽  
Author(s):  
G.V. Vinogradov ◽  
A.Ya. Malkin ◽  
N.K. Blinova ◽  
S.I. Sergeyenkov ◽  
M.P. Zabugina ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Viscoelastic Properties ◽  
Narrow Molecular Weight Distribution

Controlled and Efficient Polymerization of Methyl Methacrylate Catalyzed by Pyridinylidenaminophosphines Based Lewis Pairs

2021 ◽  
Author(s):  
Fang Ge ◽  
Sun Li ◽  
Zhe Wang ◽  
Wenzhong Zhang ◽  
Xiaowu Wang
Keyword(s):  
Molecular Weight ◽  
Methyl Methacrylate ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Living Polymerization ◽  
Narrow Molecular Weight Distribution ◽  
Synthetic Approaches ◽  
Lewis Pairs

Developing different synthetic approaches to realize controlled or living polymerization are aspirational to achieve polymers with defined molecular weight, narrow molecular weight distribution and unambiguous structures by polymer chemists. Herein,...

Remarkable kinetic stability of α-thiocarbamoyl substituted 4-methoxybenzylcations

1998 ◽  
Vol 76 (12) ◽  
pp. 1910-1915 ◽  
Author(s):  
Robert A McClelland ◽  
Victoria E Licence ◽  
John P Richard ◽  
Kathleen B Williams ◽  
Shrong-Shi Lin
Keyword(s):  
Key Words ◽  
Strong Interaction ◽  
Rate Constants ◽  
Flash Photolysis ◽  
Visible Absorption ◽  
Methyl Group ◽  
Thioamide Group ◽  
Azide Ion ◽  
Uv Visible ◽  
Leaving Groups

4-Methoxybenzyl cations bearing α-(N,N-dimethylcarbamoyl) and α-(N,N-dimethylthiocarbamoyl) substituents have been generated photochemically upon irradiation of precursors with pentafluorobenzoate or 4-methoxybenzoate leaving groups. The ions have been observed with flash photolysis in 40:60 acetonitrile:water and in 50:50 methanol:water, and rate constants were measured for their decay in solvent alone and for their capture by azide ion. The cations so studied and their lifetimes in 40% acetonitrile are 6, ArC+H-CONMe2, 0.6 μs; 2, ArC+H-CSNMe2, 7 ms; and 4, ArC+(CH3)-CSMe2, 6 ms, where Ar = 4-MeOC6H4. The cation 4 reacts with solvent by elimination of a proton from the α-methyl group, and the rate constant for solvent addition must be less than 1 s-1. The CSNMe2 substituted cations are 105-107-fold longer lived than analogs where the thioamide group has been replaced with an α-methyl. The UV-visible absorption spectra of these two cations also show significant differences from those of typical 4-methoxybenzyl cations. Thus, both the lifetimes and spectra point to a strong interaction of the benzylic centre with the thioamide group. Key words: flash photolysis, thiocarbamoyl stabilized carbocation, photosolvolysis.

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