Search results for "Vis spectra"
showing 7 items of 17 documents
Aggregation of Free-Base Octacarboxyphthalocyanine in Aqueous Solutions
1999
Results of spectral (UV-VIS) investigations on the aggregation phenomena of the freebase 2,3,9,10,16,17,23,24-octacarboxypthalocyanine are reported. Phthalocyanine exists mainly in associated (aggregated) froms in water. The aggregates are present even in very diluted (10-7 -10-6 mol/dm-3) solutions. The hydrogen bonding between the carboxyl groups of the adjacent molecules in considered. The increase in pH and temperature, as well as the presence of the cationic surfactant and alcohols (in an appropriate quantity) cause a prtial or full disaggregation. The spectrum of the monomeric phthalocyanine from has been observed. The increase in H2Pc(COOH)8 concentration, the decrease in pH, as well…
Homogeneous mixtures of polybetaines with low molecular weight salts
1996
The prepaparation of amorphous, homogeneous blends of zwitterionic polymers with various low molecular weight salts, and in particular with ionic dyes was studied. Homogeneous miscibility was achieved in many cases up to equimolar amounts of salt, even for bulky compounds. Whether miscibility is achieved, or not, depends in a subtle way on the chemical structure of the salt, but no obvious correlation between structure and miscibility could yet be revealed. Spectral shifts of the dye UV/Vis spectra in solution as well as in bulk suggest strong interactions between the polybetaines and the admired salts.
Binding and Fluorescent Sensing of Dicarboxylates by a Bis(calix[4]pyrrole)-Substituted BODIPY Dye
2013
A bis(calix[4]pyrrole)-substituted BODIPY ditopic receptor 1 has been synthesised and characterised. The binding and sensing properties of 1 towards several aliphatic and aromatic dicarboxylates have been evaluated by using UV/Vis fluorescence and 1H NMR spectroscopy. The receptor strongly binds linear α,ω-dicarboxylates of appropriate lengths (C9 and C10) by acting as a cleft. For all dicarboxylates, the binding event is detected by a bathochromic shift in the UV/Vis spectra of the receptor and by strong quenching of its fluorescence.
Copper Octacarboxyphthalocyanine Aggregation in Buffered Solutions
2008
Results of spectral UV-Vis absorption investigations on association of copper octa-carboxyphthalocyanine, CuPcOC, are reported. Influence of pH on association is discussed. In pH < 5.5 only ag gre gates are present. Monomer appears above pH = 5.5 and at pH Greater-than or equal to 6.2 only monomeric Pc forms exist. CuPcOC exhibits higher tendency to wards association in phosphate buffer solutions than in redistilled water. In pH 5.9–6.0 monomers, dimers and trimers coexist in equilibrium in 1.0×10–6 – 1.2×10–5 mol/dm3 concentration range at 25°C. The average assembling number n = 3 was determined for pH 5.6, 5.9 and 6.0 solutions. The spectrum of aggregate was calculated with two maxima at …
Dimerization of Copper Octacarboxyphthalocyanine in Aqueous Solutions
2005
Spectral absorption UV-Vis investigations on association of copper(II) octacarboxyphthalocyanine in aqueous solutions are reported. In 5.0x10-7-5.0x10-5 mol/dm3 concentration range monomers and dimers are mainly present. The calculated dimerization constant 106dm3/mol at 25°C and the hypsochromic spectral shift for the dimer 1164 cm-1 (688 nm_ 637 nm) indicate a stack-like association of molecules and suggestpi-pi interactions between Pc macrocycles in dimer and higher aggregates, in contrast to hydrogen bonding between carboxylic groups of adjacent Pc molecules.
Spectrophotometric determination of phthalocyanines Part II. Phthalocyanines stable in concentrated sulfuric acid
2001
Celem pracy było wykazanie możliwości zastosowania spektroskopii VIS do badań ilościowych różnych związków ftalocyjaniny, w szczególności niepodstawionych kompleksów z metalami, które są trwałe w środowisku stężonego kwasu siarkowego(Vl). Zaproponowano prostą metodę, analizy spektrofotometrycznej VIS, stanowiącą kontynuację wcześniej przedstawionej pracy [1], umożliwiając oznaczanie wielu kompleksów ftalocyjaniny z metalami bloku d, Mpc (gdzie M = Cu, Co, Ni, Zn oraz pc (C(32)H(16)N(8)2- = ligand ftalocyjaninowy). Analiza statystyczna wyników uzyskanych w badaniach kontrolnych wykazała, że opisana metoda może być użyteczna zarówno w zastosowaniach przemysłowych jak i badaniach naukowych.
Synteza i właściwości fizykochemiczne ftalocyjaniny manganu
2017
Ftalocyjaniny to organiczne związki chemiczne, które uzyskuje się jedynie na drodze syntezy chemicznej. Stanowią one jednak analogi strukturalne porfiryn, które naturalnie występują w przyrodzie, m.in. w takich cząsteczkach jak witamina B12 czy chlorofil. Obszerne badania dotyczące kompleksów ftalocyjanin wynikają z budowy tych związków, ponieważ cząsteczkę ftalocyjaniny można modyfikować na bardzo wiele sposobów. Wpływa to na różnorodność zastosowań ftalocyjanin, m.in. w urządzeniach elektronicznych, fotowoltaicznych, jako fotosensiblilizatory, barwniki i pigmenty. Kompleksy ftalocyjanin z takimi metalami jak mangan czy kobalt są intensywnie badane ze względu na ich interesujące właściwośc…