1,721,008 research outputs found
Mono-molecular isomerization processes of aluminium tris (8-hydroxy-quinolinate) (Alq3): a DFT study of gas-phase reaction paths
No full textDensity Functional Theory has been applied to investigate isomerization processes of aluminum tris(8-hydroxyquinolinate) (Alq3). Both mer–fac isomerization and mer-Alq3 chirality inversion have been reported. This represents an attempt to describe phenomena which could take place during Alq3 amorphous-films deposition or during solid-state changes of phase. Furthermore, it represents the opportunity to apply modern theoretical methodologies to shed light on the general problem of isomerizations in tris–chelate complexes which were widely studied experimentally and by approximate theoretical methods in the seventies and in part of the eighties
Competition between Bailar and Ray-Dutt paths in conformational interconversion of tris-chelated complexes: a DFT study
No full textAre UV-VIS and luminescence spectra of Alq3 [Aluminium tris (8-hydroxy-quinolinate)] delta-phase compatible with the presence of the fac-Alq3 isomer? A TD-DFT investigation
No full textRecently a new crystalline phase of aluminium tris(8-hydroxyquinolinate) (Alq3) called d-phase has been reported.
On the basis of luminescence data, the presence of the facial isomer has been suggested. Using time dependent density
functional theory calculations we compared the spectral features of meridianal and facial Alq3. Comparisons between
the two isomers have been used to confirm the presence of facial Alq3 in d-phase crystals. The interpretation of some
characteristics of the more studied meridianal isomer has been suggested. 2002 Published by Elsevier Science B.V
ELECTRONIC AND SPECTROSCOPIC PROPERTIES OF 4'-SUBSTITUENTS ON ZINC AND ALUMINIUM COMPLEXES WITH 5-(4'-SUBSTITUTED-PHENYLAZO)-8-HYDROXYQUINOLINES. AN EXPERIMENTAL AND COMPUTATIONAL DFT AND TD-DFT STUDY
No full textLuminescent compounds fac- and mer-Alq3 [Aluminum tris(quinoline-8-olate)]. A pure and hy-brid DFT and TD-DFT investigation of their electronic and spectroscopic properties
No full textBis(cyclopentadienyl)dihydrido Mo and W complexes as Lewis’ bases. A computational study about their adducts with BX3 (X = F, Cl) and Al(CH3)3
No full textDESIGN OF NEW MATERIALS FOR ORGANIC LIGHT EMITTING DIODES (OLEDs): 7-SUBSTITUTED 8-HYDROXYQUINOLINE COMPUNDS AS NEW LIGANDS FOR MORE STABLE ALUMINUM COMPLEXES
No full textSynthesis of mono-aryl substituted (alkylsulfanyl)porphyrazines via Suzuki cross-coupling
No full textNanohybrid of Thio-Alkylporphyrazine Noncovalently Linked to Single-Wall Carbon Nanotubes for Photoinduced Electron Transfer
No full textNon-symmetrical aryl- and arylethynyl-substituted thioalkyl-porphyrazines for optoelectronic materials: synthesis, properties, and computational studies
No full textA series of novel non-symmetrically substituted mono β-aryl and β-arylethynyl (alkylsulfanyl)porphyrazines and the corresponding Ni(II) complexes have been prepared by the Suzuki–Miyaura and Sonogashira cross-coupling reactions with the aim to investigate substituent effects on their electronic and aggregation properties. Spectroscopic, electrochemical and computational investigations show that in both aryl and arylethynyl compounds efficient electron transfer between the aryl and macrocycle moieties occurs.
The highest perturbation of the porphyrazine π-electron core is provided by strong electron-donating (NMe2) and electron withdrawing (NO2) aryl substituents, which increase and decrease the macrocycle electron density, respectively. Moreover, while in most of the compounds the LUMOs and HOMOs are mainly localized on the porphyrazine ring, in the amino-substituted derivatives the HOMO is localized on the peripheral aryl moieties and the LUMO is localized on the macrocycle. Charge-transfer electronic excitations give rise to absorptions in UV-Vis spectra of both amino- and nitro-substituted compounds. In the former such excitations occur from aryl-localized to macrocycle-localized orbitals, while backward excitations occur in the latter. Therefore, the porphyrazine ring shows an ambivalent behavior, acting as an electron acceptor in the case of the NMe2 substituted compounds and as an electron donor in the NO2-substituted derivative. In these derivatives, even macrocycle mono-substitution provides unconventional “push–pull” systems suitable for NLO. Columnar discotic mesophases are also shown by thio-octyl arylethynyl derivatives, allowing us to envisage the possibility to achieve compounds both suitable for optoelectronic applications and endowed with self-aggregation properties
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