title: Optical poling effect and optical absorption of cyan, ethylcarboxyl and tert-buthyl derivatives of 1H-pyrazolo[3,4-b]quinoline: experiment and quantum-chemical simulations.
abstract: We present here results of experimental studies and quantum-chemical simulations of optical absorption and optical poling effects performed on a new synthesized cyan, ethylcarboxyl and tert-buthyl derivatives of 1H-pyrazolo[3,4-b]quinoline incorporated into polymer matrix or dissolved in organic solutions. The efficiency of second-order optical susceptibility d vs photoinduced power density I(p) clearly saturates to certain magnitude d(eff) at sufficient power densities (I(p) > or = 1.3 GW cm(-2)). Comparing experimental data and results of semiempirical quantum-chemical simulations one can conclude that there exists generally a good correlation between the magnitude of saturated susceptibilities d(eff) and macroscopic hyperpolarizabilities for all compounds except the chromophore 1,3-dimethyl-6-cyano-[PQ] only. The discrepancy for this compound may reflect a specific contribution of surrounding polymer matrix. According to the quantum chemical analysis the methyl-containing cyan and ethylocarcoxyl derivatives reveal four/five strong absorption bands in the spectral range 200-500 nm. A substitution of the methyl groups by the phenyl group causes the substantial changes of the absorption spectra mainly in the spectral range 240-370 nm. Measured and calculated absorption spectra manifest rather good agreement mainly in the part regarding the spectral positions of the first oscillator (absorption threshold). The quantum-chemical PM3 method shows the best agreement with experiment. At the same time a considerable broadening almost of all absorption bands appears as a characteristic feature of all measured spectra. The discrepancies between the calculated and the measured spectra are attributed to electron-vibronic coupling as well as to a specific rotational dynamics of phenyl rings.
authors.affiliation: Institute for Computer Science, Technical University of Czestochowa, Armii Krajowej 17, 42-200 Czestochowa, Poland.
authors.forename: E
authors.initials: E
authors.lastname: Koścień
authors.forename: J
authors.initials: J
authors.lastname: Sanetra
authors.forename: E
authors.initials: E
authors.lastname: Gondek
authors.forename: B
authors.initials: B
authors.lastname: Jarosz
authors.forename: I V
authors.initials: IV
authors.lastname: Kityk
authors.forename: J
authors.initials: J
authors.lastname: Ebothe
authors.forename: A V
authors.initials: AV
authors.lastname: Kityk
mesh_terms: D000042:Absorption; D002244:Carbon; D008956:Models, Chemical; D008958:Models, Molecular; D015233:Models, Statistical; D008968:Molecular Conformation; D011108:Polymers / Q000737:chemistry; D011720:Pyrazoles / Q000737:chemistry*; D011789:Quantum Theory; D011804:Quinolines / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods*; D014466:Ultraviolet Rays
chemical_list: C498099:1H-pyrazolo(3,4-b)quinoline; D011108:Polymers; D011720:Pyrazoles; D011804:Quinolines; D002244:Carbon