Bicyclo[3.2.0]hepta-1,4,6-triene: synthesis, thermal rearrangement, and anion formation

In order to determine the properties of the bicycloheptatrienyl anion (Ia) (predicted to be conjugatively stabilized by Hückel Molecular Orbital Theory) the neutral precursor, bicyclo[3. 2. 0] hepta-1, 4, 6-triene (I) was prepared by the following route.

Reaction of I with potassium-t-butoxide, potassium, or lithium dicyclohexylamide gave anion Ia in very low yield. Reprotonation of I was found to occur solely at the 1 or 5 position to give triene II, isolated as to its dimers.

A study of the acidity of I and of other conjugated hydrocarbons by means of ion cyclotron resonance spectroscopy resulted in determination of the following order of relative acidities:

H₂S ˃ C₅H₆ ˃ CH₃NO₂ ˃ 1, 4- C₅H₈ ˃ I ˃ C₂H₅OH ˃ H₂O; cyclo-C₇H₈ ˃ C₂ H₅OH; фCH₃ ˃ CH₃OH

In addition, limits for the proton affinities of the conjugate bases were determined:

350 kcal/mole ˂ PA(C₅ H₅^-) ˂ 360 kcal/mole

362 kcal/mole ˂ PA(C₅H₇^-, Ia, cyclo-C₇H₇^-) ˂ 377 kcal/mole PA(фCH₂^-) ˂ 385 kcal/mole

Gas phase kinetics of the trans-XVIII to I transformation gave the following activation parameters: E_a = 43.0 kcal/mole, log A = 15.53 and ∆S^ǂ (220°) = 9.6 cu. The results were interpreted as indicating initial 1,2 bond cleavage to give the 1,3-diradical which closed to I. Similar studies on cis-XVIII gave results consistent with a surface component to the reaction (E_a = 22.7 kcal/mole; log A = 9.23, ∆S^ǂ (119°) = -18.9 eu).

The low pressure (0.01 to 1 torr) pyrolysis of trans-XVIII gave in addition to I, fulvenallene (LV), ethynylcyclopentadiene (LVI) and heptafulvalene (LVII). The relative ratios of the C₇H₆ isomers were found to be dependent upon temperature and pressure, higher relative pressure and lower temperatures favoring formation of I. The results were found to be consistent with the intermediacy of vibrationally excited I and subsequent reaction to give LV and LVI.

Study of polymer thermal and mechanical properties using a fiber Bragg grating thermal sensor

A simple and practical method for the study of polymer thermal and mechanical properties using a fiber Bragg grating (FBG) sensor is presented for the first time, in which the FBG is embedded in a typical epoxy polymer. By measuring the sensitivity change of the FBG sensor, changes of the thermal-mechanical properties of the polymer with temperature and pressure can be measured. The experimental results show that this technique is capable of providing continuous in-line monitoring such properties with high sensitivity during transformation between the glassy state and the rubbery state of a polymer within the temperature and pressure range of 20 to 180 C and 0 to 15 MPa. (c) 2007 Society of Photo-Optical Instrumentation Engineers.

Study of polymer thermal and mechanical properties using a fiber Bragg grating thermal sensor

A simple and practical method for the study of polymer thermal and mechanical properties using a fiber Bragg grating (FBG) sensor is presented for the first time, in which the FBG is embedded in a typical epoxy polymer. By measuring the sensitivity change of the FBG sensor, changes of the thermal-mechanical properties of the polymer with temperature and pressure can be measured. The experimental results show that this technique is capable of providing continuous in-line monitoring such properties with high sensitivity during transformation between the glassy state and the rubbery state of a polymer within the temperature and pressure range of 20 to 180 C and 0 to 15 MPa. (c) 2007 Society of Photo-Optical Instrumentation Engineers.

Optical near-field simulation of Sb thin film thermal lens and its application in optical recording

Using the finite-difference-time-domain method, the near-field optical distribution and properties of Sb thin film thermal lens are calculated and simulated. The results show as follows. Within the near-field distance to the output plane of thermal lens, the spot size is approximately 100 nm, and its intensity is greatly enhanced, which is higher than that of incident light. The spot shape gradually changes from ellipse to round at the distance of more than 12 nm to the output plane. The above-simulated results are further demonstrated by the static optical recording experiment. (C) 2005 American Institute of Physics.

Synthesis of nickel(II) complexes of alpha-isoxazolylazo-beta-diketones and their absorption of spin-coating films and thermal properties for HD-DVD-R

Three kinds of new nickel(II) complexes of alpha-isoxazolylazo-beta-diketones with blue-violet light absorption were synthesized. Their structures were postulated based on elemental analysis, MS and FT-IR spectra. Smooth films on K9 glass substrates were prepared using the spin-coating method. The absorption properties and thermal stability of these complexes were discussed. The static optical recording test for high density digital versatile disc-recordable (HD-DVD-R) system was also studied. (c) 2005 Elsevier B.V. All rights reserved.

Thermal, structural and optical properties of NiOx thin films deposited by reactive dc-magnetron sputtering

The NiOx thin films were deposited by reactive dc-magnetron sputtering from a nickel metal target in Ar + O-2 with the relative O-2 content 5%. The as-deposited NiOx, thin films could represent a two-component system comprising crystalline NiO particles dispersed in an amorphous Ni2O3. Decomposition temperature of the as-deposited NiO, thin films was at about 263 degrees C. After annealed at 400 degrees C for 30 min in air, the surface morphology of the films became very rough due to the decomposition of the Ni2O3, leading to the changes of the optical properties of the NiO, thin films. The reflectivity of the films annealed at 400 degrees C was lower than that of the as-deposited one and the optical contrast was 52% at 405 nm. (c) 2006 Elsevier B.V. All rights reserved.

Spectroscopic and thermal properties of short wavelength metal (II) complexes containing alpha-isoxazolylazo-beta-diketones as co-ligands

Two new azo dyes of alpha-isoxazolylazo-beta-dilcetones and their Ni(II) and Cu(II) complexes with blue-violet light wavelength were synthesized using a coupling component, different diazo components and metal (II) ions (Ni2+ and Cu2+). Based on the elemental analysis, MS spectra and FT-IR spectral analyses, azo dyes were unequivocally shown to exist as hydrazoketo and azoenol forms which were respectively obtained from the solution forms and from the solid forms. The action of sodium methoxide (NaOMe) on azo dyes in solutions converts hydrazoketo form into azoenol form, so azo dyes are coordinated with metal (II) ions as co-ligands in the azoenol forms. The solubility of all the compounds in common organic solvents such as 2,2,3,3-tetrafluoro-1-propanol (TFP) or chloroform (CHCl3) and absorption properties of spin-coating thin films were measured. The difference of absorption maxima from the complexes to their ligands was discussed. In addition, the TG analysis of the complexes was also determined, and their thermal stability was evaluated. It is found that these new metal (II) complexes had potential application for high-density digital versatile disc-recordable (HD-DVD-R) system due to their good solubility in organic solvents, reasonable and controllable absorption spectra in blue-violet light region and high thermal stability. (c) 2004 Elsevier B.V. All rights reserved.

Synthesis, spectroscopic and thermal properties of nickel (II)-azo complexes with blue-violet light wavelength

A novel azo dye containing isoxazole ring and beta-diketone derivative (TIAD) and its two nickel (II) complexes (Ni (II)-ETIAD and Ni (II)-HTIAD) were synthesized in order to obtain a blue-violet light absorption and better thermal stability as a promising organic storage material for next generation of high density digital versatile disc-recordable (HD-DVD-R) systems that uses a high numerical aperture of 0.85 at 405 nm wavelength. Their structures were confirmed on the basis of elemental analysis, MS, FT-IR, UV-Vis and magnetic data. Their solubility in 2,2,3,3-tetrafluoro-1-propanol (TFP) and absorption properties of thin film were measured. The difference of absorption maximum from the complexes to their ligands was discussed. In addition, the TG analysis of the complexes was also determined, and their thermal stability was evaluated. (C) 2004 Elsevier Ltd. All rights reserved.

Synthesis, spectroscopic properties and thermal stability of metal(II) tetraazaporphyrin complexes with two strong wavelength absorption

Three kinds of metal(II) tetraazaporphyrin complexes with blue-violet and red light wavelength absorption were synthesized by refluxing tetraazaporphyrin ligand and different metal(II) ions, respectively. Their structures were confirmed by elemental analysis, LDI-TOF-MS, FT-IR and UV-Vis. The solubility of metal(II) tetraazaporphyrin complexes in organic solvents and absorption properties of their chloroform solution and films on K9 glass in the region 250-800 nm were measured. The influence on the difference of absorption maximum from metal(II) tetraazaporphyrin complexes to tetraazaporphyrin ligand by different metal(II) ions was studied. In addition, the thermal stability of the complexes was also evaluated. (c) 2006 Elsevier Ltd. All rights reserved.