摘要:

AbstractA family of well‐defined prophyrin wires, 5,10,15,20‐tetrakis(4‐N‐ethylpyridyl)porphyrin salts [H2TEPyP4+·A] (A = 2CdI42−1; 6I−2; 4I−3), has been synthesized by hydrothermal methods and was structurally characterized by X‐ray single‐crystal diffraction. Controlling the packing of π‐π stacking backbones was achieved by means of adjusting the counterbalanced anions: tetragonal packing for1and2; hexagonal‐like for3. The optical properties related to the packing structures were studied by solid‐state diffuse reflectance spectra. The blue‐shift of Soret band demonstrated the H‐aggrega

ISSN:0009-4536    

DOI:10.1002/jccs.200600021

出版商:WILEY‐VCH Verlag    

年代:2006

数据来源: WILEY

摘要:

AbstractThe aggregation behavior of zinc protoporphyrin (ZnPP) inside nanoporous environments of anodized aluminum oxide (AAO) has been investigated through observation of the variation of UV/visible absorption and emission spectra of the system. The Soret band in the absorption spectrum of ZnPP/AAO thin‐film samples becomes much broader than that observed for ZnPP/THF solutions, and the relative intensity of the Q band is distinctly enhanced for the former. The broad Soret band overlaps the enhanced Q band increasingly as the degree of aggregation increases with increasing duration of immersion, with initial concentration of ZnPP/THF solutions, or with decreasing pore size of AAO nanotubes. A strong excitonic coupling between the Soret and Q transition dipoles causes the absorption spectrum of the ZnPP/AAO system to cover the entire visible spectral region. Emission spectra of ZnPP/AAO samples in the steady state contain multiple resolvable components assigned to monomer, dimer and higher aggregates. The observed systematic variation of emission spectra of ZnPP/AAO samples is consistent with the observation in absorption spectra of the system and reflects the significance of aggregation of ZnPP in a specific nanoporous environmen

ISSN:0009-4536    

DOI:10.1002/jccs.200600022

出版商:WILEY‐VCH Verlag    

年代:2006

数据来源: WILEY

摘要:

AbstractOptical and magnetic properties have been investigated for the structurally confined amorphous magneto‐semiconductor, ternary chalcogenide, within the nanochannels of the mesoporous host. The structural confinement induced a weak crystallographic ordering of the magneto‐semiconductor within the nanochannels. Unique optical properties were observed for this nanocomposite, which were possibly due to the size and energy quantization of the confined guest chalcogenide within the nanochannels. The structural confinement also induced the suppression of the phonon coupling to the photoexcited carriers during the carriers' recombination process. The spin‐glass freezing temperature (Tf= 4.2 K) which was the characteristic magnetic transition temperature for the amorphous bulk was shifted to 2.3 K for the confined system, possibly due to the generation of the superparamagnetic domains induced by the quantum confinement e

ISSN:0009-4536    

DOI:10.1002/jccs.200600023

出版商:WILEY‐VCH Verlag    

年代:2006

数据来源: WILEY

摘要:

AbstractIn this article various novel synthesized dyads and triad systems containing organic based electron donor and acceptor compounds linked together by flexible and rigid spacers have been described which undergo very fast (˜ ps) charge separation reactions and relatively slow energy destructive charge recombination. Various techniques have been discussed to enhance the survival duration of the charge‐separated products, resulted from photoinduced electron transfer reactions, by retarding the energy wasting charge recombination process. It has been hinted that these systems should form the basis of future artificial photosynthetic and solar energy conversion devic

ISSN:0009-4536    

DOI:10.1002/jccs.200600024

出版商:WILEY‐VCH Verlag    

年代:2006

数据来源: WILEY

摘要:

AbstractHula‐twist is a rapid diabatic process of photoisomerization. It is not volume‐demanding and its stereochemical consequence is simultaneous isomerization of a double and a single bond. Recent new examples include diene, styrene, stilbene, diphenylbutadiene and other derivatives in organic glasses at liquid nitrogen temperature. In systems where two different modes of HT are possible, a high regioselectivity was observed. Possible involvement of the volume‐conserving mechanism of isomerization in primary processes of photosensitive biopigments is disc

ISSN:0009-4536    

DOI:10.1002/jccs.200600025

出版商:WILEY‐VCH Verlag    

年代:2006

数据来源: WILEY

摘要:

AbstractDipolar compounds (abbreviated asQuPy) featuring quinoxaline acceptors and diarylamine or triarylamine donors were prepared via palladium‐catalyzed C‐N or C‐C bond formation in good yields. They possess high thermal stability with a high decomposition temperature (Td>400 °C) and exhibit no crystalline character. The emission colors of the materials vary from green to orange red and are dependent on the nature of the electron‐withdrawing segments and solvents. Two types of double‐layer organic light‐emitting diodes (OLEDs) were constructed using these dipolar compounds as hole‐transporting/emitting layers and TPBI or Alq3as an electron‐transporting layer: (I) ITO/QuPy/Alq3/Mg: Ag and (II) ITO/QuPy/TPBI/Mg: Ag (TPBI = 1,3,5‐tris(N‐phenylbenzimidazol‐2‐yl)‐benzen; Alq3= 1,3,5‐tris(N‐phenyl‐benzimidazol‐2‐yl)‐benzene). The recombination zone in most of those devices were confined in the quinoxaline layers. The green to orange colors in these devices correspond well with the film PL of the material used. The relation between the energy levels of the compounds and the performance of

ISSN:0009-4536    

DOI:10.1002/jccs.200600026

出版商:WILEY‐VCH Verlag    

年代:2006

数据来源: WILEY

摘要:

AbstractA new pyran (1) is synthesized. When molecularly dissolved in acetone,1is practically nonemissive. Addition of water induces it to cluster into nanoaggregates, which turns its emission “on” and boosts its luminescence efficiency dramatically. The color of its emission changes from green to red upon aggregat

ISSN:0009-4536    

DOI:10.1002/jccs.200600027

出版商:WILEY‐VCH Verlag    

年代:2006

数据来源: WILEY

摘要:

AbstractIn this article, we first present a brief introduction on room temperature ionic liquids based on substituted imidazolium salts that have been the focus of extensive studies in recent years. Subsequently, we summarize some of the photophysical studies made in these ionic liquids. Finally, we discuss the suitability of the imidazolium ionic liquids in optical studies taking into consideration their absorption and fluorescence behavior.

ISSN:0009-4536    

DOI:10.1002/jccs.200600028

出版商:WILEY‐VCH Verlag    

年代:2006

数据来源: WILEY

摘要:

AbstractMolecular volume is a useful property to characterize the conformation and the intermolecular interaction. The time‐resolved transient grating technique allows us to study the time‐development of the molecular volume during protein reactions. Studies on the ligand escaping process of carboxymyoglobin at room temperature in liquid phase from a viewpoint of the time‐resolved volume change are rev

ISSN:0009-4536    

DOI:10.1002/jccs.200600029

出版商:WILEY‐VCH Verlag    

年代:2006

数据来源: WILEY

ISSN:0009-4536    

DOI:10.1002/jccs.200600030

出版商:WILEY‐VCH Verlag    

年代:2006

数据来源: WILEY