scholarly journals Structure and Optical Properties of Thermochromic Schiff Bases. Charge Transfer Interaction and Proton Transfer in theN-Tetrachlorosalicylideneaniline andN-Tetrachlorosalicylidene-1-pyrenylamine Crystals

1991 ◽  
Vol 64 (3) ◽  
pp. 801-810 ◽  
Author(s):  
Tamotsu Inabe ◽  
Isabelle Gautier-Luneau ◽  
Naomi Hoshino ◽  
Kaoru Okaniwa ◽  
Hiroshi Okamoto ◽  
...  
Keyword(s):  
Optical Properties ◽  
Charge Transfer ◽  
Proton Transfer ◽  
Schiff Bases ◽  
Charge Transfer Interaction

scholarly journals Optical Nature of Non-Substituted Triphenylmethyl Cation: Crystalline State Emission, Thermochromism, and Phosphorescence

2021 ◽  
Author(s):  
Tomohiko Nishiuchi ◽  
Hikaru Sotome ◽  
Risa Fukuuchi ◽  
Kenji Kamada ◽  
Hiroshi Miyasaka ◽  
...  
Keyword(s):  
Optical Properties ◽  
Charge Transfer ◽  
Crystalline State ◽  
Color Change ◽  
Crystallographic Analysis ◽  
X Ray ◽  
Charge Transfer Interaction ◽  
Distinct Color ◽  
Crystalline Forms ◽  
Trityl Cation

Since the discovery of the triphenylmethyl (trityl) cation 120 years ago, a variety of aromatic cations having various colors and luminescence properties have been rigorously studied. Many, differently substituted trityl cations have been synthesized and their optical properties have been elucidated. However, the optical properties of the parent, non-substituted and highly reactive trityl cation, which was observed to be very weakly luminescent, have not been subjected to detailed investigation. In the effort described herein, we explored the optical nature of non-substituted trityl hexafluorophosphate (PF6) in the crystalline state. Trityl PF6 was found to exist as two crystal polymorphs including a yellow (Y) and an orange (O) form. Moreover, we observed that these crystalline forms display crystalline-state emission with different colors. The results of X-ray crystallographic analysis showed that the two polymorphs have totally different molecular packing arrangements. Furthermore, an investigation of their optical properties revealed that the O-crystal undergoes a distinct color change to yellow upon cooling as a consequence of a change in the nature of the charge transfer interaction between the cation and PF6 anion, and that both the Y and O crystal exhibit phosphorescence.

Charge transfer complexes of Schiff bases derived from 2-aminobenzothiazole with some acidic and nonacidic acceptors

1993 ◽  
Vol 71 (3) ◽  
pp. 318-324 ◽  
Author(s):  
Amany M. A. Ibrahim
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Charge Transfer ◽  
Magnetic Resonance ◽  
Proton Transfer ◽  
Schiff Bases ◽  
Electronic Absorption ◽  
Ionization Potentials ◽  
Charge Transfer Complexes ◽  
Electron Affinities ◽  
Nuclear Magnetic Resonance Spectra

When Schiff bases derived from 2-aminobenzothiazole were reacted with di- and trinitrobenzene derivatives as acidic and nonacidic acceptors in the ratio of 1:1, stable coloured charge transfer complexes (CTC's) were obtained. The structure and stoichiometry of the CTC's were studied by elemental analysis.as well as by electronic absorption and infrared and nuclear magnetic resonance spectra. The CTC's derived from nonacidic acceptors were stabilized via intermolecular π–π* and n–π* transitions while those derived from acidic acceptors were formed by intermolecular π–π* transitions and a proton transfer stabilized by resonance. The ionization potentials of the Schiff bases and the electron affinities of the nitrobenzene derivatives were calculated.

Proton Transfer in Zv-Salicylideneanilines -Effect of Charge-Transfer Interaction

1992 ◽  
Vol 216 (1) ◽  
pp. 229-234 ◽  
Author(s):  
Tamotsuinabe ◽  
Kaoru Okaniwa ◽  
Hiroshiokamoto ◽  
Tadaokimitani ◽  
Yuseimaruyama ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Proton Transfer ◽  
Charge Transfer Interaction

Fluorescence Quenching of Aminodiphenylamines with Chloromethanes

2002 ◽  
Vol 67 (8) ◽  
pp. 1154-1164 ◽  
Author(s):  
Nachiappan Radha ◽  
Meenakshisundaram Swaminathan
Keyword(s):  
Charge Transfer ◽  
Fluorescence Quenching ◽  
Ground State ◽  
Rate Constants ◽  
Quenching Mechanism ◽  
Quenching Rate ◽  
Charge Transfer Interaction ◽  
Electronically Excited ◽  
A Charge

The fluorescence quenching of 2-aminodiphenylamine (2ADPA), 4-aminodiphenylamine (4ADPA) and 4,4'-diaminodiphenylamine (DADPA) with tetrachloromethane, chloroform and dichloromethane have been studied in hexane, dioxane, acetonitrile and methanol as solvents. The quenching rate constants for the process have also been obtained by measuring the lifetimes of the fluorophores. The quenching was found to be dynamic in all cases. For 2ADPA and 4ADPA, the quenching rate constants of CCl4 and CHCl3 depend on the viscosity, whereas in the case of CH2Cl2, kq depends on polarity. The quenching rate constants for DADPA with CCl4 are viscosity-dependent but the quenching with CHCl3 and CH2Cl2 depends on the polarity of the solvents. From the results, the quenching mechanism is explained by the formation of a non-emissive complex involving a charge-transfer interaction between the electronically excited fluorophores and ground-state chloromethanes.

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