Photophysical and Complexation Behavior of (4‐Dimethylamino‐benzylidene)‐(4,6‐dimethyl‐pyrimidin‐2‐yl)‐amine

Abstract

The absorption and fluorescence characteristics of (4-dimethylamino-benzylidene)-(4,6-dimethyl-pyrimidin-2yl)-amine (SB) have been investigated in different solvents. Both the absorption and emission spectra of SB exhibit red shifts as the solvent polarity increases. This indicats a change in dipole moment of molecules upon excitation as a result of intramolecular charge transfer interaction. The fluorescence quantum yield depends strongly on the properties of the solvents, which was discussed on the bases of positive and negative solvatokinetic effects. The effect of some divalent transition metal ions such as Mn 2＋ , Co 2＋ , Ni 2＋ , Cu 2＋ , Zn 2＋ , Cd 2＋ , and Hg 2＋ on the absorption and fluorescence spectra of SB is also investigated. The results were consistent with formation of highly colored metal-SB complex which is responsible for the extreme quenching of the fluorescence of SB. The variations of both the formation constant of the complex and Stern-Volmer constant were correlated with the electronic structure of the used metal ion.

Spectrophotometric and fluorescence quenching studies of the charge transfer complexation of (4-dimethylamino-benzylidene)-(4,6-dimethyl-pyrimidin-2-yl)-amine with some organic acceptors

“…[18,19]. Tetrafluoro-1,4-benzoquinone (p-TFQ), tetrachloro-1,4-benzoquinone (p-TCQ), tetrachloro-1,2-benzoquinone (o-TCQ), tetrabromo-1,4-benzoquinone (p-TBQ), tetrabromo-1,2-benzoquinone (o-TBQ) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) were from Aldrich.…”

Swift photoswitching in a binuclear Zn(ii) metallacycle relative to a salen-type ligand

“…11,23 To understand the photodynamics of the diazo core a comparison of the photoswitching behavior of the diazo based ligands and their complexes is a must as complexation is followed by drift of electron density from the diazo core to the metal center leading to a change in dipole moment of the diazo moiety. 24 However, in most of the known complexes photoisomerization of the diazo ligands is inhibited by its chelation to the metal center through one nitrogen of the -NvNcore and the carbon/nitrogen/oxygen donor atom of the other moiety. 7,25 With an objective of developing diazo ligands capable of chelating a metal center, a new salen type ligand (H 2 L) has been designed and synthesized.…”