Potassium ion induced changes of crystal structure and fluorescence of a crown ether.
Luminescence properties and the x-ray structures of the fluorescent crown ether, 16-anthracen-ylmethyl-1,4,7,10,13-pentaoxa-16-aza-cyclooctadecane (CEA) and its complex with potassium hexafluorophosphate (CEAK) have been obtained. In the solid state CEAK gives a structured blue emission and CEA gives a broad structureless green emission. The differences in luminescence behavior are explained on the basis of crystal packing. X-ray analysis shows that every two adjacent anthracene moieties in CEA form a sandwich-like anti-parallel dimer; the green-structureless emission then arises from the pi-pi stack of the aromatic rings. In CEAK, disruption of the pi-pi stacking structure forces a large separation between the anthracene rings, which yields an anthracene monomer emission. Luminescence lifetime data support the assignments.
Ren
Qiu-Xian
QX
Department of Chemistry, University of Virginia, Charlottesville, VA 22904-4319, USA.
Douglass
Vincent
V
Xu
Wenying
W
Sabat
Michal
M
Periasamy
A
A
Demas
J N
JN
DeGraff
B A
BA
D043844:Crown Ethers / Q000737:chemistry*; D018360:Crystallography, X-Ray; D005453:Fluorescence; D036641:Microscopy, Fluorescence, Multiphoton; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D011188:Potassium / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
D043844:Crown Ethers; D011188:Potassium