Please use this identifier to cite or link to this item: http://localhost:8080/xmlui/handle/123456789/1342
Title: 26 pi Aromatic core-modified hexaphyrins: Syntheses, characterization, and structural diversities
Authors: Misra, R
Kumar, R
Chandrashekar, T K
Joshi, B S
Keywords: Substituted expanded porphyrins
Building-block
Macrocycles
Corroles
Rubyrins
Issue Date: 2007
Publisher: American Chemical Society
Citation: Journal of Organic Chemistry 72(4):1153-1160;16 Feb 2007
Abstract: Synthesis and characterization of several 26 pi core-modified hexaphyrins are reported. The synthetic methodology involved a well-known acid-catalyzed MacDonald-type condensation reaction of the required tripyrrane with electron deficient pentafluorobenzaldehyde. The nature of the product and yield depends on the nature of the acid catalyst and its concentration. Dioxahexaphyrin 9 was isolated only when 0.5 equiv of TFA was used as a catalyst, while dithiahexaphyrin 10 and diselenahexaphyrin 11 were formed with TFA, PTSA, and even in the absence of catalyst. The detailed H-1 and 2-D COSY as well as HSQC experiments reveal the solution structure as well as the conformational mobility of hexaphyrins. In the tetracationic state, 10 and 11 exhibit a four heterocyclic ring inverted structure, while only two completely inverted heterocyclic rings were observed for 9. The other four heterocyclic rings are only partially inverted in 9. All the hexaphyrins reported here show aromatic character inferred from large Delta delta values (difference in chemical shift between the most shielded and the most deshielded protons). Electronic absorption spectral studies also support the conformational changes observed upon protonation
URI: http://ir.niist.res.in:8080/jspui/handle/123456789/1342
ISSN: 0022-3263
Appears in Collections:2007

Files in This Item:
File Description SizeFormat 
2007_00031.pdf
  Restricted Access
455.12 kBAdobe PDFView/Open Request a copy


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.