Inclusion properties of 3-fluoromesotetraphenylporphyrin with C60 and C70

To improve the selectivity ratio of C-70 over C-60, a new designer molecule, viz., 3-fluoromesotetraphenylporphyrin (1) has been reported in the present investigations. Fluoresence studies reveal that the Q-absorption band of 1 gets sufficient quenching effect upon addition of both C-60 and C-70. Binding constants (K) of the C-60/1 and C-70/1 complexes are estimated to be 580 and 10,800 dm(3) mol(-1), respectively. Thus, K-C70/K-C60 is similar to 19 which is very large and even comparable with other macrocyclic host molecules like calix[5]arene, azacalix[m]arene[n]pyridine, cyclotriveratrylenophane and calixarene bisporphyrin. H-1 NMR chemical shift measurements show that the -NH- proton of 1 suffers more shifts in presence of C-70 compared to C-60. This finding al-so offers a good support in favor of high K value for C-70/1 complex as well as large selectivity ratio of C-70 over C-60 (C) 2006 Elsevier B.V. All rights reserved.