A novel pyrenyl-appended tricalix[4]arene for fluorescence-sensing of Al(III)

In acetonitrile, the tren-N-tricalix[4]arene 4 with three appended pyrenyl groups showed an enhanced fluorescence in the presence of Al3+ and, to a lesser extent, of In3+. Compound 4 was shown to form a 1: 1 complex with Al3+, the metal cation being located in the tren part. The association constant (K-a) of 4 for the Al3+ cation was calculated to be 8.7 x 10(3) M-1 in acetonitrile. (C) 2007 Elsevier Ltd. All rights reserved.