2 9,10-ANTHRACENOCRYPTAND SILVER(I) NITRATE COMPLEXES - FLUORESCENCE MODULATED BY AG+ AS A FUNCTION OF THE GEOMETRY OF THE COMPLEX

The two anthracenocryptands 3,12-octano-3,12-diaza-6,9,31,34-tetraoxa [14](9,10)anthracenophane, C30H40N2O4 and (A(22)), and 4,13-octano-4,1 3-diaza-7,10,33,36-tetraoxa[6](9, 10)anthracenophane, C32H44N2O4 (A(33 )), were designed to direct interactions between pi-electrons and Ag+. In each complex displaying 1:1 stoichiometry, Ag+ is encapsulated in the cavity of the cryptand and coordinated to O and N atoms of the dia za-crown ether. In (A(22))/Ag+, complex (I), Ag+ lies at a Ag+-anthrac ene mean plane distance of 3.01 Angstrom. Two conformations of the sil ver complex (IIA) and (IIB) are distances in the crystal lattice of (A (33))/Ag+, with different distances (5.14 and 4.46 Angstrom) between A g+ amd the anthracene plane. The fluorescence properties of the crysta ls reflect the differences on geometry between (A(22))/Ag+ and (A(33)) /Ag+. The fluorescence spectra were recorded at room temperature with a Hitachi-Perkin-Elmer MPF44 fluorimeter corrected for emission and ex citation. The same single crystals were used both for X-ray structure determination and fluorescence emission studies. The fluorescence is c ollected in a direction at right angles to the beam of the exciting li ght.