Synthesis, X‐ray structure, spectroscopic and cation complexation studies of macrocyclic ligands incorporating the 9,9′‐(ethane‐1,2‐diyl)bis(anthracene) photoactive subunit

Abstract

Abstract. Two 9,9'-(ethane-1,2-diyI)bis(anthracene) ligands, incorporating an ethano bridge, namely the bis-anthracene coronand 1 and the bis-anthracene cryptand 2, respectively, have been studied in parallel to compare their binding abilities, spectroscopic and photochemical properties in the presence and absence of cations as a function of their X-ray structure. The ethano bridge imposes a twisted shape (torsion angles between the vicinal C-H being 47" for 1 and 62" for 2a and 47" for 2b, the two conformers of compound 2), which inhibits the cation-binding ability of 1 and attenuates that of cryptand 2 (log K , = 1.8 for Naf or K f , = 4 for T1+ and = 8 for Ag'); in CH,OH, both 1 and 2 emit essentially excimer-type fluorescence at A, , 520-535 nm, which is red-shifted compared with that of the single crystals ( = 465-480 nm) where the rotation about the CH,-CH, bond is hindered. The presence of cations, which has no influence on the photocycloisomerization quantum yield of 1 (as expected), clearly affects that of 2. Cryptand 2 was shown to display photochromic properties.

Signaling Recognition Events with Fluorescent Sensors and Switches

“…The macromonocyclic relative 223 661 has no discernible excimer band but shows strong PET-type quenching of the monomer fluorescence with guests like ATP (section VIII.B). Bouas-Laurent and Desvergne have also reported bifluorophoric systems related to 110 and to 221 which showed weaker response to alkali cations …”

“…Compound 110 also binds Ag(I) because of cation−π interactions due to the anthracene lining the cryptand cavity, but no fluorescence is seen (see section VIII.C). A bifluorophoric version of 110 shows some similarities and also some interesting variations (see section IX) .…”

“…Fluorescence “on−off” switching of anthracene moieties in 119 , 110 , ,, and 185 , is seen upon binding Hg(II), Ag(I), and Cu(II) or Ni(II), respectively. The multiprotonated form of 119 must be employed for this “on−off” switching to be observed .…”

Photodimerization of anthracenes in fluid solution: structural aspects

“…1 Special features are the non symmetrical photocyclomerisation of the decaoxa(13,13)anthracenophane (Desvergne et al, 1992) 1 and the photocycloaddition of anthophorene (Scheme 12) into a regular cryptand. 24…”

“…1a illustrates the gradual disappearance of the 300-400 nm absorption band of an anthracene derivative and the growing of the 9,10+9A,10A classical photocyclomer during irradiation in the 300-400 nm range . 24 Typical UV spectra are represented in Fig. 1b: the most frequent absorption found (curve i) is characteristic of the classical 9,10: 9A,10A closure whereas curve (ii) indicates a naphthalene type absorption for 9,10+1A,4A photocycloaddition (Castellan et al, 1979); 1 in a distinct way 9,10+1A,2A cycloaddition produces spectra type (iii) due to the presence of a vinyl-substituted naphthalene (Daney et al, 1985).…”