844638-10-4Relevant articles and documents
Synthesis and luminescence spectral properties of new 2,7-dihydroxy-9H- fluoren-9-one derivatives
Kirichenko,Meshkova,Topilova,Kiriyak,Lyapunov,Kulygina,Luk'yanenko
, p. 272 - 277 (2005)
A number of new 2,7-dihydroxyfluorenone derivatives containing side-chain oligoethylene glycol fragments with terminal hydroxy, p-tolylsulfonyl, azido, and amino groups were synthesized. When the side chain has a certain length, an interaction between the
Bis(oxofluorenediyl)oxacyclophanes: Synthesis, crystal structure and complexation with paraquat in the gas phase
Lukyanenko, Nikolay G.,Kirichenko, Tatiana I.,Lyapunov, Alexander Yu,Mazepa, Alexander V.,Simonov, Yurii A.,Fonari, Marina S.,Botoshansky, Mark M.
, p. 262 - 270 (2007/10/03)
The first three representatives of the new family of oxacyclophanes incorporating two 2,7-dioxyfluorenone fragments, connected by [-CH 2CH2O-]m spacers (m=2-4), have been synthesized. The yield of the smallest oxacyclophane (m = 2) is considerably higher with respect to the larger ones (m = 3 and m = 4), which are formed in comparable yields. Molecular modeling and NMR spectra analysis of the model compounds suggest that an essential difference in oxacyclophanes yields is caused by formation of quasi-cyclic intermediates, which are preorganized for macrocyclization owing to intramolecular π-π stacking interactions between the fluorenone units. The solid-state structures of these oxacyclophanes exhibit intra- and intermolecular π-π stacking interactions that dictate their rectangular shape in the fluorenone backbone and crystal packing of the molecules with the parallel or T-shape arrangement. The crystal packing in all cases is also sustained by weak C-H...O hydrogen bonds. FAB mass spectral analysis of mixtures of the larger oxacyclophanes (m = 3 and m = 4) and a paraquat moiety revealed peaks corresponding to the loss of one and two PF 6- counterions from the 1:1 complexes formed. However, no signals were observed for complexes of the paraquat moiety with the smaller oxacyclophane (m=2). Computer molecular modeling of complexes revealed a pseudorotaxane-like incorporation of the paraquat unit, sandwiched within a macrocyclic cavity between the almost parallel-aligned fluorenone rings of the larger oxacyclophanes (m = 3 and m = 4). In contrast to this, only external complexes of the smallest oxacyclophane (m = 2) with a paraquat unit have been found in the energy window of 10 kcal mol-1.
