Crystallographic studies on a series of salts of 2,3,7-trihydroxy-9-phenyl-fluorone
摘要:
2,3,7-Trihydroxy-9-phenyl-fluorone (hereafter H(3)Z) has been synthesised in its H(4)Z(+), H(3)Z, H(2)Z(-) and Z(3)-protonation states. X-ray crystal structure determinations have been carried out for (H(4)Z)(HSO4), H(3)Z, [(EtPr2NH)-Pr-i]H(2)Z, solvated (PPh4)H(2)Z and solvated K(3)Z. In each of these salts the 9-phenyl group adopts a different orientation so as to be involved in intermolecular aromatic interactions. The 3- and 6-phenolic carbon-oxygen bond lengths show that double bond character can be delocalised from the ketone to the deprotonated phenoxide across the conjugated pi system of the fluorone. (C) 2009 Elsevier B.V. All rights reserved.