Self-assembly via Intermolecular Hydrogen-bonding Between o-/m-/p-NH2 and BF2 Groups on Dipyrromethenes

Abstract

Boron difluoride dipyrromethenes bearing configurationally different amine groups on a meso-phenyl ring were prepared and crystallized. The ortho- and para-amino groups allow the phenyl group to inductively release greater electron density into the dipyrromethenes resulting in relatively strong intermolecular hydrogen-bonding with the terminal BF(2) groups, whereas the meta-analog formed weaker hydrogen-bonds. The intensities of the (1)H NMR peaks in concentrated solutions all increased with F-decoupling. (C) 2008 Elsevier Ltd. All rights reserved.