QUADRATIC NONLINEAR SUSCEPTIBILITY OF OCTUPOLAR CHIRAL IONS

A new molecular engineering scheme which merges chirality and intramolecular charge transfer is proposed: it is shown that a central metal atom, namely ruthenium, connected in a trigonal arrangement to identical organic ligands (2,2'-bipyridine or 1,10-phenanthroline) forms a prototypical octupolar nonlinear system. The quadratic nonlinear properties of ruthenium(II)-tris(2,2'-bipyridyl (RuTB) and ruthenium(II)-(tris-1,10-phenanthroline) (RuTP) are not amenable to electric field-induced second harmonic generation experiments, owing to the absence of net dipole moment in the ground state: incoherent second harmonic scattering is used instead and leads to resonant beta magnitudes of (210+/-60) x 10(-30) esu for RuTB and (170+/-40) X 10(-30) esu for RuTP, thus demonstrating the validity of this new scheme.