The role of the cyclometalated moiety on the second order nonlinear optical properties of cationic Ir(III) organometallic NLO-phores

The second order nonlinear optical (NLO) response of the new complexes [Ir(bzq)2(5-R-1,10-phen)][Y] (bzq = cyclometallated benzo[h]quinoline; phen = phenanthroline, R = Me, NO2; Y = PF6, C12H25SO3) and [Ir(bzq)2(4-R,7-R-1,10-phen)][Y] (R = Me, Ph) have been investigated experimentally by the Electric Field Induced Second Harmonic generation (EFISH) technique in CH2Cl2 solution and compared with that of [Ir(ppy)2(5-R-1,10-phen)][PF6] (ppy = cyclometallated 2-phenylpyridine, R = Me, NO2) and [Ir(ppy)2(4-R,7-R-1,10-phen)][PF6] (R = Me, Ph). It appeared that substitution of ppy with the more π-delocalized bzq does not affect significantly the large second-order NLO response of this class of complexes.