ARTICLE This journal is © The Royal Society of Chemistry 2013J. Name., 2013, 00, 1-3 | 1 to a semiconductor surface; this complex also exhibits the most favourable absorption properties among the complexes studied.

The cyclometallated iridium(III) complexes [Ir(ppy)2(N^N)][PF6] (Hppy = 2phenylpyridine) with N^N = 4'-chloro-2,2':6',2"-terpyridine (1), 4'-methoxy-2,2':6',2"terpyridine (2), 4'-ethoxy-2,2':6',2"-terpyridine (3), 4'-methylthio-2,2':6',2"-terpyridine (4), 4'-phenylthio-2,2':6',2"-terpyridine (5) and 4'-dimethylamino-2,2':6',2"-terpyridine (6) are reported including the single crystal structures of 2{[Ir(ppy)2(1)][PF6]}. 0.6Et2O. CH2Cl2, [Ir(ppy)2(5)][PF6]. 0.5CH2Cl2 and [Ir(ppy)2(6)][PF6]. The single crystal structure of [Ir(ppy)2(3)]Cl. 2H2O. MeCN is also reported. In each complex, the 2,2':6',2"-terpyridine (tpy) ligand binds to the metal centre in a bidentate fashion with the non-coordinated pyridine ring folded into the coordination sphere and engaging in a pyridine-phenyl π-stacking interaction. Solution NMR spectra are consistent with hindered rotation of the non-coordinated pyridine ring at 298 K, with intra-cation CH...N(pyridine) hydrogen bond formation between adjacent