Seven useful mixed-ligand complexes in the form of [Ir(terpy)(L)Cl]2+ were prepared and their spectroscopic and electrochemical properties were investigated. The ligands used were terpy = 2,2':6',2''-terpyridine, L = 2,2'-bipyridine, 4,4'-dimethyl-2,2'-bipyridine, 4,4'-diphenyl-2,2'-bipyridine, 1,10-phenanthroline, 5-phenyl-1,10-phenanthroline, 4,7-diphenyl-1,10-phenanthroline, 2,3-bis(2-pyridyl)pyrazine. Synthetic methods were developed by a sequential ligand-replacement which occurred in the reaction vessel using a microwave oven. All complexes showed that LUMOs are based on the pi-system contribution of the terpyridine ligand for [Ir(terpy)(bpy)Cl]2+, [Ir(terpy)(dmbpy)Cl]2+, [Ir(terpy)(dpbpy)Cl]2+, [Ir(terpy)(phen)Cl]2+, [Ir(terpy)(dpphen)Cl]2+ and [Ir(terpy)(phphen)Cl]2+. On the other hand, the LUMO in the [Ir(terpy)(bppz)Cl]2+ complex is localized on the pi-system of the bppz ligand, whereas the HOMOs in the iridium complexes are localized on the terpyridine ligand. It was found that Ir(terpy)(L)Cl emits in a fluid solution at room temperature. The ancillary ligands, such as terpy and bpy, have been explored to extend the lifetime of the triplet 3(pi-pi') excited states of Ir(III) terpyridine complexes. Ir(III) terpyridine units with an electron donor (dmbpy) or electron acceptor substituents (terpy, dpbpy, phphen, dpphen and bppz) are found to decrease the energy of the 3LC states for use as photosensitizer molecular components in supramolecular devices. The spectroscopic and electrochemical details are also reported herein.

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A metal free blue emission by the protonated 2,2 0 :6 0 ,2 00 -terpyridine hexafluorophosphate Mono-protonated 2,2(:6(,2 00 -terpyridine (terpy) compound, 2,2(:6(,2 00 -terpyridinium hexafluorophosphate {[ter-pyH]PF 6 }, was prepared and characterized by electrospray ionization mass spectrometry, UV-Vis and emission spectroscopies, cyclic voltammogram (CV), and X-ray crystallography. The proton is located at the central pyridine nitrogen atom of terpy and was found in electron density difference map, which is completely different from the previously reported mono-protonated species, such as [terpyH]ReO 4 and [terpyH]CF 3 SO 3 . The H R in the latter species is located at the terminal pyridine nitrogen. A small difference of proton positions was found to give a drastic difference of crystal patterns. For [terpyH]PF 6 in CH 3 CN, a new p-p * band in the UV region and a blue emission (F ¼ 0.052 at room temperature) appeared whose maxima were red-shifted relative to those of the corresponding neutral terpy ligand. CV for the proton adduct showed the first reduction wave at around S0.6 V, being more positive than that of the neutral species. Finally, the density-functional theory (DFT) approach was used to investigate isomerization processes of the protonated terpy. EXPERIMENTAL ReagentsTerpy, potassium hexafluorophosphate (KPF 6 ), ruthenium(III) trichloride monohydrate (RuCl 3 ÁH 2 O), and tetrabutylammonium perchlorate (TBAP) were purchased from Aldrich and used without further purification. Acetonitrile (CH 3 CN) used in the spectroscopic and electrochemical measurements was of spectroscopic grade from Dojindo Laboratory. [terpyH]PF 6 was synthesized for the first time by modification of our previous procedure. [9] Synthesis of the mono-protonated compound [terpyH]PF 6[terpyH]PF 6 was obtained during the following synthesis for the Ru II -terpy complex. Terpy (0.117 g, 0.500 mmol) and RuCl 3 ÁH 2 O (www.interscience.wiley.com)

A series of new metal‐free blue emission compounds, i.e., diprotonated terpyH2ClPF6 (1), tterpyH2ClPF6 (2), ClterpyH2ClPF6 (3), and BterpyH2(PF6)2 (4), were prepared and characterized by electrospray ionization mass spectrometry, UV–vis spectroscopy, and cyclic voltammetry (CV). Abbreviations used are terpy = 2,2′:6′,2″‐terpyridine, tterpy = 4′‐(4‐tolyl)‐2,2′:6′,2″‐terpyridine, Clterpy = 4′‐chloro‐2,2′:6′,2″‐terpyridine, and Bterpy = 4,4′,4″‐tert‐butyl‐2,2′:6′,2″‐terpyridine. The X‐ray crystal structures of the three new compounds 1, 2, and 4 were determined. Both protonated pyridine rings of the terpyridine derivatives are hydrogen bonded intermolecularly to the adjacent Cl− ion in compounds 1, 2, and 3. The π–π* absorption bands in the UV region for 1, 2, 3, and 4 in acetonitrile were red‐shifted relative to those of the corresponding neutral compounds. All the compounds exhibited stronger emissions (around 400 nm) than their neutral counterparts. All the CVs for the diprotonated species, terpyH 22+, tterpyH 22+, ClterpyH 22+, and BterpyH 22+, showed the first reduction waves around −0.6 V, which were more positive than those of the neutral ones. Density functional theory was applied to interpret the remarkable differences in the interaction of the Cl− ion. The attachment of two protons to the two terminal Bterpy nitrogens in 4 elicits remarkable characteristics. Both positive charges on the nitrogens are delocalized over the conjugated pyridine systems and the tertiary carbonium ions are stabilized to lead to stronger emission (Φ = 0.35) than the corresponding neutral Bterpy (Φ = 0.045). CCDC 732045–732047 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from the Cambridge Crystallographic Data Centre via http://www.ccdc.cam.ac.uk/data_request/cif Copyright © 2010 John Wiley & Sons, Ltd.

Three new polypyridine iridium(III) complexes [Ir III Cl(L)-(tterpy)](PF 6 ) 2 {L = phen (1), dpphen (2), and dmbpy (3) (5) and terpy (6)} were also prepared. Abbreviations of the ligands used here are phen = 1,10-phenanthroline, dpphen = 4,7-diphenyl-1,10-phenanthroline, bpy = 2,2Ј-bipyridine, dmbpy = 4,4Ј-dimethyl-2,2Ј-bipyridine, tterpy = 4Ј-(4-tolyl)-2,2Ј:6Ј,2ЈЈ-terpyridine, and terpy = 2,2Ј:6Ј,2ЈЈ-terpyridine. The syntheses, which were accomplished in typical reaction times of fifteen minutes by using a microwave oven, were easier than a previous method. The complexes were characterized by electrospray mass spectrometry, UV/Vis spectroscopy, and cyclic voltammetry (CV). The X-ray structures of the two complexes 5 and 6 were also obtained. Cyclic voltammograms of all the [Ir III Cl(L)(tterpy)] 2+ complexes showed that the first reduction occurred at around -0.67 V, which is attributed to the re-