Journal Name COMMUNICATION This journal is © The Royal Society of Chemistry 20xx J. Name ., 2013, 00 , 1-3 | 1 Please do not adjust margins Please do not adjust margins a. Department of Industrial Chemistry “Toso Montanari”, University of Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy. E-mail: stefano.stagni@unibo.it , valentina.fiorini5@unibo.it b. Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U 1987, Perth, Australia 6845. E-mail: m.massi@curtin.edu.au. † Electronic Supplementary Information (ESI) available: [NMR ( 1 H, 13 C) and ESI-MS spectra of all the Ir(III) based species. UV-vis absorption, emission spectra recorded at r.t., 77K and neat solid r.t.; 1931 C.I.E plots for Ir(III) soft salts]. See DOI: 10.1039/x0xx00000x Received 00th January 20xx, Accepted 00th January 20xx DOI: 10.1039/x0xx00000x www.rsc.org/ Fully Ir(III) tetrazolate soft salts: the road to white-emitting ion pairs Valentina Fiorini, a * Andrea D’Ignazio, a Karen D. M. Magee, b Mark I. Ogden, b Massimiliano Massi b * and Stefano Stagni a * The first examples of anionic Ir(III) bis-tetrazolate complexes and their combination with a cationic Ir(III)tetrazole derivative forming “fully tetrazolate” Ir(III) based soft salts as O2-sensitive white emitters are described herein. Ir(III)-based ionic transition-metal complexes (Ir-iTMC) occupy a prominent position in the scenery of phosphorescent molecules to be used in solid state lighting, luminescent chemosensing and for bioimaging applications. 1 This is a direct consequence of their belonging to the family of Ir(III) cyclometalated complexes, a class of compounds that displays a combination of outstanding photo- and electroluminescent performance, together with the ease of emission colour tunability via modification of the ligand environment. In this context, even though the family of Ir-iTMC is largely dominated by cationic species with the general formula [Ir(N^C)2(L^L)] + , where the neutral ligand (L^L) is often represented by aromatic diimines (N^N), 1,2 negatively charged Ir(III) cyclometalated complexes have also attracted increasing attention in light of their favourable properties. More specifically, the studies dealing with this class of brightly phosphorescent complexes, which is centred around the archetypal [Ir(ppy)2(CN)2] - and its fluorinated analogue [Ir(F2ppy)2(CN)2] - , 3 have led to interesting results on the use of their alkali metal salts as emissive materials for light-emitting electrochemical cells (LEECs), 4 the construction of Ir(III)-Ln(III) arrays, 5 and, in combination with other cationic Ir(III) complexes, the formation of the so called “Ir-based soft salts” 6 where further colour tuning of the emission can be achieved with the combination or modulation of energy transfer processes between the ionic components. Aiming to provide a new set Ir(III) based soft salts, in which an initial element of novelty is represented by the choice of a an anionic counterpart different than the traditionally employed Ir(III) cyanometalates, we wanted to extend the family of Ir(III) tetrazolate complexes 7 with the preparation of the first examples of their negatively charged analogues. To achieve this aim, we have modified the [Ir(ppy)2(CN)2] - or [Ir(F2ppy)2(CN)2] - core structure by replacing the cyanide groups with bulkier 5-aryl tetrazolato derivatives. The newly obtained species were found to range from sky-blue to aqua emitters. Furthermore, aiming to prepare soft salts formed by exclusively Ir(III) tetrazolate ions, the anionic species were coupled with the methylated form of a previously reported red emitter, [IrTPYZ-Me] + . 7a The results presented highlight the formation of soft salts whose emission is highly dependent on the oxygen content, suggesting a potential for the luminescence-sensing response to the presence of dissolved O2, and a unique example of white-emitting Ir(III) based soft salts. The preparation of the anionic complexes has been accomplished through a slightly modified procedure by Nazeeruddin (Scheme 1), 3 where the chloride bridged Ir(III) dimer was reacted with an excess of 5-aryl tetrazole and base. The targeted anionic complexes were confirmed by NMR Figure 1: Normalized emission profiles of [F2Ir(TphCN)2] - (left, blue trace) and [Ir(TphCN)2] - (right, red trace) CH2Cl2, r.t. .