Research paper Iridium (III) 1,3-bis(aryl)triazenide complexes: Synthesis, characterization and structure M. Fernanda Ibarra-Vázquez a , Sara A. Cortes-Llamas a , A. Aarón Peregrina-Lucano a , José G. Alvarado-Rodríguez c , Ricardo Manríquez-González b , Fernando A. López-Dellamary b , Martha I. Moreno-Brambila a , I. Idalia Rangel-Salas a,⇑ a Universidad de Guadalajara, Centro Universitario de Ciencias Exactas e Ingenierías, Departamento de Química y Departamento de Farmacobiología, Blvd. Marcelino García Barragán 1421, esq. Calzada Olímpica, C.P. 44430 Guadalajara, Jalisco, Mexico b Departamento de Madera, Celulosa y Papel, km. 15.5 Carretera Guadalajara-Nogales, C.P. 45220 Zapopan, Jalisco, Mexico c Universidad Autónoma del Estado de Hidalgo, Unidad Universitaria, km 4.5 Carretera Pachuca-Tulancingo, C.P. 42184, Mineral de la Reforma, Hidalgo, Mexico article info Article history: Received 18 April 2016 Received in revised form 8 July 2016 Accepted 15 July 2016 Available online 18 July 2016 Keywords: Triazenide ligands Iridium complexes Bis(aryl)triazenes abstract Iridium (III) 1,3-bis(aryl)triazenide complexes [Cp / IrCl(ArNNNAr 0 )] (Cp / =C 5 Me 5 , Ar = Ar 0 =C 6 H 5 , 1; Ar = Ar 0 = o-CF 3 -C 6 H 4 , 2; Ar = Ar 0 = o-HOCH 2 -C 6 H 4 , 3; Ar = o-HOCH 2 -C 6 H 4 , Ar 0 = p-CH 3 -C 6 H 4 , 4) have been obtained by reaction of iridium dimer [Cp / IrCl 2 ] 2 with the corresponding triazenes in the presence of NEt 3 in CH 3 CN. The iridium complexes 1–4 were characterized by IR, ESI-MS and NMR spectroscopy. In all of the complexes, the triazenes are coordinated to iridium (III) as monoanionic bidentate N,N 0 -donor ligands. Compounds 1–4 are the first examples studied by single crystal X-ray diffraction of mononuclear bis(aryl)triazenide iridium complexes, where the N-N-N fragment effectively chelates the Ir (III) central atom. Ó 2016 Elsevier B.V. All rights reserved. 1. Introduction Triazene compounds have a variety of significant applications; e.g., as anticancer agents [1–3], as protecting groups in natural pro- duct synthesis [4] and combinatorial chemistry [5] as well as start- ing materials in polymer [6] and heterocycles synthesis [7], among others [8,9]. From a structural view, the chemistry of 1,3-bis(aryl)triazenes has received considerable attention because of their structural diversity based on monodentate [10,11], chelating [10,12,13] and bridging coordination modes [8,14,15]. In addition, triazene moiety normally acts as a monoanionic bidentate N,N-donor ligand, via dissociation of the acidic N-H proton. Triazenides are ‘‘short-bite” ligands that coordinate to a metal center to form a four-membered chelate ring [10,12,13]. Well characterized examples of triazenide complexes, coordinated via the above mentioned binding modes are known for s-block [12,16–18], group 13 [19–21] and transition metals [13–15,22]. A number of coordination studies on complexes of these ligands with rhodium and iridium in different oxidation states have been reported. For example, homoleptic mononuclear compounds [M (ArNNNAr) 3 ], in which the three ligands coordinate as N,N 0 -chelate has been described for Rh (III) and Ir (III) by means of vibrational and NMR spectroscopy as well as magnetic measurements [13]. However, most of the chemistry reported with these ligands con- cerned homo- or heterodinuclear complexes of Rh (I) and Ir (I) [14,23–25]. In contrast, mononuclear complexes containing Cp / as auxiliary ligand [26], as well as the application of complexes in transfer hydrogenation catalysis have been rarely studied. Only a few reports of triazenide complexes used in catalysis have been published. For example Fe, Cu and Zr complexes, as well as the polymer supported triazenes were screened for the addition of Et 2 Zn to benzaldehyde [27]. A supported Pd triazene complex was screened for activity in Suzuki and Sonogashira reactions, whereas a supported Ru triazene complex was screened for trans- fer hydrogenation [27]. Manganese complexes containing tri- azenide ligands were encapsulated in NaY zeolite and evaluated for styrene and cyclohexanol oxidation reactions [28]. A copper (I) triazenide complex was evaluated as a molecular electrocata- lyst, for hydrogen evolution from both acetic acid and water [29]. Calcium and strontium derivatives were shown to be catalytically active for the intramolecular hydroamination of 1-amino-2,2- http://dx.doi.org/10.1016/j.ica.2016.07.025 0020-1693/Ó 2016 Elsevier B.V. All rights reserved. ⇑ Corresponding author at: Universidad de Guadalajara, Centro Universitario de Ciencias Exactas e Ingenierías, Departamento de Química y Departamento de Farmacobiología, Blvd. Marcelino García Barragán 1421, esq. Calzada Olímpica, C.P. 44430 Guadalajara, Jalisco, Mexico. E-mail address: iirangel@yahoo.com.mx (I.I. Rangel-Salas). Inorganica Chimica Acta 451 (2016) 209–215 Contents lists available at ScienceDirect Inorganica Chimica Acta journal homepage: www.elsevier.com/locate/ica