2017. 58, 1 – UDC 548.73:541.49:546.93 CRYSTAL STRUCTURE OF IRIDIUM (III) ACETYLACETONATE COMPLEXES BEARING AXIAL BROMIDE-SUBSTITUTED PYRIDINE Q.-W. Chang, H. Cu i, C.-X. Yan, J. Jiang, Q.-S. Ye, J. Yu , J.-L. Chen, W.-P. Liu State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum Metals, Kunming Institute of Precious Metals, Kunming, China Received July, 27, 2015 Two iridium acetylacetonate complexes bearing axial bromide-substituted pyridine (3-bromopyridine, 1 and 4-bromopyridine, 2) are synthesized and their crystal structures are determined by single crystal X-ray diffraction. <...> In both complexes, a distorted octahedral geometry of the central Ir(III) atom is formed by four oxygen atoms of two acetylacetone ligands, a carbon atom of one acetylacetone ligand, and a nitrogen atom of bromide-substituted pyridine. <...> Iridium acetylacetonate complexes with the O-bond coordination and the C-bond coordination exibit excellent catalytic activation for the anti-Markovnikov hydroarylation via well defined CH activation [ 1, 2 ]. <...> The design and synthesis of Ir(acac-O,O)2(acac-C3)(H2O) and its adducts have attracted considerable attention [ 3, 4 ]. <...> Ir(acac-O,O)2(acac-C3)(H2O) is quite stable and soluble in water. <...> It also exhibits rich coordination and reaction chemistry due to the presence of the coordinated water molecule, and therefore, is a precursor for preparing numerous other Ir(acac) motifs [ 5 ]. <...> The filtrate obtained was slowly cooled to room temperature and a yellow crystalline product appeared within a week with a 85 % (0.25 g) yield. <...> The structure was solved by direct methods and refined by full-matrix least squares techniques. <...> Non-hydrogen atoms were refined with anisotropic displacement parameters. <...> All calculations were carried out using the SHELXTL program package. <...> The structures, as determined from the single crystal X-ray diffraction studies, are shown in Fig. 1. <...> Selected bond lengths and angles are summarized in Table 1. <...> As shown in Fig. 1, in both complexes, each Ir atom adopts the octahedral coordination geometry with four O atoms of the two acac ligands in the same plane; the apical positions are coordinated by the t-C <...>