L. Pazderski, J. Toušek, A. Wojtczak
Sep 29, 2008
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Influential Citations
6
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Journal
Polyhedron
Abstract
Abstract The crystal and molecular structure of potassium aquapentachloroiridate(III) (K 2 [Ir(H 2 O)Cl 5 ]) was reported. The [Ir(H 2 O)Cl 5 ] 2− anions are nearly octahedral, the axial Ir–Cl bond (2.322(2) A) being shorter than the equatorial ones (2.346(2)–2.360(2) A); the Ir–O bond length is 2.090(4) A. Ir(III) chloride complexes with 2,2′-bipyridine (LL = bpy) or 1,10-phenanthroline (LL = phen), of the general formulae K[Ir(LL)Cl 4 ] and cis -[Ir(LL) 2 Cl 2 ]Cl, were studied by far-IR and 1 H– 13 C, 1 H– 15 N HMBC/HMQC/HSQC–NMR. High-frequency 1 H NMR coordination shifts ( Δ 1H coord = δ 1H complex − δ 1H ligand ; max. ca. +1 ppm) were noted for [Ir(LL)Cl 4 ] − anions, while for cis -[Ir(LL) 2 Cl 2 ] + cations they had variable sign and magnitude ( max. ca. ±1 ppm); they were dependent on the proton position, being mostly expressed for the nitrogen-adjacent hydrogens (H(6) for bpy, H(2) for phen). 13 C NMR signals were high-frequency shifted (by max. ca. 8 ppm), whereas all 15 N nuclei were shifted to the lower frequency (by ca. 105–120 ppm). The experimental 1 H, 13 C, 15 N NMR chemical shifts were reproduced by semi-empirical quantum-chemical calculations (B3LYP/LanL2DZ+6-31G ∗∗ //B3LYP/LanL2DZ+6-31G∗).