Titanium-47 and -49 nuclear magnetic resonance spectroscopy: Chemical applications

Abstract Direct observation of 47,49 Ti resonances in a series of TiX 4 (X = Cl, Br, I, OPr i , NEt 2 ), (C 5 H 5 ) 2 TiX 2 (X = F, Cl, Br, I, N 3 , NCS), and TiX 6 2− (X = F, Br) complexes is reported. 47,49 Ti nuclei are equally sensitive to changes of halogen ligands in the (C 5 H 5 ) 2 MX 2 series as the 91 Zr nucleus. The inverse halogen dependence of δ( 47,49 Ti) is extended and placed on a more quantitative basis in the (C 5 H 5 ) 2 TiX 2 systems. The TiF 6 2− ion reveals septets for both the 47 Ti and 49 Ti resonances, with 1 J 47 Ti 19 F = 1 J 49 T 19 F = 34.0 Hz. Spin-lattice relaxation times are reported for TiCl 4 and TiF 6 2− . A detailed study of TiCl 4 reveals the dominance of a quadrupolar relaxation mechanism. Correlation times calculated from the Gierer and Wirtz relationship combined with observed T 1 results allow the quadrupole coupling constants for 47,49 Ti nuclei to be estimated as 2.8 and 2.4 MHz, respectively.