Theoretical study on metal NMR chemical shifts: Titanium complexes

✍ Scribed by H. Nakatsuji; T. Nakao

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 301 KB
• Volume: 167
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(90)85471-n

✦ Synopsis

i chemical shifts for several titanium(W) compounds have been studied theoretically by an ab initio molecular orbital method. The complexes studied here arc TiF,, TiFi-, TiCI,, Tic@, TiBr, and Ti(OMc), (MC: methyl group). The calculated values of the titanium chemical shifts compare well with the experimental values. The "inverse" halogen dependence is shown. The d-contribution is predominant for the chemical shifts, because of the partly filled nature of the d-subshell of the titanium Titanium is an early transition-metal element, belonging to the IVb group. It has two magnetically active isotopes 47Ti and 49Ti, whose natural abundances are 1.3% and 5.5%, respectively. The two NMR peaks are separated by 271 ppm and the intensities are almost the same. Although titanium compounds are quite useful as catalysts in many catalytic reactions, the amount of experimental data on the "g49Ti nuclear magnetic shielding constant is very small [ 1,2 1. In this communication, we report an ab initio theoretical study on the 47*49Ti chemical shifts of the complexes, TiF,, TiF$-, TiC14, Tic@, TiBr, and Ti(OMe), (Me: methyl group).

In this series of articles [ 3-9 1, we have studied theoretically the metal chemical shifts of Ag, Cu, Cd, Zn, Mn, MO and Sn compounds, and obtained nice correlations between theory and experiment. For the