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Density functional computation of 49 Ti NMR chemical shifts
Author(s) -
Bühl Michael,
Mauschick Frank T.
Publication year - 2004
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1405
Subject(s) - chemistry , chemical shift , substituent , limiting , density functional theory , atomic orbital , computational chemistry , analytical chemistry (journal) , atomic physics , stereochemistry , electron , physics , organic chemistry , quantum mechanics , mechanical engineering , engineering
49 Ti chemical shifts of TiX 4 (X = Cl, Br, F), TiCl n Me (4− n ) ( n = 0–3), Ti(C 5 H 5 ) 2 X 2 (X = F, Cl, Br) and Ti(CO) 6 2− were computed, using geometries optimized with the gradient‐corrected BP86 density functional, at the GIAO (gauge‐including atomic orbitals)–Hartree–Fock, BPW91, and B3LYP levels. For this set of compounds, substituent effects on δ( 49 Ti) are reasonably well described with all methods considered; judged from mean absolute deviations from experiment, B3LYP performs best. Zero‐point corrections to the δ( 49 Ti) values, evaluated from a perturbational approach based on vibrationally averaged effective geometries, turn out to be fairly small. Electric field gradients computed with the B3LYP functional do not correlate with trends in 49 Ti NMR linewidths. Attempts are reported to correlate the δ( 49 Ti) values of Ti[YC(O)CHC(O)Y] 2 Cl 2 (Y = H, Me, CF 3 , CN, F, Cl and Br) with the rate‐limiting propagation barrier for ethylene polymerization using catalysts derived from these precursors. Copyright © 2004 John Wiley & Sons, Ltd.