Solid-State¹¹⁵In and³¹P NMR Studies of Triarylphosphine Indium Trihalide Adducts

Abstract

Solid-state (115)In and (31)P NMR spectroscopy, relativistic density functional theory (DFT) calculations, and single-crystal X-ray diffraction were used to investigate a series of triarylphosphine indium(III) trihalide adducts, X(3)In(PR(3)) and X(3)In(PR(3))(2) (X = Cl, Br or I; PR(3) = triarylphosphine ligand). The electric field gradient tensors at indium as well as the indium and phosphorus magnetic shielding tensors and the direct and indirect (115)In-(31)P spin-spin coupling were characterized; for complexes possessing a C(3) symmetry axis, the anisotropy in the indirect spin-spin coupling, DeltaJ((115)In,(31)P), was also determined. The (115)In quadrupolar coupling constants, C(Q)((115)In), range from +/-1.25 +/- 0.10 to -166.0 +/- 2.0 MHz. For any given phosphine ligand, the indium nuclei are most shielded for X = I and least shielded for X = Cl, a trend also observed for other group-13 nuclei in M(III) complexes. This experimental trend, attributed to spin-orbit effects of the halogen ligands, is reproduced by the DFT calculations. The spans of the indium magnetic shielding tensors for these complexes, delta(11)-delta(33), range from 40 +/- 7 to 710 +/- 60 ppm; those determined for phosphorus range from 28 +/- 1.5 to 50 +/- 3 ppm. Values of (1)J((115)In,(31)P) range from 550 +/- 20 to 2500 +/- 20 Hz. For any given halide, the (1)J((115)In,(31)P) values generally increase with increasing basicity of the PR(3) ligand. Calculated values of (1)J((115)In,(31)P) and DeltaJ((115)In,(31)P) duplicate experimental trends and indicate that both the Fermi-contact and spin-dipolar Fermi-contact mechanisms make important contributions to the (1)J((115)In,(31)P) tensors.

Computational 19F NMR. 1. General features

“…It is in fact possible to predict the required molecular properties (nuclear shieldings and couplings) to an accuracy that enables one to use such predictions for structure determination. This has been demonstrated for ''routine'' nuclei such as 1 H or 13 C [15][16][17][18] as well as for unusual heteronuclei as 99 Ru, 119 Sn, 183 W, 195 Pt, or 199 Hg (to mention just those for which fairly systematic studies have been carried out) [18][19][20][21][22][23][24][25].…”

“…Given the good performance of the ZORA-DFT framework in the prediction of NMR shifts for many heavy-atom nuclei such as 183 W, [19][20][21][22][23][24][25] we reckoned that the approach could be extended to heavier atoms as well. Given the expected difficulty of this problem, we calculated the shifts with the SAOP model functional in addition to BP86 and PBE0, since SAOP was reported to provide improved 183 W shieldings at a modest computational cost [109].…”

A115In solid-state NMR study of low oxidation-state indium complexes

“…Recently, Chen et al have shown the utility of 115 In SSNMR for studying indium coordination complexes in which the indium is in the +3 oxidation state, 22,41 and Bryce and coworkers have reported 115 In ultra-wideline NMR spectra of two In(I)bis(imino)pyridine analogues. 42 Herein, we describe the first detailed 115 In SSNMR study of low oxidation-state indium Static (i.e., stationary sample) NMR spectra were acquired at both moderate and ultra-high magnetic field strengths (9.4 and 21.1 T) in order to accurately measure the EFG and CS tensor parameters.…”

Applications of nuclear shielding

“…The 115 In quadrupolar coupling constants, Cq( 115 In), range from AE 1.25 AE 0.10 to -166.0 AE 2.0 MHz. 221 A phase diagram for the antiferromagnetism and superconductivity in Ce 2 RhIn 8 probed by In-NQR studies under pressure (P) was reported. The quasi-two-dimensional character of antiferromagnetic spin fluctuations in the paramagnetic state at P = 0 evolves into a three-dimensional character because of the suppression of antiferromagnetic order for P W PQCP B 1.36 GPa (QCP: quantum critical point).…”

“…The 115 In quadrupolar coupling constants, C(Q)( 115 In), range from þ /-1.25 þ /-0.10 to -166.0 þ /-2.0 MHz. 229 2.13.5 Thallium ( 203, 205 Tl)(I = 1/2, 1/2). Slow cooling of melts composed of TlCl and BiCl 3 allows for the isolation of the compounds Tl 3 BiCl 6 (1) and TlBi 2 Cl 7 (2).…”