Probing the coordination environment of Ti³⁺ions coordinated to nitrogen-containing Lewis bases

Abstract

Multi-frequency continuous-wave and pulsed EPR techniques are employed to investigate the coordination of nitrogen-containing ligands to Ti(3+)-chloro complexes. Frozen solutions of TiCl3 and TiCl3(Py)3 dissolved in nitrogen-containing solvents have been investigated together with the TiCl3(Py)3 solid-state complex. For these different systems, the hyperfine and nuclear quadrupole data of Ti(3+)-bound (14)N nuclei are reported and discussed in the light of DFT computations, allowing for a detailed description of the microscopic structure of these systems.

Tuning the Ti3+ and Al3+ Synergy in an Al2O3/TiClx Catalyst To Modulate the Grade of the Produced Polyethylene

“…A detailed characterization of the paramagnetic Ti 3+ (3d 1 ) sites in the two catalysts was obtained by means of combined CW and pulse EPR experiments, which allow the elucidation of fine details concerned with the electronic and geometrical structure of such species. , The CW X-band EPR spectrum of the TEA reduced catalyst is reported in Figure B (spectrum 3a) and is characterized by the typical powder pattern of Ti 3+ species in a pseudo-octahedral coordination. − Two Ti 3+ species characterized by similar g values account for 35 and 65% of the experimental signal (Table ). These g values agree with typical values reported for MgCl 2 -based Ziegler–Natta catalysts activated with alkyl aluminum compounds. , In particular, g values reaching 1.97 have been suggested to be associated with surface alkylated Ti 3+ species in supported titanium–magnesium catalysts activated by AlR 3 .…”

Photoinduced Paramagnetic Centers in Nanocomposites Formed by Titanium Dioxide and Myristic Acid

“…This spectrum shows the same broad features observed before, on each side of the intense band at 3500 G, but, in addition, a transition of small amplitude appears at around 1750 G. These two features are characteristic of triplet states originating from an S = 1 paramagnetic center. A similar spectrum has been already observed by Morra and co-workers in some Ti complexes with nitrogen ligands and interpreted as arising from the magnetic dipole–dipole coupling between Ti 3+ ions in dimeric species . Within this context, the broad components at high field (around 3500 G) and the sharper component at low field (1750 G) are ascribable to transitions with Δ M s = ±1 and ±2, respectively.…”

“…A similar spectrum has been already observed by Morra and co-workers in some Ti complexes with nitrogen ligands and interpreted as arising from the magnetic dipole−dipole coupling between Ti 3+ ions in dimeric species. 58 Within this context, the broad components at high field (around 3500 G) and the sharper component at low field (1750 G) are ascribable to transitions with ΔM s = ±1 and ±2, respectively. In the literature, this low-field transition is named the half-field transition (HFT).…”

Controllable synthesis of 2D TiH2 nanoflakes with superior catalytic activity for low-temperature hydrogen cycling of NaAlH4

“…Electron paramagnetic resonance (EPR) measurements show the g values of 1.80, 1.88 and 1.96 arising from unpaired electron of TiCl3 complex and a characteristic seven-line spectra corresponding to Cl• radical (Fig. 3c and d) [41,42]. All these observations are in good agreement with the MD simulation results.…”