Understanding the color change of the solutions of Cp₂TiCl upon addition of water

Abstract

Reduction of red bis (cyclopentadienyl)titanium (IV) dichloride (Cp 2 TiCl 2 ) with manganese dust in dry THF produces a green solution that turns deep blue upon the addition of traces of water. Mass spectrometric analysis and DFT calculations have been performed to achieve a better understanding of the species that may be present after the interaction of water with reduced Cp 2 TiCl 2 . The deep blue solution provides a handy visual indicator for the qualitative determination of water in THF.

Cp2TiCl/H2O as a Sustainable System for the Reduction of Organic Functional Groups: Potential Application of Cp2TiCl/D2O to the Analysis of Bioactive Phenols in Olive Oil

“…In tetrahydrofuran (THF) or toluene, the Cp 2 TiCl solution is lime green. However, it turns dark blue when water is added to the solution [24,25].…”

“…Initially, aqua complex 5 was proposed as a HAT reagent (pathway A, Scheme 5) [17]. However, after extending and refining the theoretical calculations, studies of cyclic voltammetry, mass spectrometric analysis, and electro-paramagnetic resonance techniques suggested that aqua complex 6 is the active HAT reagent (pathway B, Scheme 5) [25,28]. Water as a HAT reagent was rigorously demonstrated in the transannular cyclization of caryophyllene oxide 7 (Scheme 6) [24].…”

“…The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/pr11040979/s1, Figure S1: Experimental procedures for reference [25]; Figure S2…”