On divorcing isomers, dissecting reactivity, and resolving mechanisms of propane CH and aryl CX (X=halogen) bond activations mediated by a ligated copper(III) oxo complex

Ligand‐Controlled CO2 Activation Mediated by Cationic Titanium Hydride Complexes, [LTiH]+ (L=Cp2, O)

“…The calculated cross sections of the CO 2 ‐adduct 4 and the insertion product 5 amount to 81.2 Å 2 and 77.8 Å 2 , respectively 9. Thus, while the difference in the cross sections seems modest (4 %), in line with earlier findings this difference is sufficient to separate isomers via TWIMS 8. 10 Consequently, ion/molecule reactions with CO 2 were carried out prior to the drift cell, allowing structural analysis of the carboxylated product via TWIMS.…”

“…In addition, to probe the possible formation of a formate complex ( 5 , Scheme ), generated according to Equation (2a), versus the presence of a mere CO 2 adduct complex ( 4 ), further experimental analysis was required, as ESI‐MS alone does not differentiate between the two isomers 4 and 5 . Thus, to acquire structural information of the complex at m/z 223 formed in the reaction of [Cp 2 TiH] + and CO 2 (Figure 1 b), travelling wave ion‐mobility spectrometry–mass spectrometry (TWIMS‐MS)8 was used to distinguish the potential isomers, that is, 4 and 5 , m/z 223. The calculated cross sections of the CO 2 ‐adduct 4 and the insertion product 5 amount to 81.2 Å 2 and 77.8 Å 2 , respectively 9.…”

“…The experiments were performed with i) a VG BIO‐Q mass spectrometer of QHQ configuration (Q: quadrupole, H: hexapole) equipped with an ESI source, as previously described in detail,18 and ii) a Synapt‐G2 travelling wave ion‐mobility spectrometer (TWIMS) time‐of‐flight (TOF) instrument (Waters, Manchester, UK) using a standard electrospray ionization (ESI) source, as also described previously 8. The species [OTiH] + and [Cp 2 TiH] + were generated from methanolic solutions of TiCl 4 and Cp 2 TiCl 2 , respectively 7.…”

“…Maximal yields of the desired complexes were achieved by adjusting the cone voltage ( U c ); U c determines the degree of collisional activation of the incident ions in the transfer from the ESI source to the mass spectrometer. The identity of the ions was confirmed i) by comparison with the expected isotope patterns and ii) by TWIMS analysis 8. Briefly, for the latter, the ion of interest was mass‐selected and reacted with CO 2 leaked into the “trap” region of the Synapt G2,8 prior to TWIMS separation.…”

Reactivity of Copper(III)–Oxo Complexes in the Gas Phase

“…[41,42] The phenanthroline ligand is oxidized during the generation of the [(phen)CuO] + complex by as elf-oxidationm echanism. This complex can be understood as the "benchmark" complex in the field, but it also has as erious pitfall.…”