Oxide-Supported Titanium Catalysts: Structure–Activity Relationship in Heterogeneous Catalysis, with the Choice of Support as a Key Step

Abstract

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Selective Catalytic Reduction of CO2 to CO by a Single-Site Heterobimetallic Iron–Potassium Complex Supported on Alumina

“…The DRIFT spectrum reveals that the surface OH groups of alumina (v­(O–H); 3795–3660 cm –1 ) were partially consumed by the grafting reaction (Figure ). Less reactive OH groups remain, as has been observed in the grafting of other metal complexes . Simultaneously, bands corresponding to the organic ligands appeared at 3000–2800 cm –1 (ν­(C–H)); 1466 and 1455 cm –1 (δ­(CH x )) and at 1380 and 1356 cm –1 (δ­(CH 3 )).…”

“…Less reactive OH groups remain, as has been observed in the grafting of other metal complexes. 50 Simultaneously, bands corresponding to the organic ligands appeared at 3000−2800 cm −1 (ν(C−H)); 1466 and 1455 cm −1 (δ(CH x )) and at 1380 and 1356 cm −1 (δ(CH 3 )).…”

A strategy for high ethylene polymerization performance using titanium single-site catalysts

“…The 1 H NMR (Fig. S10, ESI†) spectrum exhibited a significant broad signal at 0.90 ppm arising from protons of the neopentyl ligand: the methyl [Ti–CH 2 C(C H 3 ) 3 ] fragments of the neopentyl ligand and the methylene protons [Ti–C H 2 C(CH 3 ) 3 ], 17,18 and from the proton of the methyl and methylene proton of [Si–C H 2 CH(CH 3 ) 2 ] fragments remaining on the support. The shoulder peak appearing at 2.13 ppm is assigned to the [Si–CH 2 CH(C H 3 ) 2 ].…”

“…The catalyst 3 [(RSi-O-) 2 (Al-O-)TiNp 3 ] was then analyzed by multinuclear solid-state NMR to provide detailed information on the structure of the grafted Ti molecular complex. The 17,18 and from the proton of the methyl and methylene proton of [RSi-CH 2 CH(CH 3 ) 2 ] fragments remaining on the support. The shoulder peak appearing at 2.13 ppm is assigned to the [RSi-CH 2 CH(CH 3 ) 2 ].…”

“…However, the peak at 132.3 ppm is assumed to correspond to the [Ti-CH 2 CMe 3 ] fragment with other surroundings and more probably close to [-Al-O], which leads to a shift of the signal. 18 Moreover, complex 3 was further investigated by 27 Al-NMR, which is considered a powerful tool for the coordinative states of surface aluminum species. Fig.…”