No abstract

Grafting Ti(=NtBu)(Me Pyr) (py) (Me Pyr= 2,5-dimethylpyrrolyl, py=pyridine) onto the surface of silica partially dehydroxylated at 700 °C gives the well-defined silica-supported Ti imido complex (≡SiO)Ti(=NtBu)(Me Pyr)(py) , which is fully characterized by IR and solid-state NMR spectroscopy as well as elemental and mass balance analyses. While stoichiometric imido-transfer reactivity is typical for Ti imides, the obtained surface complex is unique in that it enables catalytic transformations involving Ti imido and oxo intermediates. In particular, it efficiently catalyzes imidation of carbonyl compounds with N-sulfinylamines by oxo/imido heterometathesis.

We expand the series of well-defined silica-supported titanium imido complexes of general formula (SiO)­Ti­(NtBu)­X­(py) n prepared via surface organometallic chemistry in order to analyze the effect of the X ligand on their catalytic properties. Two new surface complexes, (SiO)­Ti­(NtBu)­Cl­(py)2 (2s) and (SiO)­Ti­(NtBu)­Cp­(py) (3s), have been prepared and characterized with physicochemical techniques, and their performance in oxo/imido heterometathesis and other catalytic imido-transfer reactions has been studied and compared to that of the previously reported catalyst (SiO)­Ti­(NtBu)­(Me2Pyr)­(py)2 (1s; Me2Pyr = 2,5-dimethylpyrrolyl).