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Structural Studies and Catalytic Activity of MCM‐41 and MCM‐48 Modified With the Titanocenophane [SiMe 2 (η 5 ‐C 5 H 4 ) 2 ]TiCl 2
Author(s) -
Ferreira Paula,
Gonçalves Isabel S.,
Kühn Fritz E.,
Pillinger Martyn,
Rocha João,
Santos Ana M.,
Thursfield Alan
Publication year - 2000
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/(sici)1099-0682(200003)2000:3<551::aid-ejic551>3.0.co;2-e
Subject(s) - chemistry , cyclooctene , dichloromethane , catalysis , tetrahydrofuran , titanium , mesoporous material , magic angle spinning , solvent , adsorption , nuclear magnetic resonance spectroscopy , organic chemistry , inorganic chemistry
Titanium(IV)‐grafted mesoporous silicas have been prepared by diffusion of an excess of the ansa ‐bridged titanocene [SiMe 2 (η 5 ‐C 5 H 4 ) 2 ]TiCl 2 into the channels of hexagonal MCM‐41 and cubic MCM‐48 in dichloromethane or tetrahydrofuran at room temperature. The choice of solvent determines the course of the reaction and hence the activity of the resulting materials as catalysts in the catalytic epoxidation of cyclooctene with tert ‐butylhydroperoxide. Magic‐angle spinning (MAS) NMR ( 13 C, 29 Si) spectroscopy was used to characterise the local environment of the surface‐bound titanium active sites. When dichloromethane is used, the dominant species anchored to the surface are isolated ansa ‐bridged titanocene fragments. When THF is used, the [SiMe 2 (η 5 ‐C 5 H 4 ) 2 ] unit is lost with the concomitant formation of surface‐bound Ti IV species coordinated by THF molecules. These materials showed the best catalytic performance per Ti atom for the conversion of cyclooctene. All materials were further characterised by means of elemental analysis, powder X‐ray diffraction (XRD), N 2 adsorption and FTIR spectroscopy.