The adsorption of chromocene and ferrocene on silica: A solid-state NMR study

Adsorption of Metallocenes on Silica

“…[10,11] Using solid-stateN MR techniques, it could be provent hat the adsorbed species progressed into the support materiali nt he absence of any solvent. [10,11] Using solid-stateN MR techniques, it could be provent hat the adsorbed species progressed into the support materiali nt he absence of any solvent.…”

“…[10,11] In ar epresentative new experiment, al arge piece of silica gel was broughti nto contact with as ingle crystal of ferrocene under an inert gas atmosphere of N 2 in aS chlenk tube. Large pieces of carefully dried silica gel with pore diameters of about 25 and particle diameters of up to 0.7 cm were used, insteado ft he usual silica powder with particle sizes of only up to 0.2 mm, which was employed for all previous experiments.…”

“…[6] Early research in our group resulted in as tudy of paramagnetic chromocenes in adsorbed and polycrystalline form. [10,11] In all the cases described in the literature, [3][4][5][7][8][9][10][11] successful adsorption of as pecies is apparent through unique solid-state NMR featuresd ue to the high mobilities of the adsorbate moleculeso nt he surface. [9] Later,w es tudied various diamagnetic and paramagnetic metallocenes and demonstrated that they can be adsorbed on amorphous high-surface-area silica gel.…”

“…[10,11] In all the cases described in the literature, [3][4][5][7][8][9][10][11] successful adsorption of as pecies is apparent through unique solid-state NMR featuresd ue to the high mobilities of the adsorbate moleculeso nt he surface. [5,10,11] Several problemss till persist and some aspects of the direct adsorption of solids on solid supports have not yet been explored. [3][4][5][7][8][9][10][11] Most importantly,i th as been demonstratedb ys olid-state NMR techniques that the adsorption of phosphine oxidesa nd metallocenesc an take place in the absence of as olvent.…”

“…[9] Later,w es tudied various diamagnetic and paramagnetic metallocenes and demonstrated that they can be adsorbed on amorphous high-surface-area silica gel. [3][4][5][7][8][9][10][11] Most importantly,i th as been demonstratedb ys olid-state NMR techniques that the adsorption of phosphine oxidesa nd metallocenesc an take place in the absence of as olvent. [12][13][14][15] The anisotropic interactions dominatingthe signal shapes, dipolar and quadrupolar interactions, as well as the chemical shifta nisotropy (CSA) of the signals of the adsorbed species,a re averaged out.…”