Catalytic thermal C-H activation with manganese complexes: Evidence for {eta}-H{sub 2} coordination in a neutral manganese complex and its role in C-H activation
- Univ. of Rochester, NY (United States)
The reactivity of MnH{sub 3}(dmpe){sub 2} has been examined for its ability to activate C-H bonds. The complex loses H{sub 2} readily and is characterized as having an {eta}{sup 2}-H{sub 2} ligand on the basis of NMR spectroscopic and electrochemical studies. Reaction MnH{sub 3}(dmpe){sub 2} with added ligands gives MnH(L)(dmpe){sub 2} (L = CO, N{sub 2}, C{sub 2}H{sub 4}, CNR; R = t-Bu, CH{sub 2}CMe{sub 3}, 2,6-xylyl). The complex activates aromatic and benzylic C-H bonds under both thermal and photochemical conditions as determined by catalytic H/D exchange with C{sub 6}D{sub 6} or D{sub 2}. Selectivity studies were also carried out by employing catalytic H/D exchange. A mechanism is proposed, and the neighboring group participation effect is discussed for explaining C-H activation selectivity. The complex MnH(CN-2,6-xylyl)(dmpe){sub 2} crystallizes in orthorhombic space group Cmcm, with {alpha} = 12.129 MnH(N{sub 2})(dmpe){sub 2} crystallizes in orthorhombic space group Pna2, with {alpha} = 17.648 (4) A, b = 9.191 (3) A, c = 12.303 (2) A, and Z = 4. The analogous hydride MnH{sub 3}(depe){sub 2} shows two distinct types of hydrogen ligands at low temperature, the larger of which has an extremely short T{sub 1}. 26 refs., 7 figs., 9 tabs.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FG02-86ER13569
- OSTI ID:
- 412001
- Journal Information:
- Organometallics, Vol. 11, Issue 11; Other Information: PBD: Nov 1992
- Country of Publication:
- United States
- Language:
- English
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