The reaction of CH3C(CH2PPh2)3 (triphos) with [Re(O)Cl3(PPh3)2] in THF at reflux temperature yields [(η2-triphos) Re(O)Cl3] (3). Compound 3 is transformed into [(η2-triphos)ReH7] (4) by treatment with LiAlH4 in refluxing THF. The reaction of [Re(MeCN)Cl3(PPh3)2] with triphos in refluxing toluene gives fac-[(η3-triphos)ReCl3] (5) in excellent yield. Complex 5 is converted to the classical pentahydride [(η3-triphos)ReH5] (6) by treatment with NaBH4 at room temperature. The reductive elimination of H2 from 6 is promoted by monodentate ligands such as PPh3 and CO, giving substitution products of the formula [(η3-triphos)ReH3(L)] (L = PPh3 (7) or CO (8)). All the rhenium polyhydrides obtained have been characterized by spectroscopic techniques including IR and multinuclear variable-temperature NMR analysis. A detailed study of the spin-lattice relaxation time (T1) at variable temperature has shown that T1 cannot be used unambiguously to discriminate between classical and non-classical structures of rhenium polyhydrides. © 1993.
SYNTHESIS AND CHARACTERIZATION OF RHENIUM POLYHYDRIDES STABILIZED BY THE TRIPODAL LIGAND MEC(CH2PPH2)3
MAGON, Luciano;MARVELLI, Lorenza;ROSSI, Roberto
1993
Abstract
The reaction of CH3C(CH2PPh2)3 (triphos) with [Re(O)Cl3(PPh3)2] in THF at reflux temperature yields [(η2-triphos) Re(O)Cl3] (3). Compound 3 is transformed into [(η2-triphos)ReH7] (4) by treatment with LiAlH4 in refluxing THF. The reaction of [Re(MeCN)Cl3(PPh3)2] with triphos in refluxing toluene gives fac-[(η3-triphos)ReCl3] (5) in excellent yield. Complex 5 is converted to the classical pentahydride [(η3-triphos)ReH5] (6) by treatment with NaBH4 at room temperature. The reductive elimination of H2 from 6 is promoted by monodentate ligands such as PPh3 and CO, giving substitution products of the formula [(η3-triphos)ReH3(L)] (L = PPh3 (7) or CO (8)). All the rhenium polyhydrides obtained have been characterized by spectroscopic techniques including IR and multinuclear variable-temperature NMR analysis. A detailed study of the spin-lattice relaxation time (T1) at variable temperature has shown that T1 cannot be used unambiguously to discriminate between classical and non-classical structures of rhenium polyhydrides. © 1993.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
