| 15732990 |
Ezhova MB, Patrick BO, Sereviratne KN, James BR, Waller FJ, Ford ME: Interactions of Rh (III)-dihydrido-bis (phosphine) complexes with semicarbazones. Inorg Chem. 2005 Mar 7;44(5):1482-91.
Interaction of cis,trans,cis-[Rh (H) 2 (PR3) 2 (acetone) 2] PF6 complexes (R = aryl or R3 = Ph2Me, Ph2Et) under H2 with E-semicarbazones gives the Rh (III)-dihydrido-bis (phosphine)-semicarbazone species cis,trans-[Rh (H) 2 (PR3) 2{R'(R' ') C=N-N (H) CONH2}] PF6, where R' and R' ' are Ph, Et, or Me. The complexes are generally characterized by elemental analysis, 31P{1H} NMR, 1H NMR, and IR spectroscopies, and MS. X-ray analysis of three PPh3 complexes reveals chelation of E-semicarbazones by the imine-N atom and the carbonyl-O atom. In contrast, the corresponding reaction of [Rh (H) 2 (PPhMe2) 2 (acetone) 2] PF6 with acetophenone semicarbazone gives the ortho-metalated-semicarbazone species cis-[RhH (PPhMe2) 2{o-C6H4 (Me) C=N-N (H) CONH2}] PF6. The X-ray structure of E-propiophenone semicarbazone is also reported. Rhodium-catalyzed, homogeneous hydrogenation of semicarbazones was not observed even at 40 atm H2. |
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