Abstract
Chemical oxidation of the series of complexes cis-M(CO2(DPM)2(M = Cr, Mo, W: DPM = bis(diphenylphosphino)methane) has been investigated. Products have been characterized by ir, NMR, ESR, electrochemistry, and conductivity. In agreement with electrochemical data, these complexes are easier to oxidize than the analogous DPE complexes (DPE = 1,2-bis- (diphenylphosphino)ethane) and both oxidation state I and oxidation state II compounds can be obtained. In oxidation state I complexes containing the low-spin paramagnetic trans-[M(CO)2(DPM)2]+ cation are formed. ESR studies of the complexes reveal that the electron density on the phosphorus atoms is considerable. Electrochemical reduction of the trans+ cation yields trans-M(CO)2(DPM)2 while oxidation occurs via the pathway [formula omitted] In oxidation state II, six-coordinate dipositive cations are unstable and these species are not isolated. Using O2/HClO4 as the oxidant, the hydride complexes trans-[MH(CO)2(DPM)2]ClO4 are formed. With chromium this represents one of the few examples of oxidation state II carbonyl complexes. The hydrides are believed to be seven-coordinate capped octahedra, although a pentagonal-bipyramidal structure cannot be excluded. Products obtained with a range of other oxidants are also discussed.
| Original language | English |
|---|---|
| Pages (from-to) | 2526-2530 |
| Number of pages | 5 |
| Journal | Inorganic Chemistry |
| Volume | 14 |
| Issue number | 10 |
| DOIs | |
| Publication status | Published - 1 Oct 1975 |
| Externally published | Yes |