ansa-Metallocene derivatives: XV. Reversible coordination of a second CO ligand to (C5H5)2Cr(CO) and its tetramethylethanediyl-bridged analogue. Evidence for an electron-transfer catalysed ring-slippage reaction. IR studies at elevated gas pressure. II

摘要: Abstract IR spectral data reveal that the 18-electron species (C 5 H ) 2 Cr(CO) is reversibly transformed, at elevated CO pressures into a dicarbonyl complex, . Close coincidence of v (CO) absorption bands this with those (η 3 -C )(η )W(CO) and η 7 )Cr(CO) indicates it contains an -bound ring ligand. Equlibrium kinetic have been obtained for CO-induced ring-slippage reaction analogous involving tetramethylethanediyl-bridged ansa -chromocene carbonyl complex (CH 4 C -(C Cr(CO). The transformation to greatly accelerated by small amounts oxidants, i.e. formation cationic + , which appears facilitate slippage electron-transfer catalysis.