AN ETA(1)-ALDEHYDE COMPLEX AND THE ROLE OF HYDROGEN-BONDING IN ITS CONVERSION TO AN ETA(1)-IMINE COMPLEX

2-Pyridinecarboxaldehyde displaces Me(2)CO from [IrHz(Me(2)CO)(2)(PPh( 3))(2)](+) to give a chelating N,O-bound product containing an eta(1)- O-bound aldehyde group. This is converted to the eta(1)-N-bound imine complex with a variety of substituted amines. When the amine contains a suitably positioned -OH group, intramolecular O-H ... H-Ir dihydroge n bonds are detected in the products. This hydrogen bonding influences the relative rates of product formation from 2- and 4-aminophenol (ra te ratio 6:1), where only the 2-isomer is capable of forming an intram olecular H-bond.