bubbled through the solution were subjected to this treatment for at least 30 rain before heating, in order to displace the dissolved air. (3) Piperidine at initial pH ca. 10. A solution of potassium tetrachloropalladate(ll) (1.6 g, ca. 5 mmol) and piperidinium hydrochloride (0.18 g, 1.480 mmol) in water (400 cm 3) was brought to pH 10.1 with 4N NaOH. The mixture was heated under reflux for 30 min (the deposition of palladium appeared complete after ca. 22 min); the only outlet to the system passed through a trap containing 4N HCI. The mixture was made basic and distilled until no pyridine absorption bands were detected in the distillate. The black deposit was filtered off, washed with water and dried at 110 ° (yield 0.77 g; theoretical 0.52 g!). The distillate, whose spectrum was qualitatively correct for pyridine, was made up to a known volume and its optical density recorded at 257 nm. Using an extinction coefficient of 2750 for pyridine in water (8) gives a yield of 0.0977 mmol, i.e. 6.6%. No pyridine was detected in the solution from the HCI trap. (4) Cyclohexanone. The procedure at initial pH ca. 4, including product identification, has been reported (s) . Using more alkaline conditions (pH 11.6), the reaction between K2PdCI4 (50/amol) and cyclohexanone (110/amol, an excess) was complete in 140 min, as judged by the total deposition of palladium (0). (5) Soc., 63, 1320Soc., 63, (1941. (2) J. M. Gulland andT. F. Macrae, J. Cbem. Soc., 2231Soc., (1932. (3) G. W. Cooke and J. M. Gulland, J. Chem. Soc., 872 (1939). (4) R. 1. Rudakova, E. S. Rudakov, and A. K. Sheinkrnan, Chem.Heterocyclic Compounds, 40, 713 (1976). (5) have been prepared and their structures studied by molar conductance, i.r. and electronic spectra, and room temperature magnetic measurements. All the complexes are nonionic in a 0.001 M solution of formic acid. Magnetic and electronic spectral studies show that all the complexes are spin-free regular or distorted octahedra except Mn(ANH)CI2 and Co(ANH)CI2 which are tetrahedral. The distorted octahedral geometry of Cu(ANH-H)_~