Nickel Nitrosyl Iodide

The nickel complex, [Ni(NO)I], can also be prepared by the procedures outlined above. The compound is formed readily in reasonable yields, but it is significantly less stable than the iron and cobalt compounds. Moreover, although some of it can be sublimed, it decomposes slowly even below its sublimation temperature. The gram quantities used are the same as for cobalt, and no modification of the procedure is necessary until the sublimation step. No sublimation of the nickel complex takes place until the bath temperature reaches 155-165°C. At this temperature a small amount (2.5 g.) of product sublimes onto the cold probe. Anal. Calcd. for Ni(NO)I Ni, 27.22 I, 58.86. Found Ni, 26.8 I, 56.5. 

The iron compound readily sublimes and yields well-formed, black lustrous crystals. The cobalt complex will also readily sublime, but dependent upon the temperature at which the crystals are formed, they can be either black or brown in color. The crystal structures of both the cobalt and iron complexes have been determined.3 The nickel complex sublimes only in small amounts with difficulty. All three complexes are unstable to air and water, and the nickel complex readily undergoes thermal decomposition above 100°C. All three compounds will also readily form complexes with a variety of donor ligands such as tertiary arsines or phosphines. The nickel compound usually forms 2 1 adducts such as [(C6HS )3P]2Ni(NO)I, while the iron and cobalt complexes often undergo disproportionation.5 

Submitted by P. B. CHOCK, J. HALPERN, and F. E. PAULIK Checked by SAUL I. SHUPACKf and THOMAS P. DeANGELISf 

The original method1 of preparation of Zeise s salt, K[Pt(C2 H4 )C13 ]-H20, and subsequent modifications thereof2-4 all require either prolonged reaction times (7-14 days) or the use of high pressures. Furthermore, these procedures tend to yield products contaminated with potassium chloride and unreacted potassium tetrachloroplatinate(II). The improved procedure described below, which utilizes tin(II) chloride to catalyze the reaction between ethylene and the tetrachloroplatinate(II),5,6 results in the formation of Zeise s salt of high purity and in high yield within a few hours at atmospheric pressure. 

To 45 ml. of 5 M aqueous hydrochloric acid in a 125-ml. Erlenmeyer flask is added 4.5 g. of potassium tetrachloro-platinate(II) (0.00108 mole). The flask is sealed with a rubber, serum cap and deoxygenated immediately by flushing for 30 minutes with nitrogen or ethylene through a polyethylene tube extending into the solution and attached to a needle inlet, with another needle as gas outlet. (Some undissolved potassium tetrachloroplatinate(II) may remain at this stage.) Forty milli- 

---