Nickel phosphine complexes shifts

ISOTROPIC NMR SHIFTS IN PARAMAGNETIC COBALT AND NICKEL PHOSPHINE COMPLEXES. 

P Chemical shifts of some nickel dicarbonyl di(phosphine) complex... 

Nickel(ll) complexes with chelating phosphines are effective catalysts for the oligomerization of ethylene and double bond shift isomerization of olefins, with high specificity for dimeric compounds rich in Unear isomers [221,222]. 

In early patents by Halcon, molybdenum carbonyls are claimed to be active catalysts in the presence of nickel and iodide [23]. Iridium complexes are also reported to be active in the carbonylation of olefins, in the presence of other halogen [24] or other promoting co-catalysts such as phosphines, arsines, and stibines [25]. The formation of diethyl ketone and polyketones is frequently observed. Iridium catalysts are in general less active than comparable rhodium systems. Since the water-gas shift reaction becomes dominant at higher temperatures, attempts to compensate for the lack of activity by increasing the reaction temperature have been unsuccessful. 

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