DuPont ADN process

The DuPont ADN process involves hydrocyana-tion of butadiene (equations 5-8), catalyzed by air-and moisture-sensitive triarylphosphite-nickel(O) complexes [Ni(P(OAr)3)4]. The nickel is zero valent (see Oxidation Number) because it has its full complement of 10 electrons beyond the preceding inert gas (Ar) configuration, and the catalysts can actually be made directly from nickel metal and the phosphite ligands (see P-donor Ligands). The four phosphorus atoms each contribute an electron pair to give a total of 18 electrons, corresponding to the next inert gas (Kr), (see Effective Atomic Number Rule and Electronic Structure of Organometallic Compounds). 

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