Cyanophosphine derivatives: Nitrile or cyanide functionality?

Article abstract of DOI:10.1021/om000704h

Treatment of dicyanophosphines R-P(CN)₂ with 1 equiv of Schwartz's reagent, [Cp₂Zr(H)Cl]_n, led: (i) via a substitution reaction to the formation of the stable hydrocyanophosphines R-P(H)CN (R = Me, ^tBu, Mes*) or (ii) through a hydrozirconation reaction to the synthesis of the aldiminocyanophosphine R-P(CH double bond NZrCp₂Cl)CN (R = NⁱPr₂). Further addition of 1 equiv of [Cp₂Zr(H)Cl]_n to R-P(H)CN (R = Me, ^tBu, Mes*) gave the primary phosphine R-PH₂ (R = Me) or the aldimino secondary phosphine R-P(H)(CH double bond NZrCp₂Cl) (R = ^tBu, Mes*) after the hydrozirconation reaction. Interestingly, the dialdiminophosphorus compound R-P(CH double bond NZrCp₂Cl)₂ (R = NⁱPr₂) was obtained after addition of [Cp₂Zr(H)Cl]_n to R-P(CH double bond NZrCp₂Cl)CN (R = NⁱPr₂). The difference in reactivity observed for the dicyanophosphines R-P(CN)₂ with the metal hydride [Cp₂Zr(H)Cl]_n have been studied with the help of experimental analysis (UV-photoelectron spectroscopy, NMR, IR, X-ray) and computational methods.