Reactions of (Diphenylphosphinomethyl)zirconocene Chloride with B(C6F5)3: Competition between P/B and P/Zr+ Frustrated Lewis Pair Reactions

The title complex Cp2ZrCl­(CH2PPh2) reacts with B­(C6F5)3 under specific conditions by phosphinomethyl transfer to give the phosphane-stabilized salt [Cp2ZrCl+]­[Ph2PCH2B­(C6F5)3–]. X-ray crystal structure analysis showed the P–Zr coordination. This salt is trapped by phenyl isocyanate in an in situ three-component reaction to yield the respective P/Zr+ frustrated Lewis pair (FLP) addition product. In contrast, a mixture of Cp2ZrCl­(CH2PPh2)/B­(C6F5)3 and benzaldehyde under similar conditions gives the P/B FLP addition product. The Cp2ZrCl­(CH2PPh2)/B­(C6F5)3 system may form a P/B adduct [Cp2ZrCl­(CH2PPh2)·B­(C6F5)3] or a P/Zr+ adduct [Cp2ZrCl·PPh2CH2B­(C6F5)3]. From the former it seems to show P/B FLP reaction and from the latter P/Zr+ FLP behavior; the outcome is dependent on the specific reagent and reaction conditions chosen.