Preparation and Nuclear Magnetic Resonance Study of Phosphorus Compounds Containing Alkenyl Functional Groups

The phosphines PPhn(CH2CH2CH=CH2)3−n, n = 2–0, PPhn(CH2CH2CH2CH=CH2)3−n, n = 1 or 2, and PPh2CH2CH = CH2 have been synthesized and studied by 1H and 31P magnetic resonance. The n.m.r. spectra of PPh2(OCH2CH=CH2), its oxide, O=PPh2(OCH2CH=CH2), and its Arbuzov rearrangement product, O=PPh2(CH2CH=CH2), have been investigated by 31P decoupling of the proton spectrum, selective proton decoupling of the 31P spectrum, and comparison with computer-simulated spectra to determine the spin–spin coupling constants. The n.m.r. spectra of the related oxides O=PPh2CH2CH2CH=CH2, O=P(CH2CH2CH=CH2)3, and O=P(OCH2CH=CH2)3 are also assigned. The data indicate that 3JPH > 2JPH for alkenylphosphines, 2JPH is larger for phosphine oxides than for phosphines, and 3JPH is little changed in comparing phosphorus(III) with phosphorus(V) compounds.