Experimental evidence for ethylidene-d4

Article abstract of DOI:10.1021/ja00055a016

Laser flash photolysis (LFP, 351 nm, XeF excimer) of 3-methyldiazirine in the presence and absence of pyridine fails to produce a UV-vis active transient intermediate. However, LFP of 3-methyldiazirine-d₄ in pentane containing pyridine produces a transient absorption attributed to the ethylidene-d₄-pyridine ylide. A double-reciprocal plot of the optical yield of ylide (A_y^-1) versus (pyridine concentration)^-1 is linear and indicates that the lifetime of ethylidene-d₄ is 500 ps in pentane, assuming that the second-order rate constant of reaction of ethylidene-d₄ with pyridine is 1 × 10⁹ M^-1 s^-1. Laser induced fluorescence spectra of methyldiazirine and methyldiazirine-d₄ are reported and discussed.