“…While the SFG responses observed from epoxides 3 and 4 between 3050 and 3020 cm −1 are weak, they are likely to indicate the presence of the single methylene group attached to the strained epoxide ring structure in these compounds: previous SFG studies have shown that as the number of carbon atoms in a cyclic hydrocarbon decreases, and the C-C single bonds become increasingly strained, the vibrational frequencies of the methylene symmetric stretches shift beyond 3000 cm −1 (Buchbinder et al, 2011). Furthermore, the IR spectra of bromocyclopropane (Diallo and Waters, 1988), cyclopropane-d 1 (Diallo and Waters, 1988), cyclopropane-1,1-d 2 (Keeports and Eggers, 1984), cyclopropane 1,1,2,2-d 4 (Keeports and Eggers, 1984), and cyclopropane (Diallo and Waters, 1988;Spiekermann et al, 1980) all show vibrational responses beyond 3000 cm −1 . Similar frequency shifts have been observed for epoxide-containing molecules, both due to the strain of the three-membered ring and the proximity to the oxygen atom (Henbest et al, 1957).…”