Table 1.

Calculated HSAB and experimental parameters for conjugated type-2 alkenes and ­nonconjugated analogs.

Type-2 alkene	σ (× 10–3/eV)a	ω (eV)	log k2b	Uptake (log IC50)c
Acrolein	379	3.57	2.596	–4.28
NEM	406	4.73	6.536	–4.33
MVK	382	3.18	2.048	–3.48
HNE	393	3.78	0.938	–3.40
Crotonaldehyde	385	3.38	ND	ND
MA	315	2.76	–1.893	–0.34
ACR	346	2.62	–1.804	–0.36
EMA	322	2.68	ND	ND
Nonconjugatedd
Propanal	323	2.26	—	—
Allyl alcohol	276	1.63	—	—
Abbreviations: EMA, ethyl methacrylate; MA, methyl acrylate; MVK, methylvinyl ketone; ND, not determined. aFor each compound, respective lowest and highest occupied molecular orbital energies (ELUMO and EHOMO, respectively) were obtained from ground state equilibrium geometries with density functional theory calculations DFT B3LYP-6-31G* in vacuum from 6-31G* initial geometries and were used to calculate softness (σ) and the electrophilic index (ω) as described by LoPachin et al. (2012). bSecond-order reaction rates (k2) were determined for type-2 alkene reactions with l-cysteine at pH 7.4. cInhibition of synaptosomal membrane tritiated dopamine [(3H)-DA] uptake was determined in striatal synaptosomes exposed to type-2 alkenes (LoPachin et al. 2007a, 2007b). dDo not undergo the Michael reaction.