Discovery of five cyano derivatives of propene with the QUIJOTE line survey

We report the discovery of five cyano derivatives of propene towards TMC-1 with the QUIJOTE line survey: $trans$ and $cis$-crotononitrile ($t$-CH${}_3$CHCHCN, $c$-CH${}_3$CHCHCN), methacrylonitrile (CH${}_2$C(CH${}_3$)CN), and $gauche$ and $cis$-allyl cyanide ($g$-CH${}_2$CHCH${}_2$CN and $c$-CH${}_2$CHCH${}_2$CN). The observed transitions allowed us to derive a common rotational temperature of 7$\pm$1 K for all them. The derived column densities are N($t$-CH${}_3$CHCHCN)=(5$\pm$0.5)$\times$10${}^{10}$ cm${}^{-2}$, N($c$-CH${}_3$CHCHCN)=(1.3$\pm$0.2)$\times$10${}^{11}$ cm${}^{-2}$, N(CH${}_2$C(CH${}_3$)CN)=(1.0$\pm$0.1)$\times$10${}^{11}$ cm${}^{-2}$, N($g$-CH${}_2$CHCH${}_2$CN)=(8.0$\pm$0.8)$\times$10${}^{10}$ cm${}^{-2}$, and N($c$-CH${}_2$CHCH${}_2$CN)=(7.0$\pm$0.7)$\times$10${}^{10}$ cm${}^{-2}$, respectively. The abundance of cyano-propene relative to that of propene is thus $\sim$10${}^{-2}$, which is considerably lower than those of other cyano derivatives of abundant hydrocarbons. Upper limits are obtained for two ethynyl derivatives of propene ($E$ and $Z$-CH${}_3$CHCHCCH).