Roses are red, violets are blue, hey look this COSY is cool

…And Google says… Chocolates and roses for your loved ones this Valentine’s Day, what a surprise!

Hey everyone, don’t forget to bring your wallets, so you can pick up some flowers from that grocery store on your way back home from work this Valentine’s Day! Now, before you go buy those red and/or various colored roses, maybe flare those nostrils and smell around. This is just my opinion, of course, but I tend to find the aroma of roses to be one of the least pleasant of the few flowers I chose to analyze today. Before you say anything, I know roses are the epitome of a Valentine’s Day gift, but have you ever smelled lilies? Maybe spice things up a little bit this Valentine’s Day!

Anyways, as Valentine’s Day approaches, I decided to analyze the ¹H nuclear magnetic resonance (NMR) spectrum of the main aromatic component of roses, carnations, violets, lilies and chrysanthemums, which were β-damascenone, eugenol, β-ionone, linalool and α-pinene, respectively.¹ As a note, there are many chemicals that contribute to the aromatic profile of each of these flowers, however, I chose the chemicals that made up the majority of the fragrance.¹ Lastly, just as a disclaimer, if you work in a lab or around chemicals, please don’t go around smelling them randomly!

Shown in Figure 1 are the ¹H (60 MHz) NMR spectra of β-damascenone (a), eugenol (b), β-ionone (c), linalool (d) and α-pinene (e). Now, these spectra look vastly different from one another, and I could go on and on about each, but as you all know from earlier, lilies (linalool) caught my eye the most (actually, my nose, but I digress). The ¹H-¹H COSY spectrum of linalool is shown in Figure 2, with the correlations highlighted.

Figure 1. ¹H (60 MHz) NMR spectra of β-damascenone (a), eugenol (b), β-ionone (c), linalool (d) and α-pinene (e) in chloroform-d, respectively.

Figure 2. ¹H-¹H (60 MHz) COSY spectrum of linalool in chloroform-d with correlations highlighted.

Simply put, a COSY spectrum allows you to identify ¹H to ¹H through-bond correlations within a molecule. If you would like to learn a bit more about the COSY experiment, follow this link! As shown in the COSY spectrum, I highlighted some of the correlations we can observe, including: H_1a/b-H₂, H_4a/b-H_5a/b, H_5a/b-H₆ and a long-range correlation between H_4a/b-H₆.

Now that you know a little bit too much about the fragrances from each flower, I hope that you all can make an educated decision on which flowers you will buy this Valentine’s Day (lilies)! Thanks for reading and as always, if you have any questions at all, don’t hesitate to contact us!

[1] Jensen, B. A Small Guide to Nature’s Fragrances, https://www.bojensen.net/EssentialOilsEng/EssentialOils.htm (Accessed February 2022)