# Need help explaining OH-peaks in IR

I have synthesized (1S, 2S)-1,2-diphenylethene-1,2-diol, and I'm wondering why the $\ce{OH}$-peaks in the IR-spectrum looks the way it does. I would expect a broad signal (because the solution wasn't diluted, and because free $\ce{OH}$-stretch happens at $\pu{3580-3700 cm^{-1}}$). So why these two separate, distinct, signals at $\pu{3394}$ and $\pu{ 3499 cm^{-1}}$?

(the IR-spectrum)

• Could you describe the preparation method (solvent? water?) and IR technique (i.e., thin film on salt plates?)? – James Gaidis Mar 13 '18 at 13:38
• Crystalline product dissolved in diethyl ether (didn't measure the amount of product dissolved). I'm not really sure what type of IR-instrument i was using, but I placed some of the solution on the instrument and let the ether evaporate, then i ran the test. – Ola Nordmann Mar 13 '18 at 17:06
• Would be see any vicinal coupling effects? Or are only geminal ones seen in IR? – Eashaan Godbole Mar 14 '18 at 17:50

Off top of my head, I would think this is due intramolecular hydrogen bonding (a 5 membered ring), giving rise to a sharp peak at $\pu{3499.14 cm^-1}$, and intermolecular bonding, giving a slightly broader peak at $\pu{3394.45 cm^-1}$. But I don't have any references, this is just a hypothesis.