If you are into the Patchoulifragrance you might be interested in the the new silicon-based compound tricyclopropyl(1-hydroxy-1-methylethyl)silane1 which you can smell at an even lower threshhold value of 0.14 nanogram per liter air than the main natural patchouli ingredient patchoulol (2, 0.93 ng/L). The novel compound was created by a group of chemists from the University of Würzburg and Philip Kraft of the flavor and fragrance company Givaudan (Sunderkötter et al. DOI) with main ingredients bromocyclopropane, tetrachlorosilane, ethyl vinyl ether and a lot of lithium (elemental, tert-butyllithium, methyllithium). The basic idea behind the molecular design is that two compounds smell alike when key molecular parts are roughly of similar shape and with similar polar and apolar spots on its van der Waals surface. Substituting carbon for silicon has two advantages: the carbon-silicon bond is longer allowing the molecule to be constructed from less atoms and at the same time silicon decreases vapor pressure.