"How do you use Chem Draw to show the 3 dimensional nature of "
How do you use Chem Draw to show the 3 dimensional nature of molecules? For example the interaction of ethanol (CH3CH2OH) and benzoic acid (C6H5COOH): First, you need to take into account why you are being asked to draw the molecule(s) in 3 dimensions. For the ethanol/benzoic acid you wish to show the intermolecular attraction between the two molecules… the hydrogen bonding. I can think of three possible interactions: H OCH2CH3 O A C O H O C C O H O H OCH2CH3 B C O H H OCH2CH3 Which one is it? It might be one that dominates, might be all three. You could draw it in Spartan, but you would have to do the calculation a few times with the molecules arranged a few different ways to see if one type of hydrogen bonding predominates. Just go with the first calculation. (This point is sort of insignificant when you’re in gchem). Anyways, my major point was to talk about how to get the above “Lewis Structure” drawings into three dimensions. A great aid to this is to build the molecule(s) in Spartan. However, what you will see in Spartan is significantly more complicated than what you should try to draw in ChemDraw. When making drawings with ChemDraw you want to keep the most complex part of the molecules and the longest chains of the molecule in the plane of the paper (Do you want to try to draw benzene by looking the side of the hexagon and having carbons and hydrogens directly behind the first bond you draw? ). You don’t want to draw benzoic acid that looks like this: It is much easier to draw this: Take a look at the Spartan image of benzoic acid and ethanol: You’ll notice that I’ve rotated the images so that the benzene ring flat. This has the unfortunate effect of making the H‐ C‐C‐O‐H backbone of the ethanol come up and out of the plane toward you. Don’t try to draw it this way. You want that the benzene ring and the backbone of the ethanol in the plane of the page. So I’ve rotated the Spartan image: Think of it this way – if the molecular geometry around each atom center will allow you to lay all of the bonds flat – do so. So, in good conscience the entire benzoic acid molecule should be flat. If you were to draw it any other way the wedges and dashes would become too confusing. Also, the H‐C‐C‐O‐H backbone of the ethanol should also stay in the plane (leaving only the 4 hydrogens (2 on each carbon) to be either in front of or in back of the plane). To accomplish this you’ll need to flatten the ethanol out – do it in a way that puts most of the ethanol molecule away from the benzoic acid structure. When creating these drawings the most important thing for you to do is to honor the best you can the molecular geometry around each atom center.