To me it looks like it needs more water & maybe a little more shade. Otherwise I don't think it looks all that bad; it just looks a little droopy and that can happen during the hottest part of the day. Does it also look like that in the morning & evening? I know that all of my top growth is that color and only the older leaves are Dark Green. It just may be adjusting to the new environment which could take awhile.

What species of Passionflower is it?

When you mixed in some of the clay did you make sure to mix in a lot of Vermiculite or something to break the clay up so that you have proper drainage?

Have you tried to look at the roots to see if they are turning brown; maybe it's a drainage issue?

I just think as far as the color goes that it may have to do with it's adjustment to the amt of sun/Shade it is receiving. I know I have had leaves turn purple and I found out it was the plants way of creating a type of Sunscreen.

If you can be more specific about the species of the plant that would really help. If your not sure can you describe exactly what the flowers looked like when it bloomed and what type of leaf it is: 1/3/5 leaf?