I have no opinions about most chemistry. I do know that the heaviest recreational users develop issues due to it being neurotoxic, so that's worth considering.

I don't know if your designs are technical or world-building for a story? If the latter, I'd suggest https://worldbuilding.stackexchange.com as I've had good conversations there, if the former perhaps (but not as a recommendation because I'm not a chemist) https://chemistry.stackexchange.com would help?