Minecraft – How to detect a player on a specific block(s)

Your command is working perfectly fine. Make sure it runs on a clock!

It has a couple flaws though:

• not multiplayer friendly: You would teleport every player, once a bottle is in the air
• suspended player: The player will not be able to move until the bottle hits the ground, as you're constantly teleporting him. This is especially bad if you happen to throw a bottle down a high cliff.

But here is an alternative solution, that is more reliable and multiplayer friendly!
The first thing you need to do, is to set up a scoreboard achievement: (type this in chat)

/scoreboard objectives add ExpThrown stat.useItem.minecraft.experience_bottle

This will count the number of times a player has thrown an experience bottle.
The next thing you want to do is to build a clock that activates a command block with the following command:

tp @a[score_ExpThrown_min=1] x y z

That is going to teleport all the players that have thrown an experience bottle to the specified coordinates (replace x, y and z).
Now, place a comparator facing away from that command block, into a new one with this command:

scoreboard players set @a[score_ExpThrown_min=1] ExpThrown 0

That will reset the objective, so that you only get teleported once.

Well the radius is mesured from the comand block. So if you put both command blocks in the same area it changes them constantly. What you can do is try to summon a invisible armor stand in the center of the area with /summon ArmorStand ~ ~ ~ {Invisible:1, CustomName:ArmorGuy,CustomNameVisible:0} then do /execute @e[name=ArmorGuy] ~ ~ ~ your gamemode command. I'm not sure will it work cause I'm sitting on my bed and typing with tablet.