The Capital Plastics holder is inert acrylic; the holder itself will not directly cause the coin to tone. Any toning seen on the coin will be the result of the environment in which it is stored. Capital Plastics holders like the one shown are not airtight - coins stored in them can be impacted by what's in the air around them.
If you want to better protect against potential toning reactions due to the coin's surrounding environment, an Air-Tite holder with the insert ring would offer better protection. If you want it to tone...one option would be to store it in a sulfur-rich environment.