New USB-C charger to be used on an old MagSafe2 Macbook Pro
There is no adapter that goes from USB-C to Magsafe 2.  Though there is a project to create turn a USB-C into a MagSafe adapter

Tech accessories usually don't go backwards and it's usually because the old accessories don't have the capability to communicate properly with the new devices (i.e. voltage negotiation with USB-C charging).

Unfortunately, you will have to get an older charger to support that MacBook Pro.