Non-renewing leases for adopted tenants on new purchase

I'm currently in the process of purchasing a multi family property. This is my first time purchasing a multifamily and first time inheriting tenants 

Unfortunately 2 of the 3 units haven't been upkept or repaired in quite some time. They have significant general issues plus safety issues as well (like flooring falling in). 

While I'm excited to have paying tenants already in place, I'm not comfortable keeping them beyond their current leases due to the conditions of the units. I plan on mostly gutting them and renovating them asap. 

My question is, what would be the best way to give those 2 tenants notice that their leases will not be renewed? 

Im closing March 30 and their leases end May 30. I was planning on including a letter stating that im the new propwrty manager, how to pay the next couple months rent, and letting them know that their leases wont renew. Is it a good idea to let them know all that info at the same time ? Are there better options that im not considering ?