No, you cannot take a credit on your 2016 tax return, that is not allowed per IRS rules, unfortunately.
For U.S. adoption - you can claim the credit before finalization (or for a failed adoption) but you must wait one year after you incurred the expenses (so in your case, you had expenses in 2016 for adoption that has not finalized in 2017- you must wait to claim them on 2017 tax return).
For foreign adoption - qualified adoption expenses paid before and during the year are allowable as a credit for the year when it becomes final - so again on your 2017 tax return.
Please
select Adoption Credit and
Adoption Assistance Programs link for details.