Wife submitted $6500 to IRA (over 50). Combined income prevents us from deducting. Should we file separately?

Most likely this will not help to get a deduction since for married filing separately the deduction is disallowed with income of more than $10,000 MAGI. 

Please see below for additional information:

• IRA Deduction if You ARE Covered by a Retirement Plan at Work - 2018
• IRA Deduction if You Are NOT Covered by a Retirement Plan at Work - 2018 (deduction is limited only if your spouse IS covered by a retirement plan)