Aaron Craft added 16 points and five assists for the Buckeyes (24-8), who have won six straight against Purdue. Lenzelle Smith Jr. tallied nine points to surpass 1,000 for his career.
Ohio State will play Nebraska in the quarterfinals on Friday.
A.J. Hammons ended with 15 points and nine boards for the Boilermakers (15-17), who have lost seven in a row. Ronnie Johnson donated 10 points and Terone Johnson and Kendall Stephens each added 10 points.