Deshaun Thomas had 22 points and seven rebounds, and William Buford scored nine of his 11 points in the second half for the third-seeded Buckeyes (26-6). Ohio State shot 61 percent to post its second-best scoring output of the season and outrebounded Purdue 39-28.
The Buckeyes will play No. 10 Michigan in a semifinal on Saturday. The Wolverines defeated Minnesota 73-69 in overtime in an earlier quarterfinal.
D.J. Byrd scored 20 points and Terone Johnson added 15 for the Boilermakers (21-12). Robbie Hummel, Purdue's top scorer, finished with six points on 2-for-8 shooting.
The Boilermakers made 12 of 26 from 3-point range but were overwhelmed by Ohio State's size and athleticism in the paint.
Purdue missed its first five shots to fall behind 7-0, and the deficit increased to 19-11 before the Boilermakers rallied. Byrd hit 3-pointers on back-to-back possessions to cut Ohio State's lead to 33-30.
Hummel stuffed Sullinger's shot on one end and Anthony Johnson made a 3-pointer on the other end to trim Ohio State's lead to 35-33. Sullinger's 3-pointer with 34 seconds left in the first half gave the Buckeyes a 40-36 lead at the break. Ohio State shot 60 percent from the field in the first half, but Purdue hung tough by making 6 of 13 from long range.
The Buckeyes pushed their lead to 52-41 early in the second half after Sullinger scored six points during an 8-0 run.
Byrd drained another 3 to trim Ohio State's lead to 62-59, but the Buckeyes took over from there. Buford came back with a three-point play, Thomas scored on a putback, Sullinger scored on a post-up against Hummel and Buford converted another three-point play to give the Buckeyes a 72-61 lead with 5:23 remaining. A 3-pointer by Buford bumped the lead to 14, and the Buckeyes remained in control from there.
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