PHOENIX — Minnetonka, Minn.-based Carlson Real Estate Co. has acquired Opus Cotton Center, a four-building, 265,000-square-foot commercial complex in Phoenix, from Minneapolis-based Opus Real Estate Fund VI (ORE) and Phoenix-based Opus West Corp. for $46.1 million. The buyer plans to rename the property Cotton Center IV to represent the four flex buildings that make up the project. The buildings range in size from 57,055 to 82,825 square feet. At the time of acquisition, the complex was 77 percent occupied by tenants such as Inter-Tel Technologies, Genzyme Corp., Sodexho and AETNA Insurance. Brian Ackerman, Chris Toci, Pat Harlan, Mike Beall and Jim Wilson of Cushman & Wakefield brokered the transaction.