The sale of two units at Brack Capital Real Estate’s condominium conversion at 15 Union Square West may be set to shatter records for the sale of a single-family home on the square, the Corcoran Group’s Timothy Rothman told The Real Deal yesterday, since the new owner plans to combine them into one duplex spread. Rothman, a vice president at Corcoran on the Spiegelman team, represented a mystery foreign buyer in the deal for penthouse 11 and unit 10B at the building, which closed together yesterday for between $16 million and $17 million, he said, though he declined to give a specific price. The units were not on the market as a combination; their individual asking prices were $10.7 million and $6.5 million respectively. Rothman would not reveal the identity of the buyer due to a confidentiality agreement.