A private-equity executive is spending $22.5 million on a Fifth Avenue co-op owned by the late copper heiress Huguette Clark, public records show.

The co-op board also OK’d a request from Frederick Iseman, founder of CI Capital Partners, to join the $19 million unit with part of another, also Clark’s, for the additional $3.5 million.

The board had rejected a similar request from the prime minister of Qatar.