TRENTON, N.J. — Fennelly Associates has negotiated the sale of 240 West State Street, a 240,000-square-foot office building in Trenton. The undisclosed buyer plans to redevelop the 16-story property into an apartment building. Plans for the new community include a mix of studio, one and two-bedroom units, as well as amenities such as a fitness center, pool and cafe. The company will also renovate the building’s parking garage. Jerry Fennelly of Fennelly Associates represented the seller, Garden State Commercial Properties, in the deal.