A Boston real estate investment firm has purchased two Simi Valley industrial buildings for a total of $6.1 million, or $103 a square foot. Cabot Properties Inc., a private equity investor in industrial property, purchased the buildings at 2121 and 2175 Union Place, from TA Realty, also of Boston, according to real estate data firm CoStar Group Inc. The properties date to the mid-1980s and are 94 percent leased to multiple manufacturing tenants. They were marketed as part of an industrial portfolio of half a dozen properties by L.A. brokerage CBRE Inc. Brokers Darla Longo, Michael Kendall, Rebecca Finkel, Andrew Briner and Barbara Emmons of CBRE brokered both sides of the transaction.