On Sept. 6, 33-year-old Leena Barakat will mark a career milestone by becoming president and chief executive officer of Women Donors Network. The success makes her the first Palestinian American — as well as the youngest person — to take the helm of a philanthropic organization this size in the country. The San Francisco-based nonprofit’s board of directors last month chose Barakat to oversee the day-to-day operations of its philanthropic organization, which has been pursuing its vision of an equitable society for all since it was formed in 2003.