, 0000[@bb0]); program(s) used to solve structure: *SHELXS00* (Sheldrick, 0000[@bb0]); program(s) used to refine structure: *SHELXL00* (Sheldrick, 0000[@bb0]); molecular graphics: *PLATON* (Spek, 0000[@bb0]); software used to prepare material for publication: *SHELXTL* 