1,4,7,10-Tetraazacyclotridecane-1,4,7-triacetic acid, 12-((4-nitrophenyl)methyl)- 12(4-Nitrobenzyl)-1,4,7,10-tetraazacyclotridecane-1,4,7-triacetic acid 12-((4-Nitrophenyl)methyl)-1,4,7,10-tetraazacyclotridecane-1,4,7-triacetic acid 12-Nbtata 128924-92-5