2,3-9,8-bis(1-fluoro-3,4-benzo)-14,15-(1-carboxymethyl-2-carboxy-3-methyl-5,6-indolo)-21-(1-carboxymethyl-2-carboxy-3-methyl-8-benz(e)indolyl)-4,7,13,16-tetraoxa-1,10,21-triazabicyclo(8.8.5)-tricosane