Cuprate(4-), [m-[[3,3′-[[3,3′-di(hydroxy-kO)[1,1′-biphenyl]-4,4′-diyl]bis(2,1-diazenediyl-kN1)]bis[5-amino-4-(hydroxy-kO)-2,7-naphthalenedisulfonato]](8-)]]tetrakis[2,2′-(imino-kN)bis[ethanol]]di-, hy