Crystal structure of bis(biphenyl-2,2′-dicarboxylato-κ2O:O′)-bis(1-cyclopropyl-6-fluoro-4-oxo-7-(1-piperazinyl)-1,4-dihydroquinoline-3-carboxylato-κ2O,O′)dizinc(II)2.5 hydrate, C62H57N6Zn2O16.5F2