meso -Porphyrinylphosphine Oxides: Mono- and Bidentate Ligands for Supramolecular Chemistry and the Crystal Structures of Monomeric {[10,20-Diphenylporphyrinatonickel(II)-5,15-diyl]-bis-[P(O)Ph 2 ] and Polymeric Self-Coordinated {[10,20-Diphenylporphyrinatozinc(II)-5,15-diyl]-bis-[P(O)Ph 2 ]}