SELF-ASSEMBLY OF CATIONIC, TETRANUCLEAR, PT(II) AND PD(II) MACROCYCLIC SQUARES - X-RAY CRYSTAL-STRUCTURE OF [PT2-BIPYRIDYL)2(-)OSO(2)CF(3)](4)((DPPP)(4,4')

The preparation, characterization, and some chemistry of a series of u nique cationic, tetranuclear, Pt(II)- and Pd(II)-based macrocyclic squ ares are reported. A variety of bidentate ligands (bipyridine, diazapy rene, dicyanobenzene, and dicyanobiphenyl) are interacted with the squ are-planar cis-bis(phosphine) Pt and Pd bis(triflate) complexes in org anic solvents at room temperature, resulting in molecular squares in h igh isolated yields via self-assembly. All molecular squares are robus t air- and water-stable microcrystalline solids with decomposition poi nts mostly above 200 degrees C. They are generally soluble in polar or ganic solvents but not in water or nonpolar solvents like pentane, tol uene, and ether. The cyano-based macrocycles are highly fluxional in s olution, whereas the bipy and related systems are more stable. Concent ration-dependent chemical shifts are observed for the ortho and meta p rotons of 1,5-dihydroxynaphthalene, indicating host-guest interactions and inclusion phenomena. X-ray crystal structures are reported for th e molecular square [(dppp)Pt(bipy)](8+)(4)8(-)OSO(2)CF(3) (15a), as we ll as a dinuclear dicyanobenzene complex 25 and the [(dppp)M(pyrazine) ](2+)2(-)OSO(2)CF(3) (M = Pt, Pd) complexes 20a,b.