MODULAR ASSEMBLY OF HYBRID IODONIUM-TRANSITION METAL CATIONIC TETRANUCLEAR MACROCYCLIC SQUARES - SINGLE-CRYSTAL MOLECULAR-STRUCTURE OF ([(ET(3)P)(2)PD(OTF)(2)][(NC5H4C6H4)(2)I(OTF)])(2)

Interaction of bis[4-(4'-pyridyl)phenyl]iodonium triflate and bis(4-pyridyl)iodonium triflate respectively with cis-L(2)M(OSO2CF3)(2) (L = Pt3P, dppp; M = Pt, Pd) in acetone at room temperature results in hybrid iodonium-transition metal cationic tetranuclear macrocyclic squares in good isolated yields (50-100%) via self-assembly. The 4-(4'-pyridyl)phenyl compounds are stable microcrystalline solids as are the Et(3)P-chelated 4-pyridyl Pt and Pd squares whereas the dppp-chelated 4-pyridyl molecules are less stable. The single crystal X-ray molecular structure of 5d, {[(Et(3)P)(2)Pd(OTf)(2)][(NC5H4C6H4)(2)I(OTf)]}(2), shows a planar rhomboid-like geometry, rather than a perfect square, for this macrocyclic ring system.