Pd(II)- and Pt(II)-linked tetranuclear complexes as assembly units for higher ordered structures

The formation of ... Pt(II)... Br-Pt(IV)... mixed-valence complexes was utilized for the assembly of square compounds, [(en)M(4,4'-bpy)](4)(NO3)(8) (1.(NO3)(8); a: M = Pt(II), b: M = Pd(II), 4,4'-bpy = 4,4'-bipyridine), into higher ordered infinite complexes. The reaction of 1(8+) with cationic Pt(TV) complex, [PtBr2(en)(2)](2+) (2(2+)), afforded a 1 : 3 complex la (2)(3)(14+). Crystallographic analysis of this complex showed that two moieties of 2(2+) bridged at the cis corner of 1a(8+) making a stair-like infinite network, whereas another moiety of 2(2+) was accommodated in the cavity of 1a(8+). On the other hand, complexation of Ib with anionic Pt(IV) complex, PtX62- (3(2-); a: X = Cl, b: X = Br), afforded a 1:4 complex 1.(3)4. UV-vis observations suggested the formation of a linear tube structure, in which each corner of 1(8+) is bridged by the linear X-Pt-X motif of 3(2-).