No abstract

Self-assembly consists of the spontaneous generation of a well-defined. discrete supramolecular architecture from a given set of components under specific conditions. Such processes require the design of "programmed" supramolecular systems that rely on the information stored in the components and on the interaction algorithm that operates through molecular recognition events.". 21 Depending on the nature of the molecules involved, the self-assembly can be organic o r inorganic. In the assembly of supermolecules from metal ions and ligands, the latter must contain the steric program that is "read" by the metal ions following the algorithm represented by their coordination geometry. The selfassembly of a given superstructure involves three stages : recognition between the components, correct orientation so as to allow growth, and termination of the process leading to a discrete, finite supramolecular species." -31The formation of double-helical metal complexes, the helicates,[, results from the self-organization of oligobipyridine (bpy) strands and Cu' o r Ag' ions that possess tetrahedral coordination ge0metry.1~ -51 The interaction of appropriately substituted oligo-bpy strands or related ligands with metal ions prefering octahedral coordination may yield triple-helical complexes.['* 81 Closed inorganic structures have been obtained, for instance, from the self-assembly of Ni2+[9d1 or C U * + [~~] ions and bis-p-diketone type ligands, of four Pt" metal complex fragments and four 4,4bpy groups,"'' and of four C u + ions and four bispyridylpyridazine ligands." 'I The self-assembly of the helicates and related structures involves just one type of ligand and metal ion. Further progress in the understanding and the control of the self-assembly and self-organization of inorganic (as well as of purely organic) superstructures requires the conception of systems

The synthesis of new metal complexes containing the keto phosphine ligands R 1 2 PCH 2 C- 2) was obtained (PkO = η 2 (P,O)-chelated ligand). Reaction of 2 with TlPF 6 afforded the cationic compound [Rh(PkO) 2 ][PF 6 ] (3). The X-ray crystal structure determination of 3‚H 2 O shows a distorted-square-planar geometry with the two phosphorus atoms (and oxygen atoms) in cis positions. Treatment of [RhCl(CO)(PPh 3 ) 2 ] with 1 equiv of L gave [RhCl(CO)(P∼O)(PPh 3 )] (5). In the presence of TlPF 6 the cationic complex [Rh(CO)(PkO)(PPh 3 )][PF 6 ] (6) was obtained. The X-ray crystal structure determination of 6 shows a slightly distorted square planar geometry with the two phosphorus atoms in trans positions. The reaction of 5 or 6 with 1 equiv of NaOMe produced the phosphino enolate