Preparation, properties, and reactions of metal-containing heterocycles Part CVI. Three-dimensional water-soluble platinacyclophanes

Trifunctional primary phosphines of the type 1,3,5-[PH2(CH2)(n)](3)C6H3 (3b -d) were obtained via an Arbusov reaction between the 1,3,5-tris(bromoalkyl )benzenes 1b-d and P(OEt)(3) followed by a reaction of the trisphosphonates 1,3,5-[(EtO)(2)P(O)(CH2)(n)](3)C6H3 (2b-d) with LiAlH4. A straightforward conversion of these sensitive key phosphines 3b-d to the corresponding wate r-soluble ligands 1,3,5-tris[bis(hydroxymethyl)phosphinylalkyl]benzenes 4b- d and 1,3,5-tris[bis(2 ' -diethylphosphonatoethyl)phophinylalkyl]benzenes 5 b-d was achieved by formylation with formaldehyde and hydrophosphonation wi th diethyl vinylphosphonate, respectively. A five component self-assembly c onsisting of three equivalents of the platinum(II) complex Cl2Pt(NCPh)(2) a nd two equivalents of the ligands 5b-d under high dilution conditions resul ted in the formation of the nanoscaled, water-soluble triplatinacyclophanes 6b-d in high yields. However, comparable reactions with the ligands 4b-d l ed only to polymeric materials, which are insoluble in all organic solvents and water. The structures of the metallacyclophanes 6b-d were elucidated b y P-31{H-1}-, C-13{H-1}-, and Pt-195{H-1}-NMR spectroscopic investigations. (C) 2001 Elsevier Science B.V. All rights reserved.