Coordination polymers of copper(II) with some Coordination polymers of copper(II) with some dicarboxysiloxane ligands dicarboxysiloxane ligands Maria Cazacu*, Anton Airinei and Mihai Marcu “Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, 6600 Iasi, Romania Received4December2001;Accepted29June2002 Several new coordination polymers of copper(II) with different carboxylate ligands containing siloxane units were synthesized by equilibrium polycoordination reactions of copper(II) acetate with the proper dicarboxylic acid (i.e. 1,3-bis(3-carboxypropyl)tetramethyldisiloxane, a,o-bis(3-car- boxypropyl)oligodimethylsiloxane, and 1,3-bis(sebacomethyl)tetramethyldisiloxane) in solution (methanol), at room temperature. Some variations in the feed molar ratios were made. The resulting polymers having a polycoordination degree between 5 and 71 are soluble in a wide range of common organic solvents. The formation of polymers was proved by IR and UV±VIS absorption spectroscopy. The thermal behaviour of the coordination polymers was analysed by thermogravimetry in air. The silicon and copper contents and inherent viscosities were also determined. Copyright # 2002 John Wiley & Sons, Ltd. KEYWORDS: coordinationpolymer;polycoordination;siloxaneligand;copper-containingpolymers INTRODUCTION Interactionbetweenmetalionsandsomeligandsmayleadto the formation of metal-containing polymers in which the central metal ions are bound to ligand molecules. Metal- containing polymers are becoming increasingly important for fabrication of high-temperature stable materials, liquid crystalline polymers, superconductive materials, etc. 1±3 In contrasttootherkindsofhighmolecularweightcompound, metal-containing polymers can be thermally stable and so maintaintheircharacteristicsoverawiderangeoftempera- tures (e.g. high radiation stability, hydrolytic and thermo- oxidative stability, high dielectric constants, etc.). 1,4 The incorporation of metals in polymeric materials can be effected by the dispersion of fine metal powders in the polymer, metal salts, or complexes. 4 Also, ligands that selectively form complexes with some metal ions are of particular importance in various applications, such as recycling and refining of metals, purification of solutions, improving the environment, and treatment of pollutant metals,aswellasinthequalitativeandquantitativeanalysis ofmetals. 5 Polymers obtained by reaction of dicarboxylic acids with metal ions have been investigated either from the point of view of coordination chemistry or macromolecular chem- istry. The polymeric nature of the metal dicarboxylate salts dependsmainlyonthecoordinationnumberofthemetalion andthenumberofligandsinthesystem,aswellasonsteric factorsandthemethodofpreparation. 6 Systematic studies of coordination polymers have been carried out by Korshak and coworkers. 7±11 Copper, Zinc, Cadmium, Cobalt and Nickel ions form polymeric salts easily by coordination with dicarboxylic, a,o-dioxidicar- boxylic, and a,a'-dimethoxydicarboxylic acids. 8 The result- ing polymers are infusible, insoluble in common organic solvents,andmeltathightemperatures. 9 Theirinsolubilityis due to the formation of coordination networks. 8 Theuseof polysiloxane ligands could provide improved solubility for coordinationpolymers.Siloxanesarewellknownashaving lowintermolecularforces,whichareresponsibleforthelow solubility parameter (d p =7.3). 12,13 The incorporation of some transition metals in siloxane polymers 14 and the catalytic activity of these metal-coordinated polymers have been reported. 15 Also, some polyorganosiloxanes with pendant amino groups can give rise to catalytically active copper(II) complexes. 16 Inthepresentstudy,thesynthesisandcharacterizationof linear coordination polymers obtained by equilibrium polycoordination reactions between siloxane diacids as *Correspondence to: M. Cazacu, ªPetru Poniº Institute of Macromol- ecularChemistry,AleeaGr.GhicaVoda41A,6600Iasi,Romania. E-mail: mcazacu@icmpp.tuiasi.ro Copyright # 2002 John Wiley & Sons, Ltd. APPLIED ORGANOMETALLIC CHEMISTRY Appl. Organometal. Chem. 2002; 16: 643±648 Published online in Wiley InterScience (www.interscience.wiley.com). DOI:10.1002/aoc.354