Organometallic polymers polyesters

One previous synthesis of ferrocene-containing condensation polymers via interfacial methods at room temperature has been reported by Knobloch and Rauscher, who formed low molecular weight polyamides and polyesters by reacting l,l -bis(chloro-formyl)ferrocene with various diamines and diols. Further, Carraher and co-workers have utilized interfacial techniques in the formation of other types of organometallic polymers. 

For metal-containing polyesters of dimer acid, synthesis was carried out using various divalent metal ions. Metal-containing polyesters include diverse systems such as ionomers, polymer-bound coordinating ligands, organometallic polymers with metal as a part of polymer backbone, metal polymer composites, and metal-... 

One of the most important methods for obtaining organometallic polymers is poly condensation. In 1961 Knobloch and Rauscher reported the synthesis of polyesters and polyamides with ferrocene groups in their backbones using interfacial polymerization. 

In the early 70s it was announced that organotin compounds had been bonded to such plastics as polystyrene, polymethacrylate, polyester, polyvinyl chloride, and cellulose polymer backbones. " These have been termed organometallic polymers (OMP). Triethyltin hydroxide was allowed to react with a copolymer of styrene-maleic anhydride. These polymers can be incorporated in a marine paint which, when applied, would retain an anti-fouling activity through hydrolytic cleavage of the metal-oxygen-polymer bond. 

Rausch also reported the synthesis of polyurethanes however, these polymers exhibited low solubihty and they precipitated from solution during the polymerization reactions. Polyurethanes with polyether segments in their backbones have also been synthesized. It has also been reported that polyurethanes with ferrocenyl units in their backbones exhibit enhanced thermal stability. Polyesters containing ferrocenyl units in the mainchain have been the focus of numerous studies. It has been reported that many of these organometallic polymers exhibit liquid crystalline properties. " Scheme 25 shows the synthesis of a liquid crystalline polyester (103) via polycondensation reactions. Increasing the length of the alkyl chains decreased the thermal stability and glass transition temperatures of these polymers. 

In some examples it is not necessary to prepare the organometallic-coupling agent R2MX2 beforehand. Thus coating glass fibres with a heptane or alcohol solution of titanium alkoxide promotes adhesion between the fibre and polymer, e.g., acrylic, polyolefins, polyester, polyamide and other thermoplastic resins. 

The concept of transesterifications was used for polymerization reactions by Hedrick and colleagues [76]. Various biodegradable polyesters were synthesized with the l,3-dimethylimidazol-2-ylidene carbene in THF at 25 °C. Polymers such as poly(e-caprolactone) were obtained with no need of organometallic catalysts, as in classical methods. Poly(ethylene terephthalate) (PET) 97 was synthesized in the ionic liquid 98, which functions as the reaction medium and, at the same time, as a precatalyst that is activated (99) with KOt-Bu. Dimethyl terephthalate (DMT) 100 was condensed with an excess of ethylene glycol 101 to generate 102. The melt condensation of 102 was performed under vacuum using a heating ramp to 280 °C. 

Organometallic polyurethanes containing backbone polyether units have been reported.184,185 The incorporation of ferrocenyl segments into the backbone of polyurethanes enhanced thermal stability.186 There have been a number of studies on the incorporation of ferrocenyl units into the backbone of polyesters 101.187-191 A number of polymers of this class exhibited liquid crystalline properties.189-192 The thermal stability and glass transition temperatures of these polymers decreased with an increase in the length of the alkyl chains. 

The synthesis of polymers containing main-chain cobaltocenium units has also been studied as this 18-electron organometallic moiety is isoelectronic with ferrocene. The synthesis of partially soluble polyesters (4.6, E = 0, R=(CH2)4, CH2C6H4CH2) was reported using solution condensation polymerization techniques, and the soluble fractions were of low molecular weight (M 2500-4000,... 

Some examples of sequence-controlled polymers prepared by ring opening polymerization of cyclic esters have been reported. For instance, Thomas, Coates, and coworkers reported a very original method for the synthesis of alternating aliphatic polyesters.These authors used a stereoselective yttrium-based organometallic catalyst to control comonomer sequences. It had been previously shown that the polymerization of a racemic mixture of p-butyrolactone in the presence of this catalyst led to the formation of... 

Ferrocene was the starting point for organometallic chemistry nearly four decades ago and is still today one of the most studied and versatile organometallic building blocks. Ferrocene has been incorporated in polymeric systems to alter bulk properties of the material. Ferrocene possesses excellent thermal and photochemical stability and can also protect polymeric systems from photodegradation. In addition, the ferrocene building block has been used in conducting polymers and in main chain liquid crystalline polyesters. ... 

Borden, D. G., Photocrosslinkable Organometallic Polyesters, Organometal. Polymer. Symp., New Orleans 1977 [1978], pp. 115/27. 

Conjugated polymers and polymeric systems like polydiacetylene, polyacetylene, poly(arylene vinylene), polythiophene, polyaniline, polyimides, and polyesters have been widely studied for their third-order susceptibility. " In addition to pure polymeric systems, investigations of third-order nonU-neatity have also been carried out on small molecules, polymer-doped systems, hybrid inorganic-organic systems, and organometallic complexes. ... 

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