Alkynyl polymers

Vicente and co-workers have recently synthesized platinum(n) 7 and mixed platinum(II)/ gold(I) a-alkynyl polymers 8.53 The monomers were prepared via dehydrohalogenation between c -[PtCI2( PR jb I and various alkynes. Polymerization occurred via the reaction of the platinum complex with PPN[Au(acac)2], giving polymers with mixed metal backbones. 

Since the successful synthesis of the first soluble alkynyl polymer of platinum in 1977 by Hagihara and coworkers (Scheme 10.13) [66], subsequent reports on platinum- and palladium-containing polyynyl polymers by both Hagihara and Lewis are good examples of the linearity of the trans-orientation [66, 90, 91]. 

Scheme 10.13. The first soluble platinum-containing alkynyl polymer by Hagihara and coworkers.

Scheme 10.17. Luminescent platinum-containing alkynyl polymers with different aromatic spacers.

Hyper-Branched Polymers Based on Alkynyl-Metal Complexes. 48... 

Terminal-functionalized polymers such as macromonomers and telechelics are very important as prepolymer for construction of functional materials. Single-step functionalization of polymer terminal was achieved via lipase catalysis. Alcohols could initiate the ring-opening polymerizahon of lactones by lipase catalyst. The lipase CA-catalyzed polymerizahon of DDL in the presence of 2-hydroxyethyl methacrylate gave the methacryl-type polyester macromonomer, in which 2-hydroxyethyl methacrylate acted as initiator to introduce the methacryloyl group quanhtatively at the polymer terminal ( inihator method ).This methodology was expanded to the synthesis of oo-alkenyl- and alkynyl-type macromonomers by using 5-hexen-l-ol and 5-hexyn-l-ol as initiator, respechvely. 

Diethynyl-pyridine was reacted with 2 equiv. of (Me2S)AuCl to give a gold alkynyl as an insoluble coordination polymer of unknown structure. This product could be dissolved in organic solvents with cBuNG to afford the bis(isocyanide) complex with an angular structure (Scheme 50).214... 

Alkynyl halides are possible monomers for the cross-coupling polymerization, in which boronic acids are used as the organometallic counterparts. For example, bifunctional boronic acid 46 is allowed to react with l,4-di(bromoethy-nyl)benzene 138 to afford the corresponding PAE 139 as shown in Equation (64). Polymerization proceeds at room temperature in toluene in the presence of silver(i) oxide as an activator of the boron reagent. The polymer 139 is obtained in 30-50% yield showing color of red-brown to deep red-brown and slight solubility in toluene (<0.1 wt.%). The molecular weight (Mr of 139 was 1700-4300 (PDI = 1.3-3.6). 

Polymer-bound alkynyl(phenyl)iodonium salts were prepared by refluxing polymer-bound [hydroxy(tosyloxy)iodo]benzene and some alkynes in dry chloroform [141]. 

Some gold-containing polymers incorporating isocyanide assembling ligand on one side and an alkynyl moiety on the other side were described by Puddephatt and collaborators.56 Again these materials were compared to model compounds (Fig. 22). 

More recent developments exploit the energy content of readily accessible cycloalkynes based on phenyl-alkynyl structural motives, albeit not always with fullerene formation in mind. For example, the strained dehydrobenzoannulene 4 [19] could be converted by light, heat (145 °C), or pressure (20000 psi) in a topochemical polymerization reaction typical for butadiynes to a deeply coloured polymer. A similar thermochemical behaviour (strongly exothermic transformation around 200 °C) was observed for compounds 5 and 6 [20]. However, none of the systems 4-6 shows any tendency to produce spherical forms of carbon under the conditions investigated. 

Dimethylpropynylindium (XLVIII) can be prepared by the reaction of dimethylindium chloride or bromide with sodium propynide as a colorless, crystalline substance 148). Whereas indium trimethyl is monomeric in benzene, the alkynyl compound is dimeric, but only sparingly soluble in this and other aprotic noncoordinating solvents. Improved solubility has been observed in diethyl ether due to the formation of a weak adduct 148). According to crystallographic data 148), compound XLVIII can be regarded as a coordination polymer in the solid state, as indicated in Fig. 10. The axial positions on the trigonal bipyramidal coordination polyhedron of each... 

The transition metal-catalysed coupling reaction of aryl halides with alkynes (alkynylation of aryl halides) is frequently also considered as a Heck reaction [68, 108-111], Polymers containing arylacetylene and diarylacetylene units in the backbone have been obtained by the self-coupling of ethynylaryl halides [scheme (3)] and the cross-coupling of aromatic dihalides with acetylene [scheme (6)] or diethynylbenzenes [scheme (7)] [112-121]. The majority of... 

In addition to aryl alkynyl coupling reactions involving dihaloarenes and acetylenes or dialkynylarenes which lead to poly(arylene acetylene)s, it is worth noting that these polymers have also been obtained by the Pd(0)-catalysed heteropolycondensation of dialkoxy-substituted dibromoarenes with bis(tribu-tylstannyl)acetylenes [122]. 

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