Polymerization of some terminal alkynes by Ziegler-Natta catalyst systems:Fe(RCOO)(3)-AlEt3

The polymerization of 1-hexyne, 3-methyl-1-pentyne, 4-methyl-1-pentyne, and tert-butylacetylene was carried out with the following Ziegler-Natta type initiating systems: Fe(prp)(3)-AlEt3. Fe(chc)(3)-AlEt3, Fe(naph)(3)-AlEt3 ( prp = propionate, che = cyclohexanecarboxylate. naph = naphtenate). The cat alytic efficiency of these complexes was almost identical towards a same mo nomer. The polymer yield (0-100%) was highly influenced by the bulkiness of the substituent directly attached to a sp carbon. The molecular weights of the different polyalkynes obtained were relatively high (4 x 10(4)-10(5)). C-13 and H-1 NMR analyses of the polymers revealed a preferential orientat ion of the polymerization with these initiating systems, that is, the trans -configuration fraction was as high as 70%. (C) 1999 Elsevier Science Ltd. All rights reserved.