No abstract

The t he rm a l proper ties of 4 1 0 and 122 0 F butadiene-tyre ne copolym ers co n tainin g 8.58 perce nt of bound-sty rene were i n vestiga ted by m eans of an adia batic cal orimeter fr om 16 0 t o 330 0 K . The 4 1 0 F copolym er was found t o crystallize in t he temperat ure ran ge fr om 210 0 to 285 0 K . The 122 0 F co polym er did not exhibi t any crystallizatio n. The glasst ransfo:mat ion te mperat ures of t he 41 0 and 122 0 F co poly mers were 200 0 a nd 193 0 K , resp~ct lv e l y.The effects of heat tre~t me n t upon the heat capaci ty a nd t he glass-t ra nsforma tIOn te mperat ure have bee n studIed. The res ults of the hea t-capaci ty mea surem ents :vere used to co mpu te heat capacity, e nthalpy, and e nt ropy from 0 0 t o 33t}° K !"It 5-deg ltl te rv a ls.

The syntheses of a tetraazamacrocycle functionalized at nitrogen with a pendant 3-thiophene, 1 -[2-(3thienyl)ethyl]-l,4,8,1 I-tetraazacyclotetradecane (cyclamN-CH2CH2-thiophene), and its complexes with Nil1 and Cull, are described. Electro-oxidation of the pure Nil1 complex in acetonitrile electrolytes afforded only soluble oligomers. Novel conducting polymer-modified electrodes were fabricated, however, by electrocopolymerization of the Nil' complex with 3-methylthiophene. These are unusual in that both the metal centre [Ni1l-NiI1l at +I . I 5 V (saturated calomel electrode)] and the conducting polymer backbone show stable, reversible redox behaviour, with no apparent oxidative degradation of the poly(thiophene) backbone. The Ni1I-Ni1l1 redox behaviour appears unaffected by incorporation into the conducting polymer matrix. However, the NilI-Nil wave, observed at -1.40 V in solution, is entirely suppressed in the polymer, which at that potential is an electronic insulator.

The complex [Pd(O,CMe),(vdpp)]1 a [vdpp = (Ph,P), C=CH,] undergoes nucleophilic addition at the double bond with primary alcohols to afford [Pd(O,CMe),{(Ph,P),CHCH~OR}] 2 [R = Me, Et, CH,CH,C,H,S-3 or CH,C6H,(OMe),-3,4]. These were not isolated pure, but metathesis with Nal gave the corresponding diiodides 3, which were isolated, and have been fully characterised by microanalysis and infrared and NMR ('H and 31P-(1H}) spectroscopies. By using 2-(3-thieny1)ethanol as the nucleophile, the complex [Pdl,{( Ph,P),CHCH,OCH2CH,C,H,S-3}]3c was obtained, and its electrochemistry examined. The reactivity of the double bond in 1 a towards other potential weak nucleophiles has been examined. In particular, pyrrole underwent electrophilic addition with 1 a t o give, after work-up with Nal, [Pdl,{( Ph,P),CHCH,C,H,NH}] 4b. Proton NMR spectroscopy established that 4b was a mixture of 2and 3-pyrrole isomers (ca. 3: 1). The complexes [MClJvdpp)] (M = Pd lc or Pt I d ) were less reactive, but underwent addition with alcohols in the presence of NEt, as catalyst t o afford [MCI,{(Ph,P),CHCH,OR}]

Methyl-, chloro-and fluoro-substitution in the C6 ring has little effect on the oxidation of polybenzo[c]thiophene films to the p-doped conducting form, but has a marked effect on reduction to the n-doped form: poly(5,6dichlorobenzo[c]thiophene) is n-doped at E < -0.35 V (SCE).