Polymerization of acrylonitrile catalyzed by thiolate complexes of divalent and trivalent lanthanoids

Abstract

Arenethiolate complexes of lanthanoid(II) and lanthanoid(III) metals were used as initiators for the polymerization of acrylonitrile at −78 °C in THF, giving atactic and high molecular mass (Mn ≈ 105) polyacrylonitriles in good yield. © 1999 Society of Chemical Industry

The salt-free diamido complexes of lanthanide supported by β-diketiminate: Synthesis, characterization, and their catalytic activity for the polymerization of acrylonitrile and ε-caprolactone

“…Several organolanthanide complexes were reported to be able to catalyze the polymerization of acrylonitrile including [(tert-BuCp) 2 NdCH 3 ] 2 [23], (ArO) 2 Sm [24] [(g 5 :g 1 -C 5 Me 4 SiMe 2 NCMe 3 )Y(CH 2 SiMe 3 )(THF)] [25], La(C 5 Me 5 )[(CH(SiMe 3 ) 2 )] 2 (THF) [26], Ln(SAr) 3 (py) 3 (La = Sm, Yb) [27] and Ln(OAr) 3 (Ln = La, Y) [28]. However, few report concerning with the reactivity of organolanthanide amide for the acrylonitrile polymerization was reported.…”

“…For example, the conversion reaches to 69% when the loading of catalyst is 1:400 (molar ratio of Ln to monomer) at 0°C in DME for 3 (entry 5) and 51% conversion can still be obtained when the loading decreases to 1:1000 (entry 3). The catalytic activity is comparable to those of Ln(SAr) 3 (py) 3 (La = Sm, Yb) [27] and Ln(OAr) 3 (Ln = La, Y) [28] and higher than those of [(tert-BuCp) 2 NdCH 3 ] 2 [23] and [(g 5 :g 1 -C 5 Me 4-SiMe 2 NCMe 3 )Y(CH 2 SiMe 3 )(THF)] [25]. The influence of catalyst concentration on the polymerization has been investigated in DME or THF at 25°C as shown in Table 2.…”

Polymerization of acrylonitrile catalyzed by lanthanide-sodium alkoxide clusters Ln2(OCH2CH2NMe2)12(OH)2Na8 [Ln=Yb (1), Nd (2) and Sm (3)]

“…PAN can be prepared by radical polymerization or anionic polymerization, and numerous metal complexes of alkali [5][6][7], alkaline earth [8,9] and late transition metals [10 -14] have been reported as initiators for anionic polymerization of acrylonitrile. Various lanthanide metal complexes have also been found to be single-component initiators for anionic polymerization of acrylonitrile, including [(tert-BuCp) 2 NdCH 3 ] 2 [15], (ArO) 2 Sm [16], Ind 2 LnN(i-Pr) 2 (Ln=Y, Yb) [17], SmI 2 [18], [(η 5 :η 1 -C 5 Me 4 SiMe 2 NCMe 3 )Y(CH 2 SiMe 3 )(THF)] [19], La-(C 5 Me 5 )[(CH(SiMe 3 ) 2 )] 2 (THF) [20], Ln(SAr) 3 (py) 3 (La= Sm, Yb) [21], Ln(OAr) 3 (Ln=La, Y) [22] and LLn(NPh 2 ) 2 (THF) (L=N,N′-bis(2,6-dimethylphenyl)-2,4-pentanediiminate) [Ln=Yb, Nd] [23]. However, only a few lanthanide metal complexes show the desired catalytic activity, and most of these complexes are sensitive to air and moisture.…”

“…For example, the conversion was 91% for cluster 1 at room temperature for 10 min with [M]/[I]=400 (mole ratio), and 95% for cluster 2 and 90% for cluster 3 under the same conditions. Similar results were reported for polymerization initiated by Ln(SAr) 3 (Py) 3 [21]. However, the results are different from those for polymerization of ε-caprolactone using heterometallic clusters as initiators, for which the activity is highly dependent on the ionic radius of the metal [30].…”

“…The tacticity of PAN was determined from the -CH 2 C(CN)H-methine resonance at 27 [31], and the results in Tables 2 and 3 indicate that all of the polymers obtained were atactic. Similar results were found for polymerization of acrylonitrile initiated by Ln-(SAr) 3 (py) 3 (La=Sm, Yb) [21], Ln(OAr) 3 (Ln=La, Y) [22] and LLn(NPh 2 ) 2 (THF) [23]. It can also be seen from Figure 2 that there is a small peak at about 14, in addition to the main-chain -CH 2 C(CN)H-resonances.…”