Department of Chemistry and Biochemistry, University of Lethbridge, AB, Canada.
Dalton Trans. 2012 Apr 7;41(13):3701-13. doi: 10.1039/c2dt11954d. Epub 2012 Feb 15.
The diastereomerically pure P-stereogenic bis(phosphinimine) ligands 4,6-(ArN[double bond, length as m-dash]PMePh)(2)dbf [Ar = 4-isopropylphenyl (Pipp): rac-4, meso-4; Ar = 2,6-diisopropylphenyl (Dipp): rac-4a; dbf = dibenzofuran] were synthesised and complexed to zinc using a protonation-alkane elimination strategy. The cationic alkylzinc complexes thus obtained, RZn[4,6-(ArN[double bond, length as m-dash]PMePh)(2)dbf][B(Ar')(4)] [Ar = Pipp, Ar' = C(6)H(3)(CF(3))(2): rac-6 (R = Et), meso-6 (R = Et), rac-7 (R = Me) meso-7 (R = Me); Ar = Dipp: rac-6a (R = Et, Ar' = C(6)H(3)(CF(3))(2)), rac-6b (R = Et, Ar' = C(6)F(5))] were investigated for their competency as initiators for the ring-opening polymerisation of rac-lactide. The formation of polylactide was achieved under relatively mild conditions (40 °C, 2-4 h) and the microstructures of the resulting polymers exhibited a slight heterotactic bias [polymer tacticity (P(r)) = 0.51-0.63].
对映体纯的 P-手性双（膦亚胺）配体 4,6-(ArN[双键，长度为破折号]PMePh)(2)dbf [Ar = 4-异丙基苯基 (Pipp): rac-4,meso-4;Ar = 2,6-二异丙基苯基 (Dipp): rac-4a;dbf = 二苯并呋喃] 被合成，并使用质子化-烷烃消除策略与锌络合。由此获得的阳离子烷基锌配合物，RZn[4,6-(ArN[双键，长度为破折号]PMePh)(2)dbf][B(Ar')(4)] [Ar = Pipp,Ar' = C(6)H(3)(CF(3))(2): rac-6(R = Et),meso-6(R = Et),rac-7(R = Me),meso-7(R = Me);Ar = Dipp: rac-6a(R = Et,Ar' = C(6)H(3)(CF(3))(2)),rac-6b(R = Et,Ar' = C(6)F(5))] 被研究作为 rac-丙交酯开环聚合的引发剂的能力。在相对温和的条件（40°C，2-4 小时）下实现了聚丙交酯的形成，并且所得聚合物的微观结构表现出轻微的异向性偏差[聚合物立构规整度（P(r)）= 0.51-0.63]。
