偶氮苯修饰的 Pd(II)催化剂用于光调控异腈聚合研究

文章合成了一种偶氮苯基团修饰的$\mathrm{Pd}(\mathrm{II})$催化剂，用于引发非手性、手性异腈单体的聚合。由于$\mathrm{Pd}(\mathrm{II})$催化剂中偶氮苯基团在紫外光和可见光下的顺式和反式光异构化的特性，使其在可见光或紫外光（365 nm）照射下引发异腈单体聚合时表现出不同的催化行为。$\mathrm{Pd}(\mathrm{II})$催化剂引发非手性异腈单体A-1、手性异腈单体L-1和D-1聚合时，它们在可见光照射下聚合的反应速率常数约为紫外光照射下反应速率常数的6倍；$\mathrm{Pd}(\mathrm{II})$催化剂引发手性异腈单体L-1、D-1在可见光照射下聚合得到的聚合物$\mathrm{poly-L-1_{100}}$和$\mathrm{poly-D-1_{100}}$均具有光学活性，其摩尔吸光系数$(\Delta\varepsilon_{364})$分别为$-13.47$、$14.16\ \mathrm{dm}^{3}/(\mathrm{cm}\cdot\mathrm{mol})$。

An azobenzene-modified Pd(Ⅱ) catalyst was synthesized for the polymerization of achiral and chiral isocyanide monomers. Due to the cis and trans photoisomerization of azobenzene moiety on the Pd(Ⅱ) catalysts, different catalytic behaviors during the polymerization process of isocyanide monomers under visible light or UV light (365 nm) irradiation were observed. The polymerization rates of achiral isocyanide monomer A-1 and chiral isocyanide monomers L-1 and D-1 under visible light irradiation were approximately six times higher than those under UV light irradiation. And the optical helical poly-L-1 $ _{100} $ and poly-D-1 $ _{100} $ were obtained by the polymerization of chiral isocyanide monomers L-1 and D-1 under visible light irradiation using the Pd(Ⅱ) catalyst as initiator, and the molar absorptivities( $ \Delta\varepsilon_{364} $) of the polymers could be up to -13.47 dm $ ^{3} $/(cm·mol) and 14.16 dm $ ^{3} $/(cm·mol), respectively.