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合成了双(烷氧-亚胺芳氧)基钛(IV)配合物,通过IR,1H NMR和元素分析对其进行表征,X射线单晶衍射测定了其晶体结构.单晶结构分析表明,该晶体属于三斜晶系,空间群为P1,a=14.294(9)?,b=16.206(10)?,c=18.458(12)?,V=3911(4)?3,Dc=1.098 g?cm-3,μ=0.262 mm-1,F(000)=1589,Z=2,R1=0.081,wR2=0.240.实验结果表明该配合物在130℃以上能引发D,L-丙交酯单体开环聚合,可得数均分子量(Mn)为8.8×104 g/mol的聚(D,L-乳酸)(PDLLA).动力学研究表明该聚合反应对D,L-丙交酯单体浓度和催化剂浓度分别呈2级和1级,表观活化能和频率因子分别为76.63 kJ/mol和2.91×1011.通过苄基封端聚合物1H NMR谱的研究,表明钛配合物引发D,L-丙交酯开环聚合是基于以Ti—O键为活性中心引发D,L-丙交酯单体酰氧键断裂开环聚合的“配位-插入”机理.
Synthesis of bis (alkoxy - imide aryloxy) titanium (IV) complexes was characterized by IR, 1H NMR and elemental analysis, and their crystal structures were determined by X - ray single crystal diffraction. The crystal belongs to the triclinic system with space group P1, a = 14.294 (9) ?, b = 16.206 (10) ?, c = 18.458 (12) ?, V = 3911 (4)? 3, Dc = 1.098 g The experimental results show that the complex can induce D, L-lactide above 130 ℃. The results show that the complex has the best properties as follows: cm-3, μ = 0.262 mm-1, F (000) = 1589, Z = 2, R1 = 0.081, wR2 = The monomer was ring-opened and polymerized to obtain poly (D, L-lactic acid) (PDLLA) with number average molecular weight (Mn) of 8.8 × 104 g / mol.Kinetic studies showed that the polymerization reaction of D, L-lactide The concentration of the catalyst and the catalyst concentration were grade 2 and grade 1 respectively, and the apparent activation energy and frequency factor were 76.63 kJ / mol and 2.91 × 1011, respectively. The 1H NMR spectra of the benzyl terminated polymer showed that the titanium complex initiated D , L-lactide ring-opening polymerization is based on the Ti-O bond as the active center initiated D, L-lactide monomer acyl oxygen bond ring-opening polymerization “coordination - insertion ” mechanism.