Tert-butylamidinate tin(ii) complexes: high activity, single-site initiators for the controlled production of polylactide.
Tert-butylamidinate tin(ii) complexes: high activity, single-site initiators for the controlled production of polylactide.
复制标题
叔丁基脒锡 (ii) 络合物：用于控制聚丙交酯生产的高活性、单中心引发剂。
DOI：
10.1039/b706663e
复制
发表时间：
2007
影响因子：
4
通讯作者：
M. Elsegood
中科院分区：
文献类型：
--
作者：
Nonsee Nimitsiriwat;V. C. Gibson;E. L. Marshall;Andrew J. P. White;S. H. Dale;M. Elsegood
描述了两种单阴离子N，N'-双（2,6-二异丙基苯基）烷基酰胺配体的锡（ii）配位化学。与乙酰氨基酸盐的络合研究，[MeC(NAr)(2)](-), (Ar = 2,6-(i)Pr(2)C（6)H(3)）由于双（氨基酸）锡（ii）化合物[MeC(NAr)(2)](2)Sn的侧形成而复杂化。相比之下，体积较大的叔丁基氨基甲酸酯[(t)BuC(NAr)(2)]（-）使锡（ii）单卤化物、-醇氧化物和-酰胺配合物能够以高收率干净地分离出来。因此，[(t)BuC(NAr)(2)]H与(n) bui反应，随后用SnCl(2)处理生成[(t)BuC(NAr)(2)]SnCl，产率约为70%。与LiO(i)Pr、LiNMe(2)和LiNTMS(2)反应，分别生成[(t)BuC(NAr)(2)]Sn（O(i)Pr）、[(t)BuC(NAr)(2)]Sn（NMe(2)）和[(t)BuC(NAr)(2)]Sn（NTMS(2)）。报道了配合物的分子结构。配合物，和已经被研究为racc -丙交酯开环聚合的引发剂，并显示出良好控制的聚合引发剂的特征，但由于NTMS(2)单元的空间体积导致的低效引发，高分子量聚合物被观察到。与相应的β -二氯胺酸锡（ii）配合物的聚合速度更快，这与锡（ii）配位球更开放的性质相一致。
The tin(ii) coordination chemistry of two monoanionic N,N'-bis(2,6-diisopropylphenyl)alkylamidinate ligands is described. Complexation studies with the acetamidinate, [MeC(NAr)(2)](-), (Ar = 2,6-(i)Pr(2)C(6)H(3)) are complicated by the side formation of the bis(amidinate) tin(ii) compound, [MeC(NAr)(2)](2)Sn. By contrast, the bulkier tert-butylamidinate, [(t)BuC(NAr)(2)](-), allows tin(ii) mono-halide, -alkoxide and -amide complexes to be isolated cleanly in high yields. Thus, the reaction of [(t)BuC(NAr)(2)]H with (n)BuLi and subsequent treatment with SnCl(2) generates [(t)BuC(NAr)(2)]SnCl, in ca. 70% yield. Reactions of with LiO(i)Pr, LiNMe(2) and LiNTMS(2) afford [(t)BuC(NAr)(2)]Sn(O(i)Pr), [(t)BuC(NAr)(2)]Sn(NMe(2)), and [(t)BuC(NAr)(2)]Sn(NTMS(2)), respectively. The molecular structures of complexes are reported. Complexes, and have been investigated as initiators for the ring-opening polymerisation of rac-lactide: and display characteristics of well-controlled polymerisation initiators, but high molecular weight polymer is observed with due to inefficient initiation, a consequence of the steric bulk of the NTMS(2) unit. Polymerisations with and are faster than for the corresponding beta-diketiminate tin(ii) complexes, consistent with the more open nature of the tin(ii) coordination sphere.