Isocyanate- and isothiocyanate-derived Ru(IV)-based alkylidenes: synthesis, structure, and activity.
Isocyanate- and isothiocyanate-derived Ru(IV)-based alkylidenes: synthesis, structure, and activity.
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异氰酸酯和异硫氰酸酯衍生的基于 Ru(IV) 的亚烷基：合成、结构和活性。
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发表时间：
2009
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通讯作者：
M. Buchmeiser
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作者：
P. S. Kumar;K. Wurst;M. Buchmeiser
合成并表征了一系列异氰酸酯和异硫氰酸酯衍生的第二代Grubbs-Hoveyda型钌-烷叉配合物[Ru（N=C=O）（2）（IMesH（2））（=CH-2-（2-PrO）-C（6）H（4））]（1）、[Ru（N=C=O）（2）（1，3-二均三甲苯基-3，4，5，6-四氢嘧啶-2-亚基）（=CH-2-（2-PrO）-C（6）H（4））]（2）、[Ru（N=C=S）（2）（IMesH（2））（=CH-2-（2-PrO）-C（6）H（4））]（3）和[Ru（N=C=S）（2）（1，3-二均三甲苯基-3，4，5，6-四氢嘧啶-2-亚基）（=CH-2-（2-PrO）-C（6）H（4））]（4），以及它们在各种复分解反应中的活性。化合物1-4是由母体配合物[RuCl（2）（IMesH（2））（=CH-2-（2-PrO）C（6）H（4））]（5）（IMesH（2）= 1，3-bis-（2，4，6-三甲基苯基）-4，5-二氢咪唑-2-亚基）和[RuCl（2）（1，3-dimesityl-3，4，5，6-tetrahydropyrimidin-2-ylidene）（=CH-2-（2-PrO）-C（6）H（4））]（6）分别与银氰酸盐和硫氰酸盐反应。测定了1的X射线结构，证实了配体的异氰酸酯型键合。3和4中的异硫氰酸酯型键通过IR和（13）C NMR光谱明确地证实。异氰酸酯衍生的配合物1和2被发现是用于顺式-环辛-1，5-二烯（COD）的开环易位聚合（ROMP）的优良催化剂。1和2都产生反式含量约80%的聚（COD）。一级动力学与前所未有的高速率常数的聚合（k（p）=0.068和0.26 s（-1），分别）进行了观察。化合物3和4也是COD的ROMP的活性引发剂，然而，它们分别产生具有80%和67%的顺式含量的聚（COD）。配合物1和2在交叉复分解反应中也表现出良好的催化活性。最后，1-4也被发现是用于2，2-二炔丙基丙二酸二乙酯（DEPERT）的区域选择性环化聚合的优异催化剂，导致聚（DEPERT）几乎完全基于五元重复单元，即，环戊二烯-1-烯-1，2-亚乙烯基。
The synthesis and characterization of a series of isocyanate- and isothiocyanate-derived second generation Grubbs-Hoveyda-type ruthenium-alkylidene complexes, that is, [Ru(N=C=O)(2)(IMesH(2))(=CH-2-(2-PrO)-C(6)H(4))] (1), [Ru(N=C=O)(2)(1,3-dimesityl-3,4,5,6-tetrahydropyrimidin-2-ylidene)(=CH-2-(2-PrO)-C(6)H(4))] (2), [Ru(N=C=S)(2)(IMesH(2))(=CH-2-(2-PrO)-C(6)H(4))] (3), and [Ru(N=C=S)(2)(1,3-dimesityl-3,4,5,6-tetrahydropyrimidin-2-ylidene)(=CH-2-(2-PrO)-C(6)H(4))] (4), and their activity in various metathesis reactions are described. Compounds 1-4 were prepared by reaction of the parent complexes [RuCl(2)(IMesH(2))(=CH-2-(2-PrO)C(6)H(4))] (5) (IMesH(2)=1,3-bis-(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene) and [RuCl(2)(1,3-dimesityl-3,4,5,6-tetrahydropyrimidin-2-ylidene)(=CH-2-(2-PrO)-C(6)H(4))] (6) with silver cyanate and thiocyanate, respectively. The X-ray structure of 1 was determined, confirming the isocyanate-type bonding of the ligand. The isothiocyanate-type bonding in 3 and 4 was unambiguously confirmed by IR and (13)C NMR spectroscopy. The isocyanate-derived complexes 1 and 2 were found to be excellent catalysts for the ring-opening metathesis polymerization (ROMP) of cis-cycloocta-1,5-diene (COD). Both 1 and 2 yielded poly(COD) with a trans-content of about 80 %. First-order kinetics with unprecedentedly high rate constants of polymerization (k(p)=0.068 and 0.26 s(-1), respectively) were observed. Compounds 3 and 4 were also active initiators for the ROMP of COD, however, they generated poly(COD) with a cis-content of 80 and 67 %, respectively. Complexes 1 and 2 also showed good catalytic activity in cross-metathesis (CM) reactions. Finally, 1-4 were also found to be excellent catalysts for the regioselective cyclopolymerization of diethyl 2,2-dipropargylmalonate (DEDPM), resulting in poly(DEDPM) almost entirely based on five-membered repeat units, that is, cyclopent-1-ene-1,2-vinylenes.