Synthetic and Structural Studies of 2-Acylmethyl-6-R-Difunctionalized Pyridine Ligand-Containing Iron Complexes Related to [Fe]-Hydrogenase.
Synthetic and Structural Studies of 2-Acylmethyl-6-R-Difunctionalized Pyridine Ligand-Containing Iron Complexes Related to [Fe]-Hydrogenase.
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DOI：
10.1021/acs.inorgchem.5b02490
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发表时间：
2016-01
影响因子：
4.6
通讯作者：
Li-Cheng Song;Kai Xu;Xiao-feng Han;Ji-Wei Zhang
中科院分区：
文献类型：
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作者：
Li-Cheng Song;Kai Xu;Xiao-feng Han;Ji-Wei Zhang
作为[Fe]-氢化酶的活性位点模型，三齿2-酰基甲基-6-甲氧基甲氧基-双官能化的含吡啶配合物η（3）-（2-COCH2-6-MeOCH2OC5H3N）Fe（CO）2（L1）（4，L1 = I; 5，SCN; 6，PhCS 2）通过以下多步反应制备：（i）2-MeO 2 C-6-HOC 5 H 3 N与ClCH 2 OMe醚化得到2-MeO 2 C-6-MeOCH 2 OC 5 H 3 N（1），（ii）1与NaBH 4还原得到2-HOCH 2 -6-MeOCH 2 OC 5 H 3 N（2），（iii）用4-甲苯磺酰氯酯化2，得到2-TsOCH 2 -6-MeOCH 2 OC 5 H 3 N（3），（iv）用Na 2Fe（CO）4亲核取代3，然后处理所得Fe（0）中间体Na[（2-CH 2 -6-MeOCH 2 OC 5 H 3 N）Fe（CO）4]（M1）与I2反应得到配合物4，（v）4与KSCN和PhCS 2 K缩合分别得到配合物5和6。与配合物4-6的制备相反，双齿2-酰基甲基-6-甲氧基甲氧基-双官能化的含吡啶的模型配合物η（2）-（2-COCH 2 -6-MeOCH 2OC 5H3N）Fe（CO）2（I）（L2）（7，L2 = PPh 3; 8，Cy-C6 H11 NC）和η（2）-（2-COCH2-6-MeOCH2OC5H3N）Fe（CO）2（L3）（9，L3 = 2-SC 5 H4 N; 10，8-SC 9 H6 N）通过4分别与PPh 3、Cy-C6 H11 NC、2-KSC 5 H4 N和8-KSC 9 H6 N的配体交换反应制备。特别有趣的是三齿2，6-二含（酰基甲基）吡啶和2-酰基甲基-6-芳硫甲基吡啶的模型配合物η（3）-[2，6-（COCH 2）2C 5 H3 N]Fe（CO）2（L4）（11，L4 = PPh 3; 12，CO）和η（3）-2-（COCH 2 -6-ArSCH2C5H3N）Fe（CO）2（ArS）（13）ArS = PhS; 14，2-S-5-MeC4H2O），6-（TsOCH 2）2C 5 H3 N与Na 2Fe（CO）4反应，然后用配体PPh 3和CO或二硫化物（PhS）2和（2-S-5-MeC 4 H2O）2处理所得混合物。通过原位红外光谱监测配体前体3和2，6-（TsOCH 2）2C 5 H3 N与Na 2Fe（CO）4的反应，并通过中间体Na[建议使用（2-CH 2 -6-MeOCH 2 OC 5 H3 N）Fe（CO）4]（M1）、Na[（2-CH 2 -6-TsOCH 2C 5 H3 N）Fe（CO）4]（M2）和（2-COCH 2 -6-CH 2C 5 H3 N）Fe（CO）3（M3）。新化合物1-14通过元素分析、光谱学以及其中一些的X射线晶体学表征。
As active site models of [Fe]-hydrogenase, tridentate 2-acylmethyl-6-methoxymethoxy-difunctionalized pyridine-containing complexes η(3)-(2-COCH2-6-MeOCH2OC5H3N)Fe(CO)2(L1) (4, L1 = I; 5, SCN; 6, PhCS2) were prepared via the following multistep reactions: (i) etherification of 2-MeO2C-6-HOC5H3N with ClCH2OMe to give 2-MeO2C-6-MeOCH2OC5H3N (1), (ii) reduction of 1 with NaBH4 to give 2-HOCH2-6-MeOCH2OC5H3N (2), (iii) esterification of 2 with 4-toluenesulfonyl chloride to give 2-TsOCH2-6-MeOCH2OC5H3N (3), (iv) nucleophilic substitution of 3 with Na2Fe(CO)4 followed by treatment of the resulting Fe(0) intermediate Na[(2-CH2-6-MeOCH2OC5H3N)Fe(CO)4] (M1) with I2 to give complex 4, and (v) condensation of 4 with KSCN and PhCS2K to give complexes 5 and 6, respectively. In contrast to the preparation of complexes 4-6, bidentate 2-acylmethyl-6-methoxymethoxy-difunctionalized pyridine-containing model complexes η(2)-(2-COCH2-6-MeOCH2OC5H3N)Fe(CO)2(I)(L2) (7, L2 = PPh3; 8, Cy-C6H11NC) and η(2)-(2-COCH2-6-MeOCH2OC5H3N)Fe(CO)2(L3) (9, L3 = 2-SC5H4N; 10, 8-SC9H6N) were prepared by ligand exchange reactions of 4 with PPh3, Cy-C6H11NC, 2-KSC5H4N, and 8-KSC9H6N, respectively. Particularly interesting is that the tridentate 2,6-bis(acylmethyl)pyridine- and 2-acylmethyl-6-arylthiomethylpyridine-containing model complexes η(3)-[2,6-(COCH2)2C5H3N]Fe(CO)2(L4) (11, L4 = PPh3; 12, CO) and η(3)-2-(COCH2-6-ArSCH2C5H3N)Fe(CO)2(ArS) (13, ArS = PhS; 14, 2-S-5-MeC4H2O) were obtained, unexpectedly, when 2,6-(TsOCH2)2C5H3N reacted with Na2Fe(CO)4 followed by treatment of the resulting mixture with ligands PPh3 and CO or disulfides (PhS)2 and (2-S-5-MeC4H2O)2. Reactions of ligand precursors 3 and 2,6-(TsOCH2)2C5H3N with Na2Fe(CO)4 were monitored by in situ IR spectroscopy, and the possible pathways for producing complexes 4 and 11-14 via intermediates Na[(2-CH2-6-MeOCH2OC5H3N)Fe(CO)4] (M1), Na[(2-CH2-6-TsOCH2C5H3N)Fe(CO)4] (M2), and (2-COCH2-6-CH2C5H3N)Fe(CO)3 (M3) are suggested. New compounds 1-14 were characterized by elemental analysis, spectroscopy, and, for some of them, X-ray crystallography.