Binding of propylene oxide to porphyrin- and salen-M(III) cations, where M = Al, Ga, Cr, and Co
Binding of propylene oxide to porphyrin- and salen-M(III) cations, where M = Al, Ga, Cr, and Co
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DOI：
10.1021/ic048597x
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发表时间：
2005-04-18
影响因子：
4.6
通讯作者：
Zhou, ZP
中科院分区：
文献类型：
--
作者：
Chen, P;Chisholm, MH;Zhou, ZP
环氧丙烷（PO）与一系列金属阳离子LM（III）（+）的结合，其中L =四苯基卟啉（TPP），M =Al、Ga、Cr和Co，L =（R，R）-N，N '-bis（3，5-二叔丁基亚水杨基）-1，2-环己烯二胺（salen）M = Al和Cr，通过电喷雾串联质谱在气相中研究，测定了LM（PO）（2）（+）和LM（PO）（+）阳离子的相对稳定性。铬（III）和铝（III）阳离子最牢固地结合PO，并且对于M = Al，相对于salen，与TPP配位的金属中心的配位是有利的。对（TPP）M（PO）（2）（+），PO的离解顺序为M = Al > Cr，而对（TPP）M（PO）（+），PO的离解顺序为M = Cr > Al。0.5PO和（R，R-salen）AlO（2）CMe（.）1.5py生长在纯PO和吡啶，分别揭示五坐标铝（III）中心与醇盐/乙酸盐配体在轴向位置的正方形为基础的金字塔。这些结果进行了讨论，在开环聚合和共聚与PO和CO2，分别这些金属配合物的反应性。
The binding of propylene oxide (PO) to a series of metal cations LM(III)(+), where for L = tetraphenylporphyrin (TPP) M =Al, Ga, Cr, and Co, and for L = (R,R)-N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexenediamine (salen) M = Al and Cr, was studied in the gas phase by electrospray tandem mass spectroscopy, and the relative stabilities of LM(PO)(2)(+) and LM(PO)(+) cations were determined. The chromium(III) and aluminum(III) cations most tenaciously bind PO, and for M = Al, coordination to the TPP ligated metal center was favored relative to salen. For (TPP)M(PO)(2)(+), the dissociation of PO followed the order M = Al > Cr, but for (TPP)M(PO)(+) the dissociation was M = Cr > Al. The single-crystal structural determinations on (R,R-salen)AlOCHMe(S)CH(2)Cl(.)0.5PO and (R,R-salen)AlO(2)CMe(.)1.5py grown in neat PO and pyridine, respectively, reveal five-coordinate aluminum(III) centers with the alkoxide/acetate ligands in the axial position of a square-based pyramid. These results are discussed in terms of the reactivity of these metal complexes in ring-opening polymerizations and copolymerizations with PO and CO2, respectively.