A Quest for Atropisomerism in Cojoined Square-Planar Metal Complexes: Synthesis and Structures of Sterically Congested Diplatinum Ethynediyl Adducts: A Quest for Atropisomerism in Cojoined Square-Planar Metal Complexes: Synthesis and Structures of Sterica
A Quest for Atropisomerism in Cojoined Square-Planar Metal Complexes: Synthesis and Structures of Sterically Congested Diplatinum Ethynediyl Adducts: A Quest for Atropisomerism in Cojoined Square-Planar Metal Complexes: Synthesis and Structures of Sterica
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共联方形平面金属配合物中阻转异构性的探索：空间拥挤二铂乙炔二基加合物的合成和结构：共联方形平面金属配合物中阻转异构性的探索：空间的合成和结构
DOI：
10.1002/ejic.201601307
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发表时间：
2017
影响因子：
2.3
通讯作者：
Gladysz, John A.
中科院分区：
文献类型：
--
作者：
Zhang, Tianyi;Bhuvanesh, Nattamai;Gladysz, John A.
反式-[（C6 F5）（p-tol 3 P）2 Pt（Cl）]和Me 2 PhP（4当量）的反应得到反式-[（C6 F5）（Me 2 PhP）（p-tol 3 P）Pt（Cl）]（2，68%），将其在HNEt 2中在CuI（催化剂，-45 °C），得到反式-[（C6 F5）（Me 2 PhP）（p-tol 3 P）Pt（C = CSiEt 3）]（3，62%）。在nBu 4 NF/CuCl（催化剂，-45 °C）得到了一系列PtCl_2CPt络合物，其中两个膦配体在所有四个位置上都是乱序的。反式TLC得到目标络合物反式，反式-[（C6 F5）（p-tol 3 P）（Me 2 PhP）Pt（C = C）Pt（PPhMe 2）（Pp-tol 3）（C6 F5）]（4，2.3%）以及反式，反式-[（C6 F5）（Me 2 PhP）2 Pt（C = C）Pt（PPhMe 2）（Pp-tol 3）（C6 F5）]（5，5.6%）。测定了化合物2、4和5的晶体结构。后两种方法显示了PtC/CPt连杆机构的许多拥塞，并分析了各种几何特征。记录4的低温1H NMR光谱，目的是观察Me 2 PhP基团的单独信号。这将表明非对映异构关系，并为基于共同连接的正方形平面复合物的第一阻转异构体提供强有力的证据。然而，未观察到退光（CD 2Cl 2/-95 °C，CDFC 12/-100 °C）。与其他数据一起，这表明在低于-95 °C的温度下，推定的阻转异构体的相互转化在NMR时间尺度上保持快速。
The reaction oftrans‐[(C6F5)(p‐tol3P)2Pt(Cl)] and Me2PhP (4 equiv.) affordedtrans‐[(C6F5)(Me2PhP)(p‐tol3P)Pt(Cl)] (2, 68 %), which is combined with HC≡CSiEt3in HNEt2in the presence of CuI (cat., –45 °C) to yieldtrans‐[(C6F5)(Me2PhP)(p‐tol3P)Pt(C≡CSiEt3)] (3, 62 %). The reaction of2and3in HNEt2in the presence ofnBu4NF/CuCl (cat., –45 °C) gave a series of PtC≡CPt complexes in which the two phosphine ligands have scrambled over all four positions. Preparative TLC afforded the target complextrans,trans‐[(C6F5)(p‐tol3P)(Me2PhP)Pt(C≡C)Pt(PPhMe2)(Pp‐tol3)(C6F5)] (4, 2.3 %) as well astrans,trans‐[(C6F5)(Me2PhP)2Pt(C≡C)Pt(PPhMe2)(Pp‐tol3)(C6F5)] (5, 5.6 %). The crystal structures of2,4, and5were determined. The last two show much congestion about the PtC≡CPt linkage, and various geometrical features have been analyzed. Low‐temperature1H NMR spectra of4were recorded with the goal of observing separate signals for the Me2PhP groups. This would indicate a diastereotopic relationship and provide strong evidence for the first atropisomers based upon cojoined square‐planar complexes. However, no decoalescence was observed (CD2Cl2/–95 °C, CDFCl2/–100 °C). Together with other data, this suggests that interconversion of the putative atropisomers remains rapid on the NMR timescale at temperatures below –95 °C.