Phadke Neha, Findlater Michael
Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA.
Molecules. 2015 Nov 10;20(11):20195-205. doi: 10.3390/molecules201119686.
The synthesis of a series of allene complexes (POCOP)Ir(η²-RC=(.)=CR') 1b-4b (POCOP = 2,6-bis(di-tert-butylphosphonito)benzene) via isomerization of internal alkynes is reported. We have demonstrated that the application of this methodology is viable for the isomerization of a wide variety of alkyne substrates. Deuterium labeling experiments support our proposed mechanism. The structures of the allene complexes 1b-4b were determined using spectroscopic data analysis. Additionally, the solid-state molecular structure of complex 2b was determined using single crystal X-ray diffraction studies and it confirmed the assignment of an iridium-bound allene isomerization product. The rates of isomerization were measured using NMR techniques over a range of temperatures to allow determination of thermodynamic parameters. Finally, we report a preliminary step towards developing a catalytic methodology; the allene may be liberated from the metal center by exposure of the complex to an atmosphere of carbon monoxide.
报道了通过内炔烃异构化合成一系列丙二烯配合物(POCOP)Ir(η²-RC=(.)=CR') 1b - 4b (POCOP = 2,6 - 双(二叔丁基膦基)苯)。我们已经证明这种方法对于各种炔烃底物的异构化是可行的。氘标记实验支持我们提出的机理。通过光谱数据分析确定了丙二烯配合物1b - 4b的结构。此外，使用单晶X射线衍射研究确定了配合物2b的固态分子结构，并且它证实了铱结合的丙二烯异构化产物的归属。使用NMR技术在一系列温度范围内测量异构化速率以确定热力学参数。最后，我们报道了开发一种催化方法的初步步骤；通过将配合物暴露于一氧化碳气氛中，丙二烯可从金属中心释放出来。
