Kinetic Isotope Effects and Spin-Transition in Organic Reactions


报告题目:Kinetic Isotope Effects and Spin-Transition in Organic Reactions





Computational chemistry, particularly quantum mechanics methods, has become an important tool for us to understand many chemical reactions and physical properties.[1] Effect of quantum mechanics was sometimes found to induce considerable kinetic isotope effect (KIE) in some chemical reactions.[2] In this talk, I will present our proposed first excited-state carbon tunnelling in photo-induced triplet Zimmerman di-p-methane rearrangement of polycyclic molecules,[3c] which significantly enhances its 12C/13C KIE (using M06-2X, DLPNO-CCSD(T) methods and variational transition-state theory with multidimensional tunneling corrections). Also, I will show an unexpectedly small secondary H/D KIE for Fe(III)-catalyzed hetero-Diels-Alder (HDA) reaction in our combined DFT and experimental mechanistic study, even the significant bond forming involved in the transition state.[4] In addition, pronounced iron effect in quasi-classical dynamics of HDA will be discussed. Driven by the principles of economy and sustainability, earth-abundant transition-metal catalysts have been attracting the attention of many chemists. However, reaction mechanisms for first-row transition-metal catalysis are much more challenging, due to the complex and multiple electronic structures involved. I will present some of our recent mechanistic studies:[5] such as Cu(I)-catalyzed reductive CO2 coupling reaction for the oxalate formation via a mixed-valence state,[5a] Co(-I)-catalyzed hydrogenation reaction.[4] 


1 (a) Chung, L.W. et al. Chem. Rev. 2015, 115, 5678. (b) Zhang, X.; Chung, L. W.; Wu, Y.-D. Acc. Chem. Res. 2016, 49, 1302. (c) Cheng, G.-J.; Zhang, X.; Chung, L. W.; Xu, L.; Wu, Y.-D. J. Am. Chem. Soc. 2015, 137, 1706.

2. (a) Schreiner, P. R. J. Am. Chem. Soc. (perspective.) 2017, 139, 15276. (b) Schreiner, P. R.; Reisenauer, H. P.; Ley, D.; Gerbig, D.; Wu, C.-H.; Allen, W. D. Science 2011, 332, 1300. (c) Zuev, P. S.; Sheridan, R. S.; Albu, T. V.; Truhlar, D. G.; Hrovat, D. A.; Borden, W. T. Science 2003, 299, 867.

3. (a) Hixson, S. S.; Mariano, P. S.; Zimmerman, H. E. Chem. Rev. 1973, 73, 531. (b) Matute, R. A.; Houk, K. N. Angew. Chem., Int. Ed. 2012, 51, 13097. (c) Li, X.; Liao, T.; Chung, L. W. J. Am. Chem. Soc. (Commun.) 2017, 139, 16438. (d) Predicted 13C isotope effects on charge transport in organic semiconductors: Jiang, Y.; Geng, H.; Shi, W.; Peng, Q.; Zheng, X.; Shuai, Z. J. Phys. Chem. Lett. 2014, 5, 2267.

4. Manuscript in preparation.

5. (a) Lan, J.; Liao, T.; Zhang, T.; Chung, L. W. Inorg. Chem. 2017, 56, 6809. (b) Xu, L.; Chung, L. W.; Wu, Y.-D. ACS Catal. 2016, 6, 483. (d) Gao, W.; Lv, H.; Zhang, T.; Yang, Y.; Chung, L. W.; Wu, Y.-D.; Zhang, X. Chem. Sci. 2017, 8, 6419. (d) Review on Ni-catalysis: Zhang, T.; Zhang, X.; Chung, L. W. Asian J. Org., Chem. 2018, 7, 522.