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. Effect of quantum mechanics was sometimes found to induce considerable kinetic isotope effect (KIE) in some chemical reactions. 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. 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: such as Cu(I)-catalyzed reductive CO2 coupling reaction for the oxalate formation via a mixed-valence state,[5a] Co(-I)-catalyzed hydrogenation reaction.
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.