Professional Affiliations and Activities

  • Member, American Physical Society (2014 - Present)
  • Member, American Chemical Society (2014 - Present)
  • Member, American Institute of Chemical Engineers (2013 - Present)

Stanford Advisors

Current Research and Scholarly Interests

There is much interest in developing alternative transportation energy sources due to the unfavourable climate change associated with the usage of fossil fuels. Metal-air batteries, in particular, are promising candidates for this purpose due to their large theoretical specific energies (need to surpass the practical specific energy—1700 Wh/kg—of gasoline in an ICE). In practice, however, these batteries exhibit drastically lowered potentials and it is my goal to understand why this is so.

All Publications

  • Electric Field Effects in Electrochemical CO2 Reduction ACS CATALYSIS Chen, L. D., Urushihara, M., Chan, K., Norskov, J. K. 2016; 6 (10): 7133-7139
  • Direct Water Decomposition on Transition Metal Surfaces: Structural Dependence and Catalytic Screening CATALYSIS LETTERS Tsai, C., Lee, K., Yoo, J. S., Liu, X., Aljama, H., Chen, L. D., Dickens, C. F., Geisler, T. S., Guido, C. J., Joseph, T. M., Kirk, C. S., Latimer, A. A., Loong, B., McCarty, R. J., Montoya, J. H., Power, L., Singh, A. R., Willis, J. J., Winterkorn, M. M., Yuan, M., Zhao, Z., Wilcox, J., Norskov, J. K. 2016; 146 (4): 718-724
  • Theoretical Limits to the Anode Potential in Aqueous Mg-Air Batteries JOURNAL OF PHYSICAL CHEMISTRY C Chen, L. D., Norskov, J. K., Luntz, A. C. 2015; 119 (34): 19660-19667
  • Al-Air Batteries: Fundamental Thermodynamic Limitations from First-Principles Theory JOURNAL OF PHYSICAL CHEMISTRY LETTERS Chen, L. D., Norskov, J. K., Luntz, A. C. 2015; 6 (1): 175-179

    View details for DOI 10.1021/jz502422v

    View details for Web of Science ID 000347513700026

  • A mechanistic study of the [La-2(OCH3)(2)](4+)- and [(1,5,9-triazacyclododecane):Zn:(OCH3)](+)-catalyzed methanolysis of carbonates: possible application for the recycling of bisphenol A polycarbonates CANADIAN JOURNAL OF CHEMISTRY-REVUE CANADIENNE DE CHIMIE Neverov, A. A., Chen, L. D., George, S., Simon, D., Maxwell, C. I., Brown, R. S. 2013; 91 (11): 1139-1146
  • Tuning the Photoisomerization of a N boolean AND C-Chelate Organoboron Compound with a Metal-Acetylide Unit CHEMISTRY-A EUROPEAN JOURNAL Wang, N., Ko, S., Lu, J., Chen, L. D., Wang, S. 2013; 19 (17): 5314-5323


    To examine the impact of metal moieties that have different triplet energies on the photoisomerization of B(ppy)Mes2 compounds (ppy = 2-phenyl pyridine, Mes = mesityl), three metal-functionalized B(ppy)Mes2 compounds, Re-B, Au-B, and Pt-B, have been synthesized and fully characterized. The metal moieties in these three compounds are Re(CO)3(tert-Bu2 bpy)(C≡C), Au(PPh3)(C≡C), and trans-Pt(PPh3)2(C≡C)2, respectively, which are connected to the ppy chelate through the alkyne linker. Our investigation has established that the Re(I) unit completely quenches the photoisomerization of the boron unit because of a low-lying intraligand charge transfer/MLCT triplet state. The Au(I) unit, albeit with a triplet energy that is much higher than that of B(ppy)Mes2 , upon conjugation with the ppy chelate unit, substantially increases the contribution of the π→π* transition, localized on the conjugated chelate backbone in the lowest triplet state, thereby leading to a decrease in the photoisomerization quantum efficiency (QE) of the boron chromophore when excited at 365 nm. At higher excitation energies, the photoisomerization QE of Au-B is comparable to that of the silyl-alkyne-functionalized B(ppy)Mes2 (TIPS-B), which was attributable to a triplet-state-sensitization effect by the Au(I) unit. The Pt(II) unit links two B(ppy)Mes2 together in Pt-B, thereby extending the π-conjugation through both chelate backbones and leading to a very low QE of the photoisomerization. In addition, only one boron unit in Pt-B undergoes photoisomerization. The isomerization of the second boron unit is quenched by an intramolecular energy transfer of the excitation energy to the low-energy absorption band of the isomerized boron unit. TD-DFT computations and spectroscopic studies of the three metal-containing boron compounds confirm that the photoisomerization of the B(ppy)Mes2 chromophore proceeds through a triplet photoactive state and that metal units with suitable triplet energies can be used to tune this system.

    View details for DOI 10.1002/chem.201204048

    View details for Web of Science ID 000317894300014

    View details for PubMedID 23460416

  • Photo- and Thermal-Induced Multistructural Transformation of 2-Phenylazolyl Chelate Boron Compounds JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Rao, Y., Amarne, H., Chen, L. D., Brown, M. L., Mosey, N. J., Wang, S. 2013; 135 (9): 3407-3410


    The new N,C-chelate boron compounds B(2-phenylazolyl)Mes2 [Mes = mesityl; azolyl = benzothiazolyl (1a), 4-methylthiazolyl (2a), benzoxazolyl (3a), benzimidazolyl (4a)] undergo an unprecedented multistructural transformation upon light irradiation or heating, sequentially producing isomers b, c, d, and e. The dark isomers b generated by photoisomerization of a undergo a rare thermal intramolecular H-atom transfer (HAT), reducing the azole ring and generating new isomers c, which are further transformed into isomers d. Remarkably, isomers d can be converted to their diastereomers e quantitatively by heating, and e can be converted back to d by irradiation at 300 nm. The structures of isomers 1d and 1e were established by X-ray diffraction. The unusual HAT reactivity can be attributed to the geometry of the highly energetic isomers b and the relatively low aromaticity of the azole rings. The boryl unit plays a key role in the reversible interconversion of d and e, as shown by mechanistic pathways established through DFT and TD-DFT calculations.

    View details for DOI 10.1021/ja400917r

    View details for Web of Science ID 000315936700027

    View details for PubMedID 23425336

  • Stepwise Intramolecular Photoisomerization of NHC-Chelate Dimesitylboron Compounds with C-C Bond Formation and C-H Bond Insertion JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Rao, Y., Chen, L. D., Mosey, N. J., Wang, S. 2012; 134 (26): 11026-11034


    C,C-chelate dimesitylboron (BMes(2)) compounds containing an N-heterocyclic carbene (NHC) donor have been obtained. Single-crystal X-ray diffraction analyses established that the boron atom in these compounds is bound by four carbon atoms in a distorted tetrahedral geometry. Compared to previously reported N,C-chelate dimesitylboron compounds, the new C,C-chelate boron compounds have a much larger HOMO-LUMO energy gap (>3.60 eV). They do, however, respond to UV irradiation (300 nm) in the same manner as N,C-chelate BMes(2) compounds do, undergoing photoisomerization and converting to an intensely colored (yellow or orange) isomer A quantitatively, with a high quantum efficiency (0.60-0.75). NMR and single-crystal X-ray diffraction analyses established that the structure of A is similar to the dark isomers obtained from N,C-chelate BMes(2) compounds. However, unlike the N,C-chelate dark isomers that have the tendency to thermally reverse back to the light colored isomers, the isomers A of the C,C-chelate BMes(2) are thermally stable and no reverse isomerization was observed even when heated to 80 °C (or 110 °C) for hours. The most unusual finding is that isomers A undergo further photoisomerization when irradiated at 350 nm, forming a new colorless species B nearly quantitatively. NMR and single-crystal X-ray diffraction analyses established the structure of isomer B, which may be considered as an intramolecular C-H insertion product via a borylene intermediate. Mechanistic aspects of this unusual two-step photoisomerization process have been examined by DFT computational studies.

    View details for DOI 10.1021/ja304211v

    View details for Web of Science ID 000305863900050

    View details for PubMedID 22686627

  • Double Cyclization/Aryl Migration Across an Alkyne Bond Enabled by Organoboryl and Diarylplatinum Groups ANGEWANDTE CHEMIE-INTERNATIONAL EDITION Sun, C., Hudson, Z. M., Chen, L. D., Wang, S. 2012; 51 (23): 5671-5674

    View details for DOI 10.1002/anie.201201781

    View details for Web of Science ID 000304814000027

    View details for PubMedID 22539452