Single-chromophore single-molecule photocatalyst for the production of dihydrogen using low-energy light



Single-chromophore single-molecule photocatalysts for the conversion and storage of solar energy into chemical bonds are rare, inefficient and do not use significant portions of the visible spectrum. Here we show a new, air-stable bimetallic scaffold that acts as a single-chromophore photocatalyst for hydrogen-gas generation and operates with irradiation wavelengths that span the ultraviolet to the red/near-infrared. Irradiation in acidic solutions that contain an electron donor results in the catalytic production of hydrogen with 170 ± 5 turnovers in 24 hours and an initial rate of 28 turnovers per hour. The catalysis proceeds through two stepwise excited-state redox events—atypical of the currently known homogeneous photocatalysis—and features the storage of multiple redox equivalents on a dirhodium catalyst enabled by low-energy light.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Schematic representation of structures 1–3.
Fig. 2: Electronic absorption spectrum of 1.
Fig. 3: Hydrogen gas produced on the irradiation of complex 1 with red light over a period of 24 h.
Fig. 4: Mechanistic study of the reactivity of the catalytic intermediate, the one-electron reduced 1, [1]1−, in DMF in the presence of the electron donor BNAH (0.2 M).
Fig. 5: Proposed mechanism of the photocatalytic H2 production by 1.

Data availability

All the data supporting the findings of this study are available from the corresponding author upon reasonable request. Crystallographic data for structure 1 reported in this article has been deposited at the Cambridge Crystallographic Data Centre under deposition number CCDC 1871363. Copies of the data can be obtained free of charge via


  1. 1.

    Gust, D., Moore, T. A. & Moore, A. L. Solar fuels via artificial photosynthesis. Acc. Chem. Res. 42, 1890–1898 (2009).

  2. 2.

    Yano, J. & Yachandra, V. Mn4Ca cluster in photosynthesis: where and how water is oxidized to dioxygen. Chem. Rev. 114, 4175–4205 (2014).

  3. 3.

    Zeitler, K. Photoredox catalysis with visible light. Angew. Chem. Int. Ed. 48, 9785–9789 (2009).

  4. 4.

    Yuan, Y. J. et al. Hydrogen photogeneration promoted by efficient electron transfer from iridium sensitizers to colloidal MoS2 catalysts. Sci. Rep. 4, 4045 (2014).

  5. 5.

    Mirkovic, T. et al. Light absorption and energy transfer in the antenna complexes of photosynthetic organisms. Chem. Rev. 117, 249–293 (2017).

  6. 6.

    Cui, X., Li, W., Ryabchuk, P., Junge, K. & Beller, M. Bridging homogeneous and heterogeneous catalysis by heterogeneous single-metal-site catalysts. Nat. Catal. 1, 385–397 (2018).

  7. 7.

    Li, X. et al. Noncovalent assembly of a metalloporphyrin and an iron hydrogenase active-site model: photo-induced electron transfer and hydrogen generation. J. Phys. Chem. B 112, 8198–8202 (2008).

  8. 8.

    Lazarides, T. et al. Making hydrogen from water using a homogeneous system without noble metals. J. Am. Chem. Soc. 131, 9192–9194 (2009).

  9. 9.

    Kowacs, T. et al. Subtle changes to peripheral ligands enable high turnover numbers for photocatalytic hydrogen generation with supramolecular photocatalysts. Inorg. Chem. 55, 2685–2690 (2016).

  10. 10.

    Zhang, P. et al. Homogeneous photocatalytic production of hydrogen from water by a bioinspired [Fe2S2] catalyst with high turnover numbers. Dalton Trans. 39, 1204–1206 (2010).

  11. 11.

    Streich, D. et al. High-turnover photochemical hydrogen production catalyzed by a model complex of the [FeFe]-hydrogenase active site. Chem. Eur. J. 16, 60–63 (2010).

  12. 12.

    Miyake, Y. et al. Design and synthesis of diphosphine ligands bearing an osmium(ii) bis(terpyridyl) moiety as a light harvesting unit: application to photocatalytic production of dihydrogen. Organometallics 28, 5240–5243 (2009).

  13. 13.

    Cline, E. D., Adamson, S. E. & Bernhard, S. Homogeneous catalytic system for photoinduced hydrogen production utilizing iridium and rhodium complexes. Inorg. Chem. 47, 10378–10388 (2008).

  14. 14.

    Du, P., Schneider, J., Luo, G., Brennessel, W. W. & Eisenberg, R. Visible light-driven hydrogen production from aqueous protons catalyzed by molecular cobaloxime catalysts. Inorg. Chem. 48, 4952–4962 (2009).

  15. 15.

    Yu, S. et al. Efficient photocatalytic hydrogen evolution with ligand engineered all-inorganic InP and InP/ZnS colloidal quantum dots. Nat. Commun. 9, 4009 (2018).

  16. 16.

    McNamara, W. R. et al. A cobalt–dithiolene complex for the photocatalytic and electrocatalytic reduction of protons. J. Am. Chem. Soc. 133, 15368–15371 (2011).

  17. 17.

    Beiler, A. M., Khusnutdinova, D., Jacob, S. I. & Moore, G. F. Solar hydrogen production using molecular catalysts immobilized on gallium phosphide(111) A and (111)B polymer-modified photocathodes. ACS Appl. Mater. Interfaces 8, 10038–10047 (2016).

  18. 18.

    Ma, Y. et al. Titanium dioxide-based nanomaterials for photocatalytic fuel generations. Chem. Rev. 114, 9987–10043 (2014).

  19. 19.

    Breton, K. R., Bonn, A. G. & Miller, A. J. M. Molecular photoelectrocatalysts for light-driven hydrogen production. ACS Energy Lett. 3, 1128–1136 (2018).

  20. 20.

    Chambers, M. B., Kurtz, D. A., Pitman, C. L., Brennaman, M. K. & Miller, A. J. M. Efficient photochemical dihydrogen generation initiated by a bimetallic self-quenching mechanism. J. Am. Chem. Soc. 138, 13509–13512 (2016).

  21. 21.

    Caspar, J. V. & Meyer, T. J. Application of the energy gap law to nonradiative, excited-state decay. J. Phys. Chem. 87, 952–957 (1983).

  22. 22.

    Rousset, E., Chartrand, D., Ciofini, I., Marvaud, V. & Hanan, G. S. Red-light-driven photocatalytic hydrogen evolution using a ruthenium quaterpyridine complex. Chem. Commun. 51, 9261–9264 (2015).

  23. 23.

    Tsuji, Y., Yamamoto, K., Yamauchi, K. & Sakai, K. Near-infrared-light-driven hydrogen evolution from water using a polypyridyl triruthenium photosensitizer. Angew. Chem. Int. Ed. 57, 208–212 (2018).

  24. 24.

    Sayre, H. J., Millet, A., Dunbar, K. R. & Turro, C. Photocatalytic H2 production by dirhodium(ii,ii) photosensitizers with red light. Chem. Commun. 54, 8332–8334 (2018).

  25. 25.

    Kobayashi, M., Masaoka, S. & Sakai, K. Photoinduced hydrogen evolution from water based on a Z-scheme photosynthesis by a simple platinum(ii) terpyridine derivative. Angew. Chem. Int. Ed. 51, 7431–7434 (2012).

  26. 26.

    Yamamoto, K., Kitamoto, K., Yamauchi, K. & Sakai, K. Pt(ii)-catalyzed photosynthesis for H2 evolution cycling between singly and triply reduced species. Chem. Commun. 51, 14516–14519 (2015).

  27. 27.

    Hawecker, J. & Lehn, J.-M. & Ziessel, R. Efficient photochemical reduction of CO2 to CO by visible light irradiation of systems containing Re(bipy)(CO)3X or Ru(bipy)3 2+–Co2+ combinations as homogeneous catalysts. Chem. Commun. 1983, 536–538 (1983).

  28. 28.

    Wang, W., Rauchfuss, T. B., Bertini, L. & Zampella, G. Unsensitized photochemical hydrogen production catalyzed by diiron hydrides. J. Am. Chem. Soc. 134, 4525–4528 (2012).

  29. 29.

    Manbeck, G. F. et al. Hydricity, electrochemistry, and excited-state chemistry of Ir complexes for CO2 reduction. Faraday Discuss. 198, 301–317 (2017).

  30. 30.

    Garg, K. et al. Strinking differences in properties of geometric isomers of [Ir(tpy)(ppy)H]+: Experimental and computational studies of their hydricities, interaction with CO2, and photochemistry. Angew. Chem. Int. Ed. 54, 14128–14132 (2015).

  31. 31.

    Sato, S., Morikawa, T., Kajino, T. & Ishitani, O. A highly efficient mononuclear iridium complex photocatalyst for CO2 reduction under visible light. Angew. Chem. Int. Ed. 52, 988–992 (2013).

  32. 32.

    Huckaba, A. J. et al. A mononuclear tungsten photocatalyst for H2 production. ACS Catal. 8, 4828–4847 (2018).

  33. 33.

    Okazaki, R. & Masaoka, S. & Sakai, K. Photo-hydrogen-evolving activity of chloro(terpyridine)platinum(ii): a single-component molecular photocatalyst. Dalton Trans. 2009, 6127–6133 (2009).

  34. 34.

    Ogawa, M., Ajayakumar, G., Masaoka, S., Kraatz, H.-B. & Sakai, K. Platinum(ii)-based hydrogen-evolving catalysts linked to multipendant viologen acceptors: experimental and DFT indications for bimolecular pathways. Chem. Eur. J. 17, 1148–1162 (2011).

  35. 35.

    Kitamoto, K. & Sakai, K. Pigment–acceptor–catalyst triads for photochemical hydrogen evolution. Angew. Chem. Int. Ed. 126, 4706–4710 (2014).

  36. 36.

    Lin, S., Kitamoto, K., Ozawa, H. & Sakai, K. Improved photocatalytic hydrogen evolution driven by chloro(terpyridine)platinum(ii) derivatives tethered to a single pendant viologen acceptor. Dalton Trans. 45, 10643–10654 (2016).

  37. 37.

    Kitamoto, K. & Sakai, K. Photochemical H2 evolution from water catalyzed by dichloro(diphenylbipyridine)platinum(ii) derivative tethered to multiple viologen acceptors. Chem. Commun. 52, 1385–1388 (2016).

  38. 38.

    Gray, H. B. & Maverick, A. W. Solar chemistry of metal complexes. Science 214, 1201–1205 (1981).

  39. 39.

    Heyduk, A. F. & Nocera, D. G. Hydrogen produced from hydrohalic acid solutions by a two-electron mixed-valence photocatalyst. Science 293, 1639–1641 (2001).

  40. 40.

    Elgrishi, N., Teets, T. S., Chambers, M. B. & Nocera, D. G. Stability-enhanced hydrogen-evolving dirhodium photocatalysts through ligand modification. Chem. Commun. 48, 9474–9476 (2012).

  41. 41.

    Powers, D. C., Hwang, S. J., Zheng, S. L. & Nocera, D. G. Halide-bridged binuclear HX-splitting catalysts. Inorg. Chem. 53, 9122–9128 (2014).

  42. 42.

    Li, Z., Leed, N. A., Dickson-Karn, N. M., Dunbar, K. R. & Turro, C. Directional charge transfer and highly reducing and oxidizing excited states of new dirhodium(ii,ii) complexes: potential applications in solar energy conversion. Chem. Sci. 5, 727–737 (2014).

  43. 43.

    Whittemore, T. J. et al. New Rh2(ii,ii) complexes for solar energy applications: panchromatic absorption and excited-state reactivity. J. Am. Chem. Soc. 139, 14724–14732 (2017).

  44. 44.

    Whittemore, T. J. et al. Tunable Rh2(ii,ii) light absorbers as excited-state electron donors and acceptors accessible with red/near-infrared irradiation. J. Am. Chem. Soc. 140, 5161–5170 (2018).

  45. 45.

    Byrnes, M. J. et al. Observation of 1MLCT and 3MLCT excited states in quadruply bonded Mo2 and W2 complexes. J. Am. Chem. Soc. 127, 17343–17352 (2005).

  46. 46.

    Burdzinski, G. T. et al. The remarkable influence of M2δ to thienyl π conjugation in oligothiophenes incorporating MM quadruple bonds. Proc. Natl Acad. Sci. USA 105, 15247–15252 (2008).

  47. 47.

    Chisholm, M. H., Gustafson, T. L. & Turro, C. Photophysical properties of MM quadruply bonded complexes supported by carboxylate ligands, MM = Mo2, MoW, or W2. Acc. Chem. Res. 46, 529–538 (2013).

  48. 48.

    Van der Veen, A. M., Cannizzo, A., van Mourik, F., Vlcek, A. & Chergui, M. Vibrational relaxation and intersystem crossing of binuclear metal complexes in solution. J. Am. Chem. Soc. 133, 305–315 (2011).

  49. 49.

    Steigman, A. E., Rice, S. F., Gray, H. B. & Miskowski, V. M. Electronic spectroscopy of d 8–d 8 diplatinum complexes. 1A2u(dσ* → ), 3Eu(d xz,d yz → ), and 3,1B2u(* → \(d_{x^2-y^2}\)) excited states of Pt2(P2O5H2)4 4−. Inorg. Chem. 26, 1112–1116 (1987).

  50. 50.

    Montalti, M., Credi, A., Prodi, L. & Gandolfi, M. T. Handbook of Photochemistry 3rd edn Ch. 7 (CRC, 2006).

  51. 51.

    Felton, G. A. N., Glass, R. S., Lichtenbergerm, D. L. & Evans, D. H. Iron-only hydrogenase mimics. Thermodynamic aspects of the use of electrochemistry to evaluate catalytic efficiency for hydrogen generation. Inorg. Chem. 45, 9181–9184 (2006).

  52. 52.

    White, T. W., Witt, S. E., Li, Z., Dunbar, K. R. & Turro, C. New Rh2(ii,ii) architecture for the catalytic reduction of H+. Inorg. Chem. 54, 10042–10048 (2015).

  53. 53.

    Beatty, J. W. & Stephenson, C. R. J. Amine functionalization via oxidative photoredox catalysis: methodology development and complex molecule synthesis. Acc. Chem. Res. 48, 1474–1484 (2015).

  54. 54.

    Pellegrin, Y. & Odobel, F. Sacrificial electron donor reagents for solar fuel production. C. R. Chim. 20, 283–295 (2017).

  55. 55.

    Sigal, I. S., Mann, K. R. & Gray, H. B. Solar energy storage reactions. Thermal and photochemical redox reactions of polynuclear rhodium isocyanide complexes. J. Am. Chem. Soc. 102, 7252–7256 (1980).

  56. 56.

    Mann, K. et al. Solar energy storage. Production of hydrogen by 546-nm irradiation of a dinuclear rhodium(i) complex in acidic aqueous solution. J. Am. Chem. Soc. 99, 5525–5526 (1977).

  57. 57.

    Jasimuddin, S., Fukuju, K., Otsuki, J. & Sakai, K. Photocatalytic hydrogen production from water in self-assembled supramolecular iridium–cobalt systems. Chem. Commun. 46, 8466–8468 (2010).

  58. 58.

    Nomrowski, J. & Wenger, O. S. Exploiting potential inversion for photoinduced multielectron transfer and accumulation of redox equivalents in a molecular heptad. J. Am. Chem. Soc. 140, 5343–5346 (2018).

  59. 59.

    O’Neil, M. P. et al. Picosecond optical switching based on biphotonic excitation of an electron donor–acceptor–donor molecule. Science 257, 63–65 (1992).

Download references


We thank the Support from the Department of Energy, Office of Science, Office of Basic Energy Sciences (DE-SC0020243) and The Ohio State University for partial support of this work and acknowledge A. Co for her invaluable insights regarding the electrochemical results, W. Kender for discussions on the mechanistic details and the Center for Chemical and Biophysical Dynamics (CCBD) for use of the ultrafast laser facility.

Author information

T.J.W. conceptualized the molecule, synthesized and characterized 1, performed investigations, which included the transient absorption and photocatalysis experiments, co-investigated the mechanistic model and drafted the manuscript. C.X. investigated the electrochemical properties and also performed photocatalysis experiments, co-investigated the mechanistic model and reviewed and edited the results, J.H. validated electronic absorption experiments and synthesized additional material of the target complex. J.C.G. collected the crystallographic data. C.T. supervised the project, aided in the experimental and mechanistic design, acquired funding and developed and edited the manuscript.

Correspondence to C. Turro.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Methods and Supplementary data; Supplementary Tables 1–3 and Figs. 1–25.

Crystallographic data

CIF for 1; CCDC reference 1871363.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Whittemore, T.J., Xue, C., Huang, J. et al. Single-chromophore single-molecule photocatalyst for the production of dihydrogen using low-energy light. Nat. Chem. 12, 180–185 (2020).

Download citation