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Deactivation of a ruthenium(II) N-heterocyclic carbene p-cymene complex during transfer hydrogenation catalysis

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A ruthenium (II) N-heterocyclic carbene (NHC) complex was synthesized to investigate ligand dissociation as a possible deactivation pathway for the catalytic cycle of a transfer hydrogenation reaction. Diiodo(1,3-dimethylbenzimidazole-2-ylidene)(p-cymene)ruthenium(II) was synthesized for use as the catalytic species and characterized using physico-chemical, spectroscopic methods, and single crystal X-ray diffraction. The transfer of hydrogen from isopropanol to acetophenone was followed using 1H NMR. We observed 94% conversion of the substrate to the alcohol product after 1 h. We also found that the p-cymene complex decomposed during the catalytic reaction to the extent of 80% deactivation after 1 h, based on 1H NMR spectrometry. From Gaussian calculations, an ultraviolet–visible spectrum that is in excellent agreement with the actual spectrum was computed, giving insight into the nature of the absorptions observed experimentally.

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  1. 1.

    Gladiali S, Mestroni G (1998) Transition metals for organic synthesis, Beller M, Bolm C, Eds. Wiley-VCH: Weinheim, Germany, Vol 2, 97–119

  2. 2.

    Zassinovich G, Mestroni G, Gladiali S (1992) Asymmetric hydrogen transfer reactions promoted by homogenous transition metal complexes. Chem Rev 92:1051–1069. https://doi.org/10.1021/cr00013a015

  3. 3.

    Johnstone RAW, Wilby AH, Entwistle ID (1985) Heterogenous catalytic transfer hydrogenation and its relation to other methods for reduction of organic compounds. Chem Rev 85:129–170. https://doi.org/10.1021/cr00066a003

  4. 4.

    Bullock RM (2004) Catalytic ionic hydrogenations. Chem Eur J 10:2366–2374. https://doi.org/10.1002/chem.200305639

  5. 5.

    Guillena G, Ramón DJ, Yus M (2007) Alcohols as electrophiles in C–C bond-forming reactions: the hydrogen autotransfer process. Angew Chem Int Ed 46:2358–2364. https://doi.org/10.1002/anie.200603794

  6. 6.

    Nixon TD, Whittlesey MK, Williams JMJ (2009) Transition metal catalyzed reactions of alcohols using borrowing hydrogen methodology. Dalton Trans. https://doi.org/10.1039/B813383B

  7. 7.

    Dobereiner GE, Crabtree RH (2009) Dehydrogenation as a substrate-activating strategy in homogenous transition-metal catalysis. Chem Rev 110:681–703. https://doi.org/10.1021/cr900202j

  8. 8.

    Tanoue K, Yamashita M (2015) Synthesis of pincer iridium complexes bearing a boron atom and iPr-substituted phosphorous atoms: applications to catalytic transfer dehydrogenation of alkanes. Organometallics 34:4011–4017. https://doi.org/10.1021/acs.organomet.5b00376

  9. 9.

    Arduengo AJ, Dias HVR, Harlow RI, Kline M (1992) Electronic stabilization of nucleophilic carbenes. J Am Chem Soc 114:5530. https://doi.org/10.1021/ja00040a007

  10. 10.

    Lappert MF (1988) The coordination chemistry of electron rich alkenes (enetetramines). J. Organometallic Chem 358:185. https://doi.org/10.1016/0022-328X(88)87079-7

  11. 11.

    Bourissou D, Guerret O, Gabbaï FP, Bertrand G (2000) Stable carbenes. Chem Rev 100:39–92. https://doi.org/10.1021/cr940472u

  12. 12.

    Hillier AC, Lee HM, Stevens ED, Nolan SP (2001) Cationic iridium complexes bearing imidazol-2-ylidene ligands as transfer hydrogenation catalysts. Organometallics 20:4246. https://doi.org/10.1021/om0103456

  13. 13.

    Wang D, Astruc D (2015) The golden age of transfer hydrogenation. Chem Rev 115:6621–6686. https://doi.org/10.1021/acs.chemrev.5b00203

  14. 14.

    Noyori R, Hashiguchi S (1997) Asymmetric transfer hydrogenation catalyzed by chiral ruthenium complexes. Acc Chem Res 30:97–102. https://doi.org/10.1021/ar9502341

  15. 15.

    Yaşar S, Karaca EO, Șahin C, Özdemir I, Șahin O, Büyükgüngör O (2015) Novel ruthenium(II)-N-heterocyclic carbene complexes: synthesis, characterization, and catalytic application. J Organometallic Chem. https://doi.org/10.1016/j.organchem.2015.04.012

  16. 16.

    Hintermair U, Campos J, Brewster TP, Pratt LM, Schley ND, Crabtree RH (2014) Hydrogen-transfer catalysis with Cp*IrIII complexes: the influence of the ancillary ligands. ACS Catalysis 4:99–108. https://doi.org/10.1021/cs400834

  17. 17.

    Albrecht M, Miecznikowski JR, Samuel A, Faller JW, Crabtree RH (2002) Chelated iridium(III) bis-carbene complexes as air-stable catalysts for transfer hydrogenation. Organometallics 21:3596–3604. https://doi.org/10.1021/om020338x

  18. 18.

    Pàmies O, Bäckvall J-E (2001) Studies on the mechanism of metal-catalyzed hydrogen transfer from alcohols to ketones. Chem Eur J 7:5052–5058. https://doi.org/10.1002/1521-3765(20011203)7:23<5052:AID-CHEM5052>3.0.CO;2-Z

  19. 19.

    Samec JSM, Bäckvall J-E (2002) Ruthenium-catalyzed transfer hydrogenation of imines by propan-2-ol in benzene. Chem Eur J 8:2955–2961. https://doi.org/10.1002/1521-3765(20020703)8:13<2955:AID-CHEM2955>3.0.CO;2-Q

  20. 20.

    Kuhl S, Schneider R, Fort Y (2003) Transfer hydrogenation of imines catalyzed by a nickel(0)/NHC complex. Organometallics 22:4184–4186. https://doi.org/10.1021/om034046n

  21. 21.

    Farrell K, Müller-Bunz H, Albrecht M (2015) Synthesis, isomerization and catalytic transfer hydrogenation activity of rhodium(III) complexes containing both chelating dicarbenes and diphosphine ligands. Organometallics 34:5723–5733. https://doi.org/10.1021/acs.organomet.5b00809

  22. 22.

    Fernandez FE, Puerta MC, Valerga P (2012) Ruthenium(II) picolyl-NHC complexes: synthesis, characterization, and catalytic activity in amine N-alkylation and transfer hydrogenation reactions. Organometallics 31:6868–6879. https://doi.org/10.1021/om300692a

  23. 23.

    Campos J, Hintermair U, Brewster TP, Takase MK, Crabtree RH (2014) Catalyst activation by loss of cyclopentadienyl ligands in hydrogen transfer catalysis with Cp*IrIII complexes. ACS Catalysis 4:973–985. https://doi.org/10.1021/cs401138f

  24. 24.

    Grimmett MR (1997) Imidazole and benzimidazole synthesis, Academic Press, 202

  25. 25.

    CrystalClear and CrystalStructure; Rigaku/MSC: The Woodlands, TX, 2005

  26. 26.

    Sheldrick GM (2008) A short history of SHELX. Acta Cryst. A64:112–122. https://doi.org/10.1107/S0108767307043930

  27. 27.

    Frisch MJ, Trucks GW, Schlegel HB, Scuseria GE, Robb MA, Cheeseman JR, Scalmani G, Barone V, Petersson GA, Nakatsuji H, Li X, Caricato M, Marenich A, Bloino J, Janesko BG, Gomperts R, Mennucci B, Hratchian HP, Ortiz JV, Izmaylov AF, Sonnenberg JL, Williams-Young D, Ding F, Lipparini F, Egidi F, Goings J, Peng B, Petrone A, Henderson T, Ranasinghe D, Zakrzewski VG, Gao J, Rega N, Zheng G, Liang W, Hada M, Ehara M, Toyota K, Fukuda R, Hasegawa J, Ishida M, Nakajima T, Honda Y, Kitao O, Nakai H, Vreven T, Throssell K, Montgomery Jr. JA, Peralta JE, Ogliaro F, Bearpark M, Heyd JJ, Brothers E, Kudin KN, Staroverov VN, Keith T, Kobayashi R, Normand J, Raghavachari K, Rendell A, Burant JC, Iyengar SS, Tomasi J, Cossi M, Millam JM, Klene M, Adamo C, Cammi R, Ochterski JW, Martin RL, Morokuma K, Farkas O, Foresman JB, Fox DJ (2013) Gaussian 09, Revision D.01, Gaussian, Inc.: Wallingford CT

  28. 28.

    Wang HMJ, Lin IJB (1998) Facile synthesis of silver(I)-carbene complexes. Useful carbene transfer agents. Organometallics 17:972. https://doi.org/10.1021/om9709704

  29. 29.

    Ghattas W, Müller-Bunz H, Albrecht M (2010) [Ru(bpy)3]2+ analogues containing an N-heterocyclic carbene ligand. Organometallics 29:6782–6789. https://doi.org/10.1021/om100925j

  30. 30.

    Sabater S, Mata JA, Peris E (2012) Heterobimetallic iridium-ruthenium assemblies through an ambidentate triazole-diylidene ligand: electrochemical properties and catalytic behavior in a cascade reaction. Organometallics 31:6450. https://doi.org/10.1021/om300675p

  31. 31.

    Zhang Y, Chen C, Ghosh SC, Li Y, Hong SH (2010) Well defined N-heterocyclic carbine based ruthenium catalysts for direct amide synthesis from alcohols and amines. Organometallics 29:1374–1378. https://doi.org/10.1021/om901020h

  32. 32.

    Kumar S, Narayanan A, Rao MN, Shaikh MM, Ghosh P (2011) Ruthenium complexes of chelating amido-functionalized N-heterocyclic carbene ligands: synthesis, structure, and DFT studies. J Chem Sci 123(6):791–798. https://doi.org/10.10007/s12039-011-0173-5

  33. 33.

    Kauhfhold O, Flores-Figueroa A, Pape T, Hahn FE (2009) Template synthesis of ruthenium complexes with saturated and benzannulated NH, NH-stabilized N-heterocyclic carbene ligands. Organometallics 28:896–901. https://doi.org/10.1021/om800964n

  34. 34.

    Grau J, Noe V, Ciudad C, Prieto MJ, Font-Bardia M, Calvet T, Moreno V (2012) New π-arene ruthenium(II) piano-stool complexes with nitrogen ligands. J Inorg Biochem 109:72–81. https://doi.org/10.1016/j.jinorgbio.2012.01.003

  35. 35.

    Gichumbi JM, Friedrich HB, Omondi B (2016) Synthesis and characterization of piano-stool ruthenium complexes with N, N′-pyridine imine bidentate ligands and their application in styrene oxidation. J Organomet Chem 808:87–96. https://doi.org/10.1016/j.jorganchem.2016.02.015

  36. 36.

    Małecki JG, Jaworska M, Kruszynski R (2006) Synthesis, molecular, crystal and electronic structure of [(C6H6)RuCl2(picoline)]. Polyhedron 25:2519–2524. https://doi.org/10.1016/j.poly.2006.02.016

  37. 37.

    Bratsos I, Urankar D, Zangrando E, Genova-Kalou P, Košmrlj J, Alessio E, Turel I (2011) 1-(2-Picolyl)-substituted 1,2,3-triazole as novel chelating ligand for the preparation of ruthenium complexes with potential anticancer activity. Dalton Trans 40:5188–5199. https://doi.org/10.1039/c0dt01807d

  38. 38.

    Shirin Z, Pramanik A, Ghosh P, Mukherjee R (1996) Stable cyclohexadienyl complexes of ruthenium in a piano stool geometry containing a tridentate nitrogen donor ligand. First structural characterization of the (η5-cyanocyclohexadienyl)ruthenium(II) complex and spectroelectrochemical correlation. Inorg Chem 35:3431–3433. https://doi.org/10.1021/ic950750n

  39. 39.

    Horn S, Gandolfi C, Albrecht M (2011) Transfer hydrogenation of ketones and activated olefins using chelating NHC ruthenium complexes. Eur J Inorg Chem 18:2863–2868. https://doi.org/10.1002/ejic.201100143

  40. 40.

    Nini D, Hor TSA (2011) Syntheses and structures of ruthenium(II) N,S-heterocyclic carbene diphosphine complexes and their catalytic activity towards transfer hydrogenation. Chem Asian J. https://doi.org/10.1002/asia.201000930

  41. 41.

    Yigit M, Yigit B, Ozdemir I, Cetinkaya E, Cetinkaya B (2006) Active ruthenium-(N-heterocyclic carbene) complexes for hydrogenation of ketones. Appl Organomet Chem 20(5):322–327. https://doi.org/10.1002/aoc.1054

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JRM would like to thank Fairfield University for awarding him a generous sabbatical leave when part of this research was accomplished. JRM thanks Professor Robert Crabtree for hosting him during his sabbatical leave and for helpful suggestions. This work was supported by generous funding from the Fairfield University Summer Research Kuck Fund (NAB, SCB, and RMK). The authors (NAB, CAVA, SCB, MEM, and RMK) acknowledge support from Fairfield University Hardiman and Lawrence Scholarships for undergraduate research expenses. MAL is grateful for receipt of an NTID Faculty Evaluation and Development (FEAD) grant. We all thank the reviewers for helpful suggestions as we revised the manuscript.

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Correspondence to John R. Miecznikowski.

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Miecznikowski, J.R., Bernier, N.A., Van Akin, C.A. et al. Deactivation of a ruthenium(II) N-heterocyclic carbene p-cymene complex during transfer hydrogenation catalysis. Transit Met Chem 43, 21–29 (2018). https://doi.org/10.1007/s11243-017-0189-x

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