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Synthesis, characterization and catalytic transfer hydrogenation properties of Ru(II) complexes


Three half-sandwich Ru(II) complexes with the general formulae of [Ru(\(\eta\) 6-p-cymene)(L)Cl2] (where L: 2a (diethyl-4-aminobenzylphosphonate), 2b (4-aminoethylbenzoate) and 2c (4-methoxybenzylamine) containing an aniline ligands were synthesized and their structures were characterized. The Crystal structure of complex [Ru(\(\eta\) 6-p-cymene)(2c)Cl2] was investigated by single crystal X-ray diffraction studies. Each Ru(II) ion in both complexes is coordinated with a 6-p-cymene nitrogen atom, two chloride and aniline derivatives. This results in a distorted piano-stool geometry. The catalytic performances of the complexes were investigated in transfer hydrogenation reactions. The complexes catalyze the transfer hydrogenation of cyclohexanone and 2-hexanone in the presence of a base. For 2-hexanone to 2-hexanol reduction, complex [Ru(\(\eta\) 6-p-cymene)(2a)Cl2] showed the highest conversion rate (at the end of 6 h) with 97% conversion. The complexes were found to be more active catalysts in the transfer hydrogenation of cyclohexanone than that of 2-hexanone.

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  1. Erdem A, Kılınçarslan R, Şahin Ç et al (2020) Synthesis, thermal, electrochemical and catalytic behavior toward transfer hydrogenation investigations of the half-sandwich RuII complexes with 2-(2′-quinolyl)benzimidazoles. J Mol Struct.

    Article  Google Scholar 

  2. Wang D, Astruc D (2015) The Golden Age of Transfer Hydrogenation. doi:

  3. Structures MB (2008) Modern Reduction Methods

  4. Johnstone RAW, Wilby AH, Entwistle ID (1985) Heterogeneous catalytic transfer hydrogenation and its relation to other methods for reduction of organic compounds. Chem Rev 85:129–170.

    CAS  Article  Google Scholar 

  5. Zassinovich G, Mestroni G (1992) Asymmetric hydrogen transfer reactions promoted by homogeneous transition metal catalysts. Chem Rev 92:1051–1069

    CAS  Article  Google Scholar 

  6. Poz F (2016) Metal-catalysed transfer hydrogenation of ketones. Top Curr Chem 374:1–67.

    CAS  Article  Google Scholar 

  7. Pandiarajan D, Ramesh R (2013) Ruthenium(II) half-sandwich complexes containing thioamides: synthesis, structures and catalytic transfer hydrogenation of ketones. J Organomet Chem 723:26–35.

    CAS  Article  Google Scholar 

  8. Moya SA, Negrete-Vergara C, Brown K et al (2017) Transfer hydrogenation of N-benzylideneaniline catalyzed by ruthenium complexes with pincer-type phosphorus nitrogen ligands using propan-2-ol as the hydrogen source. Catal Commun 99:150–153.

    CAS  Article  Google Scholar 

  9. Morris RH (2008) Ruthenium and osmium. Handb Homog Hydrog.

    Article  Google Scholar 

  10. Çirali DE, Dayan O (2015) Synthesis of tetranuclear ruthenium (II) complex of pyridyloxy-substituted 2,2′-dioxybiphenyl-cyclotriphosphazene platform and its catalytic application in the transfer hydrogenation of ketones. Phosphorus, Sulfur Silicon Relat Elem 190:1100–1107.

    CAS  Article  Google Scholar 

  11. Carrion MC, Sepúlveda F, Jalón FA et al (2009) Base-free transfer hydrogenation of ketones using arene ruthenium(II) complexes. Organometallics 28:3822–3833.

    CAS  Article  Google Scholar 

  12. Bacchi A, Pelagatti P, Pelizzi C, Rogolino D (2009) Diastereomeric half-sandwich Ru(II) cationic complexes containing amino amide ligands. Synthesis, solution properties, crystal structure and catalytic activity in transfer hydrogenation of acetophenone. J Organomet Chem 694:3200–3211.

    CAS  Article  Google Scholar 

  13. Raja MU, Raja N, Ramesh R (2010) Transfer hydrogenation of ketones using recyclable (η 6-arene) ruthenium(II) naphthylazo-p-methyl phenolate complex. Open Catal J 3:30–33.

    CAS  Article  Google Scholar 

  14. Dolomanov OV, Bourhis LJ, Gildea RJ et al (2009) OLEX2: a complete structure solution, refinement and analysis program. J Appl Crystallogr 42:339–341.

    CAS  Article  Google Scholar 

  15. Sheldrick GM (2015) SHELXT - Integrated space-group and crystal-structure determination. Acta Crystallogr Sect A Found Crystallogr 71:3–8.

    CAS  Article  Google Scholar 

  16. Sheldrick GM (2015) Crystal structure refinement with SHELXL. Acta Crystallogr Sect C Struct Chem 71:3–8

    Article  Google Scholar 

  17. Sadık M, Karabork M, Sahin I, Kose M (2021) Half-sandwich ruthenium(II) complexes containing 4-substituted aniline derivatives: structural characterizations and catalytic properties in transfer hydrogenation of ketones. Transit Met Chem 46:457–464.

    CAS  Article  Google Scholar 

  18. Cheng B, Tehrani AA, Hu ML, Morsali A (2014) Supramolecular assemblies of Ru(ii) organometallic half-sandwich complexes. CrystEngComm 16:9125–9134.

    CAS  Article  Google Scholar 

  19. Bacchi A, Pelagatti P (2016) Organometallic chemistry meets crystal engineering to give responsive crystalline materials. Chem Commun 52:1327–1337.

    CAS  Article  Google Scholar 

  20. Tyagi D, Binnani C, Rai RK et al (2016) Ruthenium-catalyzed oxidative homocoupling of arylboronic acids in water: ligand tuned reactivity and mechanistic study. Inorg Chem 55:6332–6343.

    CAS  Article  PubMed  Google Scholar 

  21. Bacchi A, Balordi M, Cammi R et al (2008) Mechanistic insights into acetophenone transfer hydrogenation catalyzed by half-sandwich ruthenium (II) complexes containing 2-(diphenylphosphanyl) aniline-a combined experimental and theoretical study. Eur J Inorg Chem 2008(28):4462–4473.

    CAS  Article  Google Scholar 

  22. Schlatter A, Woggon WD (2008) Enantioselective transfer hydrogenation of aliphatic ketones catalyzed by ruthenium complexes linked to the secondary face of β-cyclodextrin. Adv Synth Catal 350:995–1000.

    CAS  Article  Google Scholar 

  23. Agac A, Karakaya I, Sahin I et al (2016) Synthesis of aminomethyl quinazoline based ruthenium (II) complex and its application in asymmetric transfer hydrogenation under mild conditions. J Organomet Chem 819:189–193.

    CAS  Article  Google Scholar 

  24. Ritleng V, de Vries JG (2021) Ruthenacycles and iridacycles as transfer hydrogenation catalysts. Molecules

    Article  PubMed  PubMed Central  Google Scholar 

  25. Higuera-Padilla AR, Batista AA, Colina-Vegas L et al (2017) Synthesis of the [(η6-p-cymene)Ru(dppb)Cl]PF6 complex and catalytic activity in the transfer hydrogenation of ketones. J Coord Chem 70:3541–3551.

    CAS  Article  Google Scholar 

  26. Çalik HS, Ispir E, Karabuga Ş, Aslantas M (2015) Ruthenium (II) complexes of NO ligands: Synthesis, characterization and application in transfer hydrogenation of carbonyl compounds. J Organomet Chem 801:122–129.

    CAS  Article  Google Scholar 

  27. Cavallo M, Arnodo D, Mannu A et al (2021) Deep eutectic solvents as H2-sources for Ru(II)-catalyzed transfer hydrogenation of carbonyl compounds under mild conditions. Tetrahedron 83:131997.

    CAS  Article  Google Scholar 

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The author thanks to Research Coordination Unit of Kahramanmaras Sutcu Imam University for financial support (project number: 2018/2-9 YLS) and postdoc (DOSAP) Scholarship (İrfan Şahin).

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Şahin, İ., Sevim, S. & Köse, M. Synthesis, characterization and catalytic transfer hydrogenation properties of Ru(II) complexes. Transit Met Chem 47, 77–84 (2022).

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