Electronic Influence of Different β-Diketonato Ligands on the Electrochemical Behaviour of Tris(β-Diketonato)M(III) Complexes, M = Cr, Mn and Fe

Abstract:

The reduction of the M^III/M^II metal couple of complexes Cr (β-diketonato)₃, Fe (β-diketonato)₃ and Mn (β-diketonato)₃ is reviewed and compared. The ease of reduction of the M^III/M^II couple of M(β-diketonato)₃ complexes increases according to the metal sequence Cr (β-diketonato)₃ < Fe (β-diketonato)₃ < Mn (β-diketonato)₃ (with the most positive reduction potential). Good linear relationships obtained between the reduction potential and different electronic parameters related to the β-diketonato ligand on these M^III(β-diketonato)₃ complexes, show that the ease of reduction of the M^III/M^II couple increases with decreasing acidic strength (pK_a) of the respective β-diketone ligands. It also increases with increasing total group electronegativity of the R and R' groups on the respective β-diketonato ligand (RCOCHCOR')⁻ of the M(β-diketonato)₃ complexes, (χ_R + χ_R'), as well as with an increase in the total Hammett sigma meta constants (σ_R + σ_R'), and also with increasing value of the Lever ligand electronic parameter (E_L) of ligand (RCOCHCOR')⁻.

• Periodical: Journal of Nano Research (Volume 44)
• Pages: 252-264
• DOI: https://doi.org/10.4028/www.scientific.net/JNanoR.44.252
• Online since: November 2016
• Authors: Roxanne Gostynski, Marrigje Marianne Conradie, Ren Yuan Liu, Jeanet Conradie*
• Keywords: Cyclic Voltammogram, Electrochemistry, Electronegativity, Hammett, Lever, pK_a, β-Diketone

References

[1] R.C. Mehrotra, R. Bohra, D.P. Gaur, Metal b-diketonates and allied derivatives, Academic Press, London, (1978).

[2] (a) J. Conradie, T.S. Cameron, M.A.S. Aquino, G.J. Lamprecht, J.C. Swarts, Synthetic, electrochemical and structural aspects of a series of ferrocene-containing dicarbonyl β-diketonato rhodium(I) complexes, Inorganica Chimica Acta 358 (2005).

DOI: 10.1016/j.ica.2005.02.010

[3] (a) T. A Tsotetsi, A. Kuhn, A. Muller, J. Conradie, Substitution kinetics of biphenol at dichlorobis(acetylacetonato-O, O')titanium(IV): Isolation, characterization, crystal structure and enhanced hydrolytic stability of the product bis(acetylacetonato-O, O')(biphenyldiolato-O, O')titanium(IV), Polyhedron 28 (2009).

DOI: 10.1016/j.poly.2008.10.025

[4] (a) W.C. Fernelius, J.E. Blanch, Chromium(III) Acetylacetonate: [Tris(2, 4-Pentanediono) Chromium(III)], Inorganic Syntheses 5 (1957).

DOI: 10.1002/9780470132364.ch35

[5] (a) I. Diaz-Acosta, J. Baker, W. Cordes, P. Pulay, Calculated and Experimental Geometries and Infrared Spectra of Metal Tris-Acetylacetonates: Vibrational Spectroscopy as a Probe of Molecular Structure for Ionic Complexes. Part I, J. Journal of Physical Chemistry A 105 (2001).

DOI: 10.1021/jp0028599

[6] (a) A. Fürstner, A. Leitner, M. Méndez, H. Krause, Iron-Catalyzed Cross-Coupling Reactions, J. Am. Chem. Soc. 124 (2002).

DOI: 10.1021/ja027190t

[7] F. Diederich, P.J. Stang, Metal-catalyzed Cross-coupling Reactions, Wiley-VCH, Weinheim, Germany, (1998).

[8] P.W.N.M. van Leeuwen, Homogeneous Catalysis, Kluwer Academic Publishers, P.O. Box 322, 3300, Dordrecht, The Netherlands, p.1–3.

[9] A. Kuhn, K.G. von Eschwege, J. Conradie, Electrochemical and DFT-modeled reduction of Enolized 1, 3-Diketones, Electrochimica Acta 56 (2011) 6211-6218. DOI: 10. 1016/j. electActa2011. 03. 08.

DOI: 10.1016/j.electacta.2011.03.083

[10] (a) E. Erasmus, J. Conradie, A. Muller, J.C. Swarts, Synthesis, crystal structure and electrochemistry of tetrahedral mono-β-diketonato titanocenyl complexes, Inorganica Chimica Acta 360 (2007).

DOI: 10.1016/j.ica.2006.11.010

[11] R. Liu, J. Conradie, Tris(b-diketonato)chromium(III) complexes: Effect of the b-diketonate ligand on the redox properties, Electrochimica Acta 2015, 185, 288-296. http: /dx. doi. org/10. 1016/j. electActa2015. 10. 116.

DOI: 10.1016/j.electacta.2015.10.116

[12] R. Freitag, J. Conradie, Electrochemical and Computational Chemistry Study of Mn(β-diketonato)3 complexes, Electrochimica Acta 158 (2015) 418-426. DOI: 10. 1016/j. electActa2015. 01. 147.

DOI: 10.1016/j.electacta.2015.01.147

[13] M.M. Conradie, J. Conradie, Electrochemical behaviour of Tris(b-diketonato)iron(III) complexes: A DFT and experimental study, Electrochimica Acta 152 (2015) 512-519. DOI: 10. 1016/j. electActa2014. 11. 128.

DOI: 10.1016/j.electacta.2014.11.128

[14] D.T. Sawyer, J.L. Roberts Jr, Experimental Electrochemistry for Chemists, John Wiley & Sons, New York, 1974, p.54.

[15] D.H. Evans, K.M. O'Connell, R.A. Peterson, M.J. Kelly, Cyclic Voltammetry, Journal of Chemical Education 60 (1983) 290-293. DOI: 10. 1021/ed060p290.

[16] G. Gritzner, J. Kuta, Recommendations on reporting electrode potentials in nonaqueous solvents, Pure and Applied Chemistry 56 (1984) 461-466. DOI: 10. 1351/pac198456040461.

DOI: 10.1351/pac198456040461

[17] A.J.L. Pombeiro, Electron-donor/acceptor properties of carbynes, carbenes, vinylidenes, allenylidenes and alkynyls as measured by electrochemical ligand parameters, Journal of Organometallic Chemistry 690 (2005).

DOI: 10.1016/j.jorganchem.2005.07.111

[18] A.K.L. Rahman, M.B. Hossain, M.A. Halim, D.A. Chowdhury, M.A. Salam, Studies on some diazo coupled products of chromium(III) chelates of acetylacetone and benzoylacetone, African Journal of Pure and Applied Chemistry 4 (2010).

[19] M.M. Conradie, P.H. van Rooyen, J. Conradie, Crystal and electronic structures of tris[4, 4, 4-Trifluoro-1-(2-X)-1, 3-butanedionato]iron(III) isomers (X = thienyl or furyl): An X-ray and computational study, Journal of Molecular Structure 1053 (2013).

DOI: 10.1016/j.molstruc.2013.09.014

[20] M.N. Bhattacharjee, M.K. Chaudhuri, D.T. Khathing, Direct Synthesis of Tris(acetylacetonato)manganese(III), Journal of the Chemical Society, Dalton Transactions (1982) 669-670. DOI: 10. 1039/DT9820000669.

DOI: 10.1039/dt9820000669

[21] G. te Velde, F.M. Bickelhaupt, E.J. Baerends, C.F. Guerra, S.J.A. van Gisbergen, J.G. Snijders, T.J. Ziegler, Chemistry with ADF, Journal of Computational Chemistry 22 (2001) 931-967. DOI: 10. 1002/jcc. 1056.

DOI: 10.1002/jcc.1056

[22] N.C. Handy, A.J. Cohen, Left-right correlation energy, Molecular Physics 99 (2001) 403-412. DOI: 10. 1080/00268970010018431.

DOI: 10.1080/00268970010018431

[23] C. Lee, W. Yang, R.G. Parr, Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density, Physical Review B: Condensed Matter 37 (1988) 785-789. DOI: 10. 1103/PhysRevB. 37. 785.

DOI: 10.1103/physrevb.37.785

[24] B.G. Johnson, P.M.W. Gill, J.A. Pople, The performance of a family of density functional methods, Journal of Chemical Physics 98 (1993) 5612-5626. DOI: 10. 1063/1. 464906.

DOI: 10.1063/1.464906

[25] T.V. Russo, R.L. Martin, P.J. Hay, Density Functional Calculations on First Row Transition Metals, Journal of Chemical Physics 101 (1994) 7729-7737. DOI: 10. 1063/1. 468265.

DOI: 10.1063/1.468265

[26] V. Bertolasi, P. Gilli, V. Ferretti, G. Gilli, Evidence for resonance-assisted hydrogen bonding. 2. Intercorrelation between crystal structure and spectroscopic parameters in eight intramolecularly hydrogen bonded 1, 3-diaryl-1, 3-propanedione enols, Journal of the American Chemical Society 113 (1991).

DOI: 10.1021/ja00013a030

[27] Gordy scale group electronegativities, cR, are empirical numbers that express the combined tendency of not only one atom but a group of atoms, like R = CF3 or CH3, to attract electrons including those in a covalent bond, as a function of the number of valence electrons n and the covalent radius r in Å, of groups as discussed in: (a) P.R. Wells, in: Progress in Physical Organic Chemistry, John Wiley & Sons Inc., New York, 1968, vol. 6, pp.111-145; (b) R.E. Kagarise, Relation between the Electronegativities of Adjacent Substituents and the Stretching Frequency of the Carbonyl Group, JJournal of the American Chemical Society 77 (1955).

DOI: 10.1021/ja01610a093

[28] L.P. Hammett, Some relations between reaction rates and equilibrium constants, Chemical Reviews 17 (1935) 125–136.

DOI: 10.1021/cr60056a010

[29] C. Hansch, A. Leo, R.W. Taft, A survey of Hammett substituent constants and resonance and field parameters, Chemical Reviews 91 (1991) 165–195. DOI: 10. 1021/cr00002a004.

DOI: 10.1021/cr00002a004

[30] A.B.P. Lever, Electrochemical parametrization of metal complex redox potentials, using the ruthenium(III)/ruthenium(II) couple to generate a ligand electrochemical series, Inorganic Chemistry 29 (1990) 1271–1285. DOI: 10. 1021/ic00331a030.

DOI: 10.1021/ic00331a030

[31] M.F.C. Guedes da Silva, A.M. Trzeciak, J.J. Ziółkowski, A.J.L. Pombeiro, Redox Potential, Ligand and Structural Effects in Rhodium(I) Complexes, Journal of Organometallic Chemistry 620 (2001) 174–181. DOI: 10. 1016/S0022-328X(00)00816-0.

DOI: 10.1016/s0022-328x(00)00816-0

[32] A.M. Trzeciak, B. Borak, Z. Ciunik, J.J. Ziółkowski, M.F.C. Guedes da Silva, A.J.L. Pombeiro, Structure, Electrochemistry and Hydroformylation Catalytic Activity of the Bis(pyrazolylborato) rhodium(I) Complexes [RhBp(CO)P] [P=P(NC4H4)3, PPh3, PCy3, P(C6H4OMe-4)3], European Journal of Inorganic Chemistry 2004 (2004).

DOI: 10.1002/ejic.200300517

[33] I. Kovacik, O. Gevert, H. Werner, M. Schmittel, R. Söllner, Study of the relative π-acceptor ability of unsaturated ligands : C(=C)nPh2 (n = 0, 1, 2 and 4) based on cyclic voltammetry of complexes trans-[RhCl(L)(Pi Pr3)2] (L = : C(=C)nPh2 , C2H4 and CO), Inorganica Chimica Acta 275-276 (1998).

DOI: 10.1016/s0020-1693(98)00074-7

[34] J. Conradie, Density Functional Theory Calculations of Rh-β-diketonato complexes, Journal of the Chemical Society, Dalton Transactions 44 (2015) 1503-1515. DOI: 10. 1039/c4dt02268h.

DOI: 10.1039/c4dt02268h

[35] Cambridge Structural Database (CSD), Version 5. 36, May 2015 update. Selected CSD reference codes for [Fe(β-diketonato)3] complexes: FEACAC02, FEACAC02, FEACAC03, FEACAC05, FEACAC07, FEACAC08, FEACAC09, JICMEN, JICMEN01, VUBSOA, BUPTAH, DPPDFE, DPPDFE01, DUBMES10, DUBMES11, HILVAB, TTFBFE01, TTFBFE, DUBMOC10, SOJXEU01. Selected CSD reference codes for [Cr(β-diketonato)3] complexes: ACACCR12, ACACCR, ACACCR02, ACACCR05, ACACCR07, ACACCR08, ACACCR08, ACACCR08, ACACCR08, ACACCR08, ACACCR08, ACACCR10, ACACCT, ACACCT, ACACCZ, ACACCZ01, ACACCZ02, ACRTUR, FECWAL01, FECWAL02, IGAGEC, IGAGEC01. Selected CSD reference codes for [Mn(β-diketonato)3] complexes: ACACMN02, ACACMN21, ACACMN21, ACACMN23, ACACMN23, ACACMN23, ACACMN23, ACACMN22, ACACMN22, XESPIW, JINPIF02, JINPIF, JINPIF01, NOSHUA, QAYYEU.

[36] R. Freitag, J. Conradie, Understanding the Jahn-Teller Effect in octahedral transition metal complexes – a Molecular Orbital view of the Mn(β-diketonato)3 complex, Journal of Chemical Education 90 (2013) 1692-1696. DOI: 10. 1021/ed400370p.

DOI: 10.1021/ed400370p

[37] H.S. Jarrett, Paramagnetic Resonance in Trivalent Transition Metal Complexes, Journal of Chemical Physics 27 (1957) 1298. DOI: 10. 1063/1. 1743995.

DOI: 10.1063/1.1743995

[38] S.L. Dexheimer, J.W. Gohdes, M.K. Chan, K.S. Hagen, W.H. Armstrong, M.P. Klein, Detection of EPR Spectra in S = 2 States of Trivalent Manganese Complexes, Journal of the American Ceramic Society 111 (1989) 8923-8926. DOI: 10. 1021/ja00206a028.

DOI: 10.1021/ja00206a028

[39] F.A. Cotton, G. Wilkinson, C.A. Murillo, M. Bochmann, Advanced inorganic chemistry, Sixth edition, John Wiley & Sons, New York, 1999, p.790.

DOI: 10.1007/s00897990345a

[40] M. Gerloch, J. Lewis, R.C. Slade, Paramagnetic anisotropies and zero-field splitting of some high-spin iron(III) complexes, Journal of the Chemical Society A (1969) 1422-1427. DOI: 10. 1039/J19690001422.

DOI: 10.1039/j19690001422

[41] K. Endo, M. Furukawa, H. Yamatera, H. Sano, Lifetimes of ortho-Positronium in Benzene Solutions of b-Diketonates of Iron(III) and Cobalt(III), Bulletin of the Chemical Society of Japan 53 (1980) 407-410.

DOI: 10.1246/bcsj.53.407

[42] C. Tsiamis, C. Michael, A.D. Jannakoudakis, P.D. Jannakoudakis, Structure-Redox Potential Relations of some Tris(b-dicarbonylato)iron(III) Chelates, Inorganic Chimica Acta, 120 (1986) 1-9.

DOI: 10.1016/s0020-1693(00)85454-7

[43] G. Gritzner, H. Murauer, V. Gutmann, The polarographic and voltammetric behaviour of acetylacetonato and hexafluoroacetylacetonato complexes in acetonitrile, Journal of Electroanalytical Chemistry 101 (1979).

DOI: 10.1016/s0022-0728(79)80231-4

[44] R. van Gorkum, E. Bouwman, J. Reedijk, Fast Autoxidation of Ethyl Linoleate Catalyzed by [Mn(acac)3] and Bipyridine: A Possible Drying Catalyst for Alkyd Paints, Inorganic Chemistry 43 (2004) 2456-2458. DOI: 10. 1021/ic0354217.

DOI: 10.1021/ic0354217

[45] K. Yamaguchi, D.T. Sawyer, Redox chemistry for the mononuclear tris(picolinato)- tris(acetylacetonata)-, and tris(8-quinolinata)manganese(III) complexes: Reaction mimics for the water-oxidation cofactor in photosystem II, Inorganic Chemistry 24 (1985).

DOI: 10.1021/ic00200a032

[46] W.C. du Plessis, T.G. Vosloo, J.C. Swarts, b-Diketones containing a ferrocenyl group: synthesis, structural aspects, pKa' values, group electronegativities and complexation with rhodium(I), Journal of the Chemical Society, Dalton Transactions 15 (1998).

DOI: 10.1039/a802398k

[47] M.M. Conradie, J. Conradie, Electrochemical behaviour of Tris(b-diketonato)iron(III) complexes: A DFT and experimental study, Electrochimica Acta 152 (2015) 512-519. DOI: 10. 1016/j. electActa2014. 11. 128.

DOI: 10.1016/j.electacta.2014.11.128

[48] M.M. Conradie, A.J. Muller, J. Conradie, Thienyl-containing b-diketones: synthesis, characterization, crystal structure, keto-enol kinetics, South African Journal of Chemistry 61 (2008) 13-21.

[49] A. Sudo, S. Hirayama, T. Endo, Highly efficient catalysts-acetylacetonato complexes of transition metals in the 4th period for ring-opening polymerization of 1, 3-benzoxazine, Journal of Polymer Science Part A: Polymer Chemistry 48 (2010).

DOI: 10.1002/pola.23810

[50] J.R. Bryant, J.E. Taves, J.M. Mayer, Oxidations of Hydrocarbons by Manganese(III) Tris(hexafluoroacetylacetonate), Inorganic Chemistry 41 (2002) 2769-2776. DOI: 10. 1021/ic025541z.

DOI: 10.1021/ic025541z