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Volumn 6, Issue 10, 2014, Pages 919-926

Harnessing redox activity for the formation of uranium tris(imido) compounds

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EID: 84920118476     PISSN: 17554330     EISSN: 17554349     Source Type: Journal    
DOI: 10.1038/nchem.2009     Document Type: Article
Times cited : (145)

References (48)
  • 1
    • 84856041532 scopus 로고    scopus 로고
    • The shrinking world of innocent ligands: Conventional and nonconventional redox-active ligands
    • Kaim, W. The shrinking world of innocent ligands: conventional and nonconventional redox-active ligands. Eur. J. Inorg. Chem. 2012, 343-348 (2012).
    • (2012) Eur. J. Inorg. Chem. , vol.2012 , pp. 343-348
    • Kaim, W.1
  • 2
    • 84856722613 scopus 로고    scopus 로고
    • Redox non-innocent ligands: Versatile new tools to control catalytic reactions
    • Lyaskovskyy, V. & de Bruin, B. Redox non-innocent ligands: versatile new tools to control catalytic reactions. ACS Catal. 2, 270-279 (2012).
    • (2012) ACS Catal. , vol.2 , pp. 270-279
    • Lyaskovskyy, V.1    De Bruin, B.2
  • 3
    • 80053954556 scopus 로고    scopus 로고
    • Preface: Forum on redox-active ligands
    • Chirik, P. J. Preface: forum on redox-active ligands. Inorg. Chem. 50, 9737-9740 (2011).
    • (2011) Inorg. Chem. , vol.50 , pp. 9737-9740
    • Chirik, P.J.1
  • 4
    • 76749155517 scopus 로고    scopus 로고
    • Radical ligands confer nobility on base-metal catalysts
    • Chirik, P. J. & Wieghardt, K. Radical ligands confer nobility on base-metal catalysts. Science 327, 794-795 (2010).
    • (2010) Science , vol.327 , pp. 794-795
    • Chirik, P.J.1    Wieghardt, K.2
  • 5
    • 84874069990 scopus 로고    scopus 로고
    • Group transfer reactions of d0 transition metal complexes: Redox-active ligands provide a mechanism for expanded reactivity
    • Munha, R. F., Zarkesh, R. A. & Heyduk, A. F. Group transfer reactions of d0 transition metal complexes: redox-active ligands provide a mechanism for expanded reactivity. Dalton Trans. 42, 3751-3766 (2013).
    • (2013) Dalton Trans. , vol.42 , pp. 3751-3766
    • Munha, R.F.1    Zarkesh, R.A.2    Heyduk, A.F.3
  • 6
    • 33750047554 scopus 로고    scopus 로고
    • Iron-catalyzed [2p+2p] cycloaddition of a-dienes: The importance of redox-active supporting ligands
    • Bouwkamp, M. W., Bowman, A. C., Lobkovsky, E. & Chirik, P. J. Iron-catalyzed [2p+2p] cycloaddition of a-dienes: the importance of redox-active supporting ligands. J. Am. Chem. Soc. 128, 13340-13341 (2006).
    • (2006) J. Am. Chem. Soc. , vol.128 , pp. 13340-13341
    • Bouwkamp, M.W.1    Bowman, A.C.2    Lobkovsky, E.3    Chirik, P.J.4
  • 7
    • 33750361497 scopus 로고    scopus 로고
    • Electronic structure of bis(imino)pyridine iron dichloride, monochloride, and neutral ligand complexes: A combined structural, spectroscopic, and computational study
    • Bart, S. C. et al. Electronic structure of bis(imino)pyridine iron dichloride, monochloride, and neutral ligand complexes: a combined structural, spectroscopic, and computational study. J. Am. Chem. Soc. 128, 13901-13912 (2006).
    • (2006) J. Am. Chem. Soc. , vol.128 , pp. 13901-13912
    • Bart, S.C.1
  • 8
    • 84876548815 scopus 로고    scopus 로고
    • Multi-electron reduction facilitated by a trianionic pyridine(diimine) ligand
    • Cladis, D. P., Kiernicki, J. J., Fanwick, P. E. & Bart, S. C. Multi-electron reduction facilitated by a trianionic pyridine(diimine) ligand. Chem. Commun. 49, 4169-4171 (2013).
    • (2013) Chem. Commun. , vol.49 , pp. 4169-4171
    • Cladis, D.P.1    Kiernicki, J.J.2    Fanwick, P.E.3    Bart, S.C.4
  • 9
    • 0001603304 scopus 로고
    • Intra-vs. Intermolecular a-hydrogen abstraction in the generation of multiple imido complexes: Synthesis, reactivity, and structural studies of the d0 tris(imido) functional group of tungsten
    • Morrison, D. L. et al. Intra-vs. intermolecular a-hydrogen abstraction in the generation of multiple imido complexes: synthesis, reactivity, and structural studies of the d0 tris(imido) functional group of tungsten. Organometallics 14, 2435-2446 (1995).
    • (1995) Organometallics , vol.14 , pp. 2435-2446
    • Morrison, D.L.1
  • 10
    • 84857275468 scopus 로고    scopus 로고
    • The first group 4 metal bis(imido) and tris(imido) complexes
    • Schwarz, A. D., Nielson, A. J., Kaltsoyannis, N. & Mountford, P. The first group 4 metal bis(imido) and tris(imido) complexes. Chem. Sci. 3, 819-824 (2012).
    • (2012) Chem. Sci. , vol.3 , pp. 819-824
    • Schwarz, A.D.1    Nielson, A.J.2    Kaltsoyannis, N.3    Mountford, P.4
  • 11
    • 0000072888 scopus 로고
    • Tris(phenylimido) complexes of niobium and tantalum: Preparation and properties of the d0 [M (=NR)3]- (M=Nb, Ta) functional group
    • Smith, D. P., Allen, K. D., Carducci, M. D. & Wigley, D. E. Tris(phenylimido) complexes of niobium and tantalum: preparation and properties of the d0 [M (=NR)3]- (M=Nb, Ta) functional group. Inorg. Chem. 31, 1319-1320 (1992).
    • (1992) Inorg. Chem. , vol.31 , pp. 1319-1320
    • Smith, D.P.1    Allen, K.D.2    Carducci, M.D.3    Wigley, D.E.4
  • 13
    • 43949099956 scopus 로고    scopus 로고
    • Structural and spectroscopic characterization of a charge-separated uranium benzophenone ketyl radical complex
    • Lam, O. P., Anthon, C., Heinemann, F. W., O'Connor, J. M. & Meyer, K. Structural and spectroscopic characterization of a charge-separated uranium benzophenone ketyl radical complex. J. Am. Chem. Soc. 130, 6567-6576 (2008).
    • (2008) J. Am. Chem. Soc. , vol.130 , pp. 6567-6576
    • Lam, O.P.1    Anthon, C.2    Heinemann, F.W.3    O'connor, J.M.4    Meyer, K.5
  • 14
    • 40949139695 scopus 로고    scopus 로고
    • Chargeseparation in uranium diazomethane complexes leading to C-H activation and chemical transformation
    • Lam, O. P., Feng, P. L., Heinemann, F.W., O'Connor, J. M. & Meyer, K. Chargeseparation in uranium diazomethane complexes leading to C-H activation and chemical transformation. J. Am. Chem. Soc. 130, 2806-2816 (2008).
    • (2008) J. Am. Chem. Soc. , vol.130 , pp. 2806-2816
    • Lam, O.P.1    Feng, P.L.2    Heinemann, F.W.3    O'connor, J.M.4    Meyer, K.5
  • 15
    • 0035959072 scopus 로고    scopus 로고
    • Metal-to-ligand electron transfer in diiminopyridine complexes of Mn-Zn. A theoretical study
    • Budzelaar, P. H. M., de Bruin, B., Gal, A. W., Wieghardt, K. & van Lenthe, J. H. Metal-to-ligand electron transfer in diiminopyridine complexes of Mn-Zn. A theoretical study. Inorg. Chem. 40, 4649-4655 (2001).
    • (2001) Inorg. Chem. , vol.40 , pp. 4649-4655
    • Budzelaar, P.H.M.1    De Bruin, B.2    Gal, A.W.3    Wieghardt, K.4    Van Lenthe, J.H.5
  • 16
    • 0037131450 scopus 로고    scopus 로고
    • The ability of the a,a'-diiminopyridine ligand system to accept negative charge: Isolation of paramagnetic and diamagnetic trianions
    • Enright, D., Gambarotta, S., Yap, G. P. A. & Budzelaar, P. H. M. The ability of the a,a'-diiminopyridine ligand system to accept negative charge: isolation of paramagnetic and diamagnetic trianions. Angew. Chem. Int. Ed. 41, 3873-3876 (2002).
    • (2002) Angew. Chem. Int. Ed. , vol.41 , pp. 3873-3876
    • Enright, D.1    Gambarotta, S.2    Yap, G.P.A.3    Budzelaar, P.H.M.4
  • 18
    • 84897981549 scopus 로고    scopus 로고
    • Multielectron C-O bond activation mediated by a family of reduced uranium complexes
    • Kiernicki, J. J. et al. Multielectron C-O bond activation mediated by a family of reduced uranium complexes. Inorg. Chem. 53, 3730-3741 (2014).
    • (2014) Inorg. Chem. , vol.53 , pp. 3730-3741
    • Kiernicki, J.J.1
  • 19
    • 84872554580 scopus 로고    scopus 로고
    • Oxidation and reduction of bis(imino)pyridine iron dinitrogen complexes: Evidence for formation of a chelate trianion
    • Tondreau, A. M. et al. Oxidation and reduction of bis(imino)pyridine iron dinitrogen complexes: evidence for formation of a chelate trianion. Inorg. Chem. 52, 635-646 (2013).
    • (2013) Inorg. Chem. , vol.52 , pp. 635-646
    • Tondreau, A.M.1
  • 20
    • 0034725407 scopus 로고    scopus 로고
    • Arene-bridged diuranium complexes: Inverted sandwiches supported by d backbonding
    • Diaconescu, P. L., Arnold, P. L., Baker, T. A., Mindiola, D. J. & Cummins, C. C. Arene-bridged diuranium complexes: inverted sandwiches supported by d backbonding. J. Am. Chem. Soc. 122, 6108-6109 (2000).
    • (2000) J. Am. Chem. Soc. , vol.122 , pp. 6108-6109
    • Diaconescu, P.L.1    Arnold, P.L.2    Baker, T.A.3    Mindiola, D.J.4    Cummins, C.C.5
  • 22
    • 79957454906 scopus 로고    scopus 로고
    • A delocalized arene-bridged diuranium single-molecule magnet
    • Mills, D. P. et al. A delocalized arene-bridged diuranium single-molecule magnet. Nature Chem. 3, 454-460 (2011).
    • (2011) Nature Chem. , vol.3 , pp. 454-460
    • Mills, D.P.1
  • 23
    • 84864372055 scopus 로고    scopus 로고
    • Spontaneous reduction and C-H borylation of arenes mediated by uranium(III) disproportionation
    • Arnold, P. L., Mansell, S. M., Maron, L. & McKay, D. Spontaneous reduction and C-H borylation of arenes mediated by uranium(III) disproportionation. Nature Chem. 4, 668-674 (2012).
    • (2012) Nature Chem. , vol.4 , pp. 668-674
    • Arnold, P.L.1    Mansell, S.M.2    Maron, L.3    McKay, D.4
  • 24
    • 70349772046 scopus 로고    scopus 로고
    • A new tripodal ligand system with steric and electronic modularity for uranium coordination chemistry
    • Bart, S. C., Heinemann, F. W., Anthon, C., Hauser, C. & Meyer, K. A new tripodal ligand system with steric and electronic modularity for uranium coordination chemistry. Inorg. Chem. 48, 9419-9426 (2009).
    • (2009) Inorg. Chem. , vol.48 , pp. 9419-9426
    • Bart, S.C.1    Heinemann, F.W.2    Anthon, C.3    Hauser, C.4    Meyer, K.5
  • 25
    • 7944227494 scopus 로고    scopus 로고
    • Structure, reactivity, and density functional theory analysis of the six-electron reductant, [(C5Me5)2U]2(μ-6: 6-C6H6), synthesized via a new mode of (C5Me5)3M reactivity
    • Evans,W. J., Kozimor, S. A., Ziller, J.W. & Kaltsoyannis, N. Structure, reactivity, and density functional theory analysis of the six-electron reductant, [(C5Me5)2U]2(μ-6: 6-C6H6), synthesized via a new mode of (C5Me5)3M reactivity. J. Am. Chem. Soc. 126, 14533-14547 (2004).
    • (2004) J. Am. Chem. Soc. , vol.126 , pp. 14533-14547
    • Evans, W.J.1    Kozimor, S.A.2    Ziller, J.W.3    Kaltsoyannis, N.4
  • 26
    • 29044440988 scopus 로고    scopus 로고
    • Formation of a paramagnetic Al complex and extrusion of Fe during the reaction of (diiminepyridine)Fe with AlR3 (R=Me, Et)
    • Scott, J. et al. Formation of a paramagnetic Al complex and extrusion of Fe during the reaction of (diiminepyridine)Fe with AlR3 (R=Me, Et). J. Am. Chem. Soc. 127, 17204-17206 (2005).
    • (2005) J. Am. Chem. Soc. , vol.127 , pp. 17204-17206
    • Scott, J.1
  • 27
    • 84862521024 scopus 로고    scopus 로고
    • Synthesis of U(IV) imidos from Tp∗2U(CH2Ph) (Tp∗=hydrotris(3,5-dimethylpyrazolyl)borate) by extrusion of bibenzyl
    • Matson, E. M., Crestani, M. G., Fanwick, P. E. & Bart, S. C. Synthesis of U(IV) imidos from Tp∗2U(CH2Ph) (Tp∗=hydrotris(3,5-dimethylpyrazolyl)borate) by extrusion of bibenzyl. Dalton Trans. 41, 7952-7958 (2012).
    • (2012) Dalton Trans. , vol.41 , pp. 7952-7958
    • Matson, E.M.1    Crestani, M.G.2    Fanwick, P.E.3    Bart, S.C.4
  • 28
    • 73249136546 scopus 로고    scopus 로고
    • Oxidative addition to U(V)-U(V) dimers: Facile routes to uranium(VI) bis(imido) complexes
    • Spencer, L. P., Yang, P., Scott, B. L., Batista, E. R. & Boncella, J. M. Oxidative addition to U(V)-U(V) dimers: facile routes to uranium(VI) bis(imido) complexes. Inorg. Chem. 48, 11615-11623 (2009).
    • (2009) Inorg. Chem. , vol.48 , pp. 11615-11623
    • Spencer, L.P.1    Yang, P.2    Scott, B.L.3    Batista, E.R.4    Boncella, J.M.5
  • 29
    • 84862532790 scopus 로고    scopus 로고
    • A direct route to bis(imido)uranium(V) halides via metathesis of uranium tetrachloride
    • Jilek, R. E. et al. A direct route to bis(imido)uranium(V) halides via metathesis of uranium tetrachloride. J. Am. Chem. Soc. 134, 9876-9878 (2012).
    • (2012) J. Am. Chem. Soc. , vol.134 , pp. 9876-9878
    • Jilek, R.E.1
  • 30
    • 0036006387 scopus 로고    scopus 로고
    • On the inverse trans influence. Density functional studies of [MOX5]n- (M = Pa, n = 2;M=U, n = 1;M= Np, n = 0; X = F, Cl or Br)
    • O'Grady, E. & Kaltsoyannis, N. On the inverse trans influence. Density functional studies of [MOX5]n- (M = Pa, n = 2;M=U, n = 1;M= Np, n = 0; X = F, Cl or Br). J. Chem. Soc. Dalton Trans. 1233-1239 (2002).
    • (2002) J. Chem. Soc. Dalton Trans , pp. 1233-1239
    • O'grady, E.1    Kaltsoyannis, N.2
  • 31
    • 84858640686 scopus 로고    scopus 로고
    • Synthesis of uranium(VI) terminal oxo complexes: Molecular geometry driven by the inverse trans-influence
    • Kosog, B., La Pierre, H. S., Heinemann, F.W., Liddle, S. T. & Meyer, K. Synthesis of uranium(VI) terminal oxo complexes: molecular geometry driven by the inverse trans-influence. J. Am. Chem. Soc. 134, 5284-5289 (2012).
    • (2012) J. Am. Chem. Soc. , vol.134 , pp. 5284-5289
    • Kosog, B.1    La Pierre, H.S.2    Heinemann, F.W.3    Liddle, S.T.4    Meyer, K.5
  • 32
    • 84883665422 scopus 로고    scopus 로고
    • Stable uranium(VI) methyl and acetylide complexes and the elucidation of an inverse trans influence ligand series
    • Lewis, A. J., Carroll, P. J. & Schelter, E. J. Stable uranium(VI) methyl and acetylide complexes and the elucidation of an inverse trans influence ligand series. J. Am. Chem. Soc. 135, 13185-13192 (2013).
    • (2013) J. Am. Chem. Soc. , vol.135 , pp. 13185-13192
    • Lewis, A.J.1    Carroll, P.J.2    Schelter, E.J.3
  • 33
    • 0001508275 scopus 로고
    • Electronic structure and bonding in actinyl ions in Complexes
    • (ed. Clarke, M. J.) in Structure and Bonding Series 79, Springer Berlin Heidelberg
    • Denning, R. G., Electronic structure and bonding in actinyl ions in Complexes, Clusters and Crystal Chemistry (ed. Clarke, M. J.) 215-276 (in Structure and Bonding Series 79, Springer Berlin Heidelberg, 1992).
    • (1992) Clusters and Crystal Chemistry , pp. 215-276
    • Denning, R.G.1
  • 34
    • 19644390115 scopus 로고
    • Relativistically parameterized extended Hückel calculations. IX. An iterative version with applications to some xenon, thorium and uranium compounds
    • Larsson, S. & Pyykkö, P. Relativistically parameterized extended Hückel calculations. IX. An iterative version with applications to some xenon, thorium and uranium compounds. Chem. Phys. 101, 355-369 (1986).
    • (1986) Chem. Phys. , vol.101 , pp. 355-369
    • Larsson, S.1    Pyykkö, P.2
  • 35
    • 29344470070 scopus 로고    scopus 로고
    • Synthesis of imido analogs of the uranyl ion
    • Hayton, T. W. et al. Synthesis of imido analogs of the uranyl ion. Science 310, 1941-1943 (2005).
    • (2005) Science , vol.310 , pp. 1941-1943
    • Hayton, T.W.1
  • 36
    • 0031981454 scopus 로고    scopus 로고
    • A simple preparative route to bis(imido)uranium(VI) complexes by the direct reductions of diazenes and azides
    • Warner, B. P., Scott, B. L. & Burns, C. J. A simple preparative route to bis(imido)uranium(VI) complexes by the direct reductions of diazenes and azides. Angew. Chem. Int. Ed. 37, 959-960 (1998).
    • (1998) Angew. Chem. Int. Ed. , vol.37 , pp. 959-960
    • Warner, B.P.1    Scott, B.L.2    Burns, C.J.3
  • 37
    • 26944440049 scopus 로고    scopus 로고
    • [(C5Me5)2U][(μ-Ph)2BPh2] as a four electron reductant
    • Evans, W. J., Kozimor, S. A. & Ziller, J. W. [(C5Me5)2U][(μ-Ph)2BPh2] as a four electron reductant. Chem. Commun. 4681-4683 (2005).
    • (2005) Chem. Commun. , pp. 4681-4683
    • Evans, W.J.1    Kozimor, S.A.2    Ziller, J.W.3
  • 38
    • 0000104501 scopus 로고
    • Bonding and structure of heavily p loaded complexes
    • Benson, M. T., Bryan, J. C., Burrell, A. K. & Cundari, T. R. Bonding and structure of heavily p loaded complexes. Inorg. Chem. 34, 2348-2355 (1995).
    • (1995) Inorg. Chem. , vol.34 , pp. 2348-2355
    • Benson, M.T.1    Bryan, J.C.2    Burrell, A.K.3    Cundari, T.R.4
  • 39
    • 0030165709 scopus 로고    scopus 로고
    • Quantum chemical valence indices from the one-determinantal difference approach
    • Nalewajski, R. F., Mrozek, J. & Mazur, G. Quantum chemical valence indices from the one-determinantal difference approach. Can. J. Chem. Rev. Can. Chim. 74, 1121-1130 (1996).
    • (1996) Can. J. Chem. Rev. Can. Chim. , vol.74 , pp. 1121-1130
    • Nalewajski, R.F.1    Mrozek, J.2    Mazur, G.3
  • 40
    • 0000361274 scopus 로고    scopus 로고
    • Chemical speciation of the uranyl ion under highly alkaline conditions. Synthesis, structures, and oxo ligand exchange dynamics
    • Clark, D. L. et al. Chemical speciation of the uranyl ion under highly alkaline conditions. Synthesis, structures, and oxo ligand exchange dynamics. Inorg. Chem. 38, 1456-1466 (1999).
    • (1999) Inorg. Chem. , vol.38 , pp. 1456-1466
    • Clark, D.L.1
  • 41
    • 33646928742 scopus 로고    scopus 로고
    • Density functional theory investigation of the geometric and electronic structures of [UO2(H2O)m(OH)n]2-n (n + m = 5)
    • Ingram, K. I. M., Haeller, L. J. L. & Kaltsoyannis, N. Density functional theory investigation of the geometric and electronic structures of [UO2(H2O)m(OH)n]2-n (n + m = 5). Dalton Trans. 2403-2414 (2006).
    • (2006) Dalton Trans. , pp. 2403-2414
    • Ingram, K.I.M.1    Haeller, L.J.L.2    Kaltsoyannis, N.3
  • 42
    • 84885153599 scopus 로고    scopus 로고
    • Cation-cation interactions in [(UO2)2(OH)n]4-n complexes
    • Odoh, S. O., Govind, N., Schreckenbach, G. & de Jong, W. A. Cation-cation interactions in [(UO2)2(OH)n]4-n complexes. Inorg. Chem. 52, 11269-11279 (2013).
    • (2013) Inorg. Chem. , vol.52 , pp. 11269-11279
    • Odoh, S.O.1    Govind, N.2    Schreckenbach, G.3    De Jong, W.A.4
  • 44
    • 84883505431 scopus 로고    scopus 로고
    • Do QTAIM metrics correlate with the strength of heavy element-ligand bonds?
    • Mountain, A. R. E. & Kaltsoyannis, N. Do QTAIM metrics correlate with the strength of heavy element-ligand bonds? Dalton Trans. 42, 13477-13486 (2013).
    • (2013) Dalton Trans. , vol.42 , pp. 13477-13486
    • Mountain, A.R.E.1    Kaltsoyannis, N.2
  • 45
    • 22744456984 scopus 로고    scopus 로고
    • C-H-N and C-H-S hydrogen bonds: Influence of hybridization on their strength
    • Domagala, M. & Grabowski, S. J. C-H-N and C-H-S hydrogen bonds: influence of hybridization on their strength. J. Phys. Chem. A 109, 5683-5688 (2005).
    • (2005) J. Phys. Chem. A , vol.109 , pp. 5683-5688
    • Domagala, M.1    Grabowski, S.J.2
  • 46
    • 19944414664 scopus 로고    scopus 로고
    • How short can the H-H intermolecular contact be? New findings that reveal the covalent nature of extremely strong interactions
    • Grabowski, S. J., Sokalski, W. A. & Leszczynski, J. How short can the H-H intermolecular contact be? New findings that reveal the covalent nature of extremely strong interactions. J. Phys. Chem. A 109, 4331-4341 (2005).
    • (2005) J. Phys. Chem. A , vol.109 , pp. 4331-4341
    • Grabowski, S.J.1    Sokalski, W.A.2    Leszczynski, J.3
  • 47
    • 84855830602 scopus 로고    scopus 로고
    • Electron density characteristics in bond critical point (QTAIM) versus interaction energy components (SAPT): The case of charge-assisted hydrogen bonding
    • Bankiewicz, B., Matczak, P. & Palusiak, M. Electron density characteristics in bond critical point (QTAIM) versus interaction energy components (SAPT): the case of charge-assisted hydrogen bonding. J. Phys. Chem. A 116, 452-459 (2012).
    • (2012) J. Phys. Chem. A , vol.116 , pp. 452-459
    • Bankiewicz, B.1    Matczak, P.2    Palusiak, M.3
  • 48
    • 85047668974 scopus 로고
    • A quantum chemical definition and properties
    • Gopinathan, M. S., Jug, K. & Valency, I. A quantum chemical definition and properties. Theor. Chim. Acta 63, 497-509 (1983).
    • (1983) Theor. Chim. Acta , vol.63 , pp. 497-509
    • Gopinathan, M.S.1    Jug, K.2    Valency, I.3


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