The transient radical tris(dimethylphenylphosphine)trihydridoiridium(1+): a Bronsted acid

Westerberg, D. E.; Rhodes, Larry F.; Edwin, Joseph; Geiger, William E.; Caulton, Kenneth G.

doi:10.1021/ic00005a042

Cited by 32 publications

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“…This is consistent with deprotonation of the radical cation followed by further oxidation of the resulting neutral radical in the same potential range . Similar ECE processes were also observed in the Cp 2 Fe + oxidations of H 3 Ir(PMe 2 Ph) 3 , [FeH(NCMe) (dppe) 2 ] + , CpRu(PPh 3 ) 2 H, Cp*Ru(dppf)H, Cp*Ru(PPh 3 )(H) 3 , M 2 Cp 2 (μ-H)(μ-PPh 2 ) (CO) 4 (M = Mo, W), and in other cases. In these systems, the addition of external base changes the one-electron process to a two-electron process.…”

Section: Reactivitysupporting

confidence: 83%

“…Concurrently, the dihydrogen complex formed by the initial proton transfer evolves H 2 and coordinates solvent to give more of the same cationic acetonitrile complex. Similar reaction pathways have also been proposed for the oxidations of CpRu(PPh 3 ) 2 H (the RuH 2 + complex is stable), Cp*Ru(PPh 3 )H 3 , and fac -H 3 Ir(PMe 2 Ph) 3 (the resulting [H 4 Ir(PMe 2 Ph) 3 ] + is stable) …”

Section: Reactivitymentioning

confidence: 99%

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Transition-Metal Hydride Radical Cations

Shaw

Estes

et al. 2016

Chem. Rev.

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Transition-metal hydride radical cations (TMHRCs) are involved in a variety of chemical and biochemical reactions, making a more thorough understanding of their properties essential for explaining observed reactivity and for the eventual development of new applications. Generally, these species may be treated as the ones formed by one-electron oxidation of diamagnetic analogues that are neutral or cationic. Despite the importance of TMHRCs, the generally sensitive nature of these complexes has hindered their development. However, over the last four decades, many more TMHRCs have been synthesized, characterized, isolated, or hypothesized as reaction intermediates. This comprehensive review focuses on experimental studies of TMHRCs reported through the year 2014, with an emphasis on isolated and observed species. The methods used for the generation or synthesis of TMHRCs are surveyed, followed by a discussion about the stability of these complexes. The fundamental properties of TMHRCs, especially those pertaining to the M-H bond, are described, followed by a detailed treatment of decomposition pathways. Finally, reactions involving TMHRCs as intermediates are described.

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Section: Reactivitysupporting

confidence: 83%

Section: Reactivitymentioning

confidence: 99%

Transition-Metal Hydride Radical Cations

Shaw

Estes

et al. 2016

Chem. Rev.

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“…The dichotomy between classical and nonclassical hydrides [2][3][4] and possible mechanisms of hydride fluxionality 5 have been studied extensively. A few mononuclear transient 17-electron polyhydride species have been produced by either chemical or electrochemical oxidation of the saturated polyhydride precursors, [6][7][8][9][10][11][12][13][14][15][16] whereas a greater body of work has been carried out on monohydride systems. The transient 17-electron species, [M-H] +• , usually decomposes by deprotonation, 24 the outcome being determined by the basic properties of the solvent vs M-H as well as by the reactivity of the depronotated product M • .…”

Section: Introductionmentioning

confidence: 99%

“…Polyhydrides show the same general reactivity patterns as monohydrides; for instance, treatment of Cp*Ru(PPh 3 )H 3 with Cp 2 Fe + PF 6 -in MeCN leads to H 2 evolution and formation of [Cp*Ru(PPh 3 )(MeCN) 2 ] + . 15 With the ultimate goal in mind of generating stable 17-electron polyhydride species for further activation and reactivity studies, we have synthesized new compounds of the general class (η 5 -ring)MH 3 L 2 (ring ) cyclopentadienyl ligand, M ) group 6 metal, L ) tertiary phosphine), previously reported examples of which include CpMoH 3 (dppe), 42 CpWH 3 (PMe 3 ) 2 , 43 (η 5 -C 5 H 4 Pr i )MoH 3 L 2 (L ) PMe 3 , PMe 2 Ph or L 2 ) dppe), 44 Cp*MoH 3 (PMe 3 ) 2 , 45 and CpMoH 3 (PMe 2 Ph) 2 . 46 Oxidation studies of these derivatives had not previously been reported, while protonation studies were limited to (η 5 -C 5 H 4 Pr i )MoH 3 (PMe 3 ) 2 with HCl and water to generate [(η 5 -C 5 H 4 Pr i )MoO(PMe 3 ) 2 ] + .…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Structure, and Protonation Studies of Cp*MH₃(dppe) (M = Mo, W). Pseudo-Trigonal-Prismatic vs Pseudo-Octahedral Structures for Half-Sandwich Group 6 M(IV) Derivatives

1997

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The compounds Cp*MH 3 (dppe) (M ) Mo, 1;W,2) are accessible in good yields from reacting the corresponding compound Cp*MCl 4 and LiAlH 4 in toluene/Et 2 O followed by methanolysis. The X-ray structure of 1 shows a pseudo-trigonal-prismatic geometry which is unprecedented for half-sandwich CpML 5 -type compounds. Protonation with HBF 4 ‚Et 2 OinEt 2 Oatlow temperature affords [Cp*MH 4 (dppe)] + BF 4 -salts (M ) Mo, 3;W,4). While 3 spontaneously decomposes, even at low temperatures, in coordinating solvents and CH 2 Cl 2 , 4 is stable at room temperature in MeCN. An X-ray structure of 4 is consistent with a classical tetrahydrido species with a distorted pseudo-pentagonal-bipyramidal structure. The low-temperature NMR properties, J HD e 1Hzfor 4-d 3 , and the T 1(min) value for the hydride resonance are also consistent with this structural assignment. Decomposition of 3 in MeCN at room temperature selectively affords [Cp*MoH 2 (MeCN)(dppe)] + BF 4 -, 5. The NMR properties of this complex indicate a fluxional structure with inequivalent H and P nuclei and are consistent with a pseudo-trigonal-prismatic structure analogous to that of the precursor 1. Further protonation of 5 in MeCN or direct protonation of 1 with excess acid in MeCN affords two isomers of complex [Cp*MoH(MeCN) 2 (dppe)](BF 4 ) 2 , 6 and 7. Thermal treatment in MeCN slowly converts 7 into 6 initially, but both isomers further transform into a third isomer, 8, upon prolonged heating. The structure of 6 has been elucidated by X-ray crystallography and consists of a highly distorted pseudo-octahedral geometry with relative trans MeCN ligands. The structures of 7 and 8 and mechanisms of the intercon-versions between the various isomeric structures are proposed on the basis of the solution NMR studies.

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“…It should be noted that H 2 eliminationh as been reported for cases of one-electrono xidation of diamagneticp olyhydride precursors, [31] such as [Cp*RuH 3 (PPh 3 )] (Cp* = pentamethylcyclopentadienyl), [32] [Cp*MoH 3 (dppe)] (dppe = 1,2-bis(diphenylphosphino)ethane), [33] and [IrH 3 (PMe 2 Ph) 3 ]. [34] To access the decomposition pathway of [H1H] 0 in our hydride transfer reaction, we subsequently conducted an experiment to oxidize [H1H] 0 with FcBF 4 (Fc = ferrocene). As toichiometric reaction between [H1H] 0 and FcBF 4 in CH 3 CN produces H 2 in yields of (92 AE 4) %i nt hree experiments, whereas the organoiron compounds produced are [1(NCMe) 2 ] 2 + and some insoluble particles.…”

Section: Resultsmentioning

confidence: 99%

New Class of Hydrido Iron(II) Compounds with cis‐Reactive Sites: Combination of Iron and Diphosphinodithio Ligand

Liu

Zhang

et al. 2016

Chemistry An Asian Journal

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The cationic complex [Fe(P2 S2 )(NCMe)2 ](2+) (P2 S2 =(Ph2 PC6 H4 CH2 S)2 (C2 H4 ) ([1(NCMe)2 ](2+) )), with two MeCN ligands in a cis orientation, was synthesized and characterized. The MeCN ligand in [1(NCMe)2 ](2+) undergoes further substitution by a hydride ligand or CO to give iron(II) hydrides [H1(NCMe)](+) , [H1H](0) , and [H1(CO)](+) . The order of reactivity of the hydrides was [H1H](0) >[H1(NCMe)](+) >[H1(CO)](+) , and was illustrated by their reactions toward protic acids, the organic cation of 10-methylacridinium (MeAcr(+) ) as a hydride acceptor, and intermolecular hydride transfer reactions among these ferrous compounds. For example, MeAcr(+) was reduced initially by a one-electron transfer process from [H1H](0) , resulting in competing reactions of MeAcr(.) dimerization, hydrogen atom transfer from [H1H](+) to MeAcr(.) , and decomposition of [H1H](+) . MeAcrH was produced in excellent yields through a single-step H(-) transfer from [H1(NCMe)](+) to MeAcr(+) , but [H1(CO)](+) was inactive toward MeAcr(+) .

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The transient radical tris(dimethylphenylphosphine)trihydridoiridium(1+): a Bronsted acid

Cited by 32 publications

References 0 publications

Transition-Metal Hydride Radical Cations

Transition-Metal Hydride Radical Cations

Synthesis, Structure, and Protonation Studies of Cp*MH₃(dppe) (M = Mo, W). Pseudo-Trigonal-Prismatic vs Pseudo-Octahedral Structures for Half-Sandwich Group 6 M(IV) Derivatives

New Class of Hydrido Iron(II) Compounds with cis‐Reactive Sites: Combination of Iron and Diphosphinodithio Ligand

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The transient radical tris(dimethylphenylphosphine)trihydridoiridium(1+): a Bronsted acid

Cited by 32 publications

References 0 publications

Transition-Metal Hydride Radical Cations

Transition-Metal Hydride Radical Cations

Synthesis, Structure, and Protonation Studies of Cp*MH3(dppe) (M = Mo, W). Pseudo-Trigonal-Prismatic vs Pseudo-Octahedral Structures for Half-Sandwich Group 6 M(IV) Derivatives

New Class of Hydrido Iron(II) Compounds with cis‐Reactive Sites: Combination of Iron and Diphosphinodithio Ligand

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Synthesis, Structure, and Protonation Studies of Cp*MH₃(dppe) (M = Mo, W). Pseudo-Trigonal-Prismatic vs Pseudo-Octahedral Structures for Half-Sandwich Group 6 M(IV) Derivatives