Wide range of pKa values of coordinated dihydrogen. Synthesis and properties of some .eta.2-dihydrogen and dihydride complexes of ruthenium

Jia, Guocheng; Morris, Robert H.

doi:10.1021/ja00003a022

Cited by 127 publications

(100 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, in iron complexes of a PNP ligand, the necessary pK a of the acid was determined to be less than 10.5 (a coordinated nitrogen was protonated in preference to the hydride ligand). 87,88 On the other hand, the diketiminate-bound iron hydrides are protonated by weak acids such as diisopropylaniline and diphenylhydrazine. 27 Using literature values in DMSO, 64 one can conclude that acids with pK a value up to 32 (and perhaps higher) can protonate 1a and 1b.…”

Section: Discussionmentioning

confidence: 99%

The Reactivity Patterns of Low-Coordinate Iron−Hydride Complexes

Sadique²,

Smith³

et al. 2008

J. Am. Chem. Soc.

183

177

View full text Add to dashboard Cite

Abstract:We report a survey of the reactivity of the first isolable iron-hydride complexes with a coordination number less than 5. The high-spin iron(II) complexes [( -diketiminate)Fe(µ-H)] 2 react rapidly with representative cyanide, isocyanide, alkyne, N 2, alkene, diazene, azide, CO2, carbodiimide, and Brønsted acid containing substrates. The reaction outcomes fall into three categories: (1) addition of Fe-H across a multiple bond of the substrate, (2) reductive elimination of H 2 to form iron(I) products, and (3) protonation of the hydride to form iron(II) products. The products include imide, isocyanide, vinyl, alkyl, azide, triazenido, benzo[c]cinnoline, amidinate, formate, and hydroxo complexes. These results expand the range of known bond transformations at iron complexes. Additionally, they give insight into the elementary transformations that may be possible at the iron-molybdenum cofactor of nitrogenases, which may have hydride ligands on high-spin, low-coordinate metal atoms.

show abstract

Section: Discussionmentioning

confidence: 99%

The Reactivity Patterns of Low-Coordinate Iron−Hydride Complexes

Sadique²,

Smith³

et al. 2008

J. Am. Chem. Soc.

183

177

View full text Add to dashboard Cite

show abstract

“…were isolated according to the reported preparation, [15] with typical yields of 80-90 %. The 31 P NMR spectroscopic chemical shifts are reported in Table 2.…”

Section: Methodsmentioning

confidence: 99%

“…Several pK a values for cationic metal hydride and dihydrogen complexes in CD 2 Cl 2 have been previously reported by us and the group of Jia. [14][15][16][17][18][19] The initial approach used was to find equilibria between these complexes and protonated phosphanes in which pK aq a values were reported to give a pseudoaqueous value by using 1 H and 31 P NMR spectroscopy. [15,16,18] A second approach was to construct a continuous set of overlapping equilibria to provide a more accurate ordering of acid strengths.…”

Section: Introductionmentioning

confidence: 99%

“…[14][15][16][17][18][19] The initial approach used was to find equilibria between these complexes and protonated phosphanes in which pK aq a values were reported to give a pseudoaqueous value by using 1 H and 31 P NMR spectroscopy. [15,16,18] A second approach was to construct a continuous set of overlapping equilibria to provide a more accurate ordering of acid strengths. For example, a ladder of acids with pK CD 2 Cl 2 values ranging from 9.7 to 7.0 was built and referenced arbitrarily to [HPCy 3 4 ] (Cy: cyclohexyl, pK a = 9.7) ( Table 1).…”

Section: Introductionmentioning

confidence: 99%

“…For example, a ladder of acids with pK CD 2 Cl 2 values ranging from 9.7 to 7.0 was built and referenced arbitrarily to [HPCy 3 4 ] (Cy: cyclohexyl, pK a = 9.7) ( Table 1). [15] More recently, this ladder was extended by using phosphonium tetraphenylborate salts, of which [HPBu 2 4 ] has a pK CD 2 Cl 2 value of 5.7, for example. [19] The pK CD 2 Cl 2 values are generally consistent with those values previously measured in THF.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

An Acidity Scale of Tetrafluoroborate Salts of Phosphonium and Iron Hydride Compounds in [D₂]Dichloromethane

Li¹,

Lough²,

Morris³

2007

Chemistry A European J

View full text Add to dashboard Cite

Equilibrium constants (K) for reactions between acids and the conjugate base forms of a number of phosphonium salts, [HPR3][BF4], and iron hydrides, [Fe(CO)3H(PR3)2][BF4], in CD(2)Cl(2) have been determined by means of 31P and 1H NMR spectroscopy at 20 degrees C. The anchor compound chosen for pK(CD(2)Cl(2)) determinations was [HPCy3][BF4] with a pK(CD(2)Cl(2)) value of 9.7, as assigned by literature convention (Cy: cyclohexyl). A continuous scale of pK(CD(2)Cl(2)) values covering the range from 9.7 to -3 was created and correlated with the DeltaH values reported by Angelici and co-workers and literature pK(a) values. The pK(CD(2)Cl(2)) values for 15 other hydride or dihydrogen complexes of the iron group elements and of diethyl ether were also placed on this scale. The crystal structures of [Fe(CO)3H(PCy(2)Ph)2][BF4] and [Fe(CO)3(PCy(2)Ph)2] revealed that the trans-oriented, bulky, unsymmetrical phosphane ligands distort the equatorial plane of the complexes. The acidity of iron carbonyl hydrides is an important feature of the reactions of iron hydrogenase enzymes.

show abstract

Some New Dicationic Dihydrogen Complexes of Ruthenium

Majumdar

Nanishankar

Jagirdar

2001

Eur. J. Inorg. Chem.

View full text Add to dashboard Cite

show abstract

Wide range of pKa values of coordinated dihydrogen. Synthesis and properties of some .eta.2-dihydrogen and dihydride complexes of ruthenium

Cited by 127 publications

References 4 publications

The Reactivity Patterns of Low-Coordinate Iron−Hydride Complexes

The Reactivity Patterns of Low-Coordinate Iron−Hydride Complexes

An Acidity Scale of Tetrafluoroborate Salts of Phosphonium and Iron Hydride Compounds in [D₂]Dichloromethane

Some New Dicationic Dihydrogen Complexes of Ruthenium

Contact Info

Product

Resources

About

Wide range of pKa values of coordinated dihydrogen. Synthesis and properties of some .eta.2-dihydrogen and dihydride complexes of ruthenium

Cited by 127 publications

References 4 publications

The Reactivity Patterns of Low-Coordinate Iron−Hydride Complexes

The Reactivity Patterns of Low-Coordinate Iron−Hydride Complexes

An Acidity Scale of Tetrafluoroborate Salts of Phosphonium and Iron Hydride Compounds in [D2]Dichloromethane

Some New Dicationic Dihydrogen Complexes of Ruthenium

Contact Info

Product

Resources

About

An Acidity Scale of Tetrafluoroborate Salts of Phosphonium and Iron Hydride Compounds in [D₂]Dichloromethane