Synthesis and Reactivity of a Stable Hydrido Bis(dihydrogen) Derivative in a Nitrogen Donor Environment LRuH(H2)2 (L = HB(3,5-Me2-pz), HB(3-iPr,4-Br-pz))

Moreno, Beatriz; Sabo-Étienne, Sylviane; Chaudret, Bruno; Rodríguez-Fernández, Ana; Jalón, Félix A.; Trofimenko, Swiatoslaw

doi:10.1021/ja00085a060

Cited by 56 publications

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“…A similar change in structure from trihydride to dihydrogen/hydride upon substitution of Tp for Cp ligands has been reported by Chaudret and co-workers in related ruthenium complexes. 41,42 The neutral CpRu(PR 3 )H 3 complexes are characterized as classical trihydride complexes; 43 however, substitution of the Cp ligand for Tp Me 2 results in stable complexes of the form Tp Me 2Ru(L)(H 2 )H. In this case, L can be a phosphine, nitrogen, or sulfur donor ligand.…”

Section: Discussionmentioning

confidence: 99%

Synthesis and Characterization of Hydrotris(pyrazolyl)borate Dihydrogen/Hydride Complexes of Rhodium and Iridium

1997

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Protonation of TpM(PR 3 )H 2 (M ) Rh, Ir) complexes with HBF 4 ‚Et 2 O or [H(Et 2 O) 2 ][B(Ar) 4 ] (Ar ) 3,5-(CF 3 ) 2 C 6 H 3 ) affords cationic complexes which exhibit a single hydride resonance at all accessible temperatures in the 1 H NMR spectrum. Formulation as fluxional dihydrogen/hydride complexes is indicated by short T 1 (min) values of ca. 22 ms (Ir) and 7 ms (Rh). The relaxation times are consistent with H-H bond lengths of 0.88-1.11 Å in the iridium complexes and 0.73-0.92 Å in the rhodium complexes depending on the relative rate of the dihydrogen rotational motion. In the case of the iridium complexes, partial substitution of the hydride positions with deuterium or tritium results in large temperature-dependent isotope shifts and resolvable J H-D or J H-T coupling constants. Analysis of the chemical shift and coupling constant data as a function of temperature is consistent with a preference for the heavy hydrogen isotope to occupy the hydride rather than the dihydrogen site. This analysis also provides the limiting chemical shifts of the dihydrogen and hydride ligands as well as the 1 J H-D coupling constant (ca. 25 Hz) in the bound dihydrogen ligand.Since the first report of a stable molecular hydrogen complex by Kubas, 1 the possibility that a fluxional polyhydride complex might also contain a dihydrogen ligand has been actively investigated. 2 In general, transition metal polyhydride complexes are characterized by high coordination numbers (CN 7-9) and high formal oxidation states. 3 Because several structures of nearly equivalent energy are available to seven-, eight-, and nine-coordinate complexes, rapid permutation of the hydride positions is often observed by 1 H NMR spectroscopy. As a result, structural characterization in solution depends upon indirect methods, in which the observed NMR parameters are a population-weighted average of all the hydride environments. For example, Crabtree and co-workers have employed T 1 measurements to detect short H-H contacts in a range of polyhydride complexes, including [Ir(PCy 3 ) 2 H 6 ] + and Fe-(PEtPh 2 ) 3 H 4 . 4 A quantitative treatment of relaxation in polyhydride complexes has been developed which allows useful structural information to be obtained from T 1 (min) data. [4][5][6] We have previously reported the structure and properties of cationic iridium complexes of the form [CpIr(L)H 3 ]BF 4 (L ) various PR 3 ), which have been shown to adopt iridium(V) trihydride structures in the solid state. 7,8 These complexes undergo a rapid hydride rearrangement which leads to a single hydride resonance in the 1 H NMR spectrum above ca. 220 K. However, at very low temperatures, spectra consistent with the solid state structure are obtained.In this paper we investigate the effect of substituting the Cp ligand of [CpIr(L)H 3 ]BF 4 complexes with the hydrotris(1-pyrazolyl)borate (Tp) 9 ligand. The new Tp complexes, [TpIr-(L)(H 2 )H]BF 4 (L ) PMe 3 , PPh 3 ), are formulated as dihydrogen/ hydride complexes, although only a single hydride resonance is observed...

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Section: Discussionmentioning

confidence: 99%

Synthesis and Characterization of Hydrotris(pyrazolyl)borate Dihydrogen/Hydride Complexes of Rhodium and Iridium

1997

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“…They have been mainly prepared through two procedures. Reduction of the ruthenium(III) precursors RuCl 2 Tp(PR 3 ) (PR 3 = PPh 3 ( 143 ), P i PrPh 2 ( 144 ), P i Pr 3 ( 145 ), PCy 3 ( 146 )) with NaBH 4 in a mixture of tetrahydrofuran-ethanol affords RuHTp(η 2 -H 2 )(PR 3 ) (PR 3 = PPh 3 ( 147 ), P i PrPh 2 ( 148 ), P i Pr 3 ( 149 ), PCy 3 ( 150 )), whereas the hydrogenation of RuHTp R (η 4 -COD) (Tp R = hydridetris(3,5-dimethylpyrazolyl)borate (Tp Me2 ; 151 ), hydridetris(3-isopropyl-4-bromopyrazolyl)borate (Tp′; 152 )) in the presence of a monodentate ligand leads to RuHTp R (η 2 -H 2 )L (Tp R = Tp Me2 , L = PCy 3 ( 153 ), py ( 154 ), THT ( 155 ); Tp R = Tp′, L = PCy 3 ( 156 ), py ( 157 ), THT ( 158 ), NHEt 2 ( 159 )). , The octahedral geometry of these compounds (Scheme ) has been confirmed by the X-ray structure of 149 . The H–H distance of about 1.0 Å is consistent with the T 1 (min) values found for these species. − …”

Section: Rutheniummentioning

confidence: 99%

“…Hydrogenation of 151 and 152 in the absence of a monodentate ligand yields the hydride-bis(dihydrogen) complexes RuHTp R (η 2 -H 2 ) 2 (Tp R = Tp Me2 ( 160 ), Tp′ ( 161 )), according to Scheme . These compounds have been characterized by classical analytical and spectroscopic methods, including T 1 measurements and J H–D coupling constants. , …”

Section: Rutheniummentioning

confidence: 99%

Polyhydrides of Platinum Group Metals: Nonclassical Interactions and σ-Bond Activation Reactions

2016

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The preparation, structure, dynamic behavior in solution, and reactivity of polyhydride complexes of platinum group metals, described during the last three decades, are contextualized from both organometallic and coordination chemistry points of view. These compounds, which contain dihydrogen, elongated dihydrogen, compressed dihydride, and classical dihydride ligands promote the activation of B-H, C-H, Si-H, N-H, O-H, C-C, C-N, and C-F, among other σ-bonds. In this review, it is shown that, unlike other more mature areas, the chemistry of polyhydrides offers new exciting conceptual challenges and at the same time the possibility of interacting with other fields including the conversion and storage of regenerative energy, organic synthetic chemistry, drug design, and material science. This wide range of possible interactions foresees promising advances in the near future.

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“…6 The stabilization of bis(dihydrogen) complexes has been also achieved by using hydridotris(3-isopropyl-4-bromopyrazolyl)-borate or hydridotris(3,5-dimethylpyrazolyl)borate (Tp′) as a ligand in RuTp′H(η 2 -H 2 ) 2 . 3a, 7 Osmium-hydride complexes have been shown to promote carbon-carbon and carbon-heteroatom coupling reactions. 8 However, it is difficult to rationalize the processes because the products from the reactions of these compounds with unsaturated organic molecules depend on the interactions within the OsH n units, and a further understanding of them is needed.…”

Section: Introductionmentioning

confidence: 99%

Preparation, Spectroscopic Characterization, X-ray Structure, and Theoretical Investigation of Hydride−, Dihydrogen−, and Acetone−OsTp Complexes: A Hydridotris(pyrazolyl)borate−Cyclopentadienyl Comparison

et al. 2007

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Complex OsH 3 Cl(P i Pr 3 ) 2 (1) reacts with KTp (Tp ) hydridotris(pyrazolyl)borate) in tetrahydrofuran at room temperature to give OsH 3 (κ 2 -Tp)(P i Pr 3 ) 2 (2). In toluene at 80 °C, the κ 2 -Tp complex 2 is transformed to the κ 3 -Tp derivative OsH 3 Tp(P i Pr 3 ) (3) in quantitative yield after 7 h. Protonation of 3 with HBF 4 affords the bis(dihydrogen) compound [OsTp(η 2 -H 2 ) 2 (P i Pr 3 )]BF 4 (4). In acetone complex 4 releases the coordinated hydrogen molecules in a sequential manner. At room temperature, the dihydrogensolvate complex [OsTp(η 2 -H 2 )(κ 1 -OCMe 2 )(P i Pr 3 )]BF 4 (5) is formed, while at 56 °C the loss of both hydrogen molecules gives rise to the bis-solvento derivative [OsTp(κ 1 -OCMe 2 ) 2 (P i Pr 3 )]BF 4 (6). Complexes 2-6 have been characterized by X-ray diffraction analysis, and DFT calculations support their formulation. The structures of 3-5 have been compared with those of their Cp counterparts OsH 3 Cp(P i Pr 3 ), [OsH 2 -Cp(η 2 -H 2 )(P i Pr 3 )]BF 4 , and [OsH 2 Cp(κ 1 -OCMe 2 )(P i Pr 3 )]BF 4 . The results show that the Tp ligand avoids piano stool geometries, while it enforces dispositions allowing N-Os-N angles close to 90°such as octahedron and pentagonal bipyramid.

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Synthesis and Reactivity of a Stable Hydrido Bis(dihydrogen) Derivative in a Nitrogen Donor Environment LRuH(H2)2 (L = HB(3,5-Me2-pz), HB(3-iPr,4-Br-pz))

Cited by 56 publications

References 0 publications

Synthesis and Characterization of Hydrotris(pyrazolyl)borate Dihydrogen/Hydride Complexes of Rhodium and Iridium

Synthesis and Characterization of Hydrotris(pyrazolyl)borate Dihydrogen/Hydride Complexes of Rhodium and Iridium

Polyhydrides of Platinum Group Metals: Nonclassical Interactions and σ-Bond Activation Reactions

Preparation, Spectroscopic Characterization, X-ray Structure, and Theoretical Investigation of Hydride−, Dihydrogen−, and Acetone−OsTp Complexes: A Hydridotris(pyrazolyl)borate−Cyclopentadienyl Comparison

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