Analysis of the Aromaticity of Osmabicycles Analogous to the Benzimidazolium Cation

Baya, Miguel; Esteruelas, Miguel A.; Oñate, Enrique

doi:10.1021/om200491t

Cited by 19 publications

(15 citation statements)

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“…The saline character of this compound is strongly supported by its molar conductivity of 134 Ω –1 cm 2 mol –1 , at 25 °C, in acetone. The 1 H NMR spectrum, in dichloromethane- d 2 , at room temperature is the expected one for a 16-valence-electron osmium(IV) OsH 2 X 2 (P i Pr 3 ) 2 species with a structure in the solid state that can be described as a C 2 square antiprism with two missing vertexes. , Thus, it contains at 1.28 ppm the characteristic doublet of doublets ( 3 J H–H = 7.2 Hz, 2 J H–P = 14.5 Hz) due to the P i Pr 3 methyl groups, whereas the OsH 2 unit gives rise to a triplet ( 2 J H–P = 34.7 Hz) at −19.67 ppm. The 31 P{ 1 H} NMR spectrum shows a singlet at 37.1 ppm.…”

Section: Resultsmentioning

confidence: 90%

“…On the basis of an X-ray diffraction analysis of OsH 2 (κ 2 -O 2 CCH 3 ){κ 1 -OC(O)CH 3 }(P i Pr 3 ) 2 , the coordination polyhedron around the osmium atom of these compounds has been described as halfway between a capped trigonal prism and a piano-stool geometry. If one takes as a base the structure of 2 , 4 , and related six-coordinate osmium(IV) dihydrides, the coordination polyhedron could be rationalized as a square antiprism with a missing vertex.…”

Section: Resultsmentioning

confidence: 99%

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Osmium Hydride Acetylacetonate Complexes and Their Application in Acceptorless Dehydrogenative Coupling of Alcohols and Amines and for the Dehydrogenation of Cyclic Amines

et al. 2017

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The preparation of new osmium-hydride complexes, starting from OsH 6 (P i Pr 3) 2 (1) and OsH 2 Cl 2 (P i Pr 3) 2 (2), and their catalytic activity in acceptorless dehydrogenative coupling of alcohols and amines and in dehydrogenation of cyclic amines are reported. Complex 1 reacts with acetylacetone (Hacac) to give the classical trihydride OsH 3 (acac)(P i Pr 3) 2 (3). The protonation of 3 with triflic acid (HOTf) produces the release of H 2 and the formation of the unsaturated osmium(IV)-dihydride [OsH 2 (acac)(P i Pr 3) 2 ]OTf (4), which is also prepared starting from 2 via the intermediate OsH 2 Cl(acac)(P i Pr 3) 2 (5). Treatment of acetylacetone solutions of 5 with KOH affords Os(acac) 2 (P i Pr 3) 2 (6). In presence of 5 mol% of KOH, complexes 3-6 promote the coupling of benzylalcohol and aniline to give N-benzylideneaniline and H 2. Under the same conditions, complex 3 catalyzes a wide range of analogous couplings to afford a variety of imines, including aliphatic ones, with yields between 90 and 40% after 1-48 h. Complex 3 also catalyzes the dehydrogenation of cyclic amines. According to the amount of H 2 released by each gram of employed substrate, the amines have been classified into three classes: poor-(1,2,3,4-tetrahydroquinaldine, 2-methylindoline and 2,6dimethylpiperidine), moderate-(1,2,3,4-tetrahydroquinoline and 6-methyl-1,2,3,4-tetrahydroquinoline) and good-hydrogen donors (1,2,3,4-tetrahydroisoquinoline).

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Section: Resultsmentioning

confidence: 90%

Section: Resultsmentioning

confidence: 99%

Osmium Hydride Acetylacetonate Complexes and Their Application in Acceptorless Dehydrogenative Coupling of Alcohols and Amines and for the Dehydrogenation of Cyclic Amines

et al. 2017

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“…Similarly, the observed planarity and bond length equalization, and particularly, the negative NICS values (NICS(0) = À12.6 ppm, NICS(1) = À11.9 ppm) calculated for the osmabicycle OsH 2 (k-N,N-o-HNC 6 H 4 NH)(PiPr 3 ) 2 resemble the values computed for the aromatic benzimidazolium cation (NICS(0) = À12.9 ppm, NICS(1) = À9.3 ppm). 72 This finding suggests that the p-delocalization is similar in both systems.…”

Section: Aromaticity Of Heterometallabenzenes and Related Metallacyclesmentioning

confidence: 75%

Aromaticity of metallabenzenes and related compounds

2015

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The concept of aromaticity was initially introduced in chemistry to account for the stability, reactivity, molecular structures, and other properties of many unsaturated organic compounds. Despite that, it has been extended to other species with mobile electrons including saturated systems, transition structures, and even inorganic molecules. In this review, we focus on the aromaticity of a particular family of organometallic compounds known as metallabenzenes, which are characterized by the formal replacement of a CH group in benzene by an isolobal transition metal fragment. In addition, aromaticity of related compounds such as heterometallabenzenes is considered as well. To this end, we shall describe herein the insight gained by the available experimental data as well as by the application of the state-of-the-art computational methods developed as descriptors for aromaticity together with a critical evaluation of their performance to quantitatively estimate the strength of aromaticity of these systems.

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“…237 Neutral d 6 mer-trihydrides OsH 3 (NO)(PR 3 ) 2 (PR 3 = P i Pr 3 (326), P t Bu 2 Me (327), PPh 3 (328)) have been also prepared via NaBH 4 /MeOH reduction of the corresponding cis,trans-OsH 2 Cl(NO)(PR 3 ) 2 (PR 3 = P i Pr 3 (329), P t Bu 2 Me (330), PPh 3 (331)) compounds. 91 Reaction of OsCl 3 (PR 3 ) 3 (PR 3 = PPh 3 (332), P(p-tolyl) 3 (333), PMePh 2 (334), PMe 2 Ph (335), PEtPh 2 (336), PEt 2 Ph (337)) with NaBH 4 in ethanol leads to the classical 92,94,244,245 tetrahydride complexes OsH 4 (PR 3 ) 3 (PR 3 = PPh 3 (338), P(ptolyl) 3 (339), PMePh 2 (340), PMe 2 Ph (341), PEtPh 2 (342), PEt 2 Ph ( 343)). 246−249 The structure of 341 has been determined by neutron diffraction.…”

Section: Phosphine Complexesmentioning

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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Analysis of the Aromaticity of Osmabicycles Analogous to the Benzimidazolium Cation

Cited by 19 publications

References 63 publications

Osmium Hydride Acetylacetonate Complexes and Their Application in Acceptorless Dehydrogenative Coupling of Alcohols and Amines and for the Dehydrogenation of Cyclic Amines

Osmium Hydride Acetylacetonate Complexes and Their Application in Acceptorless Dehydrogenative Coupling of Alcohols and Amines and for the Dehydrogenation of Cyclic Amines

Aromaticity of metallabenzenes and related compounds

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

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