Role of single-site catalysts in the hydrogenation of thiophenes: from models systems to effective HDS catalysts

Bianchini, Claudio; Meli, Andrea; Vizza, Francesco

doi:10.1016/j.jorganchem.2004.05.027

Cited by 35 publications

(9 citation statements)

References 73 publications

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“…In particular, by providing a singular, often mononuclear active site, homogeneous metal catalysts are generally regarded as more amenable to mechanistic investigations [15]. 6 Indeed, the homogeneous hydrogenation reactions of nitrogen-and sulfur-containing heteroarenes have been studied as partial models of industrial scale hydrodenitrogenation [16] and hydrodesulfurization [17,18] fuel refinement processes. In contrast, mechanistic models of heterogeneous reactions are often complicated by the need to account for the catalyst's amorphous, nanoscale structure as well as additional surface-related processes, e.g.…”

Section: Advantages and Disadvantagesmentioning

confidence: 99%

“…In 2012, Glorius [90] demonstrated efficient Ru-NHC-catalyzed enantioselective hydrogenation of thiophenes and benzothiophenes (Scheme 61, top). 18 Hydrogenation of monosubstituted thiophenes gave racemic product, but 2,5-disubstituted thiophenes gave enantiomeric ratios as high as 97:3. For benzothiophenes, bulky 2-substitution such as isobutyl or benzyl led to poor reactivity in comparison with that observed for smaller substituents such as n-butyl or n-decyl; excellent enantioselectivity (>96% ee), however, was observed in all cases.…”

Section: Asymmetric Hydrogenationmentioning

confidence: 99%

“…Using the same Ru-NHC system, Glorius also hydrogenated 2,4-and 2,5disubstituted furans [91] and indolizidines and benzotriazoles [92] 18 The catalyst system also hydrogenated both unsubstituted thiophene and benzothiophene in >99 yield. unsaturated backbone additionally facilitated asymmetric hydrogenation of 2-substituted benzofurans (Scheme 62) [93].…”

Section: Scheme 61 Asymmetric Hydrogenation Of Benzothiophenes and Tmentioning

confidence: 99%

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Homogeneous metal catalysis for conversion between aromatic and saturated compounds

Giustra

Ishibashi

Liu

2016

Coordination Chemistry Reviews

102

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In the past few decades, homogeneous catalysis of arene and heteroarene reduction has grown into a mature research field. In particular, hydrogenation of heteroaromatic systems facilitates rapid access to many classes of fine chemicals and pharmaceutically relevant compounds. In this review, we discuss the advancements made in the field of homogeneous metal-catalyzed arene and heteroarene hydrogenation from its early beginnings to the present day. We also review homogeneous catalysts for the reverse dehydrogenation of cyclic saturated species back to their aromatic counterparts, as well as single-catalyst systems capable of performing reversible hydrogenationdehydrogenation reactions.

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Section: Advantages and Disadvantagesmentioning

confidence: 99%

Section: Asymmetric Hydrogenationmentioning

confidence: 99%

Section: Scheme 61 Asymmetric Hydrogenation Of Benzothiophenes and Tmentioning

confidence: 99%

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Homogeneous metal catalysis for conversion between aromatic and saturated compounds

Giustra

Ishibashi

Liu

2016

Coordination Chemistry Reviews

102

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“…[3][4][5][6] The most common coordination mode of RSSR ligand is the bridging coordination where the two metals may be additionally linked by a metal-metal bond, (I) In Figure 1 furthermore, the RSSR ligand may be monodentately coordinated (II) And few examples are known where RSSR acts as bidentate ligand coordination (III) Finally, there are few reports in which coordination (IV) for an RSSR ligand is assumed. [7] Crystallographic evidence for type II (M = Ag, R = Ph; [8] M = Cu, R = CH 2 CH 2 NH 3 ; [9] M = W, R 2 =-CH 2 CH = CHCH 2 -) [10,11] and III (M = Nb, R = Me,i-Pr) [12] complexes is rare.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and study of anti-bacterial activity of complexes of diallyldisulphide from garlic

Singh¹,

Bajpai²,

Razdan³

2012

Int J Green Pharm

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Background:The development of bacterial resistance to available antibiotics and increasing incidence of multiresistant bacterial infections in hospitals and in the community has necessitated the search for new antibacterial agents to treat the bacterial infection. It has long been known that metal ions are involved in biological processes of life through bonding to the heteroatoms of the heterocyclic residues of biological molecules i.e., proteins, enzymes and nucleic acids etc. The behavior of the disulfide group as a donor in transition metal complexes has not been subjected to such detailed study as a number of other donor groups. Aim: The Diallyldisulphide is one of the main constituents of Allium sativum (Garlic). The antibacterial and antifungal activity of the Garlic is due to the presence of sulphur containing compounds. The aim of the present work was to synthesize metal complexes with Diallyldisulphide. Materials and Methods: Complexation reactions between the Diallyldisulphide and the metal ions were carried out at three different pH i.e. acidic (pH 3), neutral (pH 7) and alkaline (pH 10) using three different ratios of metal ligand namely 1:1, 1:2, 1:3, respectively. Complex formation with the ligand and all the metals took place at pH 10, indicating that complexes were stable at this pH. Studies with different metal: ligand ratio showed that in case of silver the complexation took place at 1:1 ratio. In case of divalent metals, the appropriate ratio of metal: ligand was 1:2. The structures of the new complexes obtained were determined by spectroscopic methods. Results and Discussion: Synthesized complexes were investigated for antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae and E.coli. Diallyldisulphide-silver complex exhibited significant antibacterial activity (MIC 100 µg/ mL), and was found to be effective against selected organisms. The results concluded that the metal complexes are better antibacterial agents as compared to the silversulphadiazine.

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“…Transition metal complexes having disulfido ligands S 2 2-and organic disulfide ligands RSSR (R = alkyl, aryl, …) are of significant importance in bioinorganic chemistry as well as in some transition metal assisted and homogeneously catalyzed reactions such as C-H bond activation, C-S bond formation and hydrodesulfuration reactions [1][2][3][4][5][6]. The most common coordination mode of RSSR ligands is the bridging l-1jS:2jS 0 coordination where the two metals may be additionally linked by a metal-metal bond, see I in Scheme 1.…”

Section: Introductionmentioning

confidence: 99%

Different coordination modes of the dimethyldisulfide ligand in trimethylplatinum(IV) complexes

Lindner

Wagner

Steinborn

2009

Transition Met Chem

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The reaction of [PtMe 3 (bpy)(Me 2 CO)](BF 4 ) (2) (prepared from [PtMe 3 I(bpy)] (1) plus Ag(BF 4 )) with MeSSMe resulted in the formation of [PtMe 3 (bpy)(MeSSMejS)](BF 4 ) (3). A single-crystal X-ray diffraction analysis revealed in the octahedral Pt(IV) complex (configuration index: OC-6-33), a conformation of the monodentately jS bound MeSSMe ligand (C-S-S-C 92.7(4)°) being very close to that in non-coordinated MeSSMe, thus allowing some hyperconjugative interaction stabilizing the S-S bond. The reaction of [K(18C6)][(PtMe 3 ) 2 (l-I)(l-pz) 2 ] (4; 18C6 = 18-crown-6, Hpz = pyrazole) with Ag(BF 4 ) and MeSSMe resulted in the formation of dinuclear complexes [(PtMe 3 ) 2 -(l-pz) 2 (l-MeSSMe)] existing at room temperature in acetone solution as different fast interconverting isomers. At -40°C, two isomers with a l-1jS:2jS (5a) and a l-1jS:2jS 0 (5b) coordinated MeSSMe ligand in the ratio 2:1 could be identified 1 H NMR spectroscopically. DFT calculations of type 5 complexes revealed the existence of two conformers with a l-MeSSMe-1jS:2jS ligand, which differ mainly in the C-S-S-C dihedral angle (66.4 vs. 180.0°6a/6a 0 ). They have essentially the same energy and a very low activation barrier in acetone as solvent (1.3 kcal/mol) for their mutual interconversion. A further equilibrium structure was identified to be an isomer having a l-MeSSMe-1jS:2jS 0 ligand (6b) that proved to be only 1.9 kcal/mol higher in energy than 6a/6a 0 .

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Role of single-site catalysts in the hydrogenation of thiophenes: from models systems to effective HDS catalysts

Cited by 35 publications

References 73 publications

Homogeneous metal catalysis for conversion between aromatic and saturated compounds

Homogeneous metal catalysis for conversion between aromatic and saturated compounds

Synthesis and study of anti-bacterial activity of complexes of diallyldisulphide from garlic

Different coordination modes of the dimethyldisulfide ligand in trimethylplatinum(IV) complexes

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