16873-17-9

Upstream product

• 7732-18-5 water 
• 558-20-3 methane 
• 7789-20-0 water-d2 
• 7440-23-5 sodium 
• 13537-07-0 silane-d4 
• 7440-21-3 monosilane 
• 17030-72-7 trideuteriomethylium 
• 60094-88-4 CH₂⁽²⁾H⁽¹⁺⁾ 
• 58576-33-3 CH⁽²⁾H₂⁽¹⁺⁾ 
• 1076-43-3 benzene-d6 
• 1333-74-0 hydrogen 
• 13762-18-0 half-deuterated hydrogen sulphide 
• 7783-06-4 hydrogen sulfide 
• 13536-94-2 deuterium sulfide 

Downstream Products

• 7789-20-0 water-d2 
• 14940-63-7 water 
• 1333-74-0 hydrogen 
• 7439-98-7 molybdenum 
• 13536-59-9 deuterium bromide 
• 7698-05-7 hydrogen chloride 
• 14104-45-1 deuterium iodide 
• 872215-16-2 Zr(OH)(O⁽²⁾H) 
• 872207-78-8 Zr(OH)2(⁽¹⁸⁾OH)2 
• 872207-76-6 Zr(O⁽²⁾H)4 
• 756456-88-9 zirconium tetrahydroxide 
• 14333-26-7 hydrogen fluoride 
• 16873-17-9 deuterium D2, ortho 
• 13780-28-4 ammonia-d2 

Relevant academic research and scientific papers

Introducing Water-Network-Assisted Proton Transfer for Boosted Electrocatalytic Hydrogen Evolution with Cobalt Corrole

Proton transfer is vital for many biological and chemical reactions. Hydrogen-bonded water-containing networks are often found in enzymes to assist proton transfer, but similar strategy has been rarely presented by synthetic catalysts. We herein report the Co corrole 1 with an appended crown ether unit and its boosted activity for the hydrogen evolution reaction (HER). Crystallographic and 1H NMR studies proved that the crown ether of 1 can grab water via hydrogen bonds. By using protic acids as proton sources, the HER activity of 1 was largely boosted with added water, while the activity of crown-ether-free analogues showed very small enhancement. Inhibition studies by adding 1) external 18-crown-6-ether to extract water molecules and 2) potassium ion or N-benzyl-n-butylamine to block the crown ether of 1 further confirmed its critical role in assisting proton transfer via grabbed water molecules. This work presents a synthetic example to boost HER through water-containing networks.

Activation of Molecular Hydrogen by Inter- and Intramolecular Al?N Lewis Pairs

The field of frustrated Lewis pair chemistry offers many opportunities to activate molecular hydrogen, but Al?N systems have not been established yet. In this work, we describe several intermolecular classical Al?N Lewis pairs and an intramolecular ortho-

Bis-Imidazole Methane Ligated Ruthenium(II) Complexes: Synthesis, Characterization, and Catalytic Activity for Hydrogen Production from Formic Acid in Water

A series of half sandwich arene-ruthenium complexes [(η6-arene)RuCl(κ2-L)]+ ([Ru]-1-[Ru]-10) containing bis-imidazole methane-based ligands {4,4′-(phenylmethylene)bis(2-ethyl-5-methyl-1H-imidazole)} (L1), {4,4′-((4-methoxyphenyl)methylene)bis(2-ethyl-5-methyl-1H-imidazole)} (L2), {4,4′-((2-methoxyphenyl)methylene)bis(2-ethyl-5-methyl-1H-imidazole)} (L3), {4,4′-((4-chlorophenyl)methylene)bis(2-ethyl-5-methyl-1H-imidazole)} (L4), and {4,4′-((2-chlorophenyl)methylene)bis(2-ethyl-5-methyl-1H-imidazole)} (L5) are synthesized. The synthesized and purified complexes ([Ru]-1-[Ru]-10) are further employed for hydrogen production from formic acid in aqueous medium. Among the investigated complexes, [(η6-p-cymene)RuCl(κ2-L2)]+ [Ru]-2, having Ru(II) coordinated 4-methoxy phenyl substituted bis-imidazole methane ligand (L2), outperformed over others, displaying a higher catalytic turnover of 8830 and high efficiency (TOF = 1545 h-1) with appreciably high long-term stability for formic acid dehydrogenation in water.

Ammonia-Borane Dehydrogenation Catalyzed by Dual-Mode Proton-Responsive Ir-CNNHComplexes

Metal complexes incorporating proton-responsive ligands have been proved to be superior catalysts in reactions involving the H2 molecule. In this contribution, a series of IrIII complexes based on lutidine-derived CNNH pincers containing N-heterocyclic carbene and secondary amino NHR [R = Ph (4a), tBu (4b), benzyl (4c)] donors as flanking groups have been synthesized and tested in the dehydrogenation of ammonia-borane (NH3BH3, AB) in the presence of substoichiometric amounts (2.5 equiv) of tBuOK. These preactivated derivatives are efficient catalysts in AB dehydrogenation in THF at room temperature, albeit significantly different reaction rates were observed. Thus, by using 0.4 mol% of 4a, 1.0 equiv of H2 per mole of AB was released in 8.5 min (turnover frequency (TOF50%) = 1875 h-1), while complexes 4b and 4c (0.8 mol%) exhibited lower catalytic activities (TOF50% = 55-60 h-1). 4a is currently the best performing IrIII homogeneous catalyst for AB dehydrogenation. Kinetic rate measurements show a zero-order dependence with respect to AB, and first order with the catalyst in the dehydrogenation with 4a (-d[AB]/dt = k[4a]). Conversely, the reaction with 4b is second order in AB and first order in the catalyst (-d[AB]/dt = k[4b][AB]2). Moreover, the reactions of the derivatives 4a and 4b with an excess of tBuOK (2.5 equiv) have been analyzed through NMR spectroscopy. For the former precursor, formation of the iridate 5 was observed as a result of a double deprotonation at the amine and the NHC pincer arm. In marked contrast, in the case of 4b, a monodeprotonated (at the pincer NHC-arm) species 6 is observed upon reaction with tBuOK. Complex 6 is capable of activating H2 reversibly to yield the trihydride derivative 7. Finally, DFT calculations of the first AB dehydrogenation step catalyzed by 5 has been performed at the DFT//MN15 level of theory in order to get information on the predominant metal-ligand cooperation mode.

Pd/C-Catalyzed H2 Evolution from Tetrahydroxydiboron Hydrolysis

The production of H2 from non-fossil sources is a key research challenge to contributing solving the forthcoming energy problem. Aqueous solutions of tetrahydroxydiboron have very recently appeared as a H2 source, from which both hydrogen atoms are provided by water, in the presence of highly sophisticated nanocatalysts. Herein, commercial and cheap Pd/C is shown to be an efficient and recyclable catalyst for H2 evolution upon tetrahydroxydiboron hydrolysis. Graphic Abstract: [Figure not available: see fulltext.]

Bifunctional activation of amine-boranes by the W/Pd bimetallic analogs of “frustrated Lewis pairs”

The reaction between basic [(PCP)Pd(H)] (PCP = 2,6-(CH2P(t-C4H9)2)2C6H4) and acidic [LWH(CO)3] (L = Cp (1a), Tp (1b); Cp = η5-cyclopentadienyl, Tp = κ3-hydridotris(pyrazolyl)borate) leads to the formation of bimolecular complexes [LW(CO)2(μ-CO)?Pd(PCP)] (4a,4b), which catalyze amine-borane (Me2NHBH3tBuNH2BH3) dehydrogenation. The combination of variable-temperature (1H,31P{1H},11B NMR and IR) spectroscopies and computational (ωB97XD/def2-TZVP) studies reveal the formation of an η1-borane complex [(PCP)Pd(Me2NHBH3)]+[LW(CO3)]?(5) in the first step, where a BH bond strongly binds palladium and an amine group is hydrogen-bonded to tungsten. The subsequent intracomplex proton transfer is the rate-determining step, followed by an almost barrierless hydride transfer. Bimetallic species4are easily regenerated through hydrogen evolution in the reaction between two hydrides.

Acid- and Base-Catalyzed Hydrolytic Hydrogen Evolution from Diboronic Acid

The efficient production of H2 from hydrogen-rich sources, particularly from water, is a crucial task and a great challenge, both as a sustainable energy source and on the laboratory scale for hydrogenation reactions. Herein, a facile and effective synthesis of H2 and D2 from only acid- or base-catalyzed metal-free hydrolysis of B2(OH)4, a current borylation reagent, has been developed without any transition metal or ligand. Acid-catalyzed H2 evolution was completed in 4 min, whereas the base-catalyzed process needed 6 min. The large kinetic isotopic effects for this reaction with D2O, deuteration experiments and mechanistic studies have confirmed that both H atoms of H2 originate from water using either of these reactions. This new, metal-free catalytic system holds several advantages, such as high efficiency, simplicity of operation, sustainability, economy, and potential further use.

Hydrolysis of B2pin2 over Pd/C Catalyst: High Efficiency, Mechanism, and in situ Tandem Reaction

A facile and effective synthesis of H2 or D2 from Pd/C catalyzed hydrolysis of B2pin2 has first been developed. Among them, B2pin2 is frequently used for borylation reaction, and has rarely been used for hydrogen evolution. The kinetic isotope effects (KIEs) and tandem reaction for diphenylacetylene and norbornene hydrogenation have confirmed both two H atoms of H2 gas are provided from H2O. This is contrary to other boron compounds hydrolysis (including NH3BH3, NaBH4), which generates H2 with only one H atom provided by water and the other one by boron compounds. Note that the hydrolysis of B2pin2 in D2O also provides an easy and useful synthesis of D2.

Ligand Design for Catalytic Dehydrogenation of Formic Acid to Produce High-pressure Hydrogen Gas under Base-free Conditions

A series of Cp*Ir (Cp? = pentamethylcyclopentadienyl anion) complexes with amino-functionalized ligands were developed for the production of high-pressure H2 via catalytic dehydrogenation of formic acid (DFA) in water under base-free conditions. The Ir complexes with 2,2′-bipyridine (bpy) ligands bearing amino or alkylamino groups at the para positions exhibited high activity and stability for DFA compared with complexes containing bpy ligands bearing para-hydroxyl groups. In addition, para-amino groups afforded superior catalytic stability under high-pressure conditions compared with ortho-amino groups. By exploiting these amino-functionalized Cp*Ir complexes, it was possible to continuously produce high-pressure CO-free H2 via selective DFA in water upon the addition of concentrated FA (>99.5 wt %) to the base-free solution. Systematic investigation of the ligand effects on DFA revealed that the presence of alkylamino groups on the bpy ligand enhanced the catalytic activity (initial turnover frequency, TOF), although the stability decreased with increasing alkyl chain length on the amino groups. According to a Hammett plot, the increased catalytic activity of the Ir complexes after the introduction of amino-functionalized ligands may be attributable to the electron-donating effect of para-amino groups on the bpy ligand. Based on the experimental results, a reaction mechanism is proposed that involves a hydride intermediate whose stability is affected by the position of the amino groups on the bpy ligand, as confirmed through NMR studies.

Cooperative effects of heterodinuclear IrIII?MII complexes on catalytic H2 evolution from formic acid dehydrogenation in water

Novel heterodinuclear IrIII?MII complexes (M = Co, Ni, or Cu) with two adjacent reaction sites were synthesized by using 3,5-bis(2-pyridyl)-pyrazole (Hbpp) as a structure-directing ligand and employed as catalysts for H2 evolution through formic acid dehydrogenation in water. A cooperative effect of the hetero-metal centers was observed in the H2 evolution in comparison with the corresponding mononuclear IrIII and MII complexes as the components of the IrIII?MII complexes. The H2 evolution rate for the IrIII?MII complexes was at most 350-fold higher than that of the mononuclear IrIII complex. The catalytic activity increased in the following order: IrIII?CuII complex III?CoII complex III?NiII complex . The IrIII?H intermediates of the IrIII?MII complexes were successfully detected by ultraviolet?visible, 1H , nuclear magnetic resonance, and ESI-TOF-MS spectra. The catalytic enhancement of H2 evolution by the IrIII?MII complexes indicates that the IrIII?H species formed in the IrIII moiety act as reactive species and the MII moieties act as acceleration sites by the electronic effect from the MII center to the IrIII center through the bridging bpp? ligand. The IrIII?MII complexes may also activate H2O at the 3d MII centers as a proton source to facilitate H2 evolution. In addition, the affinity of formate for the IrIII?MII complexes was investigated on the basis of Michaelis?Menten plots; the IrIII?CoII and IrIII?NiII complexes exhibited affinities that were relatively higher than that of the IrIII?CuII complex. The catalytic mechanism of H2 evolution by the IrIII?MII complexes was revealed on the basis of spectroscopic detection of reaction intermediates, kinetic analysis, and isotope labeling experiments.