Copper hydride

Last updated
Copper hydride
CuH.png
Names
IUPAC name
Copper hydride
Other names
Copper(I) hydride
Cuprous hydride
Hydridocopper(I)
Cuprane
poly[cuprane(1)]
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.229.864 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 803-023-1
PubChem CID
  • InChI=1S/Cu.H Yes check.svgY
    Key: JJFLDSOAQUJVBF-UHFFFAOYSA-N Yes check.svgY
  • [CuH]
Properties
CuH
Molar mass 64.554 g·mol−1
Melting point 100 °C (212 °F; 373 K) [1]
Hazards
GHS labelling:
GHS-pictogram-flamme.svg GHS-pictogram-exclam.svg
Warning
H228, H315, H319, H335
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 1 mg/m3 (as Cu) [2]
REL (Recommended)
TWA 1 mg/m3 (as Cu) [2]
IDLH (Immediate danger)
TWA 100 mg/m3 (as Cu) [2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Copper hydride is inorganic compound with the chemical formula CuHn where n ~ 0.95. [3] It is a red solid, rarely isolated as a pure composition, that decomposes to the elements. [4] Copper hydride is mainly produced as a reducing agent in organic synthesis and as a precursor to various catalysts. [5]

Contents

History

In 1844, the French chemist Adolphe Wurtz synthesised copper hydride for the first time. [6] He reduced an aqueous solution of copper(II) sulfate with hypophosphorous acid (H3PO2). In 2011, Panitat Hasin and Yiying Wu were the first to synthesise a metal hydride (copper hydride) using the technique of sonication. [7] Copper hydride has the distinction of being the first metal hydride discovered. In 2013, it was established by Donnerer et al. that, at least up to fifty gigapascals, copper hydride cannot be synthesised by pressure alone. However, they were successful in synthesising several copper-hydrogen alloys under pressure. [5]

Chemical properties

Structure

Wurtzite structure Wurtzite polyhedra.png
Wurtzite structure

In copper hydride, elements adopt the Wurtzite crystal structure [8] [9] (polymeric), being connected by covalent bonds. [1]

The CuH consists of a core of CuH with a shell of water and this may be largely replaced by ethanol. This offers the possibility of modifying the properties of CuH produced by aqueous routes. [10] While all methods for the synthesis of CuH result in the same bulk product, the synthetic path taken engenders differing surface properties. The different behaviors of CuH obtained by aqueous and nonaqueous routes can be ascribed to a combination of very different particle size and dissimilar surface termination, namely, bonded hydroxyls for the aqueous routes and a coordinated donor for the nonaqueous routes. [11]

Chemical reactions

CuH generally behaves as a source of H. For instance, Wurtz reported the double displacement reaction of CuH with hydrochloric acid: [12]

CuH + HCl → CuCl +H
2

When not cooled below −5 °C (23 °F), copper hydride decomposes, to produce hydrogen gas and a mixture containing elemental copper:

2 CuH → xCu•(2-x)CuH + ½x H
2
(0 < x < 2)

Solid copper hydride is the irreversible autopolymerisation product of the molecular form, and the molecular form cannot be isolated in concentration.

Production

Copper does not react with hydrogen even on heating, [13] thus copper hydrides are made indirectly from copper(I) and copper(II) precursors. Examples include the reduction of copper(II) sulfate with sodium hypophosphite in the presence of sulfuric acid, [1] or more simply with just hypophosphorous acid. [14] Other reducing agents, including classical aluminium hydrides can be used. [15]

4 Cu2+ + 6 H3PO2 + 6 H2O → 4 CuH + 6 H3PO3 + 8 H+

The reactions produce a red-colored precipitate of CuH, which is generally impure and slowly decomposes to liberate hydrogen, even at 0 °C. [14]

2 CuH → 2 Cu + H2

This slow decomposition also takes place underwater, [16] however there are reports of the material becoming pyrophoric if dried. [17]

A new synthesis method has been published in 2017 by Lousada et al. [18] In this synthesis high purity CuH nanoparticles have been obtained from basic copper carbonate, CuCO3·Cu(OH)2. [18] This method is faster and has a higher chemical yield than the copper sulfate based synthesis and produces nanoparticles of CuH with higher purity and a smaller size distribution. The obtained CuH can easily be converted to conducting thin films of Cu. These films are obtained by spraying the CuH nanoparticles in their synthesis medium into some insulating support. After drying, conducting Cu films protected by a layer of mixed copper oxides are spontaneously formed.

Reductive sonication

Copper hydride is also produced by reductive sonication. In this process, hexaaquacopper(II) and hydrogen(•) react to produce copper hydride and oxonium according to the equation:

[Cu(H2O)6]2+ + 3 H1/n (CuH)n + 2 [H3O]+ + 4 H2O

Hydrogen(•) is obtained in situ from the homolytic sonication of water. Reductive sonication produces molecular copper hydride as an intermediate. [7]

Applications in Organic Synthesis

Structure of [(Ph3P)CuH]6. Cu6H6P6.png
Structure of [(Ph3P)CuH]6.

Phosphine- and NHC-copper hydride species have been developed as reagents in organic synthesis, albeit of limited use. [19] Most widely used is [(Ph3P)CuH]6 (Stryker's reagent) for the reduction of α,β-unsaturated carbonyl compounds. [20] H2 (at least 80 psi) and hydrosilanes can be used as the terminal reductant, allowing a catalytic amount of [(Ph3P)CuH]6 to be used for conjugate reduction reactions. [21] [22]

Chiral phosphine-copper complexes catalyze hydrosilation of ketones and esters with low enanotioselectivities. [23] An enantioselective (80 to 92% ee) reduction of prochiral α,β-unsaturated esters uses Tol-BINAP complexes of copper in the presence of PMHS as the reductant. [24] Subsequently, conditions have been developed for the CuH-catalyzed hydrosilylation of ketones [25] and imines [26] proceeding with excellent levels of chemo- and enantioselectivity.

The reactivity of LnCuH species with weakly activated (e.g. styrenes, dienes) and unactivated alkenes (e.g. α-olefins) and alkynes has been recognized [27] and has served as the basis for several copper-catalyzed formal hydrofunctionalization reactions. [28] [29] [30]

"Hydridocopper"

The diatomic species CuH is a gas that has attracted the attention of spectroscopists. It polymerises upon being condensed. A well-known oligomer is octahedro-hexacuprane(6), occurring in Stryker's reagent. Hydridocopper has acidic behavior for the same reason as normal copper hydride. However, it does not form stable aqueous solutions, due in part to its autopolymerisation, and its tendency to be oxidised by water. Copper hydride reversibly precipitates from pyridine solution, as an amorphous solid. However, repeated dissolution affords the regular crystalline form, which is insoluble. Under standard conditions, molecular copper hydride autopolymerises to form the crystalline form, including under aqueous conditions, hence the aqueous production method devised by Wurtz.

Production

Molecular copper hydride can be formed by reducing copper iodide with lithium aluminium hydride in ether and pyridine. [31] 4CuI + LiAlH4 CuH + LiI + AlI3 This was discovered by E Wiberg and W Henle in 1952. [32] The solution of this CuH in the pyridine is typically dark red to dark orange. [31] A precipitate is formed if ether is added to this solution. [31] This will redissolve in pyridine. Impurities of the reaction products remain in the product. [31] In this study, it was found that the solidified diatomic substance is distinct from the Wurtzite structure. The Wurtzite substance was insoluble and was decomposed by lithium iodide, but not the solidified diatomic species. Moreover, while the Wurtzite substance's decomposition is strongly base catalysed, whereas the solidified diatomic species is not strongly affected at all. Dilts distinguishes between the two copper hydrides as the 'insoluble-' and 'soluble copper hydrides'. The soluble hydride is susceptible to pyrolysis under vacuum and proceeds to completion under 100 °C.

Amorphous copper hydride is also produced by anhydrous reduction. In this process copper(I) and tetrahydroaluminate react to produce molecular copper hydride and triiodoaluminium adducts. The molecular copper hydride is precipitated into amorphous copper hydride with the addition of diethyl ether. Amorphous copper hydride is converted into the Wurtz phase by annealing, accompanied by some decomposition. [31]

History

Hydridocopper was discovered in the vibration-rotation emission of a hollow-cathode lamp in 2000 by Bernath, who detected it at the University of Waterloo. It was first detected as a contaminant while attempting to generate NeH+ using the hollow-cathode lamp. [33] [34] Molecular copper hydride has the distinction of being the first metal hydride to be detected in this way. (1,0) (2,0) and (2,1) vibrational bands were observed along with line splitting due to the presence of two copper isotopes, 63Cu and 65Cu. [35] [36]

The A1Σ+-X1Σ+ absorption lines from CuH have been claimed to have been observed in sunspots and in the star 19 Piscium. [37] [38]

In vapour experiments, it was found that copper hydride is produced from the elements upon exposure to 310 nanometre radiation. [4]

Cu + H2 ↔ CuH + H

However, this proved to be unviable as a production method as the reaction is difficult to control. The activation barrier for the reverse reaction is virtually non-existent, which allows it to readily proceed even at 20 Kelvin.

Other copper hydrides

Related Research Articles

<span class="mw-page-title-main">Wilkinson's catalyst</span> Chemical compound

Wilkinson's catalyst is the common name for chloridotris(triphenylphosphine)rhodium(I), a coordination complex of rhodium with the formula [RhCl(PPh3)3] (Ph = phenyl). It is a red-brown colored solid that is soluble in hydrocarbon solvents such as benzene, and more so in tetrahydrofuran or chlorinated solvents such as dichloromethane. The compound is widely used as a catalyst for hydrogenation of alkenes. It is named after chemist and Nobel laureate Sir Geoffrey Wilkinson, who first popularized its use.

<span class="mw-page-title-main">Wacker process</span>

The Wacker process or the Hoechst-Wacker process refers to the oxidation of ethylene to acetaldehyde in the presence of palladium(II) chloride as the catalyst. This chemical reaction was one of the first homogeneous catalysis with organopalladium chemistry applied on an industrial scale.

The Corey–House synthesis is an organic reaction that involves the reaction of a lithium diorganylcuprate with an organic pseudohalide to form a new alkane, as well as an ill-defined organocopper species and lithium halide as byproducts.

<span class="mw-page-title-main">Fluoroantimonic acid</span> Chemical compound

Fluoroantimonic acid is a mixture of hydrogen fluoride and antimony penta­fluoride, containing various cations and anions. This substance is a superacid that can be over a billion times stronger than 100% sulfuric acid in terms of its protonating ability measured by Hammett function. It even protonates some hydro­carbons to afford pentacoordinate carbo­cations. Fluoro­antimonic acid is corrosive. For example, it cannot be contained directly in glass carboys, as it attacks glass, but can be stored in containers lined with PTFE (Teflon) or PFA polymers.

Zinc hydride is an inorganic compound with the chemical formula ZnH2. It is a white, odourless solid which slowly decomposes into its elements at room temperature; despite this it is the most stable of the binary first row transition metal hydrides. A variety of coordination compounds containing Zn–H bonds are used as reducing agents, however ZnH2 itself has no common applications.

<span class="mw-page-title-main">Liebeskind–Srogl coupling</span>

The Liebeskind–Srogl coupling reaction is an organic reaction forming a new carbon–carbon bond from a thioester and a boronic acid using a metal catalyst. It is a cross-coupling reaction. This reaction was invented by and named after Jiri Srogl from the Academy of Sciences, Czech Republic, and Lanny S. Liebeskind from Emory University, Atlanta, Georgia, USA. There are three generations of this reaction, with the first generation shown below. The original transformation used catalytic Pd(0), TFP = tris(2-furyl)phosphine as an additional ligand and stoichiometric CuTC = copper(I) thiophene-2-carboxylate as a co-metal catalyst. The overall reaction scheme is shown below.

Metal carbon dioxide complexes are coordination complexes that contain carbon dioxide ligands. Aside from the fundamental interest in the coordination chemistry of simple molecules, studies in this field are motivated by the possibility that transition metals might catalyze useful transformations of CO2. This research is relevant both to organic synthesis and to the production of "solar fuels" that would avoid the use of petroleum-based fuels.

<span class="mw-page-title-main">Krische allylation</span>

The Krische allylation involves the enantioselective iridium-catalyzed addition of an allyl group to an aldehyde or an alcohol, resulting in the formation of a secondary homoallylic alcohol. The mechanism of the Krische allylation involves primary alcohol dehydrogenation or, when using aldehyde reactants, hydrogen transfer from 2-propanol. Unlike other allylation methods, the Krische allylation avoids the use of preformed allyl metal reagents and enables the direct conversion of primary alcohols to secondary homoallylic alcohols.

In organic chemistry, the Fujiwara–Moritani reaction is a type of cross coupling reaction where an aromatic C-H bond is directly coupled to an olefinic C-H bond, generating a new C-C bond. This reaction is performed in the presence of a transition metal, typically palladium. The reaction was discovered by Yuzo Fujiwara and Ichiro Moritani in 1967. An external oxidant is required to this reaction to be run catalytically. Thus, this reaction can be classified as a C-H activation reaction, an oxidative Heck reaction, and a C-H olefination. Surprisingly, the Fujiwara–Moritani reaction was discovered before the Heck reaction.

Dialkylbiaryl phosphine ligands are phosphine ligands that are used in homogeneous catalysis. They have proved useful in Buchwald-Hartwig amination and etherification reactions as well as Negishi cross-coupling, Suzuki-Miyaura cross-coupling, and related reactions. In addition to these Pd-based processes, their use has also been extended to transformations catalyzed by nickel, gold, silver, copper, rhodium, and ruthenium, among other transition metals.

The Mukaiyama hydration is an organic reaction involving formal addition of an equivalent of water across an olefin by the action of catalytic bis(acetylacetonato)cobalt(II) complex, phenylsilane and atmospheric oxygen to produce an alcohol with Markovnikov selectivity.

<span class="mw-page-title-main">Activation of cyclopropanes by transition metals</span>

In organometallic chemistry, the activation of cyclopropanes by transition metals is a research theme with implications for organic synthesis and homogeneous catalysis. Being highly strained, cyclopropanes are prone to oxidative addition to transition metal complexes. The resulting metallacycles are susceptible to a variety of reactions. These reactions are rare examples of C-C bond activation. The rarity of C-C activation processes has been attributed to Steric effects that protect C-C bonds. Furthermore, the directionality of C-C bonds as compared to C-H bonds makes orbital interaction with transition metals less favorable. Thermodynamically, C-C bond activation is more favored than C-H bond activation as the strength of a typical C-C bond is around 90 kcal per mole while the strength of a typical unactivated C-H bond is around 104 kcal per mole.

Germanium(II) hydrides, also called germylene hydrides, are a class of Group 14 compounds consisting of low-valent germanium and a terminal hydride. They are also typically stabilized by an electron donor-acceptor interaction between the germanium atom and a large, bulky ligand.

<span class="mw-page-title-main">Lanthanocene</span>

A lanthanocene is a type of metallocene compound that contains an element from the lanthanide series. The most common lanthanocene complexes contain two cyclopentadienyl anions and an X type ligand, usually hydride or alkyl ligand.

<span class="mw-page-title-main">Mizoroki-Heck vs. Reductive Heck</span>

The Mizoroki−Heck coupling of aryl halides and alkenes to form C(sp2)–C(sp2) bonds has become a staple transformation in organic synthesis, owing to its broad functional group compatibility and varied scope. In stark contrast, the palladium-catalyzed reductive Heck reaction has received considerably less attention, despite the fact that early reports of this reaction date back almost half a century. From the perspective of retrosynthetic logic, this transformation is highly enabling because it can forge alkyl–aryl linkages from widely available alkenes, rather than from the less accessible and/or more expensive alkyl halide or organometallic C(sp3) synthons that are needed in a classical aryl/alkyl cross-coupling.

β-Carbon elimination is a type of reaction in organometallic chemistry wherein an allyl ligand bonded to a metal center is broken into the corresponding metal-bonded alkyl (aryl) ligand and an alkene. It is a subgroup of elimination reactions. Though less common and less understood than β-hydride elimination, it is an important step involved in some olefin polymerization processes and transition-metal-catalyzed organic reactions.

The Stahl oxidation is a copper-catalyzed aerobic oxidation of primary and secondary alcohols to aldehydes and ketones. Known for its high selectivity and mild reaction conditions, the Stahl oxidation offers several advantages over classical alcohol oxidations.

Jonas C. Peters is the Bren Professor of Chemistry at the California Institute of Technology and Director of the Resnick Sustainability Institute. He has contributed to the development of catalysts and photocatalysts relevant to small molecule activation.

Metal-ligand cooperativity (MLC) is a mode of reactivity in which a metal and ligand of a complex are both involved in the bond breaking or bond formation of a substrate during the course of a reaction. This ligand is an actor ligand rather than a spectator, and the reaction is generally only deemed to contain MLC if the actor ligand is doing more than leaving to provide an open coordination site. MLC is also referred to as "metal-ligand bifunctional catalysis." Note that MLC is not to be confused with cooperative binding.

<span class="mw-page-title-main">Nitro-Mannich reaction</span>

The nitro-Mannich reaction is the nucleophilic addition of a nitroalkane to an imine, resulting in the formation of a beta-nitroamine. With the reaction involving the addition of an acidic carbon nucleophile to a carbon-heteroatom double bond, the nitro-Mannich reaction is related to some of the most fundamental carbon-carbon bond forming reactions in organic chemistry, including the aldol reaction, Henry reaction and Mannich reaction.

References

  1. 1 2 3 Fitzsimons, Nuala P.; Jones, William; Herley, Patrick J. (1 January 1995). "Studies of copper hydride. Part 1.—Synthesis and solid-state stability". Journal of the Chemical Society, Faraday Transactions. 91 (4): 713–718. doi:10.1039/FT9959100713.
  2. 1 2 3 NIOSH Pocket Guide to Chemical Hazards. "#0150". National Institute for Occupational Safety and Health (NIOSH).
  3. Jordan, Abraham J.; Lalic, Gojko; Sadighi, Joseph P. (2016-07-25). "Coinage Metal Hydrides: Synthesis, Characterization, and Reactivity". Chemical Reviews. 116 (15): 8318–8372. doi:10.1021/acs.chemrev.6b00366. ISSN   0009-2665. PMID   27454444.
  4. 1 2 Aldridge, Simon; Downs, Anthony J. (2001). "Hydrides of the Main-Group Metals: New Variations on an Old Theme". Chem. Rev. 101 (11): 3305–3366. doi:10.1021/cr960151d. PMID   11840988.
  5. 1 2 Donnerer, Christian; Scheler, Thomas; Gregoryanz, Eugene (4 April 2013). "High-pressure synthesis of noble metal hydrides". The Journal of Chemical Physics. 138 (13): 134507. Bibcode:2013JChPh.138m4507D. doi:10.1063/1.4798640. PMID   23574244. Archived from the original on 24 June 2013. Retrieved 20 June 2013.
  6. Wurtz, A. (1844) "Sur l'hydrure de cuivre" (On copper hydride), Comptes rendus, 18 : 702–704.
  7. 1 2 Hasin, Panitat; Wu, Yiying (1 January 2012). "Sonochemical synthesis of copper hydride (CuH)". Chemical Communications. 48 (9): 1302–1304. doi:10.1039/C2CC15741A. PMID   22179137.
  8. Goedkoop, J. A.; Andresen, A. F. (1955). "The crystal structure of copper hydride". Acta Crystallographica. 8 (2): 118–119. doi:10.1107/S0365110X55000480.
  9. Müller, Heinz; Bradley, Albert James (1926). "CCXVII.—Copper hydride and its crystal structure". Journal of the Chemical Society (Resumed). 129: 1669–1673. doi:10.1039/JR9262901669.
  10. Bennett, Elliot L; Thomas Wilson; Patrick J Murphy; Keith Refson; Alex C Hannon; Silvia Imberti; Samantha K Callear; Gregory A Chass; Stewart F Parker (2015). "Structure and spectroscopy of CuH prepared via borohydride reduction". Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials. 71 (6): 608–612. doi:10.1107/S2052520615015176. PMC   4669994 . PMID   26634717.
  11. Bennett, Elliot L; Thomas Wilson; Patrick J Murphy; Keith Refson; Alex C Hannon; Silvia Imberti; Samantha K Callear; Gregory A Chass; Stewart F Parker (2015). "How the Surface Structure Determines the Properties of CuH". Inorganic Chemistry. 54 (5): 2213–2220. doi: 10.1021/ic5027009 . PMID   25671787.
  12. Rocke, Alan J. (2001). Nationalizing Science: Adolphe Wurtz and the Battle for French Chemistry. Cambridge, MA: MIT Press. pp. 121–122. ISBN   978-0-262-26429-7.
  13. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN   978-0-08-037941-8.
  14. 1 2 Burtovyy, R.; Utzig, E.; Tkacz, M. (2000). "Studies of the thermal decomposition of copper hydride". Thermochimica Acta. 363 (1–2): 157–163. doi:10.1016/S0040-6031(00)00594-3.
  15. Brauer, Georg (1963). Handbook of Preparative Inorganic Chemistry. Vol. 2 (2nd ed.). New York: Academic Press. p. 1004. ISBN   978-0-323-16129-9.
  16. Warf, James C.; Feitknecht, W. (1950). "Zur Kenntnis des Kupferhydrids, insbesondere der Kinetik des Zerfalls". Helvetica Chimica Acta. 33 (3): 613–639. doi:10.1002/hlca.19500330327.
  17. Goedkoop, J. A.; Andresen, A. F. (1955). "The crystal structure of copper hydride". Acta Crystallogr. 8 (2): 118–119. doi:10.1107/S0365110X55000480.
  18. 1 2 Lousada, Cláudio M.; Fernandes, Ricardo M. F.; Tarakina, Nadezda V.; Soroka, Inna L. (2017). "Synthesis of copper hydride (CuH) from CuCO3·Cu(OH)2 – a path to electrically conductive thin films of Cu". Dalton Transactions. 46 (20): 6533–6543. doi:10.1039/C7DT00511C. ISSN   1477-9226. PMID   28379275.
  19. Whitesides, George M.; San Filippo, Joseph; Stredronsky, Erwin R.; Casey, Charles P. (1969-11-01). "Reaction of copper(I) hydride with organocopper(I) compounds". Journal of the American Chemical Society. 91 (23): 6542–6544. doi:10.1021/ja01051a093. ISSN   0002-7863.
  20. John F. Daeuble and Jeffrey M. Stryker "Hexa-μ-hydrohexakis(triphenylphosphine)hexacopper" eEROS Encyclopedia of Reagents for Organic Synthesis, 2001. doi : 10.1002/047084289X.rh011m
  21. Mahoney, Wayne S.; Stryker, Jeffrey M. (1989-11-01). "Hydride-mediated homogeneous catalysis. Catalytic reduction of .alpha.,.beta.-unsaturated ketones using [(Ph3P)CuH]6 and H2". Journal of the American Chemical Society. 111 (24): 8818–8823. doi:10.1021/ja00206a008. ISSN   0002-7863.
  22. Mori, Atsunori; Fujita, Akinori (1997-01-01). "Copper(I) salt mediated 1,4-reduction of α,β-unsaturated ketones using hydrosilanes" (PDF). Chemical Communications (22): 2159–2160. doi:10.1039/a706032g. ISSN   1364-548X.
  23. Brunner, Henri; Miehling, Wolfgang (1984-10-23). "Asymmetrische katalysen". Journal of Organometallic Chemistry. 275 (2): c17–c21. doi:10.1016/0022-328X(84)85066-4.
  24. Appella, Daniel H.; Moritani, Yasunori; Shintani, Ryo; Ferreira, Eric M.; Buchwald, Stephen L. (1999-10-01). "Asymmetric Conjugate Reduction of α,β-Unsaturated Esters Using a Chiral Phosphine−Copper Catalyst". Journal of the American Chemical Society. 121 (40): 9473–9474. doi:10.1021/ja992366l. ISSN   0002-7863.
  25. Lipshutz, Bruce H.; Noson, Kevin; Chrisman, Will; Lower, Asher (2003-07-01). "Asymmetric Hydrosilylation of Aryl Ketones Catalyzed by Copper Hydride Complexed by Nonracemic Biphenyl Bis-phosphine Ligands". Journal of the American Chemical Society. 125 (29): 8779–8789. doi:10.1021/ja021391f. ISSN   0002-7863. PMID   12862472.
  26. Lipshutz, Bruce H.; Shimizu, Hideo (2004-04-19). "Copper(I)-Catalyzed Asymmetric Hydrosilylations of Imines at Ambient Temperatures". Angewandte Chemie International Edition. 43 (17): 2228–2230. doi:10.1002/anie.200353294. ISSN   1521-3773. PMID   15108129.
  27. Noh, Dongwan; Chea, Heesung; Ju, Junghwan; Yun, Jaesook (2009-08-03). "Highly Regio- and Enantioselective Copper-Catalyzed Hydroboration of Styrenes". Angewandte Chemie International Edition. 48 (33): 6062–6064. doi:10.1002/anie.200902015. ISSN   1521-3773. PMID   19591178.
  28. Miki, Yuya; Hirano, Koji; Satoh, Tetsuya; Miura, Masahiro (2013-10-04). "Copper-Catalyzed Intermolecular Regioselective Hydroamination of Styrenes with Polymethylhydrosiloxane and Hydroxylamines". Angewandte Chemie International Edition. 52 (41): 10830–10834. doi:10.1002/anie.201304365. ISSN   1521-3773. PMID   24038866.
  29. Zhu, Shaolin; Niljianskul, Nootaree; Buchwald, Stephen L. (2013-10-23). "Enantio- and Regioselective CuH-Catalyzed Hydroamination of Alkenes". Journal of the American Chemical Society. 135 (42): 15746–15749. doi:10.1021/ja4092819. ISSN   0002-7863. PMC   3874865 . PMID   24106781.
  30. Uehling, Mycah R.; Rucker, Richard P.; Lalic, Gojko (2014-06-18). "Catalytic Anti-Markovnikov Hydrobromination of Alkynes". Journal of the American Chemical Society. 136 (24): 8799–8803. doi:10.1021/ja503944n. ISSN   0002-7863. PMID   24896663.
  31. 1 2 3 4 5 Dilts, J. A.; D. F. Shriver (1968). "Nature of soluble copper(I) hydride". Journal of the American Chemical Society. 90 (21): 5769–5772. doi:10.1021/ja01023a020. ISSN   0002-7863.
  32. E Wiberg & W Henle (1952). "Über die Dämpfung der elektromagnetischen Eigenschwingungen des Systems Erde — Luft — Ionosphäre". Zeitschrift für Naturforschung A. 7 (3–4): 250. Bibcode:1952ZNatA...7..250S. doi: 10.1515/zna-1952-3-404 .
  33. Bernath, P. F. (2000). "6 Infrared emission spectroscopy" (PDF). Annual Reports on the Progress of Chemistry, Section C. 96 (1): 202. doi:10.1039/B001200I. ISSN   0260-1826. Archived from the original (PDF) on 2015-04-02. Retrieved 2013-02-23.
  34. Ram, R.S.; P.F. Bernath; J.W. Brault (1985). "Fourier transform emission spectroscopy of NeH+". Journal of Molecular Spectroscopy. 113 (2): 451–457. Bibcode:1985JMoSp.113..451R. doi:10.1016/0022-2852(85)90281-4. ISSN   0022-2852.
  35. Ram, R. S.; P.F. Bernath; J.W. Brault (1985). Cameron, David G; Grasselli, Jeannette G (eds.). "Infrared Fourier Transform Emission Spectroscopy of CuH and NeH+". Proc. SPIE. Fourier and Computerized Infrared Spectroscopy. 553: 774–775. Bibcode:1985SPIE..553..374R. doi:10.1117/12.970862. S2CID   93779370.
  36. Seto, Jenning Y.; Zulfikar Morbi; Frank Charron; Sang K. Lee; Peter F. Bernath; Robert J. Le Roy (1999). "Vibration-rotation emission spectra and combined isotopomer analyses for the coinage metal hydrides: CuH & CuD, AgH & AgD, and AuH & AuD". The Journal of Chemical Physics. 110 (24): 11756. Bibcode:1999JChPh.11011756S. doi:10.1063/1.479120. ISSN   0021-9606. S2CID   43929297.
  37. Wojslaw, Robert S.; Benjamin F. Peery (May 1976). "Identification of Novel Molecules in the Spectrum of 19 Piscium". The Astrophysical Journal Supplement. 31: 75–92. Bibcode:1976ApJS...31...75W. doi:10.1086/190375.
  38. Fernando, W. T. M. L.; L. C. O'Brien; P. F. Bernath (1990). "Fourier Transform Emission Spectroscopy of the A1Σ+-X1Σ+ Transition of CuD" (PDF). Journal of Molecular Spectroscopy. 139 (2): 461–464. Bibcode:1990JMoSp.139..461F. doi:10.1016/0022-2852(90)90084-4. ISSN   0022-2852. Archived from the original (PDF) on 2005-03-10. Retrieved 2013-02-20.