Copper(I) hydroxide

Copper(I) hydroxide
Names
Other names
Cuprous hydroxide; Copper monohydroxide
Identifiers
3D model (JSmol)
ChemSpider
  • InChI=1S/Cu.H2O/h;1H2/q+1;/p-1
    Key: ZMHWUUMELDFBCZ-UHFFFAOYSA-M
  • [OH-].[Cu+]
Properties
CuOH
Molar mass 80.55 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Copper(I) hydroxide is the inorganic compound with the chemical formula of CuOH. Little evidence exists for its existence. A similar situation applies to the monohydroxides of gold(I) and silver(I). Solid CuOH has been claimed however as an unstable yellow-red solid.[1] The topic has been the subject of theoretical analysis.[2] Copper(I) hydroxide would also be expect to easily oxidise to copper(II) hydroxide:

4CuOH + 2 H2O + O2 → 4Cu(OH)2

It would also be expected to rapidly dehydrate:

2CuOH → Cu2O + H2O

Solid CuOH would be of interest as a possible intermediate in the formation of copper(I) oxide (Cu2O), which has diverse applications.[3] e.g.forapplications for use in solar cells.[4]

Solid CuOH

Theoretical calculations predict that CuOH would be stable. Specifically, the dissociation of Cu(OH)2− leading to CuOH is subject to an energy of 62 ± 3 kcal/mol.[3]

Cu(OH)−2 → CuOH + OH−

Without evidence for its existence, CuOH has been invoked as a catalyst in organic synthesis[5]

Gaseous CuOH

Gaseous CuOH has been characterized spectroscopically using intracavity laser spectroscopy,[6] single vibronic level emission,[7] and microwave spectroscopic detection.[8]

CuOH is calculated to be bent, with the point group Cs. In this case, the bond distance of the Cu-O bond was 1.818 Å and the bond distance of the O-H bond was 0.960 Å. The bond angle for this geometry was 131.9°. The compound is highly ionic in character, which is why this angle is not exactly 120°. Structural parameters for linear CuOH have also been examined computationally.[3]

Ligand-stabilized Cu(I) hydroxides

Structure of a CuOH(IPr) complex. Color code: blue = N, copper = Cu, red = O, white = C, H.

Although simple CuOH compounds are fairly elusive or restricted to the gas-phase within spectrometers, some derivatives are well characterized.

Specifically cuprous hydroxides have been prepared using bulky NHC co-ligands.[9] In addition to Cu(IPr)OH, the dimer [Cu(IPr)]2OH]+ (as its BF−4 salt)[10]) and the aquo complex [Cu(IPr)]OH2]+ (as its SbF−6) have been characterized by X-ray crystallography.[11]

References

  1. ^ Soroka, Inna L.; Shchukarev, Andrey; Jonsson, Mats; Tarakina, Nadezda V.; Korzhavyi, Pavel A. (2013). "Cuprous hydroxide in a solid form: does it exist?". Dalton Transactions. 42 (26): 9585–94. doi:10.1039/C3DT50351H. PMID 23673918.
  2. ^ Korzhavyi, P.A.; Soroka, I.; Boman, M.; Johansson, B. (2011). "Thermodynamics of stable and metastable Cu-OH compounds". Solid State Phenomena. 172: 973–78. doi:10.4028/www.scientific.net/SSP.172-174.973. S2CID 137644376.
  3. ^ a b c Illas, F.; Rubio, J.; Centellas, F.; Virgili, J. (1984). "Molecular Structure of Copper (I) Hydroxide and Copper Hydroxide (1-) (Cu (OH)2-). An ab initio Study". The Journal of Physical Chemistry. 88 (22): 5225–28. doi:10.1021/j150666a022.
  4. ^ "Thin film deposition of Cu2O and Application for Solar Cells". Solar Energy. 1, 80 (6): 715–22. 2006. doi:10.1016/j.solener.2005.10.012.
  5. ^ Luo, K.; Li, W.; Lin, J.; Jin, Y. (2019). "Tandem Reaction of Heterocyclic Ketene Aminals with Diazoesters: Synthesis of Pyrimidopyrrolidone Derivatives". Tetrahedron Letters. 60 (41): 151136. doi:10.1016/j.tetlet.2019.151136. S2CID 203143147.
  6. ^ Harms, J.C.; O'Brien, L.C.; O'Brien, J.J. (2019). "Rotational Analysis of the [15.1] A "–X~ 1A′ Transition of CuOH and CuOD Observed at High Resolution with Intracavity Laser Spectroscopy". Journal of Molecular Spectroscopy. 362: 8–13. doi:10.1016/j.jms.2019.05.013. S2CID 191158971.
  7. ^ Tao, C.; Mukarakate, C.; Reid, S.A. (2007). "Single Vibronic Level Emission Spectroscopy and Fluorescence Lifetime of the B~ 1A "→ X~ 1A′ System of CuOH and CuOD". Chemical Physics Letters. 449 (4–6): 282–85. doi:10.1016/j.cplett.2007.10.084.
  8. ^ Whitham, C.J.; Ozeki, H.; Saito, S. (1999). "Microwave spectroscopic detection of transition metal hydroxides: CuOH and AgOH". The Journal of Chemical Physics. 15, 110 (23): 11109–12. doi:10.1063/1.479051. hdl:10098/1528.
  9. ^ Fortman, George C.; Slawin, Alexandra M. Z.; Nolan, Steven P. (2010). "A Versatile Cuprous Synthon: [Cu(IPr)(OH)] (IPr = 1,3 Bis(diisopropylphenyl)imidazol-2-ylidene)". Organometallics. 29 (17): 3966–3972. doi:10.1021/om100733n.
  10. ^ Ibrahim, Houssein; Guillot, Régis; Cisnetti, Federico; Gautier, Arnaud (2014). "[{Cu(IPr)}2(μ-OH)][BF4]: Synthesis and Halide-Free CuAAC Catalysis". Chemical Communications. 50 (54): 7154–7156. doi:10.1039/C4CC03346A. PMID 24854111.
  11. ^ Muñoz-Castro, Alvaro; Wang, Guocang; Ponduru, Tharun Teja; Dias, H. V. Rasika (2021). "Synthesis and Characterization of N-Heterocyclic Carbene–M⋯OEt2 Complexes (M = Cu, Ag, Au). Analysis of Solvated Auxiliary-Ligand Free [(NHC)M]+ Species". Physical Chemistry Chemical Physics. 23 (2): 1577–1583. doi:10.1039/D0CP05222A. PMID 33406199.