Copper Compounds

Direct Evidence of Subsurface Oxygen Formation in Oxide‐Derived Cu by X‐ray Photoelectron Spectroscopy

“…After air calcination of the polycrystalline Cu specimen, the as‐prepared Cu oxide precursor exhibits a dark and rough appearance (Figure S1a), which is the typical color of cupric oxide (CuO). [14] The electrically insulating characteristics of a thick CuO layer resulted in extensive charge build‐up making XPS studies unfeasible. After the H 2 reduction treatment, the OD‐Cu exhibits a shining orange/pink color (see Figure S1b), indicating the oxide has been reduced across the entire sample surface.…”

“…After the H 2 reduction treatment, the OD‐Cu exhibits a shining orange/pink color (see Figure S1b), indicating the oxide has been reduced across the entire sample surface. [14] A representative XPS survey spectrum of the OD‐Cu recorded using 3266 eV photons is shown in Figure S2, depicting presence of copper and oxygen without detectable traces of the common contaminants from the ambient heat treatment or from the vacuum chamber, for example, S, Si, and C. Figure S3 shows the XPS Cu 2p region of OD‐Cu probed with multiple different photon energies for depth profiling and Cu 2 O (reference sample prepared separately), where its two spin‐orbit split components feature at 932.8 eV for 2p 3/2 and 952.6 eV for 2p 1/2 can be clearly seen. In addition to the spin‐orbit split components, the Cu 2 O reference sample also shows two additional weak satellites between the two spin‐orbit split peaks.…”

Direct Evidence of Subsurface Oxygen Formation in Oxide‐Derived Cu by X‐ray Photoelectron Spectroscopy

“…After air calcination of the polycrystalline Cu specimen, the as‐prepared Cu oxide precursor exhibits a dark and rough appearance (Figure S1a), which is the typical color of cupric oxide (CuO). [14] The electrically insulating characteristics of a thick CuO layer resulted in extensive charge build‐up making XPS studies unfeasible. After the H 2 reduction treatment, the OD‐Cu exhibits a shining orange/pink color (see Figure S1b), indicating the oxide has been reduced across the entire sample surface.…”

“…After the H 2 reduction treatment, the OD‐Cu exhibits a shining orange/pink color (see Figure S1b), indicating the oxide has been reduced across the entire sample surface. [14] A representative XPS survey spectrum of the OD‐Cu recorded using 3266 eV photons is shown in Figure S2, depicting presence of copper and oxygen without detectable traces of the common contaminants from the ambient heat treatment or from the vacuum chamber, for example, S, Si, and C. Figure S3 shows the XPS Cu 2p region of OD‐Cu probed with multiple different photon energies for depth profiling and Cu 2 O (reference sample prepared separately), where its two spin‐orbit split components feature at 932.8 eV for 2p 3/2 and 952.6 eV for 2p 1/2 can be clearly seen. In addition to the spin‐orbit split components, the Cu 2 O reference sample also shows two additional weak satellites between the two spin‐orbit split peaks.…”

Mechanistic Development and Recent Applications of the Chan–Lam Amination

“…With regard to the frequently troublesome (and often academic) question of stoichiometry, the early studies used superstoichiometric (1–2 equiv) Cu­(OAc) 2 , − with Evans specifically demonstrating that stoichiometric amounts of Cu­(OAc) 2 and aerobic conditions were required for the C–O bond forming process to proceed in good yield . Mechanistically, the process is believed to require Cu­(II) at the outset; however, in situ Cu­(I) disproportionation or oxidation of Cu­(I) , likely explains why Cu­(I) sources can be used.…”

“…Although the number of examples is lower, the use of Cu­(II) halides (CuCl 2 , CuBr 2 ) has been reported. Despite halogenation of arylboronic acids and derivatives being known to proceed via ipso -substitution using X 2 generated in situ by the well-known Cu­(II)/X – → Cu­(I)/X 2 redox process (Scheme ), ,, coupling to counteranions derived from the Cu source has not been reported. However, this is somewhat achievable under certain circumstances; for example, acetate esters are not reported when using Cu­(OAc) 2 , although it is possible to prepare phenolate esters by Chan–Lam of AcOH (and other carboxylic acids) using Cu­(OTf) 2 …”

Superhydrophobic anti-corrosion coatings for metal surfaces: a systematic review from fabrication to performance

“…93 In the protection of copper and its alloys, their excellent electrical conductivity, thermal conductivity, and ductility make them widely used in electronics and heat exchange applications, yet they also face significant corrosion challenges. 94 Wang et al 95 constructed a superhydrophobic-superoleophilic photothermal coating on a copper mesh surface, achieving a corrosion protection efficiency of 97.7%, significantly expanding the potential for copper applications in complex humid environments. Xia et al 96 developed a superhydrophobic coating featuring grass-like microstructures composed of orthorhombic Cu(OH) 2 and monoclinic CuO on copper foil, which effectively delayed the oxidation and corrosion processes of copper in simulated corrosive environments.…”

Direct Evidence of Subsurface Oxygen Formation in Oxide‐Derived Cu by X‐ray Photoelectron Spectroscopy

“…After air calcination of the polycrystalline Cu specimen, the as‐prepared Cu oxide precursor exhibits a dark and rough appearance (Figure S1a), which is the typical color of cupric oxide (CuO). [14] The electrically insulating characteristics of a thick CuO layer resulted in extensive charge build‐up making XPS studies unfeasible. After the H 2 reduction treatment, the OD‐Cu exhibits a shining orange/pink color (see Figure S1b), indicating the oxide has been reduced across the entire sample surface.…”

“…After the H 2 reduction treatment, the OD‐Cu exhibits a shining orange/pink color (see Figure S1b), indicating the oxide has been reduced across the entire sample surface. [14] A representative XPS survey spectrum of the OD‐Cu recorded using 3266 eV photons is shown in Figure S2, depicting presence of copper and oxygen without detectable traces of the common contaminants from the ambient heat treatment or from the vacuum chamber, for example, S, Si, and C. Figure S3 shows the XPS Cu 2p region of OD‐Cu probed with multiple different photon energies for depth profiling and Cu 2 O (reference sample prepared separately), where its two spin‐orbit split components feature at 932.8 eV for 2p 3/2 and 952.6 eV for 2p 1/2 can be clearly seen. In addition to the spin‐orbit split components, the Cu 2 O reference sample also shows two additional weak satellites between the two spin‐orbit split peaks.…”

Mechanistic Development and Recent Applications of the Chan–Lam Amination

“…With regard to the frequently troublesome (and often academic) question of stoichiometry, the early studies used superstoichiometric (1–2 equiv) Cu­(OAc) 2 , − with Evans specifically demonstrating that stoichiometric amounts of Cu­(OAc) 2 and aerobic conditions were required for the C–O bond forming process to proceed in good yield . Mechanistically, the process is believed to require Cu­(II) at the outset; however, in situ Cu­(I) disproportionation or oxidation of Cu­(I) , likely explains why Cu­(I) sources can be used.…”

“…Although the number of examples is lower, the use of Cu­(II) halides (CuCl 2 , CuBr 2 ) has been reported. Despite halogenation of arylboronic acids and derivatives being known to proceed via ipso -substitution using X 2 generated in situ by the well-known Cu­(II)/X – → Cu­(I)/X 2 redox process (Scheme ), ,, coupling to counteranions derived from the Cu source has not been reported. However, this is somewhat achievable under certain circumstances; for example, acetate esters are not reported when using Cu­(OAc) 2 , although it is possible to prepare phenolate esters by Chan–Lam of AcOH (and other carboxylic acids) using Cu­(OTf) 2 …”

Superhydrophobic anti-corrosion coatings for metal surfaces: a systematic review from fabrication to performance

“…93 In the protection of copper and its alloys, their excellent electrical conductivity, thermal conductivity, and ductility make them widely used in electronics and heat exchange applications, yet they also face significant corrosion challenges. 94 Wang et al 95 constructed a superhydrophobic-superoleophilic photothermal coating on a copper mesh surface, achieving a corrosion protection efficiency of 97.7%, significantly expanding the potential for copper applications in complex humid environments. Xia et al 96 developed a superhydrophobic coating featuring grass-like microstructures composed of orthorhombic Cu(OH) 2 and monoclinic CuO on copper foil, which effectively delayed the oxidation and corrosion processes of copper in simulated corrosive environments.…”

Direct Evidence of Subsurface Oxygen Formation in Oxide‐Derived Cu by X‐ray Photoelectron Spectroscopy

“…After air calcination of the polycrystalline Cu specimen, the as‐prepared Cu oxide precursor exhibits a dark and rough appearance (Figure S1a), which is the typical color of cupric oxide (CuO). [14] The electrically insulating characteristics of a thick CuO layer resulted in extensive charge build‐up making XPS studies unfeasible. After the H 2 reduction treatment, the OD‐Cu exhibits a shining orange/pink color (see Figure S1b), indicating the oxide has been reduced across the entire sample surface.…”

“…After the H 2 reduction treatment, the OD‐Cu exhibits a shining orange/pink color (see Figure S1b), indicating the oxide has been reduced across the entire sample surface. [14] A representative XPS survey spectrum of the OD‐Cu recorded using 3266 eV photons is shown in Figure S2, depicting presence of copper and oxygen without detectable traces of the common contaminants from the ambient heat treatment or from the vacuum chamber, for example, S, Si, and C. Figure S3 shows the XPS Cu 2p region of OD‐Cu probed with multiple different photon energies for depth profiling and Cu 2 O (reference sample prepared separately), where its two spin‐orbit split components feature at 932.8 eV for 2p 3/2 and 952.6 eV for 2p 1/2 can be clearly seen. In addition to the spin‐orbit split components, the Cu 2 O reference sample also shows two additional weak satellites between the two spin‐orbit split peaks.…”

Mechanistic Development and Recent Applications of the Chan–Lam Amination

“…With regard to the frequently troublesome (and often academic) question of stoichiometry, the early studies used superstoichiometric (1–2 equiv) Cu­(OAc) 2 , − with Evans specifically demonstrating that stoichiometric amounts of Cu­(OAc) 2 and aerobic conditions were required for the C–O bond forming process to proceed in good yield . Mechanistically, the process is believed to require Cu­(II) at the outset; however, in situ Cu­(I) disproportionation or oxidation of Cu­(I) , likely explains why Cu­(I) sources can be used.…”

“…Although the number of examples is lower, the use of Cu­(II) halides (CuCl 2 , CuBr 2 ) has been reported. Despite halogenation of arylboronic acids and derivatives being known to proceed via ipso -substitution using X 2 generated in situ by the well-known Cu­(II)/X – → Cu­(I)/X 2 redox process (Scheme ), ,, coupling to counteranions derived from the Cu source has not been reported. However, this is somewhat achievable under certain circumstances; for example, acetate esters are not reported when using Cu­(OAc) 2 , although it is possible to prepare phenolate esters by Chan–Lam of AcOH (and other carboxylic acids) using Cu­(OTf) 2 …”

Superhydrophobic anti-corrosion coatings for metal surfaces: a systematic review from fabrication to performance

“…93 In the protection of copper and its alloys, their excellent electrical conductivity, thermal conductivity, and ductility make them widely used in electronics and heat exchange applications, yet they also face significant corrosion challenges. 94 Wang et al 95 constructed a superhydrophobic-superoleophilic photothermal coating on a copper mesh surface, achieving a corrosion protection efficiency of 97.7%, significantly expanding the potential for copper applications in complex humid environments. Xia et al 96 developed a superhydrophobic coating featuring grass-like microstructures composed of orthorhombic Cu(OH) 2 and monoclinic CuO on copper foil, which effectively delayed the oxidation and corrosion processes of copper in simulated corrosive environments.…”