Journal of the American Chemical Society
Article
Agilent 5973 mass detector operating at 70 eV. HRMS EI (m/z) was
tested on a Waters-Micromass QuattroMicro. ICP-OES measurement
was conducted with a PerkinElmer Optima 3000 DV.
concentration used in the TA experiment is 0.2 mg/mL, and the
substrate concentration is kept at 2 mg/mL.
General Procedure for Preparation of Perovskite Catalyst.
CsPbBr3 nanocrystals (NCs) were synthesized by modifying the hot
injection method previously reported.18−20 First, a Cs-oleate solution
was prepared by charging a 100 mL 3-neck flask with Cs2CO3(0.16g)
along with octadecene (6 mL, ODE) and oleic acid (2.5 mL, OA) and
drying for 1 h under a vacuum at 120 °C. The Cs-oleate solution was
then followed by N2 sparging at 150 °C until all of the Cs2CO3
dissolved in ODE. In a separate 100 mL 3-neck flask, 10 mL of ODE
and PbBr2(0.178 g, 0.486 mmol) was dried for 1 h under a vacuum at
120 °C and subsequently purged with N2 followed by an injection of
both oleylamine (1 mL) and OA (1 mL). Once the Pb salts dissolved,
the temperature was raised to 180 °C, and the prepared Cs-oleate
solution (2.1 mL) was swiftly injected into the reactor. After five
seconds, the yellow-green reaction mixture was cooled by an ice bath
and subsequently washed with tert-butanol (10 mL) and ethyl acetate
(30 mL). After centrifuging at 9000 rpm for 5 min, a yellow-green
precipitate was obtained and air-dried overnight.
Preparation of Cu:CsPbBr3 NCs. A 20 mg portion of CsPbBr3 NCs
were resuspended in toluene (10 mL) followed by the addition of
CuBr salt (5 mg), and the mixture was stirred vigorously in the dark
for 2 h. The resulting yellow-green solution mixture was centrifuged at
9000 rpm for 5 min. The supernatant was discarded, and the
Cu:CsPbBr3 NCs pellet was dried in an vacuum oven at 50 °C
overnight. CuI or CuCl exchanges were performed under the identical
Photocatalytic Reaction Setup. The amine substrate (0.1
mmol), CH2Cl2 (1.5 mL), Cu:CsPbBr3 (2 mg), and stirring bar
were added to a 4 mL vial under ambient conditions. Then the
reaction mixture was irradiated with a Kessil Blue LED (456 nm,
distance to the reaction vial ca. 30 cm) at room temperature under an
open air atmosphere (attached a 1 mm diameter venting needle into
the sealed cap) for 18 h. Upon completion, the reaction mixture was
concentrated and the residue was purified by a column chromatog-
raphy.
The photocatalyst was reused via centrifugation from the reaction
mixture (0.5 mmol scale) and was reapplied at the same scale with the
substrate (e.g., 1a). The photocatalyst is active for at least four cycles
with the yield noted as 84%, 78%, 73%, and 71%. The catalytic
turnover number based on Cu was calculated according to the
recentrifuge method.
ASSOCIATED CONTENT
■
sı
* Supporting Information
The Supporting Information is available free of charge at
General Information and general procedure for prepara-
tion of perovskite catalyst, EPR experiment, XRD of long
time Cu ion-exchange samples, DFT calculation experi-
ment, ICP-OES measurement, controlled IR experiment
to illustrate substrate-absorbed intermediate m-2, ultra-
fast transient absorption study, electrochemical experi-
ment, radical trapping experiment, NMR of key
intermediates, mass spectra of key intermediates, X-ray
crystallography data of key intermediates, control
experiments in homogeneous system, scope table,
further banding-tuning of Cu:CsPbBr3 with TMSCl,
general procedure for preparation of substrates, general
procedure for photocatalytic N−N Bond coupling, CVs
of electrochemical experiment, spectra of H, 13C, and
1
19F NMR spectra, references (PDF)
Accession Codes
supplementary crystallographic data for this paper. These data
uk, or by contacting The Cambridge Crystallographic Data
Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44
1223 336033.
AUTHOR INFORMATION
■
Corresponding Author
Yong Yan − Department of Chemistry and Biochemistry, San
Diego State University, San Diego, California 92182, United
TON = moles of product/mol of Cu = [0.5 mmol*(84%+78%
+73%+71%)]/(1%*2 mg/579.8 g/mol) = 44600
Authors
EPR Study. The reaction mixture containing substrate 7a (0.1
mmol), CH2Cl2(1 mL) and Cu:CsPbBr3 (2 mg) was added into an
EPR tube (Magnettech MS-5000 (X band)). The reaction mixture
was gently bubbled with air for 15 min before the measurement. The
reaction mixture was irradiated in situ with the blue LED at room
temperature at various times. The EPR measurement was also
recorded at different times when the light was blocked. For details, see
TA Experiment Setup. Transient absorption measurement is
based on the Ti:sapphire laser amplifier (Coherent Astrella, 800 nm,
pulse duration ∼60 fs, ∼5 mJ/pulse, and 1 kHz repetition rate) and
the pump−probe transient absorption spectrometer (Helios, Ultrafast
System). The fundamental beam (800 nm) is split in two beams. One
beam is sent to an optical parametric amplifier to generate the pump
pulse at 480 nm (2.6 eV), and its intensity is attenuated by two
neutral density filter wheels. The other 800 nm beam was focused into
a sapphire to generate a white light probe. Probe delay can be up to
∼3 ns and is tuned by a delay line. The pump and probe are focused
and overlapped onto the sample. The probe size is ∼200 μm, and
pump beam size is ∼400 μm. The beam size is defined as the radius of
an aperture that contains (1/e2) of the total power. The samples are
constantly stirred to give reactants enough time to diffuse. In the TA
experiment, the excitation density is kept low (∼6 nJ/pulse or 7.65 ×
109 photons/pulse)20 such that no multiple excitons are generated in
the nanocrystals to complicate our reaction kinetics. The nanocrystals
Jovan San Martin − Department of Chemistry and
Biochemistry, San Diego State University, San Diego,
California 92182, United States
Xianghua Zeng − Department of Chemistry and Biochemistry,
San Diego State University, San Diego, California 92182,
United States; College of Biological, Chemical Science and
Engineering, Jiaxing University, Jiaxing 314001, China
Xihan Chen − National Renewable Energy Laboratory,
Collin Miller − Department of Chemistry and Biochemistry,
San Diego State University, San Diego, California 92182,
United States
Chuang Han − Department of Chemistry and Biochemistry,
San Diego State University, San Diego, California 92182,
United States
Yixiong Lin − Department of Chemistry and Biochemistry,
San Diego State University, San Diego, California 92182,
United States
Nobuyuki Yamamoto − Department of Chemistry and
Biochemistry, San Diego State University, San Diego,
California 92182, United States
11367
J. Am. Chem. Soc. 2021, 143, 11361−11369