Inorganic Chemistry
Article
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C NMR (300 MHz, CD OD, 25 °C): δ 158.74 (4C), 157.93,
354 nm picosecond laser pulsed at 10 MHz (LDH-DC-405,
PicoQuant) was focused into a 1 cm quartz cell with a 0.85 NA
microscope objective. The fluorescence collected with the same
objective passed through a 366 nm long-pass dichroic mirror
(Chroma T510lpxrxt), a 364 nm notch filter (Chroma ZET405nf),
and a 425 nm long pass emission filter (Chroma ET425lp) and was
focused to an avalanche photodiode (PD-050-CTE, MPD). The laser
controller (PDL-800-D, PicoQuant) and the APD were connected to
a TCSPC card (PicoHarp 300, PicoQuant). The power of irradiation
was controlled to obtain less than 1% of the detection events in order
to avoid pile-up effects on the recorded histogram. Allura Red
(analytical standard Sigma-Aldrich) was used to obtain the IRF under
the same conditions of irradiation. All data were obtained and treated
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48.75, 148.04 (2C), 147.90 (2C), 146.39, 137.25 (2C), 136.94 (2C),
34.62, 134.10, 129.01, 128.01, 127.45, 123.74 (2C), 123.25 (2C),
22.50 (2C), 122.29 (2C), 120.49, 60.33 (2C), 59.74 (2C), 57.15,
4.13.
HR-MS (DART ): m/z 552.28775 [L + H] calcd for C H N .
IR (ATR): 3007(w), 2824(w), 1588(m), 1432(m), 755(s) cm .
Anal. Calcd for C H N : C, 76.20; H, 6.03; N, 17.77. Found: C,
6.48; H, 6.26; N, 17.57.
Synthesis of [Zn L][OTf] . A mixture of L (100 mg, 0.25 mmol)
and zinc triflate (70 mg, 0.27 mmol) in CH OH was stirred at room
temperature overnight. Subsequently, the reaction mixture was filtered
through Celite 540, and the solvent was removed under reduced
pressure to give a white crystalline powder. Yield: 97%. This product
was examined carefully by mass spectrometry, IR-ATR, elemental
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in SymphoTime 64 software (PicoQuant).
Computational Details. The geometry optimizations of 1:1 and
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analysis, and NMR spectroscopy.
2:2 [Zn L] /GTP complexes were carried out with the three-
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H NMR (300 MHz, CD OD, 25 °C): δ 9.42 (s, 1H), 8.80−8.79
parameter exchange-correlation functional of Becke−Lee−Yang−Parr
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(
m, 2H), 8.40−8.39 (m, 2H), 8.33−8.27 (m, 2H), 8.12−8.06 (m,
(B3LYP) and the LANL2DZ basis set, that takes into consideration
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H), 7.94−7.89 (m, 2H), 7.85−81 (m, 3H), 7.73−7.71 (m, 2H),
.51−7.38 (m, 5H), 4.62 (s, 2H), 4.56 (s, 2H), 4.36 (s, 2H), 4.31 (s,
H), 4.01 (s, 2H), 3.93 (s, 2H).
relativistic effects.
Additionally, the contribution due to the
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electronic dispersion was considered by the Grimme-D3 correction.
This level of theory is known as B3LYP-D3/LANL2DZ. A no
imaginary frequencies criterion was considered in the geometry
optimization. Finally, the electron density was analyzed through the
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C NMR (75 MHz, MeOD, 25 °C): δ 154.53 (2C), 154.14 (2C),
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(
52.24, 148.32 (2C), 146.96 (2C), 145.42, 141.95 (2C), 140.49 (2C),
35.89, 134.29, 132.25, 130.96, 130.10, 128.83, 125.64 (4C), 124.51
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Laplacian of the electron density (−∇
)
and Atoms in Molecules
ρ
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2C), 124.36 (2C), 122.58, 59.07 (2C), 58.72 (2C), 55.68, 48.33.
(AIM) analysis proposed by Bader. All presented calculations were
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F-NMR (282 MHz, CD OD, 25 °C): δ −80.04 ppm.
carried out with NWChem 6.6, while the topological results were
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MS (ESI ): m/z 1127.9 [Zn L + 3(OTf)] and 489.6 dicationic
complex [Zn L + 2(OTf)] .
obtained with the wave function analyzer Multiwfn 3.3.7.
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IR (ATR): 3441(w), 3283(w), 2930(w), 1610(w), 1446(w),
286(m), 1217(s), 1168(s), 1022(s), 629(s).
ASSOCIATED CONTENT
sı Supporting Information
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Anal. Calcd for C H N 2[Zn(CF SO ) ]·3(CH OH):
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C H F N O S Zn : C, 36.69; H, 3.30; N, 7.13. Found: C,
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6.89; H, 3.38; N, 7.07.
Spectrophotometric and H and 31P NMR Titration Experi-
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1H, 13C, 19F, HSQC, and DEPT NMR spectra of 2 and
3, L, and [Zn L][OTf] ; MS-DART of L; MS-ESI of
ments. The absorption spectra were recorded after additions of
aliquots of GTP stock solution to buffered (40 mM, MOPS at pH =
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[
.0 and ionic strength of 0.05 M NaCl) aqueous solutions of
[
Zn L][OTf] and [Zn L] + GTP; and Atoms in
Zn L][OTf] (150 μM) in a quartz cuvette placed in a compartment
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of a Cary 100 Agilent spectrophotometer thermostated at 25 ± 0.1 °C
with a recirculating water bath.
NMR titration experiments were performed on a 300 MHz
spectrometer with more concentrated stock solutions of ATP and
GTP in D O, adding aliquots of them to [Zn L][OTf] solutions
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Corresponding Author
Alejandro Dorazco-Gonzalez − Instituto de Quimica,
Universidad Nacional Autonoma de Mexico, Ciudad
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directly in NMR tubes. In the cases of P titration experiments, the
spectra were recorded at 121.5 MHz using H PO as an external
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standard. Aliquots of concentrated stock solution of [Zn L][OTf]
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were added to ATP and GTP (4.0 mM) solutions directly in NMR
tubes.
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Fluorimetric Titration Experiments. Titration experiments
were performed by adding aliquots of stock solutions of anions and
guanosine to a buffered aqueous solution containing MOPS (40 mM
at pH = 7.0) of [Zn L][OTf] (15 μM). In all of these experiments,
Authors
Ivan J. Bazany-Rodríguez − Instituto de Quimica, Universidad
Nacional Auto
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n
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ico
04510, Distrito Federal de Mexico, Mexico
María K. Salomon-Flores − Instituto de Quimica, Universidad
the ionic strength was adjusted to 0.05 M with NaCl.
After the addition of anions, the solution was equilibrated for 1 min
at room temperature before recording the emission spectrum
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(
excitation at 325 nm, 650 V) using a 10 mm quartz cuvette. The
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4510, Distrito Federal de Mexico, Mexico
Joanatan M. Bautista-Renedo − Centro Conjunto de
experimental data were fitted to the corresponding eqs 1 and 2 using
nonlinear least-squares regression with Microcal Origin 8.1 for the 1:1
model and the HypSpec−Hyperquad program for more complex
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Investigacion
Toluca de Lerdo, Estado de Mex
Nelly Gonzalez-Rivas − Centro Conjunto de Investigacion
Quimica Sustentable UAEM-UNAM, 50200 Toluca de Lerdo,
Estado de Mexico, Mexico
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models.
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The selectivity experiments were performed by adding aliquots of
stock solutions of the respective sodium salts of all anions, at a final
concentration of [X] = 300 μM, to buffered aqueous solutions
containing MOPS (40 mM at pH = 7.0) of [Zn L][OTf] (15 μM),
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and the emission intensities at 410 nm (excited at 325 nm) were
recorded. All spectrophotometric experiments were performed in
triplicate, and the mean values are reported.
Fluorescence Lifetime Measurements. A Time Correlated
Single Photon Counting (TCSPC) system coupled to a custom-built
confocal microscope was used to acquire the fluorescence lifetimes. A
Notes
The authors declare no competing financial interest.
J
Inorg. Chem. XXXX, XXX, XXX−XXX