Full Paper
(25 equiv) and NEt3 (50 equiv) in CH2Cl2 (200 mL) was added. The re-
action solution was warmed to room temperature, stirred over-
night and monitored by means of UV/Vis spectroscopy through-
out; an intense feature at l=413 nm owing to the formation of
the corresponding quinone was observed.[67] After 16–18 h, the re-
action was quenched with 0.5m HCl (3 mL). The aqueous solution
was extracted with CH2Cl2 (33 mL) and the combined organic
phases were dried over MgSO4. The solvent was reduced in vacuo,
followed by NMR spectroscopic characterisation.[31] The quantity of
the quinone formed was determined from the extinction coeffi-
cient of the quinone, yielding 14 turnovers per dinuclear copper
peroxide species after 20 min. The 7,8-dione of quinoline was de-
tected by HRMS (EI): m/z calcd for C9H5O2N: 159.0319; found:
159.0310, which corresponded to the quinone with the appropri-
[CuCl2{HC(3-tBuPz)2(1-MeIm)}] (C1)
Copper(II) chloride (0.17 g, 1.00 mmol) was suspended in methanol
(5 mL), resulting in a green–brown slurry. A solution of L (0.34 g,
1.00 mmol) dissolved in methanol (5 mL) was added dropwise to
the copper-salt mixture and after stirring for 16 h at room temper-
ature a deep-green solid precipitated. Storage of the mixture at
room temperature resulted in single crystals suitable for XRD analy-
sis (0.14 g, 0.29 mmol, 30%). IR (ATR): n˜ =3100 (vw, CHarom), 2902
(w, CHarom), 2865 (w, CHaliph), 1518 (m), 1474 (w), 1459 (w), 1417 (w),
1350 (m), 1229 (m), 1204 (w), 1152 (w), 1081 (w), 1054 (w), 970 (w),
861 (m), 831 (w), 811 (m), 803 (vs), 782 (vs), 770 (vs), 756 (m), 728
(w), 699 (m), 669 (w), 634 (w), 627 (w), 614 (m), 603 cmÀ1 (m); MS
(FAB+): m/z (%): 440 (16) [63Cu37ClL]+ and [65Cu35ClL]+, 438 (20)
[63Cu35ClL]+, 405 (20) [65CuL]+, 403 (40) [63CuL]+, 342 (15) [L]+, 217
(100) [HC(3-tBuPz)(1-MeIm)]+; elemental analysis calcd (%) for
C19H28Cl2CuN6 (474.92 gmolÀ1): C 48.1, H 5.9, N 17.7; found: C 47.9,
H 6.0, N 17.7.
1
ate calculated isotope. H NMR (400 MHz, CD3OD): d=6.90 (m, 1H),
7.80 (m, 1H), 7.92 (m, 1H), 8.20 (m, 1H), 8.54 ppm (m, 1H).
Stoichiometric reaction of P(SbF6)2
The reactions of P(SbF6)2 with sodium p-X-phenolates (X=H,
CO2Me, OMe, Me, F) at 195 K ([P(SbF6)2]=1 mm, [substrate]=1, 2,
5, 10, 15 and 20 equiv per dimer) were optically monitored by fol-
lowing the decay of the peroxide species until no change in the
absorption spectrum was evident. In all reactions, solutions of
P(SbF6)2 were prepared by the “injection” method at 195 K to give
a final volume of 10 mL. After stabilisation of the optical spectrum,
excess O2 was removed by five cycles of vacuum/N2 purging and
five min of purging the solution with N2. The substrate solutions
were added quickly in one portion. The data for each reaction
were reasonably fitted with a single exponential to obtain the
pseudo-first-order rate constant, kobs. The saturation behaviour of
kobs with respect to [phenolate] was fitted to the equation in
Figure 9 to obtain the rate constant for the oxidation reaction, kox,
and the association constant, Keq. Substrate characterisation was
performed as described previously.[31] The resulting NMR spectra
are given in the Supporting Information.
[CuBr2{HC(3-tBuPz)2(1-MeIm)}]·MeCN (C2)
An orange solution of L (0.17 g, 0.50 mmol) dissolved in THF (1 mL)
was added dropwise to a deep-green solution of copper(II) bro-
mide (0.11 g, 0.50 mmol) dissolved in acetonitrile (2 mL). The solu-
tion was stirred at room temperature for 3 h, which resulted in the
precipitation of a brown solid. The solid was recrystallised from
acetonitrile (4 mL) by making sure to cool the solution slowly (over
5 h). Storage of the solution at 241 K resulted in small brown crys-
tals suitable for XRD analysis after 4 d (0.21 g, 0.35 mmol, 70%). IR
(ATR): n˜ =3118 (w, CHarom.), 3101 (w, CHarom.), 2966 (m, CHarom.), 2908
(w, CHarom.), 2867 (w, CHaliph.), 1737 (vw), 1639 (w), 1552 (w), 1523
(m), 1516 (m), 1484 (m), 1459 (m), 1415 (m), 1362 (m), 1345 (m),
1335 (w), 1286 (w), 1232 (vs), 1207 (m), 1156 (m), 1084 (m), 1067
(m), 1030 (w), 1018 (w), 986 (w), 971 (m), 928 (vw), 861 (m), 833
(m), 804 (vs), 774 (vs), 725 (m), 699 (s), 669 cmÀ1 (w); MS (FAB+):
m/z (%): 744 (11) [C38H56N1263Cu]+, 487 (3) [C1813CH28N665Cu81Br]+,
486 (12) [C19H28N665Cu81Br]+, 485 (10) [C1813CH28N663Cu81Br]+,
[C1813CH28N665Cu79Br]+,
484
(37)
[C19H28N663Cu81Br]+,
[C19H28N665Cu79Br]+, 483 (8) [C1813CH28N663Cu79Br]+, 482 (26)
[C19H28N663Cu79Br]+, 403 (76) [C19H28N663Cu]+, 341 (100) [C19H29N6]+,
217 (100) [C12H17N4]+; elemental analysis calcd (%) for
C19H28N6CuBr2 (563.83 gmolÀ1): C 40.47, H 5.01, N 14.91; found: C
40.52, H 5.17, N 14.28.
Acknowledgements
Financial support by the Deutsche Forschungsgemeinschaft
(DFG) (DFG-FOR1405 and SFB749-B10) is gratefully acknowl-
edged. Calculation time is gratefully acknowledged from the
OCuLUS Cluster at the PC2 Paderborn and the Leibniz-Rechen-
zentrum München. M.B. gratefully acknowledges provision of
beamtime by the European Radiation Synchrotron Facility
(ESRF, Grenoble, France), and we also thank Olivier Maton and
Dr. Suresh Gatla for help during the measurements. I.I.-B. and
M.D. gratefully acknowledge support through the “Solar Tech-
nologies Go Hybrid” initiative of the State of Bavaria. S.H.-P.
and C.W. thank Ulrich Herber for help with NMR spectroscopy
measurements.
[Cu2O2{HC(3-tBuPz)2(1-MeIm)}2][SbF6]2 (P(SbF6)2)
A solution of L (0.16 mmol, 54 mg) dissolved in CH2Cl2 (5 mL) was
added in one portion to CuCl (0.17 mmol, 17 mg). The resulting
suspension was stirred for 45 min to 1 h. With vigorous shaking,
a solution of AgSbF6 (0.17 mmol, 61 mg) dissolved in THF (250 mL)
was added and AgCl precipitated to produce the precursor solu-
tion. This solution could be filtered through a syringe filter (VWR,
130 mm, 0.45 mm). CH2Cl2 (10 mL) was added to a UV/Vis measure-
ment cell and cooled to 195 K. Oxygen was bubbled through the
solvent for 5 min to generate an oxygen-saturated solution before
the precursor solution (1 mL) was added, resulting in an immediate
colour change to deep violet. Formation of the peroxide complex
was followed by UV/Vis spectroscopy.
Keywords: copper
· biomimetic synthesis · kinetics · N
ligands · structure–activity relationships
[2] B. Wu, Curr. Top. Med. Chem. 2014, 14, 1425–1449.
Catalytic reaction of P(SbF6)2 with 8-hydroxyquinoline
[3] Y. Matoba, T. Kumagai, A. Yamamoto, H. Yoshitsu, M. Sugiyama, J. Biol.
Compound P(SbF6)2 was prepared as described above and its de-
velopment was followed by UV/Vis spectroscopy. After stabilisation
of the optical spectrum, a solution containing 8-hydroxyquinoline
Chem. Eur. J. 2015, 21, 17639 – 17649
17647
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim