5 Experimental Part
5.1 General Remarks
All reactions involving moisture- or air-sensitive reagents or products were performed under an atmosphere of nitrogen using pre-dried glassware and standard Schlenk techniques. If not otherwise mentioned yields refer to isolated compounds, estimated to be >95% pure as determined by 1H-NMR.
Chromatography
Analytical thin layer chromatography (TLC) was performed on Merck, silica gel 60 F254 aluminum sheets. Detection was performed under UV light at 254 or 365 nm or developed by treatment with a potassium permanganate solution followed by careful warming or iodine spray technique.
Chromatographic purification of products was accomplished by flash column chromatography on Merck Geduran® silica gel, grade 60 (0.040–0.063 mm, 230–400 mesh ASTM).
High-performance Liquid Chromatography
Analytical high-performance liquid chromatography (HPLC) for determination of the enantiomeric excess was performed on an Agilent 1260/1290 Infinity equipped with Daicel CHIRALPAK IA-3 or IC-3 (4.6 mm × 250 mm, 3 μm particle size, 1 mL/min flow rate). Preparative HPLC from Agilent 1260 Infinity equipped with VP 250/16 Nucleodur 100-10 C18 ec column.
Recycling Preparative HPLC
Recycling preparative HPLC or gel permeation chromatography (GPC) was performed on a Japan Analytical Industries (JAI) LC-92XX II NEXT system equipped with a JAIGEL 2.5HR or JAIGEL 2HH column. Chloroform was used as the solvent.
Cyclic Voltammetry
Cyclic Voltammetry (CV) spectra were measured using a Metrohm Autolab PGSTAT204 workstation using a glassy-carbon disc electrode (3.0 mm diameter, CH Instruments) as a working electrode, a platinum wire (1.0 mm diameter, 99.99%, chempur) as a counter electrode and a
5 Experimental Part
Ag/AgCl electrode as a reference electrode. The CV spectra were measured with n-Bu4NPF6 (0.1 M
in 1,2-DCE, Sigma-Aldrich) as electrolyte and a sample concentration of 4 mM, at a 100 mV∙s–1 scanning rate. The data were analysed with NOVA 2.1.3 software (Metrohm)
Electron Paramagnetic Resonance
Continuous-wave (CW) electron paramagnetic resonance (EPR) spectra were recorded at X-band microwave frequencies (9 GHz) using a Bruker ElexSys E500 spectrometer with a Bruker SuperX CW bridge. The spectrometer was equipped with the Bruker SHQ rectangular microwave cavity (Bruker 4122SHQ) and a helium flow cryostat (Oxford Instruments) for low temperature experiments.
Fluorescence Spectroscopy
Fluorescence excitation and emission data in solution were recorded on a Jasco® FP-8500 spectrofluorometer. The scan speed was adjusted to 500 or 1000 nm/min. All compounds were measured at a concentration of 1 mg∙L–1 in CHCl3.
UV-VIS Spectroscopy
UV-Visible Spectroscopy was performed on a Jasco® V-770 spectrophotometer. A baseline in the appropriate solvent was obtained prior to recording spectra.
Gas Chromatography
Gas chromatographic analysis (GC) was performed on an Agilent 7890A GC system or Agilent 7890B GC System equipped with an Agilent HP-5 column (30 m, 0.320 mm diameter, 0.25 μm film thickness) and a flame-ionization detector (FID) using hydrogen as the carrier gas. Gas chromatography coupled with mass spectrometry (GC-MS) was performed on the same instrument equipped with an Agilent HP-5MS column (30 m, 0.250 mm diameter, 0.25 μm film thickness) and an Agilent 5875C Triple-Axis-Detector or an Agilent 5977B MSD. Mass spectra were obtained with electron-ionization (EI) at 70 eV in positive ion mode.
5.1 General Remarks
Infrared Spectroscopy
Infrared (IR) spectra were recorded on a Bruker Alpha-P FT-IR spectrometer with a diamond ATR probe in the range of 4000–400 cm–1. Liquid samples were measured as film and solid samples neat. Analysis of the spectral data was carried out using Opus 6 software. Absorption is given in wavenumbers (cm−1).
Mass Spectrometry
Electron-ionization (EI) and EI high resolution mass spectra (HR-MS) were recorded on a Jeol AccuTOF instrument at 70 eV. Electrospray-ionization (ESI) mass spectra were obtained on Bruker micrOTOF and maXis instruments. All systems are equipped with time-of-flight (TOF) analyzers.
Liquid injection field desorption/ionization (LIFDI) mass spectra were measured on a Jeol AccuTOF instrument with a Linden CMS. The ratios of mass to charge (m/z) are indicated and the intensity relative to the base peak (I = 100) is given in parenthesis.
Melting Points
Melting points (m.p.) were measured on a Stuart® Melting Point Apparatus SMP3 from Barloworld Scientific. All values are uncorrected.
Nuclear Magnetic Resonance Spectroscopy
Nuclear magnetic resonance (NMR) spectra were recorded on Varian Mercury Plus 300, Inova 500, Inova 600 or Bruker Avance III 300, Avance III HD 300, Avance III 400, Avance III HD 400, Avance Neo 400, Avance III HD 500 spectrometer. All measurements were performed at 298 K. Chemical shifts (δ) are reported in ppm. 1H- and 13C-NMR spectra were calibrated using the residual proton peak or carbon peak of the deuterated solvent, respectively (see table). For 19F- and 31P-NMR spectra were referenced using CFCl3 and 85% phosphoric acid as external standard, respectively.
Solvent 1H-NMR 13C-NMR
CDCl3 7.26 ppm 77.16 ppm
CD2Cl2 5.32 ppm 53.84 ppm
DMSO-d6 2.50 ppm 39.52 ppm
Acetone-d6 2.05 ppm 29.84, 206.26 ppm
5 Experimental Part
The observed multiplicities are reported as follows: s (singlet), d (doublet), t (triplet), q (quartet), p (pentet), hept (heptet), m (multiplet) or combinations thereof. The coupling constants J are given in Hertz (Hz). All spectra were analyzed using Mestrelab Research MestReNova v. 10.0.2 software.
Crystal Structure Analysis
X-ray structures were measured on a Bruker D8 Venture four-circle-diffractometer from Bruker AXS GmbH equipped with a Photon II detector purchased from Bruker AXS GmbH and using microfocus IμS Cu/Mo radiation from Incoatec GmbH with HELIOS mirror optics and single-hole collimator from Bruker AXS GmbH.
Vacuum
A pressure of approx. 4∙10–1 mbar was measured on the employed rotary vane pump RZ6 from Vacuubrand®.
Solvents
All solvents used for work-up and purification were distilled prior to use. Solvents used in reactions involving air- or moisture-sensitive compounds were dried, distilled, and stored under an inert atmosphere of nitrogen or argon according to the following standard procedures.
Solvents purified by solvent purification system (SPS-800) from M. Braun: Dichloromethane, diethyl ether, N,N-dimethylformamide, tetrahydrofuran, toluene.
Solvents dried and distilled over Na using benzophenone as indicator: 1,4-Dioxane, n-hexane, toluene, o-xylene.
5.1 General Remarks Solvents dried and distilled over CaH2: 1,2-Dichloroethane, N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, N-methyl-2-pyrrolidone, pyridine, triethylamine.
Solvents dried over molecular sieve and degassed by freeze-pump-thaw cycles: Acetonitrile (3 Å), acetonitrile-d3 (3 Å), tert-butylbenzene (4 Å), chloroform-d (4 Å), dichloromethane-d2 (4 Å), 2-methyltetrahydrofuran (4 Å), tetrahydrofuran-d8 (4 Å), toluene-d8 (4 Å).
Methanol was dried and distilled over Mg(OMe)2.
Water was degassed before its use by repeated freeze-pump-thaw cycles.
Reagents
Chemicals obtained from commercial sources were used without further purification unless stated otherwise. K2CO3 was dried at 140 °C and 4∙10–1 mbar for 16 h and stored under an atmosphere of N2.
The following compounds were synthesized according to previously described literature protocols:
2-Arylpyridines 68a, 68d, 68e, 68h,[115] ruthenacycle 98, 218,[46] purines 123a, 123d,[116]
123l–123n,[117] ketimines 135,[118] 1-bromo-1-methylcyclohexane (136a),[119] 2-arylpyrimidines 139a–139c, 139e–139g,[120] 2-(o-tolyl)pyrimidine (139d),[121] 4-butyl-1-(2-methoxyphenyl)-1H-1,2,3-triazole (139m),[41] arylpyrazoles 147a, 147d–147j,[122] 4-bromo-1-phenyl-1H-pyrazole (147b),[123] 3,5-dimethyl-1-phenyl-1H-pyrazole (147c),[124] [Ru(O2CAd)2(p-cymene)] (163),[33]
[Ru(OPiv)2(p-cymene)],[33] benzyl chlorides 142d–142e, 186n,[125] BODIPY 186a,[126] 2,7-diiodo-9H-fluorene (215a),[127] 3,6-diiodo-9H-carbazole (215b),[128] and tris(4-iodophenyl)amine (215c).[129]
The following chemicals were kindly provided by the persons named below:
Karsten Rauch: [RuCl2(p-cymene)]2, [Ru(O2CMes)2(p-cymene)] (33), [Ru(OAc)2(p-cymene)] (181).
Dr. David J. Burns: purines 123e–123g.
Dr. Svenja Warratz: Ru@SiO2 (152), [RuCl2(PhCMe3)]2, Ru(OAc)2(PPh3)2, Ru(OAc)2(PPh3)3. Prof. Dr. Hongjun Ren: 1-(4-bromophenyl)pyrene (165d).
Nikolaos Kaplaneris: 5-chloro-N-phenylpyrimidin-2-amine (125a), 2-(4-methoxyphenyl)-4,5-dihydrooxazole (139i), 2-(4-bromophenyl)-4,5-2-(4-methoxyphenyl)-4,5-dihydrooxazole (139j),
2-(2-ethoxyphenyl)-4,5-5 Experimental Part
dihydrooxazole (139k), 2-bromo-1-morpholinopropan-1-one (140e), methyl 2,5-dibromopentanoate (140f), 2-bromo-N,N-diethylpropanamide (140h), (tetrahydrofuran-2-yl)methyl 2-bromopropanoate (140l), benzoic acid 178.
Dr. Torben Rogge: 2-(2-methoxyphenyl)pyridine (68f), 2-[2-(trifluoromethyl)phenyl]pyridine (68g).
Dr. Joachim Loup: chiral phosphoramidite ligands.