4.1.1. Preparative Procedures
All manipulations were performed using standard Schlenk and dry-box techniques under an atmosphere of nitrogen or argon. Traces of oxygen and moisture were removed from the inert gases by passing them over a BASF R 3-11 (CuO/MgSiO3) catalyst, through concentrated H2SO4, over coarsely granulated silica gel and over P4O10
supported on pumice gravel, in that order.
4.1.2. Solvent Purification
All solvents were degassed and distilled from appropriate drying agents under an atmosphere of dry, oxygen-free nitrogen prior to use.
Boiling the solvents under reflux for at least four hours preceded the distillation process. Pentane and hexane were distilled from LiAlH4, toluene, xylene and decahydronaphthalene from Na, Et2O and THF from Na/benzophenone, and CH2Cl2 and CH3CN from CaH2. Acetone was doubly distilled, first from P4O10 and then from K2CO3.
All deuterated solvents were degassed and stored over molecular sieves, which had previously been dried for several hours under high vacuum at 200 °C. In the case of THF-d8, this was additionally distilled from Na/benzophenone and then stored over molecular sieves treated in the aforementioned manner.
4.1.3. Starting Materials
The compounds 6a,b,[9b,d] 7a-c,[9b,d,e] 9a,[12c] 11c,[9e] 55,[51d]
58,[51d] 60-63,[51,52] Ag[Al{OC(CF3)3}4],[36] [Au(PPh3)][PF6],[17b]
[LAuCl] (L = CO,[44] THT,[45] PPh3[ ]75) and [Cp*M(NCCH3)3][(SbF6)2] (M = Rh, Ir)[47b] were prepared according to literature procedures.
Samples of Ag[Al{OC(CF3)3}4] for preliminary investigations were generously donated by Prof. Ingo Krossing and co-workers (EPFL, Lausanne, Switzerland). The complex [Cp′′RhCl(NCCH3)2][BF4][47b]
was kindly donated by Dr. Sergei Konchenko (Russian Academy of Sciences (Siberian Division), Novosibirsk, Russia). The compounds 80[60] and 91[71] were munificently provided by Dr. Joachim Wachter (University of Regensburg).
[Cu(CH3CN)4][PF6] (Aldrich), AgOTf (Fluka), AgClO4 (Strem), AgPF6 (Aldrich), AgSbF6 (Lancaster), AgNO2 (Fluka), AgNO3
(Aldrich) and TlPF6 (Strem) were transferred to a dry-box for storage and used as received. CuCl (Strem) and CuBr (Strem) were purified before use, under a nitrogen atmosphere, by washing with the appropriate, degased aqueous hydrohalic acid (half-concentrated), followed by H2O, EtOH and Et2O. The resulting solids were then dried at room temperature under high vacuum and stored in a dry box. CuI (Aldrich) was purified and stored in a similar manner, the only difference being that a mixture of aqueous HCl (half-concentrated) and KI was used as the first washing medium.
The polymers 43a-c for the solid-state MAS-NMR investigations were prepared according to the literature procedures.[32a,33]
4.1.4. Characterisation Methods
Solution NMR spectra were obtained by the NMR departments of the universities of Karlsruhe and Regensburg using either a Bruker AC250 (University of Karlsruhe) or a Bruker AVANCE400 or 600 (University of Regensburg) spectrometer. Samples were referenced against TMS (1H, 13C), Al(NO3)3 in D2O (27Al), CFCl3 (19F) and 85%
H3PO4 (31P) as external standards. Chemical shifts are reported in ppm, according to the δ-scale, and the coupling constants J in Hz. The NMR spectra were processed using the 1D-WINNMR programme.[ ]76
The solid-state 31P MAS-NMR spectra of polymers 43a-c[33] were recorded by Dr. Gunther Brunklaus (research group of Prof. Hellmut Eckert, University of Münster) on a Bruker DSX400 solid-state spectrometer in a 2.5 mm probe. The spectrum of 43a was acquired at 121.49 MHz using a spinning rate of 30 kHz and those of 43b,c at 162.01 MHz using spinning rates of 33 kHz. A rotor-synchronised Hahn spin-echo sequence, generated with 90° pulse lengths of about 4 µs and relaxation delays of 3 minutes (280 scans), was used to record the spectra and samples were referenced against 85% H3PO4 as an external standard.
The solid-state 31P MAS-NMR spectra of polymers 66a-c and 83 were recorded by Dr. Long Zhang (research group of Prof. Hellmut Eckert, University of Münster) on a Bruker DSX400 solid-state spectrometer in 2.5 mm probes. The spectra were acquired at 162.01 MHz using spinning rates of 25 and 30 kHz. A rotor synchronised Hahn spin-echo sequence, generated with 90° pulse lengths of about 4 µs and relaxation delays of 3 minutes (280 scans), was used to record the spectra and samples were referenced against 85% H3PO4 as an
65
106.01 MHz using single-pulse acquisition with short pulses of 1 µs at spinning rates of 30-33 kHz.
The solid-state 31P MAS-NMR spectra of compounds 71, 74, 78 and 92c were recorded by Dipl. Phys. Christian Gröger (research group of Prof. Eike Brunner, University of Regensburg) on a Bruker AVANCE300 solid-state spectrometer in 2.5 mm probes. All spectra were acquired at 121.50 MHz using a solid echo sequence and spinning rates of 20 and 30 kHz, and samples were referenced against NaH2PO4
as an external standard.
ESI-MS spectra were acquired by the MS departments of the universities of Karlsruhe and Regensburg either on an Ionspec ULTIMA FT-ICR (University of Karlsruhe) or a ThermoQuest Finnigan TSQ 7000 (University of Regensburg) spectrometer. The identity of the observed fragments was assigned according to the mass/charge (m/z) ratio and by comparison of the experimental spectra with simulated spectra, which were generated using software available on the Internet.[ ]77 The peak with the highest relative abundance is reported for each isotopic band.
IR spectra were recorded either on a Bruker IFS 280 (University of Karlsruhe) or a Varian FTS 2000 (University of Regensburg) spectrometer, in the form of KBr discs or CH2Cl2 solutions. Spectra at the University of Regensburg were recorded with the assistance of Mrs.
Petra Lugauer. Signals are reported in cm-1.
Molecular mass determinations were performed under the supervision of Dr. Roland Neueder (Institute of Physical Chemistry, University of Regensburg) using a Knauer K-7000 vapour pressure osmometer, at 28 °C. The osmometer was calibrated using 0.01, 0.03, 0.05 and 0.1 M solutions of benzil in CH2Cl2.
Elemental analyses were performed by the microanalytical laboratories of the universities of Karlsruhe and Regensburg.
Melting and decomposition points were determined with the assistance of Mrs. Petra Lugauer using a Büchi S, Büchi 510 or Büchi SMP-20 melting point apparatus, and are uncorrected.
All X-ray crystallographic analyses were performed either by Prof. Manfred Scheer, the X-ray crystallography department of the University of Regensburg or Dr. Alexander V. Virovets (Russian Academy of Sciences (Siberian Division), Novosibirsk, Russia). The data were collected either on a STOE IPDS or an Oxford Diffraction Xcalibur 3 CCD diffractometer. The structures were solved using either SIR-97[ ]78 or SHELXS-97[ ]79 and refined using SHELXL-97[ ]80 with anisotropic displacements for non-hydrogen atoms. Hydrogen atoms were located in idealised positions and refined isotropically according
to the riding model. Pictorial representations of the structures were generated using the Diamond programme.[ ]81
4.1.5. Theoretical Calculations
Theoretical calculations related to compounds 42g and 83 were executed by Prof. Ingo Krossing (EPFL, Lausanne, Switzerland) at the density functional theory (DFT) level using the TURBOMOLE programme package.[ ]82 The 28 and 46 electron cores of Mo and Ag were replaced by a quasi-relativistic effective core potential.[ ]83 All species were fully optimised using the BP86[ ]84 exchange-correlation functional along with the SV(P) basis set,[ ]85 and solvation energies were calculated using the conductor-like screening model (COSMO) approach.[ ]86 31P-NMR shift calculations, performed at the BP86/SV(P) level for 42g (Mo and Ag: SVPalls2 all-electron basis set optimised for NMR calculations) and at the BP86/TZVPP level for 83 (Ag:
TZVPPalls2 all-electron basis set optimised for NMR calculations),[ ]87 were done as single points on the BP86/SV(P) optimised geometries.
The Born-Haber cycles for 42g and 83 were generated based on the theoretical results by Prof. Krossing.
Theoretical calculations on the model compounds 66a´,b´ (related to polymers 43a,b and 66a,b) and calculations related to compound 81 were performed by Dr. Marek Sierka (Humboldt University, Berlin) at the DFT level using the TURBOMOLE programme package.[82] The BP86[84] exchange-correlation functional was employed along with the TZVP basis and auxiliary basis sets[85,87, ]88 for the structure optimisations. In order to speed up calculations, the Coulomb part was evaluated by using the MARI-J method.[85, ]89 The 31P chemical shifts of the model compounds 66a´,b´ were calculated within the GIAO approach[ ]90 using a more extended TZP basis set on P, which is known to yield reasonably accurate NMR chemical shielding constants.[87b,90, ]91 In the calculations related to compound 81, quasi-relativistic pseudopotentials were used for the elements Mo and Ag[83, ]92 and solvation energies were calculated using the COSMO approach.[86]
Pictorial representations of calculated structures were prepared using the Diamond programme.[81]