Cationic microporous polymer networks by polymerisation of weakly coordinating cations with CO 2-storage ability †

Microporous organic polymer networks with weakly coordinating cations in their backbone have been synthesised by metal catalysed C–C bond forming reactions. A functionalised tetraphenylphosphonium ion was synthesised and successfully used as a tecton in a co-polymerisation with tetrakis(4bromophenyl) methane using nickel catalysed Yamamoto coupling and with triethynylbenzene in a palladium catalysed Songashira–Hagihara reaction. The microporous materials showed an apparent BET surface area of 1455 m g 1 and 540 m g , respectively. The Yamamoto product provide a CO2 uptake of 2.49 mmol g 1 at 273 K and 1 bar. After ion exchange with chloride CO2 uptake is further increased to 2.85 mmol g .


S1
General: Unless otherwise noted, all commercially available compounds were used as provided without further purification. Inert reactions were carried out using standard schlenk technique or in an MBraun glovebox type MB 120 BG. Nitrogen physisorption isotherms were measured at 77 K up to 1 bar using an Autosorb-1 MP from Quantachrome. Pore size distributions were calculated using the Autosorb software and a pore model for carbon with slit pores. 1 H-NMR, 31 P-NMR and 13 C-NMR were recorded on a Bruker DRX 200 spectrometer in the given solvent. Data are reported in the following order: chemical shift (δ) in ppm; number of protons; multiplicities are indicated br (broadened singlet), s (singlet), d (doublet), t (triplet), m (multiplet); coupling constants (J) are in Hertz (Hz). Solid state CP/MAS NMR spectras was recorded with a Bruker AVANCE II 400 spectrometer and 4 mm double resonance MAS (Magic angle spinning) probes. IR measurements were performed on a Varian IR spectrometer equipped with the attenuated total reflectance (ATR) cell and are reported in terms of frequency of absorption (cm -1 ); intensities are indicated vs (very strong), s (strong), m (medium), w (weak). CO 2 -sorption studies were performed on a Micromeritics Gemini III 2375 at 195 and 273 K. The EDX-spectra was recorded with a Philips XL 20, equipped with EDX-Detector.

Materials.
PCl 3 and Ni(COD) 2 were obtained from Acros and were used as received. All other chemicals and solvents were obtained from Sigma-Aldrich and used as received. Anhydrous grade solvents were used throughout (Sigma-Aldrich and Acros). All chemicals used had a purity of 97% or greater. Tetrakis(4-bromophenyl) methane was synthesised according to previously reported literature. 1

Synthesis of tris(4-bromophenyl)phosphine:
1,4-Dibromobenzene (3.51 g, 15 mmol) was dissolved in THF (30 mL) in a pre-dried schlenk flask. A solution of n-buthyllithium (2.5 M solution in hexane, 6.60 mL, 16.5 mmol) was added dropwise over 30 min while stirring. The resulting colourless suspension was stirred for 90 min at -78 °C. Phosphorous trichloride (0.48 mL, 5.50 mmol) was added drop wise to the stirred suspension over 45 minutes at -78 °C upon which the suspension turned increasingly red and clear. Towards the end of the addition, the solution turned quickly yellow. The mixture was then slowly warmed to room temperature over two hours. A saturated solution of sodium chloride (20 mL) was added, the organic layer separated and the aqueous layer extracted with diethyl ether (3 x 100 mL). The combined organic layers were dried over sodium sulfate and the solvent was removed in vacuo. The raw product was purified via column chromatography from n-hexane. After removal of the solvent the oily residue was dissolved in chloroform and the solvent removed in vacuo twice.
The product was obtained as a colourless solid (1.472 g, 60 % yield).

Synthesis of CPN-1-Cl:
Ion exchange was carried out by slurrying 100 mg CPN-1-Br overnight in a mixture of brine (50 mL) and MeOH (50 mL) and then filtered off. This procedure was repeated two more times. After the third repetition the material was washed by soxhlet extraction with methanol and dried overnight at 50° C in a vacuum oven.
A yellowish fluffy powder was obtained.