New zinc catalysts bearing ligands that contain a pyrrolidine scaffold were synthesized and tested successfully in the coupling of CO2 with terminal and internal epoxides. These catalysts provide excellent activity and total selectivity to the corresponding cyclic carbonates, even for challenging substrates such as cyclohexene oxide, trans‐1,2‐epoxybutane, and methyl epoxioleate. The robustness of the most active catalytic system was demonstrated by turnover numbers of up to 1840 for propylene oxide. The recycling of this catalytic system was performed up to five times without relevant loss of activity using this substrate.

A clean route is described for the preparation of 1.3 % (w/w) supported rhodium nanoparticle (3.0 ± 0.7 nm) catalysts onto commercial ion-exchange resins. Their application to the liquid-phase hydrogenation reaction of C=C bonds shows the most active species are obtained under catalytic conditions at room temperature and 1 bar H2. The heterogeneous catalyst shows excellent activity, selectivity and reusability in the hydrogenation reaction of alkenes and substituted arenes under very undemanding conditions. The results are discussed in terms of support effect on the catalytic efficiency.

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The PNNP ligand (R,R)-{PPh 2 (2-C 6 H 4 )CH=N(pyrrolidine-NBn)-} 2 2 was prepared by condensation between 2-diphenylphosphino benzaldehyde and the pyrrolidine-substituted diamine 1. Reduction with NaBH 4 in MeOH afforded (R,R)-{PPh 2 (2-C 6 H 4 )CH-NH(pyrrolidine-NBn)-} 2 3. The corresponding iron(II) complexes [FeCl 2 (2)] (4), [Fe(CH 3 CN) 2 (2)](BF 4 ) 2 (5) and [Fe(CH 3 CN) 2 (2)](PF 6 ) 2 (6) were synthesized and fully character-[a] 4212 Figure 3. Atom labels for [FeCl 2 (2 H )] (a) tbp-N1N2, (b) tpb-N1N3, (c) oct-N1N3, and (d) td-N1N3 structures. Hydrogen atoms are omitted for clarity. Phenyl groups attached to P are not displayed. Synthesis of [Fe(MeCN) 2 (2)](BF 4 ) 2 (5):(2) (0.135 mmol) in 4 mL of MeCN was added to a solution of Fe(BF 4 ) 2 ·6H 2 O (0.133 mmol) in 1 mL of MeCN. After stirring for 3 h, the red solution was evaporated to dryness. Then, 1 mL of CH 2 Cl 2 was added to re-dissolve the deep red powder. Ether (8 mL) was added to the solution and a precipitate started to form. The solid was filtered under nitrogen via cannula and washed repeatedly with ether to afford an orange solid in 81 % yield. 1 H-NMR (CD 2 Cl 2, 400 MHz, δ in ppm): 8.82-8.77 (m, 2H, CH= CN), 8.06-7.96 (m, 3H, Ar-), 7.77-7.21 (m, 21H, Ar-), 6.99 (t, 1H, J = 8Hz, Ar-), 6.88 (t, 1H, J = 8Hz, Ar-), 6.79-6.68 (m, 5H, Ar-), 6.43 (t, 2H, J = 8Hz Ar-), 5.32 (s, 2H, CH 2 -Ph, -CH 2 -), 4.98-4.92 (m, 1H, -CH-), 4.80-4.71 (m, 2H, -CH 2 -), 4.55-4.50 (m, 1H, -CH 2 -), 4.19-4.07 (m, 2H, -CH 2 -), 1.87 (s, 3H, CH 3 CN, -CH 3 ), 1.76 (s, 3H, CH 3 CN, -CH 3 ). 31 P{ 1 H}-NMR (CD 2 Cl 2, 161MHz, δ in ppm): 52.32 (d, J P-P = 42Hz) and 51.65 (J P-P = 42Hz). 11 B{ 1 H}-NMR (CD 2 Cl 2, 128.51MHz, δ in ppm): -1.03. 19 F{ 1 H}-NMR (CD 2 Cl 2, 376.8MHz, δ in ppm): -150.05. ESI-HRMS: Calculated forSynthesis of [Fe(MeCN) 2 (2)](PF 6 ) 2 (6): NaPF 6 (16 mg, 0.095 mmol) was added to a solution of 5 (50 mg, 0.047 mmol) in dichloromethane (4 mL). After stirring for 1 h the resulting orange mixture was filtered through a small pad of Celite and the solvents evaporated to dryness to give 6 as an orange solid in 90 % yield. 1 H-NMR (CD 2 Cl 2, 400 MHz, δ in ppm): 8.80 (br s, 1H, CH=CN), 8.71 (br s, 1H, CH=CN), 8.04-7.97 (m, 2H, Ar-), 7.78-7.20 (m, 22H, Ar-), 7.02 (t, 1H, J = 8Hz, Ar-), 6.87 (t, 1H, J = 8Hz, Ar-), 6.80-6.71 (m, 5H, Ar-), 6.36 (t, 2H, J = 8Hz, Ar-), 5.21-5.14 (m, 1H, -CH-), 4.82-4.76 (m, 4H, -CH 2 -), 4.55-4.50 (m, 1H, -CH-), 4.13-4.08 (m, 2H, -CH 2 -), 1.86 (s, 3H, CH 3 CN, -CH 3 ), 1.75 (s, 3H, CH 3 CN, -CH 3 ). 31 P{ 1 H}-NMR (CD 2 Cl 2, 161MHz, δ in ppm): 51.98 (d, J P-P = 43.7Hz), 51.13(d, J P-P = 43.7Hz), -144.3 (sept,

Robust Zinc Complexes that Contain Pyrrolidine-Based Ligands as Recyclable Catalysts for the Synthesis of Cyclic Carbonates from Carbon Dioxide andEpoxides. -The shown complex (ZNC) provides the best yields. -(MERCADE, E.; ZANGRANDO, E.; CLAVER*, C.; GODARD, C.; ChemCatChem 8 (2016) 1, 234-243, http://dx.