Table 1.
CO2/CHO ROCOP data for catalysts 1–8 compared with selected high‐performance literature catalysts (See Figure 1 for reaction scheme).[a]
|
Entry |
[LMg(II)M(II)(OAc)2] M, cat # |
Conv. [%][b] |
CO2 [%][c] |
Polym. [%][d] |
TON[e] |
TOF [h−1][f] |
k p [mM−1 s−1][g] |
k rel [h] |
M n [kg mol−1] [Ð][i] |
|---|---|---|---|---|---|---|---|---|---|
|
1 |
Mg, 1 |
57 |
>99 |
>99 |
2280 |
295 (±60) |
9.7 (±0.2) |
1.0 |
9.2 [1.15] |
|
2 |
Cr, 2 |
40 |
>99 |
>99 |
1600 |
103 (±19) |
3.4 (±0.1) |
0.4 |
4.0 [1.15] |
|
3 |
Mn, 3 |
76 |
>99 |
90 |
3040 |
362 (±31) |
11.9 (±0.2) |
1.2 |
4.1 [1.23] |
|
4 |
Fe, 4 |
59 |
>99 |
>99 |
2360 |
1071 (±33) |
34.7 (±0.3) |
3.6 |
8.4 [1.11] |
|
5 |
Co, 5 |
59 |
>99 |
>99 |
2360 |
1056 (±19) |
34.7 (±0.1) |
3.6 |
8.0 [1.11] |
|
6 |
Ni, 6 |
60 |
>99 |
>99 |
2400 |
632 (±34) |
20.7 (±0.2) |
2.2 |
6.3 [1.16] |
|
7 |
Cu, 7 |
47 |
>99 |
94 |
1880 |
136 (±3) |
4.5 (±0.1) |
0.5 |
6.5 [1/15] |
|
8 |
Zn, 8 |
37 |
>99 |
>99 |
1480 |
506 (±16) |
14.4 (±0.1) |
1.5 |
5.0 [1.17] |
|
9[j][28] |
[(proline)Zn2] |
n.r |
>99 |
>99 |
1684 |
149 |
– |
– |
n.r |
|
10[k][17d] |
[(trisalen)Zn3Ce(OAc)3] |
45 |
>99 |
>99 |
900 |
300 |
– |
– |
15.0 [1.20] |
|
11[l][29] |
[(L′)Zn2Na(I(OAc)] |
49 |
86 |
97 |
1960 |
478 |
– |
– |
5.6 [1.29] |
|
12[m][30] |
[(salen[NR3]+)Co(DNP)2] |
26 |
>99 |
>99 |
1315 |
263 |
– |
– |
48.2 [1.12] |
|
13[n][31] |
[(L′′)Ni2(OBz)2(MeOH)] |
18 |
>99 |
>99 |
288 |
96 |
– |
– |
8.7 [1.21] |
[a] Reaction conditions: [cat]0:[CHD]0:[CHO]0=1 : 20 : 4000, 0.025 mol% catalyst loading (2.44 mM), 20 equivalents trans‐1,2‐cyclohexanediol, CHD, (48.8 mM), neat CHO (6 mL, 9.9 M), 1 bar CO2, 100 °C. [b] Expressed as a percentage of epoxide conversion against the theoretical maximum (100 %). [c] Expressed as a percentage of CO2 uptake against ether linkage formation. [d] Expressed as a percentage of polymer selectivity against cyclic carbonate formation. [e] Turn over number (TON)=number of moles of monomer converted/number of moles of catalyst. [f] Turn over frequency (TOF)=TON/hour. [g] k p=polymerization rate coefficient=k obs/[cat]1 where k obs is calculated from the gradient of the semi logarithmic plot of ln([CHO]t/[CHO]0) vs. time (s). [h] k rel=relative polymerization rate coefficient=k p(MMg)/k p(MgMg). [i] Determined by SEC analysis, in THF, calibrated with narrow‐M n polystyrene standards; dispersity values in parentheses. [j] Reaction conditions: 0.1 mol% catalyst loading, 1 bar CO2, 80 °C. [k] Reaction conditions: 0.05 mol% catalyst loading, neat CHO (9.9 M), 3 bar CO2, 100 °C. [l] Reaction conditions: 0.025 mol%, 20 equiv. CHD, 100 °C, 1 bar CO2. [m] Reaction conditions: 0.02 mol% catalyst loading, 1 bar CO2, 50 °C. [n] Reaction conditions: 0.0625 mol% catalyst loading, neat CHO (100 mmol), 1 bar CO2, 100 °C. n.r=not reported. For illustrations of the literature catalyst structures, and explanations of the ancillary ligand abbreviations used, see Figure S17.