Table 2 Hydroboration of CO2 with catalyst [2]2–

From: Transforming carbon dioxide into a methanol surrogate using modular transition metal-free Zintl ions

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Entry

[Na(18c6)]2[2] (mol %)[a]

Time (h)

T (°C)

MeOBBN Conv. (%)[b]

CH2(OBBN)2 Conv. (%)[b]

TON [c]

TOF (h–1) [c]

1

10

1

RT

51

0

5

5

2

1.0

3

RT

58

39

97(58)

33(19)

3

0.10

1.75

50

80

19

1000(800)

571(457)

4

0.10

1.35

60

81

18

1000(810)

741(600)

5

0.10

2

70

50

5

550(500)

224(250)

6

0.05

72

RT

>99

0

2000

28

7

0.05

7.5

40

50

25

1500 (1000)

200(133)

8

0.05

4.3

50

80

19

2000 (1600)

465(372)

9

0.05

3

60

80

2

1760 (1600)

586(533)

10

0.01

400

RT

94

0

9400

24

11

0.01

66

50

96

0

9600

145

  1. No carboxyl-borane or methane formation was observed by 1H NMR spectroscopy.
  2. [a]Relative to B–H bonds.
  3. [b]Determined by 1H NMR spectroscopy, based on C–H bond formation using hexamethylbenzene as an internal standard.
  4. [c]TON and TOF considering only MeOBBN formation given in parentheses.
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