234
2.5 nm. The catalytic activity of these ruthenium nanoparticles was evaluated in the
hydrogenation of various unsaturated substrates such as long-chain alkenes under
1 bar of hydrogen at room temperature (Table 5.5).
Fig. 5.9 Chemical structures of randomly methylated β-cyclodextrin (RaMe-β-CD) and hydroxypropylated β-cyclodextrin (HP-β-CD)
Table 5.4 Description of randomly methylated cyclodextrins
Abbreviation
n
Average number of OH groups substituted per glucopyranose
unit
RaMe-α-cyclodextrin
6 1.8
RaMe-β-cyclodextrin
(1.8)
7 1.8
RaMe-β-cyclodextrin
(0.7)
7 0.7
RaMe-γ-cyclodextrin
8 1.8
Table 5.5 Hydrogenation of long-chain alkenes in presence of RaMe-cyclodextrin-stabilized Ru
nanoparticles
a
Entry
Substrate
Cyclodextrin (SD
b )
Turnover frequency (h
−1 )
c
1
Decene
RaMe-α-cyclodextrin
17
2
Decene
RaMe-β-cyclodextrin (0.7)
18
3
Decene
RaMe-β-cyclodextrin (1.8)
17
4
Decene
RaMe-γ-cyclodextrin
22
5
Dodecene
RaMe-β-cyclodextrin (1.8)
15
6
Tetradecene
RaMe-β-cyclodextrin (1.8)
12
Adapted from Denicourt-Nowicki et al. (2007)
a
Reaction conditions: catalyst (1.4  ×  10
−5   mol), cyclodextrin (1.4  ×  10
−4   mol), substrate
(1.4  ×  10
−3   mol), hydrogen pressure (1  bar), temperature (20  °C), stirring rate (1500  rpm),
10 mL water
b
SD substitution degree
c
Turnover frequency defined as number of mol of substrate per mol of ruthenium per hour
S. Noël et al.