428
L. M. Martínez-Prieto and P. W. N. M. van Leeuwen
N
N
N
N
OH HO
SIPhOH
SIDPhNp
N
N
SIPr
N
N
N
N
IiPr 2 Me 2
IMes
N
N
ItBuEt
b)
c)
N
N
IPrSO 3
IMesSO 3
d)
SO 3 K
N
N
SO 3 K
N
N
tBu
tBu
ItBu
N
N
IPr
a)
Fig. 12.20 a NHCs used by Chaudret et al. in Ref. [68]. b Non-isolable chiral N-heterocyclic
carbenes used by Chaudret and Glorius in Ref. [70]. c Isolable N-heterocyclic carbenes used by
Lara and Martínez-Prieto in Ref. [71]. d Sulfonated N-heterocyclic carbenes used by Chaudret and
Martínez-Prieto in Ref. [76]
presented good levels of catalytic activity, but Ru NPs stabilized with the naphthalene
derivative showed better activity than the other one. The lower catalytic activity of
Ru-SIPhOH NPs was ascribed to the limited access of the substrate to the reactive
sites of these NPs. It is principally due to the π-interactions between the aromatic
rings and the metal surface and the strong interaction between hydroxyl groups of
the ligand and the ruthenium. Shortly after, Lara, Martínez-Prieto and co-workers
prepared a family of NHC-stabilized Ru NPs (Fig. 12.20c), including a chiral NHC
[71]. They investigated their surface chemistry using the CO as probe molecule and